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>
77 #include "sched_cpupri.h"
80 * Convert user-nice values [ -20 ... 0 ... 19 ]
81 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
84 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
85 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
86 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
89 * 'User priority' is the nice value converted to something we
90 * can work with better when scaling various scheduler parameters,
91 * it's a [ 0 ... 39 ] range.
93 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
94 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
95 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
98 * Helpers for converting nanosecond timing to jiffy resolution
100 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
102 #define NICE_0_LOAD SCHED_LOAD_SCALE
103 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
106 * These are the 'tuning knobs' of the scheduler:
108 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
109 * Timeslices get refilled after they expire.
111 #define DEF_TIMESLICE (100 * HZ / 1000)
114 * single value that denotes runtime == period, ie unlimited time.
116 #define RUNTIME_INF ((u64)~0ULL)
120 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
121 * Since cpu_power is a 'constant', we can use a reciprocal divide.
123 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
125 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
129 * Each time a sched group cpu_power is changed,
130 * we must compute its reciprocal value
132 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
134 sg
->__cpu_power
+= val
;
135 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
139 static inline int rt_policy(int policy
)
141 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
146 static inline int task_has_rt_policy(struct task_struct
*p
)
148 return rt_policy(p
->policy
);
152 * This is the priority-queue data structure of the RT scheduling class:
154 struct rt_prio_array
{
155 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
156 struct list_head xqueue
[MAX_RT_PRIO
]; /* exclusive queue */
157 struct list_head squeue
[MAX_RT_PRIO
]; /* shared queue */
160 struct rt_bandwidth
{
161 /* nests inside the rq lock: */
162 spinlock_t rt_runtime_lock
;
165 struct hrtimer rt_period_timer
;
168 static struct rt_bandwidth def_rt_bandwidth
;
170 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
172 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
174 struct rt_bandwidth
*rt_b
=
175 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
181 now
= hrtimer_cb_get_time(timer
);
182 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
187 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
190 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
194 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
196 rt_b
->rt_period
= ns_to_ktime(period
);
197 rt_b
->rt_runtime
= runtime
;
199 spin_lock_init(&rt_b
->rt_runtime_lock
);
201 hrtimer_init(&rt_b
->rt_period_timer
,
202 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
203 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
204 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
207 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
211 if (rt_b
->rt_runtime
== RUNTIME_INF
)
214 if (hrtimer_active(&rt_b
->rt_period_timer
))
217 spin_lock(&rt_b
->rt_runtime_lock
);
219 if (hrtimer_active(&rt_b
->rt_period_timer
))
222 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
223 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
224 hrtimer_start(&rt_b
->rt_period_timer
,
225 rt_b
->rt_period_timer
.expires
,
228 spin_unlock(&rt_b
->rt_runtime_lock
);
231 #ifdef CONFIG_RT_GROUP_SCHED
232 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
234 hrtimer_cancel(&rt_b
->rt_period_timer
);
239 * sched_domains_mutex serializes calls to arch_init_sched_domains,
240 * detach_destroy_domains and partition_sched_domains.
242 static DEFINE_MUTEX(sched_domains_mutex
);
244 #ifdef CONFIG_GROUP_SCHED
246 #include <linux/cgroup.h>
250 static LIST_HEAD(task_groups
);
252 /* task group related information */
254 #ifdef CONFIG_CGROUP_SCHED
255 struct cgroup_subsys_state css
;
258 #ifdef CONFIG_FAIR_GROUP_SCHED
259 /* schedulable entities of this group on each cpu */
260 struct sched_entity
**se
;
261 /* runqueue "owned" by this group on each cpu */
262 struct cfs_rq
**cfs_rq
;
263 unsigned long shares
;
266 #ifdef CONFIG_RT_GROUP_SCHED
267 struct sched_rt_entity
**rt_se
;
268 struct rt_rq
**rt_rq
;
270 struct rt_bandwidth rt_bandwidth
;
274 struct list_head list
;
276 struct task_group
*parent
;
277 struct list_head siblings
;
278 struct list_head children
;
281 #ifdef CONFIG_USER_SCHED
285 * Every UID task group (including init_task_group aka UID-0) will
286 * be a child to this group.
288 struct task_group root_task_group
;
290 #ifdef CONFIG_FAIR_GROUP_SCHED
291 /* Default task group's sched entity on each cpu */
292 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
293 /* Default task group's cfs_rq on each cpu */
294 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
297 #ifdef CONFIG_RT_GROUP_SCHED
298 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
299 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
302 #define root_task_group init_task_group
305 /* task_group_lock serializes add/remove of task groups and also changes to
306 * a task group's cpu shares.
308 static DEFINE_SPINLOCK(task_group_lock
);
310 #ifdef CONFIG_FAIR_GROUP_SCHED
311 #ifdef CONFIG_USER_SCHED
312 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
314 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
318 * A weight of 0, 1 or ULONG_MAX can cause arithmetics problems.
319 * (The default weight is 1024 - so there's no practical
320 * limitation from this.)
323 #define MAX_SHARES (ULONG_MAX - 1)
325 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
328 /* Default task group.
329 * Every task in system belong to this group at bootup.
331 struct task_group init_task_group
;
333 /* return group to which a task belongs */
334 static inline struct task_group
*task_group(struct task_struct
*p
)
336 struct task_group
*tg
;
338 #ifdef CONFIG_USER_SCHED
340 #elif defined(CONFIG_CGROUP_SCHED)
341 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
342 struct task_group
, css
);
344 tg
= &init_task_group
;
349 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
350 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
352 #ifdef CONFIG_FAIR_GROUP_SCHED
353 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
354 p
->se
.parent
= task_group(p
)->se
[cpu
];
357 #ifdef CONFIG_RT_GROUP_SCHED
358 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
359 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
365 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
367 #endif /* CONFIG_GROUP_SCHED */
369 /* CFS-related fields in a runqueue */
371 struct load_weight load
;
372 unsigned long nr_running
;
377 struct rb_root tasks_timeline
;
378 struct rb_node
*rb_leftmost
;
380 struct list_head tasks
;
381 struct list_head
*balance_iterator
;
384 * 'curr' points to currently running entity on this cfs_rq.
385 * It is set to NULL otherwise (i.e when none are currently running).
387 struct sched_entity
*curr
, *next
;
389 unsigned long nr_spread_over
;
391 #ifdef CONFIG_FAIR_GROUP_SCHED
392 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
395 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
396 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
397 * (like users, containers etc.)
399 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
400 * list is used during load balance.
402 struct list_head leaf_cfs_rq_list
;
403 struct task_group
*tg
; /* group that "owns" this runqueue */
407 /* Real-Time classes' related field in a runqueue: */
409 struct rt_prio_array active
;
410 unsigned long rt_nr_running
;
411 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
412 int highest_prio
; /* highest queued rt task prio */
415 unsigned long rt_nr_migratory
;
421 /* Nests inside the rq lock: */
422 spinlock_t rt_runtime_lock
;
424 #ifdef CONFIG_RT_GROUP_SCHED
425 unsigned long rt_nr_boosted
;
428 struct list_head leaf_rt_rq_list
;
429 struct task_group
*tg
;
430 struct sched_rt_entity
*rt_se
;
437 * We add the notion of a root-domain which will be used to define per-domain
438 * variables. Each exclusive cpuset essentially defines an island domain by
439 * fully partitioning the member cpus from any other cpuset. Whenever a new
440 * exclusive cpuset is created, we also create and attach a new root-domain
450 * The "RT overload" flag: it gets set if a CPU has more than
451 * one runnable RT task.
456 struct cpupri cpupri
;
461 * By default the system creates a single root-domain with all cpus as
462 * members (mimicking the global state we have today).
464 static struct root_domain def_root_domain
;
469 * This is the main, per-CPU runqueue data structure.
471 * Locking rule: those places that want to lock multiple runqueues
472 * (such as the load balancing or the thread migration code), lock
473 * acquire operations must be ordered by ascending &runqueue.
480 * nr_running and cpu_load should be in the same cacheline because
481 * remote CPUs use both these fields when doing load calculation.
483 unsigned long nr_running
;
484 #define CPU_LOAD_IDX_MAX 5
485 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
486 unsigned char idle_at_tick
;
488 unsigned long last_tick_seen
;
489 unsigned char in_nohz_recently
;
491 /* capture load from *all* tasks on this cpu: */
492 struct load_weight load
;
493 unsigned long nr_load_updates
;
499 #ifdef CONFIG_FAIR_GROUP_SCHED
500 /* list of leaf cfs_rq on this cpu: */
501 struct list_head leaf_cfs_rq_list
;
503 #ifdef CONFIG_RT_GROUP_SCHED
504 struct list_head leaf_rt_rq_list
;
508 * This is part of a global counter where only the total sum
509 * over all CPUs matters. A task can increase this counter on
510 * one CPU and if it got migrated afterwards it may decrease
511 * it on another CPU. Always updated under the runqueue lock:
513 unsigned long nr_uninterruptible
;
515 struct task_struct
*curr
, *idle
;
516 unsigned long next_balance
;
517 struct mm_struct
*prev_mm
;
524 struct root_domain
*rd
;
525 struct sched_domain
*sd
;
527 /* For active balancing */
530 /* cpu of this runqueue: */
533 struct task_struct
*migration_thread
;
534 struct list_head migration_queue
;
537 #ifdef CONFIG_SCHED_HRTICK
538 unsigned long hrtick_flags
;
539 ktime_t hrtick_expire
;
540 struct hrtimer hrtick_timer
;
543 #ifdef CONFIG_SCHEDSTATS
545 struct sched_info rq_sched_info
;
547 /* sys_sched_yield() stats */
548 unsigned int yld_exp_empty
;
549 unsigned int yld_act_empty
;
550 unsigned int yld_both_empty
;
551 unsigned int yld_count
;
553 /* schedule() stats */
554 unsigned int sched_switch
;
555 unsigned int sched_count
;
556 unsigned int sched_goidle
;
558 /* try_to_wake_up() stats */
559 unsigned int ttwu_count
;
560 unsigned int ttwu_local
;
563 unsigned int bkl_count
;
565 struct lock_class_key rq_lock_key
;
568 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
570 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
572 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
575 static inline int cpu_of(struct rq
*rq
)
585 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
586 * See detach_destroy_domains: synchronize_sched for details.
588 * The domain tree of any CPU may only be accessed from within
589 * preempt-disabled sections.
591 #define for_each_domain(cpu, __sd) \
592 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
594 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
595 #define this_rq() (&__get_cpu_var(runqueues))
596 #define task_rq(p) cpu_rq(task_cpu(p))
597 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
599 static inline void update_rq_clock(struct rq
*rq
)
601 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
605 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
607 #ifdef CONFIG_SCHED_DEBUG
608 # define const_debug __read_mostly
610 # define const_debug static const
614 * Debugging: various feature bits
617 #define SCHED_FEAT(name, enabled) \
618 __SCHED_FEAT_##name ,
621 #include "sched_features.h"
626 #define SCHED_FEAT(name, enabled) \
627 (1UL << __SCHED_FEAT_##name) * enabled |
629 const_debug
unsigned int sysctl_sched_features
=
630 #include "sched_features.h"
635 #ifdef CONFIG_SCHED_DEBUG
636 #define SCHED_FEAT(name, enabled) \
639 static __read_mostly
char *sched_feat_names
[] = {
640 #include "sched_features.h"
646 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
648 filp
->private_data
= inode
->i_private
;
653 sched_feat_read(struct file
*filp
, char __user
*ubuf
,
654 size_t cnt
, loff_t
*ppos
)
661 for (i
= 0; sched_feat_names
[i
]; i
++) {
662 len
+= strlen(sched_feat_names
[i
]);
666 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
670 for (i
= 0; sched_feat_names
[i
]; i
++) {
671 if (sysctl_sched_features
& (1UL << i
))
672 r
+= sprintf(buf
+ r
, "%s ", sched_feat_names
[i
]);
674 r
+= sprintf(buf
+ r
, "NO_%s ", sched_feat_names
[i
]);
677 r
+= sprintf(buf
+ r
, "\n");
678 WARN_ON(r
>= len
+ 2);
680 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
688 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
689 size_t cnt
, loff_t
*ppos
)
699 if (copy_from_user(&buf
, ubuf
, cnt
))
704 if (strncmp(buf
, "NO_", 3) == 0) {
709 for (i
= 0; sched_feat_names
[i
]; i
++) {
710 int len
= strlen(sched_feat_names
[i
]);
712 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
714 sysctl_sched_features
&= ~(1UL << i
);
716 sysctl_sched_features
|= (1UL << i
);
721 if (!sched_feat_names
[i
])
729 static struct file_operations sched_feat_fops
= {
730 .open
= sched_feat_open
,
731 .read
= sched_feat_read
,
732 .write
= sched_feat_write
,
735 static __init
int sched_init_debug(void)
737 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
742 late_initcall(sched_init_debug
);
746 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
749 * Number of tasks to iterate in a single balance run.
750 * Limited because this is done with IRQs disabled.
752 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
755 * period over which we measure -rt task cpu usage in us.
758 unsigned int sysctl_sched_rt_period
= 1000000;
760 static __read_mostly
int scheduler_running
;
763 * part of the period that we allow rt tasks to run in us.
766 int sysctl_sched_rt_runtime
= 950000;
768 static inline u64
global_rt_period(void)
770 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
773 static inline u64
global_rt_runtime(void)
775 if (sysctl_sched_rt_period
< 0)
778 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
781 unsigned long long time_sync_thresh
= 100000;
783 static DEFINE_PER_CPU(unsigned long long, time_offset
);
784 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
787 * Global lock which we take every now and then to synchronize
788 * the CPUs time. This method is not warp-safe, but it's good
789 * enough to synchronize slowly diverging time sources and thus
790 * it's good enough for tracing:
792 static DEFINE_SPINLOCK(time_sync_lock
);
793 static unsigned long long prev_global_time
;
795 static unsigned long long __sync_cpu_clock(unsigned long long time
, int cpu
)
798 * We want this inlined, to not get tracer function calls
799 * in this critical section:
801 spin_acquire(&time_sync_lock
.dep_map
, 0, 0, _THIS_IP_
);
802 __raw_spin_lock(&time_sync_lock
.raw_lock
);
804 if (time
< prev_global_time
) {
805 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
806 time
= prev_global_time
;
808 prev_global_time
= time
;
811 __raw_spin_unlock(&time_sync_lock
.raw_lock
);
812 spin_release(&time_sync_lock
.dep_map
, 1, _THIS_IP_
);
817 static unsigned long long __cpu_clock(int cpu
)
819 unsigned long long now
;
822 * Only call sched_clock() if the scheduler has already been
823 * initialized (some code might call cpu_clock() very early):
825 if (unlikely(!scheduler_running
))
828 now
= sched_clock_cpu(cpu
);
834 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
835 * clock constructed from sched_clock():
837 unsigned long long cpu_clock(int cpu
)
839 unsigned long long prev_cpu_time
, time
, delta_time
;
842 local_irq_save(flags
);
843 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
844 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
845 delta_time
= time
-prev_cpu_time
;
847 if (unlikely(delta_time
> time_sync_thresh
)) {
848 time
= __sync_cpu_clock(time
, cpu
);
849 per_cpu(prev_cpu_time
, cpu
) = time
;
851 local_irq_restore(flags
);
855 EXPORT_SYMBOL_GPL(cpu_clock
);
857 #ifndef prepare_arch_switch
858 # define prepare_arch_switch(next) do { } while (0)
860 #ifndef finish_arch_switch
861 # define finish_arch_switch(prev) do { } while (0)
864 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
866 return rq
->curr
== p
;
869 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
870 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
872 return task_current(rq
, p
);
875 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
879 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
881 #ifdef CONFIG_DEBUG_SPINLOCK
882 /* this is a valid case when another task releases the spinlock */
883 rq
->lock
.owner
= current
;
886 * If we are tracking spinlock dependencies then we have to
887 * fix up the runqueue lock - which gets 'carried over' from
890 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
892 spin_unlock_irq(&rq
->lock
);
895 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
896 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
901 return task_current(rq
, p
);
905 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
909 * We can optimise this out completely for !SMP, because the
910 * SMP rebalancing from interrupt is the only thing that cares
915 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
916 spin_unlock_irq(&rq
->lock
);
918 spin_unlock(&rq
->lock
);
922 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
926 * After ->oncpu is cleared, the task can be moved to a different CPU.
927 * We must ensure this doesn't happen until the switch is completely
933 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
937 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
940 * __task_rq_lock - lock the runqueue a given task resides on.
941 * Must be called interrupts disabled.
943 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
947 struct rq
*rq
= task_rq(p
);
948 spin_lock(&rq
->lock
);
949 if (likely(rq
== task_rq(p
)))
951 spin_unlock(&rq
->lock
);
956 * task_rq_lock - lock the runqueue a given task resides on and disable
957 * interrupts. Note the ordering: we can safely lookup the task_rq without
958 * explicitly disabling preemption.
960 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
966 local_irq_save(*flags
);
968 spin_lock(&rq
->lock
);
969 if (likely(rq
== task_rq(p
)))
971 spin_unlock_irqrestore(&rq
->lock
, *flags
);
975 static void __task_rq_unlock(struct rq
*rq
)
978 spin_unlock(&rq
->lock
);
981 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
984 spin_unlock_irqrestore(&rq
->lock
, *flags
);
988 * this_rq_lock - lock this runqueue and disable interrupts.
990 static struct rq
*this_rq_lock(void)
997 spin_lock(&rq
->lock
);
1002 static void __resched_task(struct task_struct
*p
, int tif_bit
);
1004 static inline void resched_task(struct task_struct
*p
)
1006 __resched_task(p
, TIF_NEED_RESCHED
);
1009 #ifdef CONFIG_SCHED_HRTICK
1011 * Use HR-timers to deliver accurate preemption points.
1013 * Its all a bit involved since we cannot program an hrt while holding the
1014 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1017 * When we get rescheduled we reprogram the hrtick_timer outside of the
1020 static inline void resched_hrt(struct task_struct
*p
)
1022 __resched_task(p
, TIF_HRTICK_RESCHED
);
1025 static inline void resched_rq(struct rq
*rq
)
1027 unsigned long flags
;
1029 spin_lock_irqsave(&rq
->lock
, flags
);
1030 resched_task(rq
->curr
);
1031 spin_unlock_irqrestore(&rq
->lock
, flags
);
1035 HRTICK_SET
, /* re-programm hrtick_timer */
1036 HRTICK_RESET
, /* not a new slice */
1037 HRTICK_BLOCK
, /* stop hrtick operations */
1042 * - enabled by features
1043 * - hrtimer is actually high res
1045 static inline int hrtick_enabled(struct rq
*rq
)
1047 if (!sched_feat(HRTICK
))
1049 if (unlikely(test_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
)))
1051 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1055 * Called to set the hrtick timer state.
1057 * called with rq->lock held and irqs disabled
1059 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1061 assert_spin_locked(&rq
->lock
);
1064 * preempt at: now + delay
1067 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1069 * indicate we need to program the timer
1071 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1073 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1076 * New slices are called from the schedule path and don't need a
1077 * forced reschedule.
1080 resched_hrt(rq
->curr
);
1083 static void hrtick_clear(struct rq
*rq
)
1085 if (hrtimer_active(&rq
->hrtick_timer
))
1086 hrtimer_cancel(&rq
->hrtick_timer
);
1090 * Update the timer from the possible pending state.
1092 static void hrtick_set(struct rq
*rq
)
1096 unsigned long flags
;
1098 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1100 spin_lock_irqsave(&rq
->lock
, flags
);
1101 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1102 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1103 time
= rq
->hrtick_expire
;
1104 clear_thread_flag(TIF_HRTICK_RESCHED
);
1105 spin_unlock_irqrestore(&rq
->lock
, flags
);
1108 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1109 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1116 * High-resolution timer tick.
1117 * Runs from hardirq context with interrupts disabled.
1119 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1121 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1123 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1125 spin_lock(&rq
->lock
);
1126 update_rq_clock(rq
);
1127 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1128 spin_unlock(&rq
->lock
);
1130 return HRTIMER_NORESTART
;
1133 static void hotplug_hrtick_disable(int cpu
)
1135 struct rq
*rq
= cpu_rq(cpu
);
1136 unsigned long flags
;
1138 spin_lock_irqsave(&rq
->lock
, flags
);
1139 rq
->hrtick_flags
= 0;
1140 __set_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1141 spin_unlock_irqrestore(&rq
->lock
, flags
);
1146 static void hotplug_hrtick_enable(int cpu
)
1148 struct rq
*rq
= cpu_rq(cpu
);
1149 unsigned long flags
;
1151 spin_lock_irqsave(&rq
->lock
, flags
);
1152 __clear_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1153 spin_unlock_irqrestore(&rq
->lock
, flags
);
1157 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1159 int cpu
= (int)(long)hcpu
;
1162 case CPU_UP_CANCELED
:
1163 case CPU_UP_CANCELED_FROZEN
:
1164 case CPU_DOWN_PREPARE
:
1165 case CPU_DOWN_PREPARE_FROZEN
:
1167 case CPU_DEAD_FROZEN
:
1168 hotplug_hrtick_disable(cpu
);
1171 case CPU_UP_PREPARE
:
1172 case CPU_UP_PREPARE_FROZEN
:
1173 case CPU_DOWN_FAILED
:
1174 case CPU_DOWN_FAILED_FROZEN
:
1176 case CPU_ONLINE_FROZEN
:
1177 hotplug_hrtick_enable(cpu
);
1184 static void init_hrtick(void)
1186 hotcpu_notifier(hotplug_hrtick
, 0);
1189 static void init_rq_hrtick(struct rq
*rq
)
1191 rq
->hrtick_flags
= 0;
1192 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1193 rq
->hrtick_timer
.function
= hrtick
;
1194 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1197 void hrtick_resched(void)
1200 unsigned long flags
;
1202 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1205 local_irq_save(flags
);
1206 rq
= cpu_rq(smp_processor_id());
1208 local_irq_restore(flags
);
1211 static inline void hrtick_clear(struct rq
*rq
)
1215 static inline void hrtick_set(struct rq
*rq
)
1219 static inline void init_rq_hrtick(struct rq
*rq
)
1223 void hrtick_resched(void)
1227 static inline void init_hrtick(void)
1233 * resched_task - mark a task 'to be rescheduled now'.
1235 * On UP this means the setting of the need_resched flag, on SMP it
1236 * might also involve a cross-CPU call to trigger the scheduler on
1241 #ifndef tsk_is_polling
1242 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1245 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1249 assert_spin_locked(&task_rq(p
)->lock
);
1251 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1254 set_tsk_thread_flag(p
, tif_bit
);
1257 if (cpu
== smp_processor_id())
1260 /* NEED_RESCHED must be visible before we test polling */
1262 if (!tsk_is_polling(p
))
1263 smp_send_reschedule(cpu
);
1266 static void resched_cpu(int cpu
)
1268 struct rq
*rq
= cpu_rq(cpu
);
1269 unsigned long flags
;
1271 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1273 resched_task(cpu_curr(cpu
));
1274 spin_unlock_irqrestore(&rq
->lock
, flags
);
1279 * When add_timer_on() enqueues a timer into the timer wheel of an
1280 * idle CPU then this timer might expire before the next timer event
1281 * which is scheduled to wake up that CPU. In case of a completely
1282 * idle system the next event might even be infinite time into the
1283 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1284 * leaves the inner idle loop so the newly added timer is taken into
1285 * account when the CPU goes back to idle and evaluates the timer
1286 * wheel for the next timer event.
1288 void wake_up_idle_cpu(int cpu
)
1290 struct rq
*rq
= cpu_rq(cpu
);
1292 if (cpu
== smp_processor_id())
1296 * This is safe, as this function is called with the timer
1297 * wheel base lock of (cpu) held. When the CPU is on the way
1298 * to idle and has not yet set rq->curr to idle then it will
1299 * be serialized on the timer wheel base lock and take the new
1300 * timer into account automatically.
1302 if (rq
->curr
!= rq
->idle
)
1306 * We can set TIF_RESCHED on the idle task of the other CPU
1307 * lockless. The worst case is that the other CPU runs the
1308 * idle task through an additional NOOP schedule()
1310 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1312 /* NEED_RESCHED must be visible before we test polling */
1314 if (!tsk_is_polling(rq
->idle
))
1315 smp_send_reschedule(cpu
);
1320 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1322 assert_spin_locked(&task_rq(p
)->lock
);
1323 set_tsk_thread_flag(p
, tif_bit
);
1327 #if BITS_PER_LONG == 32
1328 # define WMULT_CONST (~0UL)
1330 # define WMULT_CONST (1UL << 32)
1333 #define WMULT_SHIFT 32
1336 * Shift right and round:
1338 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1340 static unsigned long
1341 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1342 struct load_weight
*lw
)
1346 if (!lw
->inv_weight
)
1347 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)/(lw
->weight
+1);
1349 tmp
= (u64
)delta_exec
* weight
;
1351 * Check whether we'd overflow the 64-bit multiplication:
1353 if (unlikely(tmp
> WMULT_CONST
))
1354 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1357 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1359 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1362 static inline unsigned long
1363 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1365 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1368 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1374 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1381 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1382 * of tasks with abnormal "nice" values across CPUs the contribution that
1383 * each task makes to its run queue's load is weighted according to its
1384 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1385 * scaled version of the new time slice allocation that they receive on time
1389 #define WEIGHT_IDLEPRIO 2
1390 #define WMULT_IDLEPRIO (1 << 31)
1393 * Nice levels are multiplicative, with a gentle 10% change for every
1394 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1395 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1396 * that remained on nice 0.
1398 * The "10% effect" is relative and cumulative: from _any_ nice level,
1399 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1400 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1401 * If a task goes up by ~10% and another task goes down by ~10% then
1402 * the relative distance between them is ~25%.)
1404 static const int prio_to_weight
[40] = {
1405 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1406 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1407 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1408 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1409 /* 0 */ 1024, 820, 655, 526, 423,
1410 /* 5 */ 335, 272, 215, 172, 137,
1411 /* 10 */ 110, 87, 70, 56, 45,
1412 /* 15 */ 36, 29, 23, 18, 15,
1416 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1418 * In cases where the weight does not change often, we can use the
1419 * precalculated inverse to speed up arithmetics by turning divisions
1420 * into multiplications:
1422 static const u32 prio_to_wmult
[40] = {
1423 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1424 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1425 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1426 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1427 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1428 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1429 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1430 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1433 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1436 * runqueue iterator, to support SMP load-balancing between different
1437 * scheduling classes, without having to expose their internal data
1438 * structures to the load-balancing proper:
1440 struct rq_iterator
{
1442 struct task_struct
*(*start
)(void *);
1443 struct task_struct
*(*next
)(void *);
1447 static unsigned long
1448 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1449 unsigned long max_load_move
, struct sched_domain
*sd
,
1450 enum cpu_idle_type idle
, int *all_pinned
,
1451 int *this_best_prio
, struct rq_iterator
*iterator
);
1454 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1455 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1456 struct rq_iterator
*iterator
);
1459 #ifdef CONFIG_CGROUP_CPUACCT
1460 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1462 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1465 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1467 update_load_add(&rq
->load
, load
);
1470 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1472 update_load_sub(&rq
->load
, load
);
1476 static unsigned long source_load(int cpu
, int type
);
1477 static unsigned long target_load(int cpu
, int type
);
1478 static unsigned long cpu_avg_load_per_task(int cpu
);
1479 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1480 #else /* CONFIG_SMP */
1482 #ifdef CONFIG_FAIR_GROUP_SCHED
1483 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1488 #endif /* CONFIG_SMP */
1490 #include "sched_stats.h"
1491 #include "sched_idletask.c"
1492 #include "sched_fair.c"
1493 #include "sched_rt.c"
1494 #ifdef CONFIG_SCHED_DEBUG
1495 # include "sched_debug.c"
1498 #define sched_class_highest (&rt_sched_class)
1500 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1502 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1505 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1507 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1510 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1516 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1522 static void set_load_weight(struct task_struct
*p
)
1524 if (task_has_rt_policy(p
)) {
1525 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1526 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1531 * SCHED_IDLE tasks get minimal weight:
1533 if (p
->policy
== SCHED_IDLE
) {
1534 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1535 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1539 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1540 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1543 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1545 sched_info_queued(p
);
1546 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1550 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1552 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1557 * __normal_prio - return the priority that is based on the static prio
1559 static inline int __normal_prio(struct task_struct
*p
)
1561 return p
->static_prio
;
1565 * Calculate the expected normal priority: i.e. priority
1566 * without taking RT-inheritance into account. Might be
1567 * boosted by interactivity modifiers. Changes upon fork,
1568 * setprio syscalls, and whenever the interactivity
1569 * estimator recalculates.
1571 static inline int normal_prio(struct task_struct
*p
)
1575 if (task_has_rt_policy(p
))
1576 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1578 prio
= __normal_prio(p
);
1583 * Calculate the current priority, i.e. the priority
1584 * taken into account by the scheduler. This value might
1585 * be boosted by RT tasks, or might be boosted by
1586 * interactivity modifiers. Will be RT if the task got
1587 * RT-boosted. If not then it returns p->normal_prio.
1589 static int effective_prio(struct task_struct
*p
)
1591 p
->normal_prio
= normal_prio(p
);
1593 * If we are RT tasks or we were boosted to RT priority,
1594 * keep the priority unchanged. Otherwise, update priority
1595 * to the normal priority:
1597 if (!rt_prio(p
->prio
))
1598 return p
->normal_prio
;
1603 * activate_task - move a task to the runqueue.
1605 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1607 if (task_contributes_to_load(p
))
1608 rq
->nr_uninterruptible
--;
1610 enqueue_task(rq
, p
, wakeup
);
1611 inc_nr_running(p
, rq
);
1615 * deactivate_task - remove a task from the runqueue.
1617 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1619 if (task_contributes_to_load(p
))
1620 rq
->nr_uninterruptible
++;
1622 dequeue_task(rq
, p
, sleep
);
1623 dec_nr_running(p
, rq
);
1627 * task_curr - is this task currently executing on a CPU?
1628 * @p: the task in question.
1630 inline int task_curr(const struct task_struct
*p
)
1632 return cpu_curr(task_cpu(p
)) == p
;
1635 /* Used instead of source_load when we know the type == 0 */
1636 unsigned long weighted_cpuload(const int cpu
)
1638 return cpu_rq(cpu
)->load
.weight
;
1641 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1643 set_task_rq(p
, cpu
);
1646 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1647 * successfuly executed on another CPU. We must ensure that updates of
1648 * per-task data have been completed by this moment.
1651 task_thread_info(p
)->cpu
= cpu
;
1655 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1656 const struct sched_class
*prev_class
,
1657 int oldprio
, int running
)
1659 if (prev_class
!= p
->sched_class
) {
1660 if (prev_class
->switched_from
)
1661 prev_class
->switched_from(rq
, p
, running
);
1662 p
->sched_class
->switched_to(rq
, p
, running
);
1664 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1670 * Is this task likely cache-hot:
1673 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1678 * Buddy candidates are cache hot:
1680 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1683 if (p
->sched_class
!= &fair_sched_class
)
1686 if (sysctl_sched_migration_cost
== -1)
1688 if (sysctl_sched_migration_cost
== 0)
1691 delta
= now
- p
->se
.exec_start
;
1693 return delta
< (s64
)sysctl_sched_migration_cost
;
1697 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1699 int old_cpu
= task_cpu(p
);
1700 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1701 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1702 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1705 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1707 #ifdef CONFIG_SCHEDSTATS
1708 if (p
->se
.wait_start
)
1709 p
->se
.wait_start
-= clock_offset
;
1710 if (p
->se
.sleep_start
)
1711 p
->se
.sleep_start
-= clock_offset
;
1712 if (p
->se
.block_start
)
1713 p
->se
.block_start
-= clock_offset
;
1714 if (old_cpu
!= new_cpu
) {
1715 schedstat_inc(p
, se
.nr_migrations
);
1716 if (task_hot(p
, old_rq
->clock
, NULL
))
1717 schedstat_inc(p
, se
.nr_forced2_migrations
);
1720 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1721 new_cfsrq
->min_vruntime
;
1723 __set_task_cpu(p
, new_cpu
);
1726 struct migration_req
{
1727 struct list_head list
;
1729 struct task_struct
*task
;
1732 struct completion done
;
1736 * The task's runqueue lock must be held.
1737 * Returns true if you have to wait for migration thread.
1740 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1742 struct rq
*rq
= task_rq(p
);
1745 * If the task is not on a runqueue (and not running), then
1746 * it is sufficient to simply update the task's cpu field.
1748 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1749 set_task_cpu(p
, dest_cpu
);
1753 init_completion(&req
->done
);
1755 req
->dest_cpu
= dest_cpu
;
1756 list_add(&req
->list
, &rq
->migration_queue
);
1762 * wait_task_inactive - wait for a thread to unschedule.
1764 * The caller must ensure that the task *will* unschedule sometime soon,
1765 * else this function might spin for a *long* time. This function can't
1766 * be called with interrupts off, or it may introduce deadlock with
1767 * smp_call_function() if an IPI is sent by the same process we are
1768 * waiting to become inactive.
1770 void wait_task_inactive(struct task_struct
*p
)
1772 unsigned long flags
;
1778 * We do the initial early heuristics without holding
1779 * any task-queue locks at all. We'll only try to get
1780 * the runqueue lock when things look like they will
1786 * If the task is actively running on another CPU
1787 * still, just relax and busy-wait without holding
1790 * NOTE! Since we don't hold any locks, it's not
1791 * even sure that "rq" stays as the right runqueue!
1792 * But we don't care, since "task_running()" will
1793 * return false if the runqueue has changed and p
1794 * is actually now running somewhere else!
1796 while (task_running(rq
, p
))
1800 * Ok, time to look more closely! We need the rq
1801 * lock now, to be *sure*. If we're wrong, we'll
1802 * just go back and repeat.
1804 rq
= task_rq_lock(p
, &flags
);
1805 running
= task_running(rq
, p
);
1806 on_rq
= p
->se
.on_rq
;
1807 task_rq_unlock(rq
, &flags
);
1810 * Was it really running after all now that we
1811 * checked with the proper locks actually held?
1813 * Oops. Go back and try again..
1815 if (unlikely(running
)) {
1821 * It's not enough that it's not actively running,
1822 * it must be off the runqueue _entirely_, and not
1825 * So if it wa still runnable (but just not actively
1826 * running right now), it's preempted, and we should
1827 * yield - it could be a while.
1829 if (unlikely(on_rq
)) {
1830 schedule_timeout_uninterruptible(1);
1835 * Ahh, all good. It wasn't running, and it wasn't
1836 * runnable, which means that it will never become
1837 * running in the future either. We're all done!
1844 * kick_process - kick a running thread to enter/exit the kernel
1845 * @p: the to-be-kicked thread
1847 * Cause a process which is running on another CPU to enter
1848 * kernel-mode, without any delay. (to get signals handled.)
1850 * NOTE: this function doesnt have to take the runqueue lock,
1851 * because all it wants to ensure is that the remote task enters
1852 * the kernel. If the IPI races and the task has been migrated
1853 * to another CPU then no harm is done and the purpose has been
1856 void kick_process(struct task_struct
*p
)
1862 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1863 smp_send_reschedule(cpu
);
1868 * Return a low guess at the load of a migration-source cpu weighted
1869 * according to the scheduling class and "nice" value.
1871 * We want to under-estimate the load of migration sources, to
1872 * balance conservatively.
1874 static unsigned long source_load(int cpu
, int type
)
1876 struct rq
*rq
= cpu_rq(cpu
);
1877 unsigned long total
= weighted_cpuload(cpu
);
1882 return min(rq
->cpu_load
[type
-1], total
);
1886 * Return a high guess at the load of a migration-target cpu weighted
1887 * according to the scheduling class and "nice" value.
1889 static unsigned long target_load(int cpu
, int type
)
1891 struct rq
*rq
= cpu_rq(cpu
);
1892 unsigned long total
= weighted_cpuload(cpu
);
1897 return max(rq
->cpu_load
[type
-1], total
);
1901 * Return the average load per task on the cpu's run queue
1903 static unsigned long cpu_avg_load_per_task(int cpu
)
1905 struct rq
*rq
= cpu_rq(cpu
);
1906 unsigned long total
= weighted_cpuload(cpu
);
1907 unsigned long n
= rq
->nr_running
;
1909 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1913 * find_idlest_group finds and returns the least busy CPU group within the
1916 static struct sched_group
*
1917 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1919 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1920 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1921 int load_idx
= sd
->forkexec_idx
;
1922 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1925 unsigned long load
, avg_load
;
1929 /* Skip over this group if it has no CPUs allowed */
1930 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1933 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1935 /* Tally up the load of all CPUs in the group */
1938 for_each_cpu_mask(i
, group
->cpumask
) {
1939 /* Bias balancing toward cpus of our domain */
1941 load
= source_load(i
, load_idx
);
1943 load
= target_load(i
, load_idx
);
1948 /* Adjust by relative CPU power of the group */
1949 avg_load
= sg_div_cpu_power(group
,
1950 avg_load
* SCHED_LOAD_SCALE
);
1953 this_load
= avg_load
;
1955 } else if (avg_load
< min_load
) {
1956 min_load
= avg_load
;
1959 } while (group
= group
->next
, group
!= sd
->groups
);
1961 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1967 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1970 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1973 unsigned long load
, min_load
= ULONG_MAX
;
1977 /* Traverse only the allowed CPUs */
1978 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
1980 for_each_cpu_mask(i
, *tmp
) {
1981 load
= weighted_cpuload(i
);
1983 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1993 * sched_balance_self: balance the current task (running on cpu) in domains
1994 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1997 * Balance, ie. select the least loaded group.
1999 * Returns the target CPU number, or the same CPU if no balancing is needed.
2001 * preempt must be disabled.
2003 static int sched_balance_self(int cpu
, int flag
)
2005 struct task_struct
*t
= current
;
2006 struct sched_domain
*tmp
, *sd
= NULL
;
2008 for_each_domain(cpu
, tmp
) {
2010 * If power savings logic is enabled for a domain, stop there.
2012 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2014 if (tmp
->flags
& flag
)
2019 cpumask_t span
, tmpmask
;
2020 struct sched_group
*group
;
2021 int new_cpu
, weight
;
2023 if (!(sd
->flags
& flag
)) {
2029 group
= find_idlest_group(sd
, t
, cpu
);
2035 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
2036 if (new_cpu
== -1 || new_cpu
== cpu
) {
2037 /* Now try balancing at a lower domain level of cpu */
2042 /* Now try balancing at a lower domain level of new_cpu */
2045 weight
= cpus_weight(span
);
2046 for_each_domain(cpu
, tmp
) {
2047 if (weight
<= cpus_weight(tmp
->span
))
2049 if (tmp
->flags
& flag
)
2052 /* while loop will break here if sd == NULL */
2058 #endif /* CONFIG_SMP */
2061 * try_to_wake_up - wake up a thread
2062 * @p: the to-be-woken-up thread
2063 * @state: the mask of task states that can be woken
2064 * @sync: do a synchronous wakeup?
2066 * Put it on the run-queue if it's not already there. The "current"
2067 * thread is always on the run-queue (except when the actual
2068 * re-schedule is in progress), and as such you're allowed to do
2069 * the simpler "current->state = TASK_RUNNING" to mark yourself
2070 * runnable without the overhead of this.
2072 * returns failure only if the task is already active.
2074 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2076 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2077 unsigned long flags
;
2081 if (!sched_feat(SYNC_WAKEUPS
))
2085 rq
= task_rq_lock(p
, &flags
);
2086 old_state
= p
->state
;
2087 if (!(old_state
& state
))
2095 this_cpu
= smp_processor_id();
2098 if (unlikely(task_running(rq
, p
)))
2101 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2102 if (cpu
!= orig_cpu
) {
2103 set_task_cpu(p
, cpu
);
2104 task_rq_unlock(rq
, &flags
);
2105 /* might preempt at this point */
2106 rq
= task_rq_lock(p
, &flags
);
2107 old_state
= p
->state
;
2108 if (!(old_state
& state
))
2113 this_cpu
= smp_processor_id();
2117 #ifdef CONFIG_SCHEDSTATS
2118 schedstat_inc(rq
, ttwu_count
);
2119 if (cpu
== this_cpu
)
2120 schedstat_inc(rq
, ttwu_local
);
2122 struct sched_domain
*sd
;
2123 for_each_domain(this_cpu
, sd
) {
2124 if (cpu_isset(cpu
, sd
->span
)) {
2125 schedstat_inc(sd
, ttwu_wake_remote
);
2133 #endif /* CONFIG_SMP */
2134 schedstat_inc(p
, se
.nr_wakeups
);
2136 schedstat_inc(p
, se
.nr_wakeups_sync
);
2137 if (orig_cpu
!= cpu
)
2138 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2139 if (cpu
== this_cpu
)
2140 schedstat_inc(p
, se
.nr_wakeups_local
);
2142 schedstat_inc(p
, se
.nr_wakeups_remote
);
2143 update_rq_clock(rq
);
2144 activate_task(rq
, p
, 1);
2148 check_preempt_curr(rq
, p
);
2150 p
->state
= TASK_RUNNING
;
2152 if (p
->sched_class
->task_wake_up
)
2153 p
->sched_class
->task_wake_up(rq
, p
);
2156 task_rq_unlock(rq
, &flags
);
2161 int wake_up_process(struct task_struct
*p
)
2163 return try_to_wake_up(p
, TASK_ALL
, 0);
2165 EXPORT_SYMBOL(wake_up_process
);
2167 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2169 return try_to_wake_up(p
, state
, 0);
2173 * Perform scheduler related setup for a newly forked process p.
2174 * p is forked by current.
2176 * __sched_fork() is basic setup used by init_idle() too:
2178 static void __sched_fork(struct task_struct
*p
)
2180 p
->se
.exec_start
= 0;
2181 p
->se
.sum_exec_runtime
= 0;
2182 p
->se
.prev_sum_exec_runtime
= 0;
2183 p
->se
.last_wakeup
= 0;
2184 p
->se
.avg_overlap
= 0;
2186 #ifdef CONFIG_SCHEDSTATS
2187 p
->se
.wait_start
= 0;
2188 p
->se
.sum_sleep_runtime
= 0;
2189 p
->se
.sleep_start
= 0;
2190 p
->se
.block_start
= 0;
2191 p
->se
.sleep_max
= 0;
2192 p
->se
.block_max
= 0;
2194 p
->se
.slice_max
= 0;
2198 INIT_LIST_HEAD(&p
->rt
.run_list
);
2200 INIT_LIST_HEAD(&p
->se
.group_node
);
2202 #ifdef CONFIG_PREEMPT_NOTIFIERS
2203 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2207 * We mark the process as running here, but have not actually
2208 * inserted it onto the runqueue yet. This guarantees that
2209 * nobody will actually run it, and a signal or other external
2210 * event cannot wake it up and insert it on the runqueue either.
2212 p
->state
= TASK_RUNNING
;
2216 * fork()/clone()-time setup:
2218 void sched_fork(struct task_struct
*p
, int clone_flags
)
2220 int cpu
= get_cpu();
2225 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2227 set_task_cpu(p
, cpu
);
2230 * Make sure we do not leak PI boosting priority to the child:
2232 p
->prio
= current
->normal_prio
;
2233 if (!rt_prio(p
->prio
))
2234 p
->sched_class
= &fair_sched_class
;
2236 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2237 if (likely(sched_info_on()))
2238 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2240 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2243 #ifdef CONFIG_PREEMPT
2244 /* Want to start with kernel preemption disabled. */
2245 task_thread_info(p
)->preempt_count
= 1;
2251 * wake_up_new_task - wake up a newly created task for the first time.
2253 * This function will do some initial scheduler statistics housekeeping
2254 * that must be done for every newly created context, then puts the task
2255 * on the runqueue and wakes it.
2257 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2259 unsigned long flags
;
2262 rq
= task_rq_lock(p
, &flags
);
2263 BUG_ON(p
->state
!= TASK_RUNNING
);
2264 update_rq_clock(rq
);
2266 p
->prio
= effective_prio(p
);
2268 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2269 activate_task(rq
, p
, 0);
2272 * Let the scheduling class do new task startup
2273 * management (if any):
2275 p
->sched_class
->task_new(rq
, p
);
2276 inc_nr_running(p
, rq
);
2278 check_preempt_curr(rq
, p
);
2280 if (p
->sched_class
->task_wake_up
)
2281 p
->sched_class
->task_wake_up(rq
, p
);
2283 task_rq_unlock(rq
, &flags
);
2286 #ifdef CONFIG_PREEMPT_NOTIFIERS
2289 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2290 * @notifier: notifier struct to register
2292 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2294 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2296 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2299 * preempt_notifier_unregister - no longer interested in preemption notifications
2300 * @notifier: notifier struct to unregister
2302 * This is safe to call from within a preemption notifier.
2304 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2306 hlist_del(¬ifier
->link
);
2308 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2310 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2312 struct preempt_notifier
*notifier
;
2313 struct hlist_node
*node
;
2315 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2316 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2320 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2321 struct task_struct
*next
)
2323 struct preempt_notifier
*notifier
;
2324 struct hlist_node
*node
;
2326 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2327 notifier
->ops
->sched_out(notifier
, next
);
2332 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2337 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2338 struct task_struct
*next
)
2345 * prepare_task_switch - prepare to switch tasks
2346 * @rq: the runqueue preparing to switch
2347 * @prev: the current task that is being switched out
2348 * @next: the task we are going to switch to.
2350 * This is called with the rq lock held and interrupts off. It must
2351 * be paired with a subsequent finish_task_switch after the context
2354 * prepare_task_switch sets up locking and calls architecture specific
2358 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2359 struct task_struct
*next
)
2361 fire_sched_out_preempt_notifiers(prev
, next
);
2362 prepare_lock_switch(rq
, next
);
2363 prepare_arch_switch(next
);
2367 * finish_task_switch - clean up after a task-switch
2368 * @rq: runqueue associated with task-switch
2369 * @prev: the thread we just switched away from.
2371 * finish_task_switch must be called after the context switch, paired
2372 * with a prepare_task_switch call before the context switch.
2373 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2374 * and do any other architecture-specific cleanup actions.
2376 * Note that we may have delayed dropping an mm in context_switch(). If
2377 * so, we finish that here outside of the runqueue lock. (Doing it
2378 * with the lock held can cause deadlocks; see schedule() for
2381 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2382 __releases(rq
->lock
)
2384 struct mm_struct
*mm
= rq
->prev_mm
;
2390 * A task struct has one reference for the use as "current".
2391 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2392 * schedule one last time. The schedule call will never return, and
2393 * the scheduled task must drop that reference.
2394 * The test for TASK_DEAD must occur while the runqueue locks are
2395 * still held, otherwise prev could be scheduled on another cpu, die
2396 * there before we look at prev->state, and then the reference would
2398 * Manfred Spraul <manfred@colorfullife.com>
2400 prev_state
= prev
->state
;
2401 finish_arch_switch(prev
);
2402 finish_lock_switch(rq
, prev
);
2404 if (current
->sched_class
->post_schedule
)
2405 current
->sched_class
->post_schedule(rq
);
2408 fire_sched_in_preempt_notifiers(current
);
2411 if (unlikely(prev_state
== TASK_DEAD
)) {
2413 * Remove function-return probe instances associated with this
2414 * task and put them back on the free list.
2416 kprobe_flush_task(prev
);
2417 put_task_struct(prev
);
2422 * schedule_tail - first thing a freshly forked thread must call.
2423 * @prev: the thread we just switched away from.
2425 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2426 __releases(rq
->lock
)
2428 struct rq
*rq
= this_rq();
2430 finish_task_switch(rq
, prev
);
2431 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2432 /* In this case, finish_task_switch does not reenable preemption */
2435 if (current
->set_child_tid
)
2436 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2440 * context_switch - switch to the new MM and the new
2441 * thread's register state.
2444 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2445 struct task_struct
*next
)
2447 struct mm_struct
*mm
, *oldmm
;
2449 prepare_task_switch(rq
, prev
, next
);
2451 oldmm
= prev
->active_mm
;
2453 * For paravirt, this is coupled with an exit in switch_to to
2454 * combine the page table reload and the switch backend into
2457 arch_enter_lazy_cpu_mode();
2459 if (unlikely(!mm
)) {
2460 next
->active_mm
= oldmm
;
2461 atomic_inc(&oldmm
->mm_count
);
2462 enter_lazy_tlb(oldmm
, next
);
2464 switch_mm(oldmm
, mm
, next
);
2466 if (unlikely(!prev
->mm
)) {
2467 prev
->active_mm
= NULL
;
2468 rq
->prev_mm
= oldmm
;
2471 * Since the runqueue lock will be released by the next
2472 * task (which is an invalid locking op but in the case
2473 * of the scheduler it's an obvious special-case), so we
2474 * do an early lockdep release here:
2476 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2477 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2480 /* Here we just switch the register state and the stack. */
2481 switch_to(prev
, next
, prev
);
2485 * this_rq must be evaluated again because prev may have moved
2486 * CPUs since it called schedule(), thus the 'rq' on its stack
2487 * frame will be invalid.
2489 finish_task_switch(this_rq(), prev
);
2493 * nr_running, nr_uninterruptible and nr_context_switches:
2495 * externally visible scheduler statistics: current number of runnable
2496 * threads, current number of uninterruptible-sleeping threads, total
2497 * number of context switches performed since bootup.
2499 unsigned long nr_running(void)
2501 unsigned long i
, sum
= 0;
2503 for_each_online_cpu(i
)
2504 sum
+= cpu_rq(i
)->nr_running
;
2509 unsigned long nr_uninterruptible(void)
2511 unsigned long i
, sum
= 0;
2513 for_each_possible_cpu(i
)
2514 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2517 * Since we read the counters lockless, it might be slightly
2518 * inaccurate. Do not allow it to go below zero though:
2520 if (unlikely((long)sum
< 0))
2526 unsigned long long nr_context_switches(void)
2529 unsigned long long sum
= 0;
2531 for_each_possible_cpu(i
)
2532 sum
+= cpu_rq(i
)->nr_switches
;
2537 unsigned long nr_iowait(void)
2539 unsigned long i
, sum
= 0;
2541 for_each_possible_cpu(i
)
2542 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2547 unsigned long nr_active(void)
2549 unsigned long i
, running
= 0, uninterruptible
= 0;
2551 for_each_online_cpu(i
) {
2552 running
+= cpu_rq(i
)->nr_running
;
2553 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2556 if (unlikely((long)uninterruptible
< 0))
2557 uninterruptible
= 0;
2559 return running
+ uninterruptible
;
2563 * Update rq->cpu_load[] statistics. This function is usually called every
2564 * scheduler tick (TICK_NSEC).
2566 static void update_cpu_load(struct rq
*this_rq
)
2568 unsigned long this_load
= this_rq
->load
.weight
;
2571 this_rq
->nr_load_updates
++;
2573 /* Update our load: */
2574 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2575 unsigned long old_load
, new_load
;
2577 /* scale is effectively 1 << i now, and >> i divides by scale */
2579 old_load
= this_rq
->cpu_load
[i
];
2580 new_load
= this_load
;
2582 * Round up the averaging division if load is increasing. This
2583 * prevents us from getting stuck on 9 if the load is 10, for
2586 if (new_load
> old_load
)
2587 new_load
+= scale
-1;
2588 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2595 * double_rq_lock - safely lock two runqueues
2597 * Note this does not disable interrupts like task_rq_lock,
2598 * you need to do so manually before calling.
2600 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2601 __acquires(rq1
->lock
)
2602 __acquires(rq2
->lock
)
2604 BUG_ON(!irqs_disabled());
2606 spin_lock(&rq1
->lock
);
2607 __acquire(rq2
->lock
); /* Fake it out ;) */
2610 spin_lock(&rq1
->lock
);
2611 spin_lock(&rq2
->lock
);
2613 spin_lock(&rq2
->lock
);
2614 spin_lock(&rq1
->lock
);
2617 update_rq_clock(rq1
);
2618 update_rq_clock(rq2
);
2622 * double_rq_unlock - safely unlock two runqueues
2624 * Note this does not restore interrupts like task_rq_unlock,
2625 * you need to do so manually after calling.
2627 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2628 __releases(rq1
->lock
)
2629 __releases(rq2
->lock
)
2631 spin_unlock(&rq1
->lock
);
2633 spin_unlock(&rq2
->lock
);
2635 __release(rq2
->lock
);
2639 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2641 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2642 __releases(this_rq
->lock
)
2643 __acquires(busiest
->lock
)
2644 __acquires(this_rq
->lock
)
2648 if (unlikely(!irqs_disabled())) {
2649 /* printk() doesn't work good under rq->lock */
2650 spin_unlock(&this_rq
->lock
);
2653 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2654 if (busiest
< this_rq
) {
2655 spin_unlock(&this_rq
->lock
);
2656 spin_lock(&busiest
->lock
);
2657 spin_lock(&this_rq
->lock
);
2660 spin_lock(&busiest
->lock
);
2666 * If dest_cpu is allowed for this process, migrate the task to it.
2667 * This is accomplished by forcing the cpu_allowed mask to only
2668 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2669 * the cpu_allowed mask is restored.
2671 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2673 struct migration_req req
;
2674 unsigned long flags
;
2677 rq
= task_rq_lock(p
, &flags
);
2678 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2679 || unlikely(cpu_is_offline(dest_cpu
)))
2682 /* force the process onto the specified CPU */
2683 if (migrate_task(p
, dest_cpu
, &req
)) {
2684 /* Need to wait for migration thread (might exit: take ref). */
2685 struct task_struct
*mt
= rq
->migration_thread
;
2687 get_task_struct(mt
);
2688 task_rq_unlock(rq
, &flags
);
2689 wake_up_process(mt
);
2690 put_task_struct(mt
);
2691 wait_for_completion(&req
.done
);
2696 task_rq_unlock(rq
, &flags
);
2700 * sched_exec - execve() is a valuable balancing opportunity, because at
2701 * this point the task has the smallest effective memory and cache footprint.
2703 void sched_exec(void)
2705 int new_cpu
, this_cpu
= get_cpu();
2706 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2708 if (new_cpu
!= this_cpu
)
2709 sched_migrate_task(current
, new_cpu
);
2713 * pull_task - move a task from a remote runqueue to the local runqueue.
2714 * Both runqueues must be locked.
2716 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2717 struct rq
*this_rq
, int this_cpu
)
2719 deactivate_task(src_rq
, p
, 0);
2720 set_task_cpu(p
, this_cpu
);
2721 activate_task(this_rq
, p
, 0);
2723 * Note that idle threads have a prio of MAX_PRIO, for this test
2724 * to be always true for them.
2726 check_preempt_curr(this_rq
, p
);
2730 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2733 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2734 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2738 * We do not migrate tasks that are:
2739 * 1) running (obviously), or
2740 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2741 * 3) are cache-hot on their current CPU.
2743 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2744 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2749 if (task_running(rq
, p
)) {
2750 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2755 * Aggressive migration if:
2756 * 1) task is cache cold, or
2757 * 2) too many balance attempts have failed.
2760 if (!task_hot(p
, rq
->clock
, sd
) ||
2761 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2762 #ifdef CONFIG_SCHEDSTATS
2763 if (task_hot(p
, rq
->clock
, sd
)) {
2764 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2765 schedstat_inc(p
, se
.nr_forced_migrations
);
2771 if (task_hot(p
, rq
->clock
, sd
)) {
2772 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2778 static unsigned long
2779 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2780 unsigned long max_load_move
, struct sched_domain
*sd
,
2781 enum cpu_idle_type idle
, int *all_pinned
,
2782 int *this_best_prio
, struct rq_iterator
*iterator
)
2784 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2785 struct task_struct
*p
;
2786 long rem_load_move
= max_load_move
;
2788 if (max_load_move
== 0)
2794 * Start the load-balancing iterator:
2796 p
= iterator
->start(iterator
->arg
);
2798 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2801 * To help distribute high priority tasks across CPUs we don't
2802 * skip a task if it will be the highest priority task (i.e. smallest
2803 * prio value) on its new queue regardless of its load weight
2805 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2806 SCHED_LOAD_SCALE_FUZZ
;
2807 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2808 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2809 p
= iterator
->next(iterator
->arg
);
2813 pull_task(busiest
, p
, this_rq
, this_cpu
);
2815 rem_load_move
-= p
->se
.load
.weight
;
2818 * We only want to steal up to the prescribed amount of weighted load.
2820 if (rem_load_move
> 0) {
2821 if (p
->prio
< *this_best_prio
)
2822 *this_best_prio
= p
->prio
;
2823 p
= iterator
->next(iterator
->arg
);
2828 * Right now, this is one of only two places pull_task() is called,
2829 * so we can safely collect pull_task() stats here rather than
2830 * inside pull_task().
2832 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2835 *all_pinned
= pinned
;
2837 return max_load_move
- rem_load_move
;
2841 * move_tasks tries to move up to max_load_move weighted load from busiest to
2842 * this_rq, as part of a balancing operation within domain "sd".
2843 * Returns 1 if successful and 0 otherwise.
2845 * Called with both runqueues locked.
2847 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2848 unsigned long max_load_move
,
2849 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2852 const struct sched_class
*class = sched_class_highest
;
2853 unsigned long total_load_moved
= 0;
2854 int this_best_prio
= this_rq
->curr
->prio
;
2858 class->load_balance(this_rq
, this_cpu
, busiest
,
2859 max_load_move
- total_load_moved
,
2860 sd
, idle
, all_pinned
, &this_best_prio
);
2861 class = class->next
;
2862 } while (class && max_load_move
> total_load_moved
);
2864 return total_load_moved
> 0;
2868 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2869 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2870 struct rq_iterator
*iterator
)
2872 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2876 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2877 pull_task(busiest
, p
, this_rq
, this_cpu
);
2879 * Right now, this is only the second place pull_task()
2880 * is called, so we can safely collect pull_task()
2881 * stats here rather than inside pull_task().
2883 schedstat_inc(sd
, lb_gained
[idle
]);
2887 p
= iterator
->next(iterator
->arg
);
2894 * move_one_task tries to move exactly one task from busiest to this_rq, as
2895 * part of active balancing operations within "domain".
2896 * Returns 1 if successful and 0 otherwise.
2898 * Called with both runqueues locked.
2900 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2901 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2903 const struct sched_class
*class;
2905 for (class = sched_class_highest
; class; class = class->next
)
2906 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2913 * find_busiest_group finds and returns the busiest CPU group within the
2914 * domain. It calculates and returns the amount of weighted load which
2915 * should be moved to restore balance via the imbalance parameter.
2917 static struct sched_group
*
2918 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2919 unsigned long *imbalance
, enum cpu_idle_type idle
,
2920 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2922 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2923 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2924 unsigned long max_pull
;
2925 unsigned long busiest_load_per_task
, busiest_nr_running
;
2926 unsigned long this_load_per_task
, this_nr_running
;
2927 int load_idx
, group_imb
= 0;
2928 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2929 int power_savings_balance
= 1;
2930 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2931 unsigned long min_nr_running
= ULONG_MAX
;
2932 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2935 max_load
= this_load
= total_load
= total_pwr
= 0;
2936 busiest_load_per_task
= busiest_nr_running
= 0;
2937 this_load_per_task
= this_nr_running
= 0;
2938 if (idle
== CPU_NOT_IDLE
)
2939 load_idx
= sd
->busy_idx
;
2940 else if (idle
== CPU_NEWLY_IDLE
)
2941 load_idx
= sd
->newidle_idx
;
2943 load_idx
= sd
->idle_idx
;
2946 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2949 int __group_imb
= 0;
2950 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2951 unsigned long sum_nr_running
, sum_weighted_load
;
2953 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2956 balance_cpu
= first_cpu(group
->cpumask
);
2958 /* Tally up the load of all CPUs in the group */
2959 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2961 min_cpu_load
= ~0UL;
2963 for_each_cpu_mask(i
, group
->cpumask
) {
2966 if (!cpu_isset(i
, *cpus
))
2971 if (*sd_idle
&& rq
->nr_running
)
2974 /* Bias balancing toward cpus of our domain */
2976 if (idle_cpu(i
) && !first_idle_cpu
) {
2981 load
= target_load(i
, load_idx
);
2983 load
= source_load(i
, load_idx
);
2984 if (load
> max_cpu_load
)
2985 max_cpu_load
= load
;
2986 if (min_cpu_load
> load
)
2987 min_cpu_load
= load
;
2991 sum_nr_running
+= rq
->nr_running
;
2992 sum_weighted_load
+= weighted_cpuload(i
);
2996 * First idle cpu or the first cpu(busiest) in this sched group
2997 * is eligible for doing load balancing at this and above
2998 * domains. In the newly idle case, we will allow all the cpu's
2999 * to do the newly idle load balance.
3001 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3002 balance_cpu
!= this_cpu
&& balance
) {
3007 total_load
+= avg_load
;
3008 total_pwr
+= group
->__cpu_power
;
3010 /* Adjust by relative CPU power of the group */
3011 avg_load
= sg_div_cpu_power(group
,
3012 avg_load
* SCHED_LOAD_SCALE
);
3014 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
3017 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3020 this_load
= avg_load
;
3022 this_nr_running
= sum_nr_running
;
3023 this_load_per_task
= sum_weighted_load
;
3024 } else if (avg_load
> max_load
&&
3025 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3026 max_load
= avg_load
;
3028 busiest_nr_running
= sum_nr_running
;
3029 busiest_load_per_task
= sum_weighted_load
;
3030 group_imb
= __group_imb
;
3033 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3035 * Busy processors will not participate in power savings
3038 if (idle
== CPU_NOT_IDLE
||
3039 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3043 * If the local group is idle or completely loaded
3044 * no need to do power savings balance at this domain
3046 if (local_group
&& (this_nr_running
>= group_capacity
||
3048 power_savings_balance
= 0;
3051 * If a group is already running at full capacity or idle,
3052 * don't include that group in power savings calculations
3054 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
3059 * Calculate the group which has the least non-idle load.
3060 * This is the group from where we need to pick up the load
3063 if ((sum_nr_running
< min_nr_running
) ||
3064 (sum_nr_running
== min_nr_running
&&
3065 first_cpu(group
->cpumask
) <
3066 first_cpu(group_min
->cpumask
))) {
3068 min_nr_running
= sum_nr_running
;
3069 min_load_per_task
= sum_weighted_load
/
3074 * Calculate the group which is almost near its
3075 * capacity but still has some space to pick up some load
3076 * from other group and save more power
3078 if (sum_nr_running
<= group_capacity
- 1) {
3079 if (sum_nr_running
> leader_nr_running
||
3080 (sum_nr_running
== leader_nr_running
&&
3081 first_cpu(group
->cpumask
) >
3082 first_cpu(group_leader
->cpumask
))) {
3083 group_leader
= group
;
3084 leader_nr_running
= sum_nr_running
;
3089 group
= group
->next
;
3090 } while (group
!= sd
->groups
);
3092 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3095 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3097 if (this_load
>= avg_load
||
3098 100*max_load
<= sd
->imbalance_pct
*this_load
)
3101 busiest_load_per_task
/= busiest_nr_running
;
3103 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3106 * We're trying to get all the cpus to the average_load, so we don't
3107 * want to push ourselves above the average load, nor do we wish to
3108 * reduce the max loaded cpu below the average load, as either of these
3109 * actions would just result in more rebalancing later, and ping-pong
3110 * tasks around. Thus we look for the minimum possible imbalance.
3111 * Negative imbalances (*we* are more loaded than anyone else) will
3112 * be counted as no imbalance for these purposes -- we can't fix that
3113 * by pulling tasks to us. Be careful of negative numbers as they'll
3114 * appear as very large values with unsigned longs.
3116 if (max_load
<= busiest_load_per_task
)
3120 * In the presence of smp nice balancing, certain scenarios can have
3121 * max load less than avg load(as we skip the groups at or below
3122 * its cpu_power, while calculating max_load..)
3124 if (max_load
< avg_load
) {
3126 goto small_imbalance
;
3129 /* Don't want to pull so many tasks that a group would go idle */
3130 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3132 /* How much load to actually move to equalise the imbalance */
3133 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3134 (avg_load
- this_load
) * this->__cpu_power
)
3138 * if *imbalance is less than the average load per runnable task
3139 * there is no gaurantee that any tasks will be moved so we'll have
3140 * a think about bumping its value to force at least one task to be
3143 if (*imbalance
< busiest_load_per_task
) {
3144 unsigned long tmp
, pwr_now
, pwr_move
;
3148 pwr_move
= pwr_now
= 0;
3150 if (this_nr_running
) {
3151 this_load_per_task
/= this_nr_running
;
3152 if (busiest_load_per_task
> this_load_per_task
)
3155 this_load_per_task
= SCHED_LOAD_SCALE
;
3157 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3158 busiest_load_per_task
* imbn
) {
3159 *imbalance
= busiest_load_per_task
;
3164 * OK, we don't have enough imbalance to justify moving tasks,
3165 * however we may be able to increase total CPU power used by
3169 pwr_now
+= busiest
->__cpu_power
*
3170 min(busiest_load_per_task
, max_load
);
3171 pwr_now
+= this->__cpu_power
*
3172 min(this_load_per_task
, this_load
);
3173 pwr_now
/= SCHED_LOAD_SCALE
;
3175 /* Amount of load we'd subtract */
3176 tmp
= sg_div_cpu_power(busiest
,
3177 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3179 pwr_move
+= busiest
->__cpu_power
*
3180 min(busiest_load_per_task
, max_load
- tmp
);
3182 /* Amount of load we'd add */
3183 if (max_load
* busiest
->__cpu_power
<
3184 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3185 tmp
= sg_div_cpu_power(this,
3186 max_load
* busiest
->__cpu_power
);
3188 tmp
= sg_div_cpu_power(this,
3189 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3190 pwr_move
+= this->__cpu_power
*
3191 min(this_load_per_task
, this_load
+ tmp
);
3192 pwr_move
/= SCHED_LOAD_SCALE
;
3194 /* Move if we gain throughput */
3195 if (pwr_move
> pwr_now
)
3196 *imbalance
= busiest_load_per_task
;
3202 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3203 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3206 if (this == group_leader
&& group_leader
!= group_min
) {
3207 *imbalance
= min_load_per_task
;
3217 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3220 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3221 unsigned long imbalance
, const cpumask_t
*cpus
)
3223 struct rq
*busiest
= NULL
, *rq
;
3224 unsigned long max_load
= 0;
3227 for_each_cpu_mask(i
, group
->cpumask
) {
3230 if (!cpu_isset(i
, *cpus
))
3234 wl
= weighted_cpuload(i
);
3236 if (rq
->nr_running
== 1 && wl
> imbalance
)
3239 if (wl
> max_load
) {
3249 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3250 * so long as it is large enough.
3252 #define MAX_PINNED_INTERVAL 512
3255 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3256 * tasks if there is an imbalance.
3258 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3259 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3260 int *balance
, cpumask_t
*cpus
)
3262 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3263 struct sched_group
*group
;
3264 unsigned long imbalance
;
3266 unsigned long flags
;
3271 * When power savings policy is enabled for the parent domain, idle
3272 * sibling can pick up load irrespective of busy siblings. In this case,
3273 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3274 * portraying it as CPU_NOT_IDLE.
3276 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3277 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3280 schedstat_inc(sd
, lb_count
[idle
]);
3283 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3290 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3294 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3296 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3300 BUG_ON(busiest
== this_rq
);
3302 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3305 if (busiest
->nr_running
> 1) {
3307 * Attempt to move tasks. If find_busiest_group has found
3308 * an imbalance but busiest->nr_running <= 1, the group is
3309 * still unbalanced. ld_moved simply stays zero, so it is
3310 * correctly treated as an imbalance.
3312 local_irq_save(flags
);
3313 double_rq_lock(this_rq
, busiest
);
3314 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3315 imbalance
, sd
, idle
, &all_pinned
);
3316 double_rq_unlock(this_rq
, busiest
);
3317 local_irq_restore(flags
);
3320 * some other cpu did the load balance for us.
3322 if (ld_moved
&& this_cpu
!= smp_processor_id())
3323 resched_cpu(this_cpu
);
3325 /* All tasks on this runqueue were pinned by CPU affinity */
3326 if (unlikely(all_pinned
)) {
3327 cpu_clear(cpu_of(busiest
), *cpus
);
3328 if (!cpus_empty(*cpus
))
3335 schedstat_inc(sd
, lb_failed
[idle
]);
3336 sd
->nr_balance_failed
++;
3338 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3340 spin_lock_irqsave(&busiest
->lock
, flags
);
3342 /* don't kick the migration_thread, if the curr
3343 * task on busiest cpu can't be moved to this_cpu
3345 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3346 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3348 goto out_one_pinned
;
3351 if (!busiest
->active_balance
) {
3352 busiest
->active_balance
= 1;
3353 busiest
->push_cpu
= this_cpu
;
3356 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3358 wake_up_process(busiest
->migration_thread
);
3361 * We've kicked active balancing, reset the failure
3364 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3367 sd
->nr_balance_failed
= 0;
3369 if (likely(!active_balance
)) {
3370 /* We were unbalanced, so reset the balancing interval */
3371 sd
->balance_interval
= sd
->min_interval
;
3374 * If we've begun active balancing, start to back off. This
3375 * case may not be covered by the all_pinned logic if there
3376 * is only 1 task on the busy runqueue (because we don't call
3379 if (sd
->balance_interval
< sd
->max_interval
)
3380 sd
->balance_interval
*= 2;
3383 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3384 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3389 schedstat_inc(sd
, lb_balanced
[idle
]);
3391 sd
->nr_balance_failed
= 0;
3394 /* tune up the balancing interval */
3395 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3396 (sd
->balance_interval
< sd
->max_interval
))
3397 sd
->balance_interval
*= 2;
3399 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3400 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3406 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3407 * tasks if there is an imbalance.
3409 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3410 * this_rq is locked.
3413 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3416 struct sched_group
*group
;
3417 struct rq
*busiest
= NULL
;
3418 unsigned long imbalance
;
3426 * When power savings policy is enabled for the parent domain, idle
3427 * sibling can pick up load irrespective of busy siblings. In this case,
3428 * let the state of idle sibling percolate up as IDLE, instead of
3429 * portraying it as CPU_NOT_IDLE.
3431 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3432 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3435 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3437 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3438 &sd_idle
, cpus
, NULL
);
3440 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3444 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3446 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3450 BUG_ON(busiest
== this_rq
);
3452 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3455 if (busiest
->nr_running
> 1) {
3456 /* Attempt to move tasks */
3457 double_lock_balance(this_rq
, busiest
);
3458 /* this_rq->clock is already updated */
3459 update_rq_clock(busiest
);
3460 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3461 imbalance
, sd
, CPU_NEWLY_IDLE
,
3463 spin_unlock(&busiest
->lock
);
3465 if (unlikely(all_pinned
)) {
3466 cpu_clear(cpu_of(busiest
), *cpus
);
3467 if (!cpus_empty(*cpus
))
3473 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3474 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3475 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3478 sd
->nr_balance_failed
= 0;
3483 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3484 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3485 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3487 sd
->nr_balance_failed
= 0;
3493 * idle_balance is called by schedule() if this_cpu is about to become
3494 * idle. Attempts to pull tasks from other CPUs.
3496 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3498 struct sched_domain
*sd
;
3499 int pulled_task
= -1;
3500 unsigned long next_balance
= jiffies
+ HZ
;
3503 for_each_domain(this_cpu
, sd
) {
3504 unsigned long interval
;
3506 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3509 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3510 /* If we've pulled tasks over stop searching: */
3511 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3514 interval
= msecs_to_jiffies(sd
->balance_interval
);
3515 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3516 next_balance
= sd
->last_balance
+ interval
;
3520 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3522 * We are going idle. next_balance may be set based on
3523 * a busy processor. So reset next_balance.
3525 this_rq
->next_balance
= next_balance
;
3530 * active_load_balance is run by migration threads. It pushes running tasks
3531 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3532 * running on each physical CPU where possible, and avoids physical /
3533 * logical imbalances.
3535 * Called with busiest_rq locked.
3537 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3539 int target_cpu
= busiest_rq
->push_cpu
;
3540 struct sched_domain
*sd
;
3541 struct rq
*target_rq
;
3543 /* Is there any task to move? */
3544 if (busiest_rq
->nr_running
<= 1)
3547 target_rq
= cpu_rq(target_cpu
);
3550 * This condition is "impossible", if it occurs
3551 * we need to fix it. Originally reported by
3552 * Bjorn Helgaas on a 128-cpu setup.
3554 BUG_ON(busiest_rq
== target_rq
);
3556 /* move a task from busiest_rq to target_rq */
3557 double_lock_balance(busiest_rq
, target_rq
);
3558 update_rq_clock(busiest_rq
);
3559 update_rq_clock(target_rq
);
3561 /* Search for an sd spanning us and the target CPU. */
3562 for_each_domain(target_cpu
, sd
) {
3563 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3564 cpu_isset(busiest_cpu
, sd
->span
))
3569 schedstat_inc(sd
, alb_count
);
3571 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3573 schedstat_inc(sd
, alb_pushed
);
3575 schedstat_inc(sd
, alb_failed
);
3577 spin_unlock(&target_rq
->lock
);
3582 atomic_t load_balancer
;
3584 } nohz ____cacheline_aligned
= {
3585 .load_balancer
= ATOMIC_INIT(-1),
3586 .cpu_mask
= CPU_MASK_NONE
,
3590 * This routine will try to nominate the ilb (idle load balancing)
3591 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3592 * load balancing on behalf of all those cpus. If all the cpus in the system
3593 * go into this tickless mode, then there will be no ilb owner (as there is
3594 * no need for one) and all the cpus will sleep till the next wakeup event
3597 * For the ilb owner, tick is not stopped. And this tick will be used
3598 * for idle load balancing. ilb owner will still be part of
3601 * While stopping the tick, this cpu will become the ilb owner if there
3602 * is no other owner. And will be the owner till that cpu becomes busy
3603 * or if all cpus in the system stop their ticks at which point
3604 * there is no need for ilb owner.
3606 * When the ilb owner becomes busy, it nominates another owner, during the
3607 * next busy scheduler_tick()
3609 int select_nohz_load_balancer(int stop_tick
)
3611 int cpu
= smp_processor_id();
3614 cpu_set(cpu
, nohz
.cpu_mask
);
3615 cpu_rq(cpu
)->in_nohz_recently
= 1;
3618 * If we are going offline and still the leader, give up!
3620 if (cpu_is_offline(cpu
) &&
3621 atomic_read(&nohz
.load_balancer
) == cpu
) {
3622 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3627 /* time for ilb owner also to sleep */
3628 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3629 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3630 atomic_set(&nohz
.load_balancer
, -1);
3634 if (atomic_read(&nohz
.load_balancer
) == -1) {
3635 /* make me the ilb owner */
3636 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3638 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3641 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3644 cpu_clear(cpu
, nohz
.cpu_mask
);
3646 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3647 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3654 static DEFINE_SPINLOCK(balancing
);
3657 * It checks each scheduling domain to see if it is due to be balanced,
3658 * and initiates a balancing operation if so.
3660 * Balancing parameters are set up in arch_init_sched_domains.
3662 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3665 struct rq
*rq
= cpu_rq(cpu
);
3666 unsigned long interval
;
3667 struct sched_domain
*sd
;
3668 /* Earliest time when we have to do rebalance again */
3669 unsigned long next_balance
= jiffies
+ 60*HZ
;
3670 int update_next_balance
= 0;
3673 for_each_domain(cpu
, sd
) {
3674 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3677 interval
= sd
->balance_interval
;
3678 if (idle
!= CPU_IDLE
)
3679 interval
*= sd
->busy_factor
;
3681 /* scale ms to jiffies */
3682 interval
= msecs_to_jiffies(interval
);
3683 if (unlikely(!interval
))
3685 if (interval
> HZ
*NR_CPUS
/10)
3686 interval
= HZ
*NR_CPUS
/10;
3689 if (sd
->flags
& SD_SERIALIZE
) {
3690 if (!spin_trylock(&balancing
))
3694 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3695 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3697 * We've pulled tasks over so either we're no
3698 * longer idle, or one of our SMT siblings is
3701 idle
= CPU_NOT_IDLE
;
3703 sd
->last_balance
= jiffies
;
3705 if (sd
->flags
& SD_SERIALIZE
)
3706 spin_unlock(&balancing
);
3708 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3709 next_balance
= sd
->last_balance
+ interval
;
3710 update_next_balance
= 1;
3714 * Stop the load balance at this level. There is another
3715 * CPU in our sched group which is doing load balancing more
3723 * next_balance will be updated only when there is a need.
3724 * When the cpu is attached to null domain for ex, it will not be
3727 if (likely(update_next_balance
))
3728 rq
->next_balance
= next_balance
;
3732 * run_rebalance_domains is triggered when needed from the scheduler tick.
3733 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3734 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3736 static void run_rebalance_domains(struct softirq_action
*h
)
3738 int this_cpu
= smp_processor_id();
3739 struct rq
*this_rq
= cpu_rq(this_cpu
);
3740 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3741 CPU_IDLE
: CPU_NOT_IDLE
;
3743 rebalance_domains(this_cpu
, idle
);
3747 * If this cpu is the owner for idle load balancing, then do the
3748 * balancing on behalf of the other idle cpus whose ticks are
3751 if (this_rq
->idle_at_tick
&&
3752 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3753 cpumask_t cpus
= nohz
.cpu_mask
;
3757 cpu_clear(this_cpu
, cpus
);
3758 for_each_cpu_mask(balance_cpu
, cpus
) {
3760 * If this cpu gets work to do, stop the load balancing
3761 * work being done for other cpus. Next load
3762 * balancing owner will pick it up.
3767 rebalance_domains(balance_cpu
, CPU_IDLE
);
3769 rq
= cpu_rq(balance_cpu
);
3770 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3771 this_rq
->next_balance
= rq
->next_balance
;
3778 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3780 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3781 * idle load balancing owner or decide to stop the periodic load balancing,
3782 * if the whole system is idle.
3784 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3788 * If we were in the nohz mode recently and busy at the current
3789 * scheduler tick, then check if we need to nominate new idle
3792 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3793 rq
->in_nohz_recently
= 0;
3795 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3796 cpu_clear(cpu
, nohz
.cpu_mask
);
3797 atomic_set(&nohz
.load_balancer
, -1);
3800 if (atomic_read(&nohz
.load_balancer
) == -1) {
3802 * simple selection for now: Nominate the
3803 * first cpu in the nohz list to be the next
3806 * TBD: Traverse the sched domains and nominate
3807 * the nearest cpu in the nohz.cpu_mask.
3809 int ilb
= first_cpu(nohz
.cpu_mask
);
3811 if (ilb
< nr_cpu_ids
)
3817 * If this cpu is idle and doing idle load balancing for all the
3818 * cpus with ticks stopped, is it time for that to stop?
3820 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3821 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3827 * If this cpu is idle and the idle load balancing is done by
3828 * someone else, then no need raise the SCHED_SOFTIRQ
3830 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3831 cpu_isset(cpu
, nohz
.cpu_mask
))
3834 if (time_after_eq(jiffies
, rq
->next_balance
))
3835 raise_softirq(SCHED_SOFTIRQ
);
3838 #else /* CONFIG_SMP */
3841 * on UP we do not need to balance between CPUs:
3843 static inline void idle_balance(int cpu
, struct rq
*rq
)
3849 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3851 EXPORT_PER_CPU_SYMBOL(kstat
);
3854 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3855 * that have not yet been banked in case the task is currently running.
3857 unsigned long long task_sched_runtime(struct task_struct
*p
)
3859 unsigned long flags
;
3863 rq
= task_rq_lock(p
, &flags
);
3864 ns
= p
->se
.sum_exec_runtime
;
3865 if (task_current(rq
, p
)) {
3866 update_rq_clock(rq
);
3867 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3868 if ((s64
)delta_exec
> 0)
3871 task_rq_unlock(rq
, &flags
);
3877 * Account user cpu time to a process.
3878 * @p: the process that the cpu time gets accounted to
3879 * @cputime: the cpu time spent in user space since the last update
3881 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3883 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3886 p
->utime
= cputime_add(p
->utime
, cputime
);
3888 /* Add user time to cpustat. */
3889 tmp
= cputime_to_cputime64(cputime
);
3890 if (TASK_NICE(p
) > 0)
3891 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3893 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3897 * Account guest cpu time to a process.
3898 * @p: the process that the cpu time gets accounted to
3899 * @cputime: the cpu time spent in virtual machine since the last update
3901 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3904 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3906 tmp
= cputime_to_cputime64(cputime
);
3908 p
->utime
= cputime_add(p
->utime
, cputime
);
3909 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3911 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3912 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3916 * Account scaled user cpu time to a process.
3917 * @p: the process that the cpu time gets accounted to
3918 * @cputime: the cpu time spent in user space since the last update
3920 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3922 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3926 * Account system cpu time to a process.
3927 * @p: the process that the cpu time gets accounted to
3928 * @hardirq_offset: the offset to subtract from hardirq_count()
3929 * @cputime: the cpu time spent in kernel space since the last update
3931 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3934 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3935 struct rq
*rq
= this_rq();
3938 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3939 account_guest_time(p
, cputime
);
3943 p
->stime
= cputime_add(p
->stime
, cputime
);
3945 /* Add system time to cpustat. */
3946 tmp
= cputime_to_cputime64(cputime
);
3947 if (hardirq_count() - hardirq_offset
)
3948 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3949 else if (softirq_count())
3950 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3951 else if (p
!= rq
->idle
)
3952 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3953 else if (atomic_read(&rq
->nr_iowait
) > 0)
3954 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3956 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3957 /* Account for system time used */
3958 acct_update_integrals(p
);
3962 * Account scaled system cpu time to a process.
3963 * @p: the process that the cpu time gets accounted to
3964 * @hardirq_offset: the offset to subtract from hardirq_count()
3965 * @cputime: the cpu time spent in kernel space since the last update
3967 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3969 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3973 * Account for involuntary wait time.
3974 * @p: the process from which the cpu time has been stolen
3975 * @steal: the cpu time spent in involuntary wait
3977 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3979 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3980 cputime64_t tmp
= cputime_to_cputime64(steal
);
3981 struct rq
*rq
= this_rq();
3983 if (p
== rq
->idle
) {
3984 p
->stime
= cputime_add(p
->stime
, steal
);
3985 if (atomic_read(&rq
->nr_iowait
) > 0)
3986 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3988 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3990 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3994 * This function gets called by the timer code, with HZ frequency.
3995 * We call it with interrupts disabled.
3997 * It also gets called by the fork code, when changing the parent's
4000 void scheduler_tick(void)
4002 int cpu
= smp_processor_id();
4003 struct rq
*rq
= cpu_rq(cpu
);
4004 struct task_struct
*curr
= rq
->curr
;
4008 spin_lock(&rq
->lock
);
4009 update_rq_clock(rq
);
4010 update_cpu_load(rq
);
4011 curr
->sched_class
->task_tick(rq
, curr
, 0);
4012 spin_unlock(&rq
->lock
);
4015 rq
->idle_at_tick
= idle_cpu(cpu
);
4016 trigger_load_balance(rq
, cpu
);
4020 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
4022 void __kprobes
add_preempt_count(int val
)
4027 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4029 preempt_count() += val
;
4031 * Spinlock count overflowing soon?
4033 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4036 EXPORT_SYMBOL(add_preempt_count
);
4038 void __kprobes
sub_preempt_count(int val
)
4043 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4046 * Is the spinlock portion underflowing?
4048 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4049 !(preempt_count() & PREEMPT_MASK
)))
4052 preempt_count() -= val
;
4054 EXPORT_SYMBOL(sub_preempt_count
);
4059 * Print scheduling while atomic bug:
4061 static noinline
void __schedule_bug(struct task_struct
*prev
)
4063 struct pt_regs
*regs
= get_irq_regs();
4065 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4066 prev
->comm
, prev
->pid
, preempt_count());
4068 debug_show_held_locks(prev
);
4069 if (irqs_disabled())
4070 print_irqtrace_events(prev
);
4079 * Various schedule()-time debugging checks and statistics:
4081 static inline void schedule_debug(struct task_struct
*prev
)
4084 * Test if we are atomic. Since do_exit() needs to call into
4085 * schedule() atomically, we ignore that path for now.
4086 * Otherwise, whine if we are scheduling when we should not be.
4088 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4089 __schedule_bug(prev
);
4091 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4093 schedstat_inc(this_rq(), sched_count
);
4094 #ifdef CONFIG_SCHEDSTATS
4095 if (unlikely(prev
->lock_depth
>= 0)) {
4096 schedstat_inc(this_rq(), bkl_count
);
4097 schedstat_inc(prev
, sched_info
.bkl_count
);
4103 * Pick up the highest-prio task:
4105 static inline struct task_struct
*
4106 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4108 const struct sched_class
*class;
4109 struct task_struct
*p
;
4112 * Optimization: we know that if all tasks are in
4113 * the fair class we can call that function directly:
4115 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4116 p
= fair_sched_class
.pick_next_task(rq
);
4121 class = sched_class_highest
;
4123 p
= class->pick_next_task(rq
);
4127 * Will never be NULL as the idle class always
4128 * returns a non-NULL p:
4130 class = class->next
;
4135 * schedule() is the main scheduler function.
4137 asmlinkage
void __sched
schedule(void)
4139 struct task_struct
*prev
, *next
;
4140 unsigned long *switch_count
;
4142 int cpu
, hrtick
= sched_feat(HRTICK
);
4146 cpu
= smp_processor_id();
4150 switch_count
= &prev
->nivcsw
;
4152 release_kernel_lock(prev
);
4153 need_resched_nonpreemptible
:
4155 schedule_debug(prev
);
4161 * Do the rq-clock update outside the rq lock:
4163 local_irq_disable();
4164 update_rq_clock(rq
);
4165 spin_lock(&rq
->lock
);
4166 clear_tsk_need_resched(prev
);
4168 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4169 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4170 signal_pending(prev
))) {
4171 prev
->state
= TASK_RUNNING
;
4173 deactivate_task(rq
, prev
, 1);
4175 switch_count
= &prev
->nvcsw
;
4179 if (prev
->sched_class
->pre_schedule
)
4180 prev
->sched_class
->pre_schedule(rq
, prev
);
4183 if (unlikely(!rq
->nr_running
))
4184 idle_balance(cpu
, rq
);
4186 prev
->sched_class
->put_prev_task(rq
, prev
);
4187 next
= pick_next_task(rq
, prev
);
4189 if (likely(prev
!= next
)) {
4190 sched_info_switch(prev
, next
);
4196 context_switch(rq
, prev
, next
); /* unlocks the rq */
4198 * the context switch might have flipped the stack from under
4199 * us, hence refresh the local variables.
4201 cpu
= smp_processor_id();
4204 spin_unlock_irq(&rq
->lock
);
4209 if (unlikely(reacquire_kernel_lock(current
) < 0))
4210 goto need_resched_nonpreemptible
;
4212 preempt_enable_no_resched();
4213 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4216 EXPORT_SYMBOL(schedule
);
4218 #ifdef CONFIG_PREEMPT
4220 * this is the entry point to schedule() from in-kernel preemption
4221 * off of preempt_enable. Kernel preemptions off return from interrupt
4222 * occur there and call schedule directly.
4224 asmlinkage
void __sched
preempt_schedule(void)
4226 struct thread_info
*ti
= current_thread_info();
4229 * If there is a non-zero preempt_count or interrupts are disabled,
4230 * we do not want to preempt the current task. Just return..
4232 if (likely(ti
->preempt_count
|| irqs_disabled()))
4236 add_preempt_count(PREEMPT_ACTIVE
);
4238 sub_preempt_count(PREEMPT_ACTIVE
);
4241 * Check again in case we missed a preemption opportunity
4242 * between schedule and now.
4245 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4247 EXPORT_SYMBOL(preempt_schedule
);
4250 * this is the entry point to schedule() from kernel preemption
4251 * off of irq context.
4252 * Note, that this is called and return with irqs disabled. This will
4253 * protect us against recursive calling from irq.
4255 asmlinkage
void __sched
preempt_schedule_irq(void)
4257 struct thread_info
*ti
= current_thread_info();
4259 /* Catch callers which need to be fixed */
4260 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4263 add_preempt_count(PREEMPT_ACTIVE
);
4266 local_irq_disable();
4267 sub_preempt_count(PREEMPT_ACTIVE
);
4270 * Check again in case we missed a preemption opportunity
4271 * between schedule and now.
4274 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4277 #endif /* CONFIG_PREEMPT */
4279 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4282 return try_to_wake_up(curr
->private, mode
, sync
);
4284 EXPORT_SYMBOL(default_wake_function
);
4287 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4288 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4289 * number) then we wake all the non-exclusive tasks and one exclusive task.
4291 * There are circumstances in which we can try to wake a task which has already
4292 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4293 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4295 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4296 int nr_exclusive
, int sync
, void *key
)
4298 wait_queue_t
*curr
, *next
;
4300 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4301 unsigned flags
= curr
->flags
;
4303 if (curr
->func(curr
, mode
, sync
, key
) &&
4304 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4310 * __wake_up - wake up threads blocked on a waitqueue.
4312 * @mode: which threads
4313 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4314 * @key: is directly passed to the wakeup function
4316 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4317 int nr_exclusive
, void *key
)
4319 unsigned long flags
;
4321 spin_lock_irqsave(&q
->lock
, flags
);
4322 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4323 spin_unlock_irqrestore(&q
->lock
, flags
);
4325 EXPORT_SYMBOL(__wake_up
);
4328 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4330 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4332 __wake_up_common(q
, mode
, 1, 0, NULL
);
4336 * __wake_up_sync - wake up threads blocked on a waitqueue.
4338 * @mode: which threads
4339 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4341 * The sync wakeup differs that the waker knows that it will schedule
4342 * away soon, so while the target thread will be woken up, it will not
4343 * be migrated to another CPU - ie. the two threads are 'synchronized'
4344 * with each other. This can prevent needless bouncing between CPUs.
4346 * On UP it can prevent extra preemption.
4349 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4351 unsigned long flags
;
4357 if (unlikely(!nr_exclusive
))
4360 spin_lock_irqsave(&q
->lock
, flags
);
4361 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4362 spin_unlock_irqrestore(&q
->lock
, flags
);
4364 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4366 void complete(struct completion
*x
)
4368 unsigned long flags
;
4370 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4372 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4373 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4375 EXPORT_SYMBOL(complete
);
4377 void complete_all(struct completion
*x
)
4379 unsigned long flags
;
4381 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4382 x
->done
+= UINT_MAX
/2;
4383 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4384 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4386 EXPORT_SYMBOL(complete_all
);
4388 static inline long __sched
4389 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4392 DECLARE_WAITQUEUE(wait
, current
);
4394 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4395 __add_wait_queue_tail(&x
->wait
, &wait
);
4397 if ((state
== TASK_INTERRUPTIBLE
&&
4398 signal_pending(current
)) ||
4399 (state
== TASK_KILLABLE
&&
4400 fatal_signal_pending(current
))) {
4401 __remove_wait_queue(&x
->wait
, &wait
);
4402 return -ERESTARTSYS
;
4404 __set_current_state(state
);
4405 spin_unlock_irq(&x
->wait
.lock
);
4406 timeout
= schedule_timeout(timeout
);
4407 spin_lock_irq(&x
->wait
.lock
);
4409 __remove_wait_queue(&x
->wait
, &wait
);
4413 __remove_wait_queue(&x
->wait
, &wait
);
4420 wait_for_common(struct completion
*x
, long timeout
, int state
)
4424 spin_lock_irq(&x
->wait
.lock
);
4425 timeout
= do_wait_for_common(x
, timeout
, state
);
4426 spin_unlock_irq(&x
->wait
.lock
);
4430 void __sched
wait_for_completion(struct completion
*x
)
4432 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4434 EXPORT_SYMBOL(wait_for_completion
);
4436 unsigned long __sched
4437 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4439 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4441 EXPORT_SYMBOL(wait_for_completion_timeout
);
4443 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4445 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4446 if (t
== -ERESTARTSYS
)
4450 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4452 unsigned long __sched
4453 wait_for_completion_interruptible_timeout(struct completion
*x
,
4454 unsigned long timeout
)
4456 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4458 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4460 int __sched
wait_for_completion_killable(struct completion
*x
)
4462 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4463 if (t
== -ERESTARTSYS
)
4467 EXPORT_SYMBOL(wait_for_completion_killable
);
4470 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4472 unsigned long flags
;
4475 init_waitqueue_entry(&wait
, current
);
4477 __set_current_state(state
);
4479 spin_lock_irqsave(&q
->lock
, flags
);
4480 __add_wait_queue(q
, &wait
);
4481 spin_unlock(&q
->lock
);
4482 timeout
= schedule_timeout(timeout
);
4483 spin_lock_irq(&q
->lock
);
4484 __remove_wait_queue(q
, &wait
);
4485 spin_unlock_irqrestore(&q
->lock
, flags
);
4490 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4492 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4494 EXPORT_SYMBOL(interruptible_sleep_on
);
4497 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4499 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4501 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4503 void __sched
sleep_on(wait_queue_head_t
*q
)
4505 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4507 EXPORT_SYMBOL(sleep_on
);
4509 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4511 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4513 EXPORT_SYMBOL(sleep_on_timeout
);
4515 #ifdef CONFIG_RT_MUTEXES
4518 * rt_mutex_setprio - set the current priority of a task
4520 * @prio: prio value (kernel-internal form)
4522 * This function changes the 'effective' priority of a task. It does
4523 * not touch ->normal_prio like __setscheduler().
4525 * Used by the rt_mutex code to implement priority inheritance logic.
4527 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4529 unsigned long flags
;
4530 int oldprio
, on_rq
, running
;
4532 const struct sched_class
*prev_class
= p
->sched_class
;
4534 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4536 rq
= task_rq_lock(p
, &flags
);
4537 update_rq_clock(rq
);
4540 on_rq
= p
->se
.on_rq
;
4541 running
= task_current(rq
, p
);
4543 dequeue_task(rq
, p
, 0);
4545 p
->sched_class
->put_prev_task(rq
, p
);
4548 p
->sched_class
= &rt_sched_class
;
4550 p
->sched_class
= &fair_sched_class
;
4555 p
->sched_class
->set_curr_task(rq
);
4557 enqueue_task(rq
, p
, 0);
4559 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4561 task_rq_unlock(rq
, &flags
);
4566 void set_user_nice(struct task_struct
*p
, long nice
)
4568 int old_prio
, delta
, on_rq
;
4569 unsigned long flags
;
4572 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4575 * We have to be careful, if called from sys_setpriority(),
4576 * the task might be in the middle of scheduling on another CPU.
4578 rq
= task_rq_lock(p
, &flags
);
4579 update_rq_clock(rq
);
4581 * The RT priorities are set via sched_setscheduler(), but we still
4582 * allow the 'normal' nice value to be set - but as expected
4583 * it wont have any effect on scheduling until the task is
4584 * SCHED_FIFO/SCHED_RR:
4586 if (task_has_rt_policy(p
)) {
4587 p
->static_prio
= NICE_TO_PRIO(nice
);
4590 on_rq
= p
->se
.on_rq
;
4592 dequeue_task(rq
, p
, 0);
4596 p
->static_prio
= NICE_TO_PRIO(nice
);
4599 p
->prio
= effective_prio(p
);
4600 delta
= p
->prio
- old_prio
;
4603 enqueue_task(rq
, p
, 0);
4606 * If the task increased its priority or is running and
4607 * lowered its priority, then reschedule its CPU:
4609 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4610 resched_task(rq
->curr
);
4613 task_rq_unlock(rq
, &flags
);
4615 EXPORT_SYMBOL(set_user_nice
);
4618 * can_nice - check if a task can reduce its nice value
4622 int can_nice(const struct task_struct
*p
, const int nice
)
4624 /* convert nice value [19,-20] to rlimit style value [1,40] */
4625 int nice_rlim
= 20 - nice
;
4627 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4628 capable(CAP_SYS_NICE
));
4631 #ifdef __ARCH_WANT_SYS_NICE
4634 * sys_nice - change the priority of the current process.
4635 * @increment: priority increment
4637 * sys_setpriority is a more generic, but much slower function that
4638 * does similar things.
4640 asmlinkage
long sys_nice(int increment
)
4645 * Setpriority might change our priority at the same moment.
4646 * We don't have to worry. Conceptually one call occurs first
4647 * and we have a single winner.
4649 if (increment
< -40)
4654 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4660 if (increment
< 0 && !can_nice(current
, nice
))
4663 retval
= security_task_setnice(current
, nice
);
4667 set_user_nice(current
, nice
);
4674 * task_prio - return the priority value of a given task.
4675 * @p: the task in question.
4677 * This is the priority value as seen by users in /proc.
4678 * RT tasks are offset by -200. Normal tasks are centered
4679 * around 0, value goes from -16 to +15.
4681 int task_prio(const struct task_struct
*p
)
4683 return p
->prio
- MAX_RT_PRIO
;
4687 * task_nice - return the nice value of a given task.
4688 * @p: the task in question.
4690 int task_nice(const struct task_struct
*p
)
4692 return TASK_NICE(p
);
4694 EXPORT_SYMBOL(task_nice
);
4697 * idle_cpu - is a given cpu idle currently?
4698 * @cpu: the processor in question.
4700 int idle_cpu(int cpu
)
4702 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4706 * idle_task - return the idle task for a given cpu.
4707 * @cpu: the processor in question.
4709 struct task_struct
*idle_task(int cpu
)
4711 return cpu_rq(cpu
)->idle
;
4715 * find_process_by_pid - find a process with a matching PID value.
4716 * @pid: the pid in question.
4718 static struct task_struct
*find_process_by_pid(pid_t pid
)
4720 return pid
? find_task_by_vpid(pid
) : current
;
4723 /* Actually do priority change: must hold rq lock. */
4725 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4727 BUG_ON(p
->se
.on_rq
);
4730 switch (p
->policy
) {
4734 p
->sched_class
= &fair_sched_class
;
4738 p
->sched_class
= &rt_sched_class
;
4742 p
->rt_priority
= prio
;
4743 p
->normal_prio
= normal_prio(p
);
4744 /* we are holding p->pi_lock already */
4745 p
->prio
= rt_mutex_getprio(p
);
4750 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4751 * @p: the task in question.
4752 * @policy: new policy.
4753 * @param: structure containing the new RT priority.
4755 * NOTE that the task may be already dead.
4757 int sched_setscheduler(struct task_struct
*p
, int policy
,
4758 struct sched_param
*param
)
4760 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4761 unsigned long flags
;
4762 const struct sched_class
*prev_class
= p
->sched_class
;
4765 /* may grab non-irq protected spin_locks */
4766 BUG_ON(in_interrupt());
4768 /* double check policy once rq lock held */
4770 policy
= oldpolicy
= p
->policy
;
4771 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4772 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4773 policy
!= SCHED_IDLE
)
4776 * Valid priorities for SCHED_FIFO and SCHED_RR are
4777 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4778 * SCHED_BATCH and SCHED_IDLE is 0.
4780 if (param
->sched_priority
< 0 ||
4781 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4782 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4784 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4788 * Allow unprivileged RT tasks to decrease priority:
4790 if (!capable(CAP_SYS_NICE
)) {
4791 if (rt_policy(policy
)) {
4792 unsigned long rlim_rtprio
;
4794 if (!lock_task_sighand(p
, &flags
))
4796 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4797 unlock_task_sighand(p
, &flags
);
4799 /* can't set/change the rt policy */
4800 if (policy
!= p
->policy
&& !rlim_rtprio
)
4803 /* can't increase priority */
4804 if (param
->sched_priority
> p
->rt_priority
&&
4805 param
->sched_priority
> rlim_rtprio
)
4809 * Like positive nice levels, dont allow tasks to
4810 * move out of SCHED_IDLE either:
4812 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4815 /* can't change other user's priorities */
4816 if ((current
->euid
!= p
->euid
) &&
4817 (current
->euid
!= p
->uid
))
4821 #ifdef CONFIG_RT_GROUP_SCHED
4823 * Do not allow realtime tasks into groups that have no runtime
4826 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4830 retval
= security_task_setscheduler(p
, policy
, param
);
4834 * make sure no PI-waiters arrive (or leave) while we are
4835 * changing the priority of the task:
4837 spin_lock_irqsave(&p
->pi_lock
, flags
);
4839 * To be able to change p->policy safely, the apropriate
4840 * runqueue lock must be held.
4842 rq
= __task_rq_lock(p
);
4843 /* recheck policy now with rq lock held */
4844 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4845 policy
= oldpolicy
= -1;
4846 __task_rq_unlock(rq
);
4847 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4850 update_rq_clock(rq
);
4851 on_rq
= p
->se
.on_rq
;
4852 running
= task_current(rq
, p
);
4854 deactivate_task(rq
, p
, 0);
4856 p
->sched_class
->put_prev_task(rq
, p
);
4859 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4862 p
->sched_class
->set_curr_task(rq
);
4864 activate_task(rq
, p
, 0);
4866 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4868 __task_rq_unlock(rq
);
4869 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4871 rt_mutex_adjust_pi(p
);
4875 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4878 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4880 struct sched_param lparam
;
4881 struct task_struct
*p
;
4884 if (!param
|| pid
< 0)
4886 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4891 p
= find_process_by_pid(pid
);
4893 retval
= sched_setscheduler(p
, policy
, &lparam
);
4900 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4901 * @pid: the pid in question.
4902 * @policy: new policy.
4903 * @param: structure containing the new RT priority.
4906 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4908 /* negative values for policy are not valid */
4912 return do_sched_setscheduler(pid
, policy
, param
);
4916 * sys_sched_setparam - set/change the RT priority of a thread
4917 * @pid: the pid in question.
4918 * @param: structure containing the new RT priority.
4920 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4922 return do_sched_setscheduler(pid
, -1, param
);
4926 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4927 * @pid: the pid in question.
4929 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4931 struct task_struct
*p
;
4938 read_lock(&tasklist_lock
);
4939 p
= find_process_by_pid(pid
);
4941 retval
= security_task_getscheduler(p
);
4945 read_unlock(&tasklist_lock
);
4950 * sys_sched_getscheduler - get the RT priority of a thread
4951 * @pid: the pid in question.
4952 * @param: structure containing the RT priority.
4954 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4956 struct sched_param lp
;
4957 struct task_struct
*p
;
4960 if (!param
|| pid
< 0)
4963 read_lock(&tasklist_lock
);
4964 p
= find_process_by_pid(pid
);
4969 retval
= security_task_getscheduler(p
);
4973 lp
.sched_priority
= p
->rt_priority
;
4974 read_unlock(&tasklist_lock
);
4977 * This one might sleep, we cannot do it with a spinlock held ...
4979 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4984 read_unlock(&tasklist_lock
);
4988 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
4990 cpumask_t cpus_allowed
;
4991 cpumask_t new_mask
= *in_mask
;
4992 struct task_struct
*p
;
4996 read_lock(&tasklist_lock
);
4998 p
= find_process_by_pid(pid
);
5000 read_unlock(&tasklist_lock
);
5006 * It is not safe to call set_cpus_allowed with the
5007 * tasklist_lock held. We will bump the task_struct's
5008 * usage count and then drop tasklist_lock.
5011 read_unlock(&tasklist_lock
);
5014 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
5015 !capable(CAP_SYS_NICE
))
5018 retval
= security_task_setscheduler(p
, 0, NULL
);
5022 cpuset_cpus_allowed(p
, &cpus_allowed
);
5023 cpus_and(new_mask
, new_mask
, cpus_allowed
);
5025 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
5028 cpuset_cpus_allowed(p
, &cpus_allowed
);
5029 if (!cpus_subset(new_mask
, cpus_allowed
)) {
5031 * We must have raced with a concurrent cpuset
5032 * update. Just reset the cpus_allowed to the
5033 * cpuset's cpus_allowed
5035 new_mask
= cpus_allowed
;
5045 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5046 cpumask_t
*new_mask
)
5048 if (len
< sizeof(cpumask_t
)) {
5049 memset(new_mask
, 0, sizeof(cpumask_t
));
5050 } else if (len
> sizeof(cpumask_t
)) {
5051 len
= sizeof(cpumask_t
);
5053 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5057 * sys_sched_setaffinity - set the cpu affinity of a process
5058 * @pid: pid of the process
5059 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5060 * @user_mask_ptr: user-space pointer to the new cpu mask
5062 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5063 unsigned long __user
*user_mask_ptr
)
5068 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5072 return sched_setaffinity(pid
, &new_mask
);
5076 * Represents all cpu's present in the system
5077 * In systems capable of hotplug, this map could dynamically grow
5078 * as new cpu's are detected in the system via any platform specific
5079 * method, such as ACPI for e.g.
5082 cpumask_t cpu_present_map __read_mostly
;
5083 EXPORT_SYMBOL(cpu_present_map
);
5086 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5087 EXPORT_SYMBOL(cpu_online_map
);
5089 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5090 EXPORT_SYMBOL(cpu_possible_map
);
5093 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5095 struct task_struct
*p
;
5099 read_lock(&tasklist_lock
);
5102 p
= find_process_by_pid(pid
);
5106 retval
= security_task_getscheduler(p
);
5110 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5113 read_unlock(&tasklist_lock
);
5120 * sys_sched_getaffinity - get the cpu affinity of a process
5121 * @pid: pid of the process
5122 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5123 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5125 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5126 unsigned long __user
*user_mask_ptr
)
5131 if (len
< sizeof(cpumask_t
))
5134 ret
= sched_getaffinity(pid
, &mask
);
5138 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5141 return sizeof(cpumask_t
);
5145 * sys_sched_yield - yield the current processor to other threads.
5147 * This function yields the current CPU to other tasks. If there are no
5148 * other threads running on this CPU then this function will return.
5150 asmlinkage
long sys_sched_yield(void)
5152 struct rq
*rq
= this_rq_lock();
5154 schedstat_inc(rq
, yld_count
);
5155 current
->sched_class
->yield_task(rq
);
5158 * Since we are going to call schedule() anyway, there's
5159 * no need to preempt or enable interrupts:
5161 __release(rq
->lock
);
5162 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5163 _raw_spin_unlock(&rq
->lock
);
5164 preempt_enable_no_resched();
5171 static void __cond_resched(void)
5173 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5174 __might_sleep(__FILE__
, __LINE__
);
5177 * The BKS might be reacquired before we have dropped
5178 * PREEMPT_ACTIVE, which could trigger a second
5179 * cond_resched() call.
5182 add_preempt_count(PREEMPT_ACTIVE
);
5184 sub_preempt_count(PREEMPT_ACTIVE
);
5185 } while (need_resched());
5188 int __sched
_cond_resched(void)
5190 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5191 system_state
== SYSTEM_RUNNING
) {
5197 EXPORT_SYMBOL(_cond_resched
);
5200 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5201 * call schedule, and on return reacquire the lock.
5203 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5204 * operations here to prevent schedule() from being called twice (once via
5205 * spin_unlock(), once by hand).
5207 int cond_resched_lock(spinlock_t
*lock
)
5209 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5212 if (spin_needbreak(lock
) || resched
) {
5214 if (resched
&& need_resched())
5223 EXPORT_SYMBOL(cond_resched_lock
);
5225 int __sched
cond_resched_softirq(void)
5227 BUG_ON(!in_softirq());
5229 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5237 EXPORT_SYMBOL(cond_resched_softirq
);
5240 * yield - yield the current processor to other threads.
5242 * This is a shortcut for kernel-space yielding - it marks the
5243 * thread runnable and calls sys_sched_yield().
5245 void __sched
yield(void)
5247 set_current_state(TASK_RUNNING
);
5250 EXPORT_SYMBOL(yield
);
5253 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5254 * that process accounting knows that this is a task in IO wait state.
5256 * But don't do that if it is a deliberate, throttling IO wait (this task
5257 * has set its backing_dev_info: the queue against which it should throttle)
5259 void __sched
io_schedule(void)
5261 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5263 delayacct_blkio_start();
5264 atomic_inc(&rq
->nr_iowait
);
5266 atomic_dec(&rq
->nr_iowait
);
5267 delayacct_blkio_end();
5269 EXPORT_SYMBOL(io_schedule
);
5271 long __sched
io_schedule_timeout(long timeout
)
5273 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5276 delayacct_blkio_start();
5277 atomic_inc(&rq
->nr_iowait
);
5278 ret
= schedule_timeout(timeout
);
5279 atomic_dec(&rq
->nr_iowait
);
5280 delayacct_blkio_end();
5285 * sys_sched_get_priority_max - return maximum RT priority.
5286 * @policy: scheduling class.
5288 * this syscall returns the maximum rt_priority that can be used
5289 * by a given scheduling class.
5291 asmlinkage
long sys_sched_get_priority_max(int policy
)
5298 ret
= MAX_USER_RT_PRIO
-1;
5310 * sys_sched_get_priority_min - return minimum RT priority.
5311 * @policy: scheduling class.
5313 * this syscall returns the minimum rt_priority that can be used
5314 * by a given scheduling class.
5316 asmlinkage
long sys_sched_get_priority_min(int policy
)
5334 * sys_sched_rr_get_interval - return the default timeslice of a process.
5335 * @pid: pid of the process.
5336 * @interval: userspace pointer to the timeslice value.
5338 * this syscall writes the default timeslice value of a given process
5339 * into the user-space timespec buffer. A value of '0' means infinity.
5342 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5344 struct task_struct
*p
;
5345 unsigned int time_slice
;
5353 read_lock(&tasklist_lock
);
5354 p
= find_process_by_pid(pid
);
5358 retval
= security_task_getscheduler(p
);
5363 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5364 * tasks that are on an otherwise idle runqueue:
5367 if (p
->policy
== SCHED_RR
) {
5368 time_slice
= DEF_TIMESLICE
;
5369 } else if (p
->policy
!= SCHED_FIFO
) {
5370 struct sched_entity
*se
= &p
->se
;
5371 unsigned long flags
;
5374 rq
= task_rq_lock(p
, &flags
);
5375 if (rq
->cfs
.load
.weight
)
5376 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5377 task_rq_unlock(rq
, &flags
);
5379 read_unlock(&tasklist_lock
);
5380 jiffies_to_timespec(time_slice
, &t
);
5381 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5385 read_unlock(&tasklist_lock
);
5389 static const char stat_nam
[] = "RSDTtZX";
5391 void sched_show_task(struct task_struct
*p
)
5393 unsigned long free
= 0;
5396 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5397 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5398 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5399 #if BITS_PER_LONG == 32
5400 if (state
== TASK_RUNNING
)
5401 printk(KERN_CONT
" running ");
5403 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5405 if (state
== TASK_RUNNING
)
5406 printk(KERN_CONT
" running task ");
5408 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5410 #ifdef CONFIG_DEBUG_STACK_USAGE
5412 unsigned long *n
= end_of_stack(p
);
5415 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5418 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5419 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5421 show_stack(p
, NULL
);
5424 void show_state_filter(unsigned long state_filter
)
5426 struct task_struct
*g
, *p
;
5428 #if BITS_PER_LONG == 32
5430 " task PC stack pid father\n");
5433 " task PC stack pid father\n");
5435 read_lock(&tasklist_lock
);
5436 do_each_thread(g
, p
) {
5438 * reset the NMI-timeout, listing all files on a slow
5439 * console might take alot of time:
5441 touch_nmi_watchdog();
5442 if (!state_filter
|| (p
->state
& state_filter
))
5444 } while_each_thread(g
, p
);
5446 touch_all_softlockup_watchdogs();
5448 #ifdef CONFIG_SCHED_DEBUG
5449 sysrq_sched_debug_show();
5451 read_unlock(&tasklist_lock
);
5453 * Only show locks if all tasks are dumped:
5455 if (state_filter
== -1)
5456 debug_show_all_locks();
5459 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5461 idle
->sched_class
= &idle_sched_class
;
5465 * init_idle - set up an idle thread for a given CPU
5466 * @idle: task in question
5467 * @cpu: cpu the idle task belongs to
5469 * NOTE: this function does not set the idle thread's NEED_RESCHED
5470 * flag, to make booting more robust.
5472 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5474 struct rq
*rq
= cpu_rq(cpu
);
5475 unsigned long flags
;
5478 idle
->se
.exec_start
= sched_clock();
5480 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5481 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5482 __set_task_cpu(idle
, cpu
);
5484 spin_lock_irqsave(&rq
->lock
, flags
);
5485 rq
->curr
= rq
->idle
= idle
;
5486 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5489 spin_unlock_irqrestore(&rq
->lock
, flags
);
5491 /* Set the preempt count _outside_ the spinlocks! */
5492 #if defined(CONFIG_PREEMPT)
5493 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5495 task_thread_info(idle
)->preempt_count
= 0;
5498 * The idle tasks have their own, simple scheduling class:
5500 idle
->sched_class
= &idle_sched_class
;
5504 * In a system that switches off the HZ timer nohz_cpu_mask
5505 * indicates which cpus entered this state. This is used
5506 * in the rcu update to wait only for active cpus. For system
5507 * which do not switch off the HZ timer nohz_cpu_mask should
5508 * always be CPU_MASK_NONE.
5510 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5513 * Increase the granularity value when there are more CPUs,
5514 * because with more CPUs the 'effective latency' as visible
5515 * to users decreases. But the relationship is not linear,
5516 * so pick a second-best guess by going with the log2 of the
5519 * This idea comes from the SD scheduler of Con Kolivas:
5521 static inline void sched_init_granularity(void)
5523 unsigned int factor
= 1 + ilog2(num_online_cpus());
5524 const unsigned long limit
= 200000000;
5526 sysctl_sched_min_granularity
*= factor
;
5527 if (sysctl_sched_min_granularity
> limit
)
5528 sysctl_sched_min_granularity
= limit
;
5530 sysctl_sched_latency
*= factor
;
5531 if (sysctl_sched_latency
> limit
)
5532 sysctl_sched_latency
= limit
;
5534 sysctl_sched_wakeup_granularity
*= factor
;
5539 * This is how migration works:
5541 * 1) we queue a struct migration_req structure in the source CPU's
5542 * runqueue and wake up that CPU's migration thread.
5543 * 2) we down() the locked semaphore => thread blocks.
5544 * 3) migration thread wakes up (implicitly it forces the migrated
5545 * thread off the CPU)
5546 * 4) it gets the migration request and checks whether the migrated
5547 * task is still in the wrong runqueue.
5548 * 5) if it's in the wrong runqueue then the migration thread removes
5549 * it and puts it into the right queue.
5550 * 6) migration thread up()s the semaphore.
5551 * 7) we wake up and the migration is done.
5555 * Change a given task's CPU affinity. Migrate the thread to a
5556 * proper CPU and schedule it away if the CPU it's executing on
5557 * is removed from the allowed bitmask.
5559 * NOTE: the caller must have a valid reference to the task, the
5560 * task must not exit() & deallocate itself prematurely. The
5561 * call is not atomic; no spinlocks may be held.
5563 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
5565 struct migration_req req
;
5566 unsigned long flags
;
5570 rq
= task_rq_lock(p
, &flags
);
5571 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
5576 if (p
->sched_class
->set_cpus_allowed
)
5577 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5579 p
->cpus_allowed
= *new_mask
;
5580 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
5583 /* Can the task run on the task's current CPU? If so, we're done */
5584 if (cpu_isset(task_cpu(p
), *new_mask
))
5587 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
5588 /* Need help from migration thread: drop lock and wait. */
5589 task_rq_unlock(rq
, &flags
);
5590 wake_up_process(rq
->migration_thread
);
5591 wait_for_completion(&req
.done
);
5592 tlb_migrate_finish(p
->mm
);
5596 task_rq_unlock(rq
, &flags
);
5600 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5603 * Move (not current) task off this cpu, onto dest cpu. We're doing
5604 * this because either it can't run here any more (set_cpus_allowed()
5605 * away from this CPU, or CPU going down), or because we're
5606 * attempting to rebalance this task on exec (sched_exec).
5608 * So we race with normal scheduler movements, but that's OK, as long
5609 * as the task is no longer on this CPU.
5611 * Returns non-zero if task was successfully migrated.
5613 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5615 struct rq
*rq_dest
, *rq_src
;
5618 if (unlikely(cpu_is_offline(dest_cpu
)))
5621 rq_src
= cpu_rq(src_cpu
);
5622 rq_dest
= cpu_rq(dest_cpu
);
5624 double_rq_lock(rq_src
, rq_dest
);
5625 /* Already moved. */
5626 if (task_cpu(p
) != src_cpu
)
5628 /* Affinity changed (again). */
5629 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5632 on_rq
= p
->se
.on_rq
;
5634 deactivate_task(rq_src
, p
, 0);
5636 set_task_cpu(p
, dest_cpu
);
5638 activate_task(rq_dest
, p
, 0);
5639 check_preempt_curr(rq_dest
, p
);
5643 double_rq_unlock(rq_src
, rq_dest
);
5648 * migration_thread - this is a highprio system thread that performs
5649 * thread migration by bumping thread off CPU then 'pushing' onto
5652 static int migration_thread(void *data
)
5654 int cpu
= (long)data
;
5658 BUG_ON(rq
->migration_thread
!= current
);
5660 set_current_state(TASK_INTERRUPTIBLE
);
5661 while (!kthread_should_stop()) {
5662 struct migration_req
*req
;
5663 struct list_head
*head
;
5665 spin_lock_irq(&rq
->lock
);
5667 if (cpu_is_offline(cpu
)) {
5668 spin_unlock_irq(&rq
->lock
);
5672 if (rq
->active_balance
) {
5673 active_load_balance(rq
, cpu
);
5674 rq
->active_balance
= 0;
5677 head
= &rq
->migration_queue
;
5679 if (list_empty(head
)) {
5680 spin_unlock_irq(&rq
->lock
);
5682 set_current_state(TASK_INTERRUPTIBLE
);
5685 req
= list_entry(head
->next
, struct migration_req
, list
);
5686 list_del_init(head
->next
);
5688 spin_unlock(&rq
->lock
);
5689 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5692 complete(&req
->done
);
5694 __set_current_state(TASK_RUNNING
);
5698 /* Wait for kthread_stop */
5699 set_current_state(TASK_INTERRUPTIBLE
);
5700 while (!kthread_should_stop()) {
5702 set_current_state(TASK_INTERRUPTIBLE
);
5704 __set_current_state(TASK_RUNNING
);
5708 #ifdef CONFIG_HOTPLUG_CPU
5710 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5714 local_irq_disable();
5715 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5721 * Figure out where task on dead CPU should go, use force if necessary.
5722 * NOTE: interrupts should be disabled by the caller
5724 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5726 unsigned long flags
;
5733 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5734 cpus_and(mask
, mask
, p
->cpus_allowed
);
5735 dest_cpu
= any_online_cpu(mask
);
5737 /* On any allowed CPU? */
5738 if (dest_cpu
>= nr_cpu_ids
)
5739 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5741 /* No more Mr. Nice Guy. */
5742 if (dest_cpu
>= nr_cpu_ids
) {
5743 cpumask_t cpus_allowed
;
5745 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5747 * Try to stay on the same cpuset, where the
5748 * current cpuset may be a subset of all cpus.
5749 * The cpuset_cpus_allowed_locked() variant of
5750 * cpuset_cpus_allowed() will not block. It must be
5751 * called within calls to cpuset_lock/cpuset_unlock.
5753 rq
= task_rq_lock(p
, &flags
);
5754 p
->cpus_allowed
= cpus_allowed
;
5755 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5756 task_rq_unlock(rq
, &flags
);
5759 * Don't tell them about moving exiting tasks or
5760 * kernel threads (both mm NULL), since they never
5763 if (p
->mm
&& printk_ratelimit()) {
5764 printk(KERN_INFO
"process %d (%s) no "
5765 "longer affine to cpu%d\n",
5766 task_pid_nr(p
), p
->comm
, dead_cpu
);
5769 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5773 * While a dead CPU has no uninterruptible tasks queued at this point,
5774 * it might still have a nonzero ->nr_uninterruptible counter, because
5775 * for performance reasons the counter is not stricly tracking tasks to
5776 * their home CPUs. So we just add the counter to another CPU's counter,
5777 * to keep the global sum constant after CPU-down:
5779 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5781 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5782 unsigned long flags
;
5784 local_irq_save(flags
);
5785 double_rq_lock(rq_src
, rq_dest
);
5786 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5787 rq_src
->nr_uninterruptible
= 0;
5788 double_rq_unlock(rq_src
, rq_dest
);
5789 local_irq_restore(flags
);
5792 /* Run through task list and migrate tasks from the dead cpu. */
5793 static void migrate_live_tasks(int src_cpu
)
5795 struct task_struct
*p
, *t
;
5797 read_lock(&tasklist_lock
);
5799 do_each_thread(t
, p
) {
5803 if (task_cpu(p
) == src_cpu
)
5804 move_task_off_dead_cpu(src_cpu
, p
);
5805 } while_each_thread(t
, p
);
5807 read_unlock(&tasklist_lock
);
5811 * Schedules idle task to be the next runnable task on current CPU.
5812 * It does so by boosting its priority to highest possible.
5813 * Used by CPU offline code.
5815 void sched_idle_next(void)
5817 int this_cpu
= smp_processor_id();
5818 struct rq
*rq
= cpu_rq(this_cpu
);
5819 struct task_struct
*p
= rq
->idle
;
5820 unsigned long flags
;
5822 /* cpu has to be offline */
5823 BUG_ON(cpu_online(this_cpu
));
5826 * Strictly not necessary since rest of the CPUs are stopped by now
5827 * and interrupts disabled on the current cpu.
5829 spin_lock_irqsave(&rq
->lock
, flags
);
5831 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5833 update_rq_clock(rq
);
5834 activate_task(rq
, p
, 0);
5836 spin_unlock_irqrestore(&rq
->lock
, flags
);
5840 * Ensures that the idle task is using init_mm right before its cpu goes
5843 void idle_task_exit(void)
5845 struct mm_struct
*mm
= current
->active_mm
;
5847 BUG_ON(cpu_online(smp_processor_id()));
5850 switch_mm(mm
, &init_mm
, current
);
5854 /* called under rq->lock with disabled interrupts */
5855 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5857 struct rq
*rq
= cpu_rq(dead_cpu
);
5859 /* Must be exiting, otherwise would be on tasklist. */
5860 BUG_ON(!p
->exit_state
);
5862 /* Cannot have done final schedule yet: would have vanished. */
5863 BUG_ON(p
->state
== TASK_DEAD
);
5868 * Drop lock around migration; if someone else moves it,
5869 * that's OK. No task can be added to this CPU, so iteration is
5872 spin_unlock_irq(&rq
->lock
);
5873 move_task_off_dead_cpu(dead_cpu
, p
);
5874 spin_lock_irq(&rq
->lock
);
5879 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5880 static void migrate_dead_tasks(unsigned int dead_cpu
)
5882 struct rq
*rq
= cpu_rq(dead_cpu
);
5883 struct task_struct
*next
;
5886 if (!rq
->nr_running
)
5888 update_rq_clock(rq
);
5889 next
= pick_next_task(rq
, rq
->curr
);
5892 migrate_dead(dead_cpu
, next
);
5896 #endif /* CONFIG_HOTPLUG_CPU */
5898 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5900 static struct ctl_table sd_ctl_dir
[] = {
5902 .procname
= "sched_domain",
5908 static struct ctl_table sd_ctl_root
[] = {
5910 .ctl_name
= CTL_KERN
,
5911 .procname
= "kernel",
5913 .child
= sd_ctl_dir
,
5918 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5920 struct ctl_table
*entry
=
5921 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5926 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5928 struct ctl_table
*entry
;
5931 * In the intermediate directories, both the child directory and
5932 * procname are dynamically allocated and could fail but the mode
5933 * will always be set. In the lowest directory the names are
5934 * static strings and all have proc handlers.
5936 for (entry
= *tablep
; entry
->mode
; entry
++) {
5938 sd_free_ctl_entry(&entry
->child
);
5939 if (entry
->proc_handler
== NULL
)
5940 kfree(entry
->procname
);
5948 set_table_entry(struct ctl_table
*entry
,
5949 const char *procname
, void *data
, int maxlen
,
5950 mode_t mode
, proc_handler
*proc_handler
)
5952 entry
->procname
= procname
;
5954 entry
->maxlen
= maxlen
;
5956 entry
->proc_handler
= proc_handler
;
5959 static struct ctl_table
*
5960 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5962 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5967 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5968 sizeof(long), 0644, proc_doulongvec_minmax
);
5969 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5970 sizeof(long), 0644, proc_doulongvec_minmax
);
5971 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5972 sizeof(int), 0644, proc_dointvec_minmax
);
5973 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5974 sizeof(int), 0644, proc_dointvec_minmax
);
5975 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5976 sizeof(int), 0644, proc_dointvec_minmax
);
5977 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5978 sizeof(int), 0644, proc_dointvec_minmax
);
5979 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5980 sizeof(int), 0644, proc_dointvec_minmax
);
5981 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5982 sizeof(int), 0644, proc_dointvec_minmax
);
5983 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5984 sizeof(int), 0644, proc_dointvec_minmax
);
5985 set_table_entry(&table
[9], "cache_nice_tries",
5986 &sd
->cache_nice_tries
,
5987 sizeof(int), 0644, proc_dointvec_minmax
);
5988 set_table_entry(&table
[10], "flags", &sd
->flags
,
5989 sizeof(int), 0644, proc_dointvec_minmax
);
5990 /* &table[11] is terminator */
5995 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5997 struct ctl_table
*entry
, *table
;
5998 struct sched_domain
*sd
;
5999 int domain_num
= 0, i
;
6002 for_each_domain(cpu
, sd
)
6004 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6009 for_each_domain(cpu
, sd
) {
6010 snprintf(buf
, 32, "domain%d", i
);
6011 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6013 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6020 static struct ctl_table_header
*sd_sysctl_header
;
6021 static void register_sched_domain_sysctl(void)
6023 int i
, cpu_num
= num_online_cpus();
6024 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6027 WARN_ON(sd_ctl_dir
[0].child
);
6028 sd_ctl_dir
[0].child
= entry
;
6033 for_each_online_cpu(i
) {
6034 snprintf(buf
, 32, "cpu%d", i
);
6035 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6037 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6041 WARN_ON(sd_sysctl_header
);
6042 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6045 /* may be called multiple times per register */
6046 static void unregister_sched_domain_sysctl(void)
6048 if (sd_sysctl_header
)
6049 unregister_sysctl_table(sd_sysctl_header
);
6050 sd_sysctl_header
= NULL
;
6051 if (sd_ctl_dir
[0].child
)
6052 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6055 static void register_sched_domain_sysctl(void)
6058 static void unregister_sched_domain_sysctl(void)
6064 * migration_call - callback that gets triggered when a CPU is added.
6065 * Here we can start up the necessary migration thread for the new CPU.
6067 static int __cpuinit
6068 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6070 struct task_struct
*p
;
6071 int cpu
= (long)hcpu
;
6072 unsigned long flags
;
6077 case CPU_UP_PREPARE
:
6078 case CPU_UP_PREPARE_FROZEN
:
6079 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6082 kthread_bind(p
, cpu
);
6083 /* Must be high prio: stop_machine expects to yield to it. */
6084 rq
= task_rq_lock(p
, &flags
);
6085 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6086 task_rq_unlock(rq
, &flags
);
6087 cpu_rq(cpu
)->migration_thread
= p
;
6091 case CPU_ONLINE_FROZEN
:
6092 /* Strictly unnecessary, as first user will wake it. */
6093 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6095 /* Update our root-domain */
6097 spin_lock_irqsave(&rq
->lock
, flags
);
6099 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6100 cpu_set(cpu
, rq
->rd
->online
);
6102 spin_unlock_irqrestore(&rq
->lock
, flags
);
6105 #ifdef CONFIG_HOTPLUG_CPU
6106 case CPU_UP_CANCELED
:
6107 case CPU_UP_CANCELED_FROZEN
:
6108 if (!cpu_rq(cpu
)->migration_thread
)
6110 /* Unbind it from offline cpu so it can run. Fall thru. */
6111 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6112 any_online_cpu(cpu_online_map
));
6113 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6114 cpu_rq(cpu
)->migration_thread
= NULL
;
6118 case CPU_DEAD_FROZEN
:
6119 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6120 migrate_live_tasks(cpu
);
6122 kthread_stop(rq
->migration_thread
);
6123 rq
->migration_thread
= NULL
;
6124 /* Idle task back to normal (off runqueue, low prio) */
6125 spin_lock_irq(&rq
->lock
);
6126 update_rq_clock(rq
);
6127 deactivate_task(rq
, rq
->idle
, 0);
6128 rq
->idle
->static_prio
= MAX_PRIO
;
6129 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6130 rq
->idle
->sched_class
= &idle_sched_class
;
6131 migrate_dead_tasks(cpu
);
6132 spin_unlock_irq(&rq
->lock
);
6134 migrate_nr_uninterruptible(rq
);
6135 BUG_ON(rq
->nr_running
!= 0);
6138 * No need to migrate the tasks: it was best-effort if
6139 * they didn't take sched_hotcpu_mutex. Just wake up
6142 spin_lock_irq(&rq
->lock
);
6143 while (!list_empty(&rq
->migration_queue
)) {
6144 struct migration_req
*req
;
6146 req
= list_entry(rq
->migration_queue
.next
,
6147 struct migration_req
, list
);
6148 list_del_init(&req
->list
);
6149 complete(&req
->done
);
6151 spin_unlock_irq(&rq
->lock
);
6155 case CPU_DYING_FROZEN
:
6156 /* Update our root-domain */
6158 spin_lock_irqsave(&rq
->lock
, flags
);
6160 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6161 cpu_clear(cpu
, rq
->rd
->online
);
6163 spin_unlock_irqrestore(&rq
->lock
, flags
);
6170 /* Register at highest priority so that task migration (migrate_all_tasks)
6171 * happens before everything else.
6173 static struct notifier_block __cpuinitdata migration_notifier
= {
6174 .notifier_call
= migration_call
,
6178 void __init
migration_init(void)
6180 void *cpu
= (void *)(long)smp_processor_id();
6183 /* Start one for the boot CPU: */
6184 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6185 BUG_ON(err
== NOTIFY_BAD
);
6186 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6187 register_cpu_notifier(&migration_notifier
);
6193 #ifdef CONFIG_SCHED_DEBUG
6195 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6196 cpumask_t
*groupmask
)
6198 struct sched_group
*group
= sd
->groups
;
6201 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6202 cpus_clear(*groupmask
);
6204 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6206 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6207 printk("does not load-balance\n");
6209 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6214 printk(KERN_CONT
"span %s\n", str
);
6216 if (!cpu_isset(cpu
, sd
->span
)) {
6217 printk(KERN_ERR
"ERROR: domain->span does not contain "
6220 if (!cpu_isset(cpu
, group
->cpumask
)) {
6221 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6225 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6229 printk(KERN_ERR
"ERROR: group is NULL\n");
6233 if (!group
->__cpu_power
) {
6234 printk(KERN_CONT
"\n");
6235 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6240 if (!cpus_weight(group
->cpumask
)) {
6241 printk(KERN_CONT
"\n");
6242 printk(KERN_ERR
"ERROR: empty group\n");
6246 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6247 printk(KERN_CONT
"\n");
6248 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6252 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6254 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6255 printk(KERN_CONT
" %s", str
);
6257 group
= group
->next
;
6258 } while (group
!= sd
->groups
);
6259 printk(KERN_CONT
"\n");
6261 if (!cpus_equal(sd
->span
, *groupmask
))
6262 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6264 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6265 printk(KERN_ERR
"ERROR: parent span is not a superset "
6266 "of domain->span\n");
6270 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6272 cpumask_t
*groupmask
;
6276 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6280 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6282 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6284 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6289 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6299 # define sched_domain_debug(sd, cpu) do { } while (0)
6302 static int sd_degenerate(struct sched_domain
*sd
)
6304 if (cpus_weight(sd
->span
) == 1)
6307 /* Following flags need at least 2 groups */
6308 if (sd
->flags
& (SD_LOAD_BALANCE
|
6309 SD_BALANCE_NEWIDLE
|
6313 SD_SHARE_PKG_RESOURCES
)) {
6314 if (sd
->groups
!= sd
->groups
->next
)
6318 /* Following flags don't use groups */
6319 if (sd
->flags
& (SD_WAKE_IDLE
|
6328 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6330 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6332 if (sd_degenerate(parent
))
6335 if (!cpus_equal(sd
->span
, parent
->span
))
6338 /* Does parent contain flags not in child? */
6339 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6340 if (cflags
& SD_WAKE_AFFINE
)
6341 pflags
&= ~SD_WAKE_BALANCE
;
6342 /* Flags needing groups don't count if only 1 group in parent */
6343 if (parent
->groups
== parent
->groups
->next
) {
6344 pflags
&= ~(SD_LOAD_BALANCE
|
6345 SD_BALANCE_NEWIDLE
|
6349 SD_SHARE_PKG_RESOURCES
);
6351 if (~cflags
& pflags
)
6357 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6359 unsigned long flags
;
6360 const struct sched_class
*class;
6362 spin_lock_irqsave(&rq
->lock
, flags
);
6365 struct root_domain
*old_rd
= rq
->rd
;
6367 for (class = sched_class_highest
; class; class = class->next
) {
6368 if (class->leave_domain
)
6369 class->leave_domain(rq
);
6372 cpu_clear(rq
->cpu
, old_rd
->span
);
6373 cpu_clear(rq
->cpu
, old_rd
->online
);
6375 if (atomic_dec_and_test(&old_rd
->refcount
))
6379 atomic_inc(&rd
->refcount
);
6382 cpu_set(rq
->cpu
, rd
->span
);
6383 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6384 cpu_set(rq
->cpu
, rd
->online
);
6386 for (class = sched_class_highest
; class; class = class->next
) {
6387 if (class->join_domain
)
6388 class->join_domain(rq
);
6391 spin_unlock_irqrestore(&rq
->lock
, flags
);
6394 static void init_rootdomain(struct root_domain
*rd
)
6396 memset(rd
, 0, sizeof(*rd
));
6398 cpus_clear(rd
->span
);
6399 cpus_clear(rd
->online
);
6401 cpupri_init(&rd
->cpupri
);
6404 static void init_defrootdomain(void)
6406 init_rootdomain(&def_root_domain
);
6407 atomic_set(&def_root_domain
.refcount
, 1);
6410 static struct root_domain
*alloc_rootdomain(void)
6412 struct root_domain
*rd
;
6414 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6418 init_rootdomain(rd
);
6424 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6425 * hold the hotplug lock.
6428 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6430 struct rq
*rq
= cpu_rq(cpu
);
6431 struct sched_domain
*tmp
;
6433 /* Remove the sched domains which do not contribute to scheduling. */
6434 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6435 struct sched_domain
*parent
= tmp
->parent
;
6438 if (sd_parent_degenerate(tmp
, parent
)) {
6439 tmp
->parent
= parent
->parent
;
6441 parent
->parent
->child
= tmp
;
6445 if (sd
&& sd_degenerate(sd
)) {
6451 sched_domain_debug(sd
, cpu
);
6453 rq_attach_root(rq
, rd
);
6454 rcu_assign_pointer(rq
->sd
, sd
);
6457 /* cpus with isolated domains */
6458 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6460 /* Setup the mask of cpus configured for isolated domains */
6461 static int __init
isolated_cpu_setup(char *str
)
6463 int ints
[NR_CPUS
], i
;
6465 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6466 cpus_clear(cpu_isolated_map
);
6467 for (i
= 1; i
<= ints
[0]; i
++)
6468 if (ints
[i
] < NR_CPUS
)
6469 cpu_set(ints
[i
], cpu_isolated_map
);
6473 __setup("isolcpus=", isolated_cpu_setup
);
6476 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6477 * to a function which identifies what group(along with sched group) a CPU
6478 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6479 * (due to the fact that we keep track of groups covered with a cpumask_t).
6481 * init_sched_build_groups will build a circular linked list of the groups
6482 * covered by the given span, and will set each group's ->cpumask correctly,
6483 * and ->cpu_power to 0.
6486 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6487 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6488 struct sched_group
**sg
,
6489 cpumask_t
*tmpmask
),
6490 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6492 struct sched_group
*first
= NULL
, *last
= NULL
;
6495 cpus_clear(*covered
);
6497 for_each_cpu_mask(i
, *span
) {
6498 struct sched_group
*sg
;
6499 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6502 if (cpu_isset(i
, *covered
))
6505 cpus_clear(sg
->cpumask
);
6506 sg
->__cpu_power
= 0;
6508 for_each_cpu_mask(j
, *span
) {
6509 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6512 cpu_set(j
, *covered
);
6513 cpu_set(j
, sg
->cpumask
);
6524 #define SD_NODES_PER_DOMAIN 16
6529 * find_next_best_node - find the next node to include in a sched_domain
6530 * @node: node whose sched_domain we're building
6531 * @used_nodes: nodes already in the sched_domain
6533 * Find the next node to include in a given scheduling domain. Simply
6534 * finds the closest node not already in the @used_nodes map.
6536 * Should use nodemask_t.
6538 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6540 int i
, n
, val
, min_val
, best_node
= 0;
6544 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6545 /* Start at @node */
6546 n
= (node
+ i
) % MAX_NUMNODES
;
6548 if (!nr_cpus_node(n
))
6551 /* Skip already used nodes */
6552 if (node_isset(n
, *used_nodes
))
6555 /* Simple min distance search */
6556 val
= node_distance(node
, n
);
6558 if (val
< min_val
) {
6564 node_set(best_node
, *used_nodes
);
6569 * sched_domain_node_span - get a cpumask for a node's sched_domain
6570 * @node: node whose cpumask we're constructing
6571 * @span: resulting cpumask
6573 * Given a node, construct a good cpumask for its sched_domain to span. It
6574 * should be one that prevents unnecessary balancing, but also spreads tasks
6577 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6579 nodemask_t used_nodes
;
6580 node_to_cpumask_ptr(nodemask
, node
);
6584 nodes_clear(used_nodes
);
6586 cpus_or(*span
, *span
, *nodemask
);
6587 node_set(node
, used_nodes
);
6589 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6590 int next_node
= find_next_best_node(node
, &used_nodes
);
6592 node_to_cpumask_ptr_next(nodemask
, next_node
);
6593 cpus_or(*span
, *span
, *nodemask
);
6598 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6601 * SMT sched-domains:
6603 #ifdef CONFIG_SCHED_SMT
6604 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6605 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6608 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6612 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6618 * multi-core sched-domains:
6620 #ifdef CONFIG_SCHED_MC
6621 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6622 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6625 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6627 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6632 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6633 cpus_and(*mask
, *mask
, *cpu_map
);
6634 group
= first_cpu(*mask
);
6636 *sg
= &per_cpu(sched_group_core
, group
);
6639 #elif defined(CONFIG_SCHED_MC)
6641 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6645 *sg
= &per_cpu(sched_group_core
, cpu
);
6650 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6651 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6654 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6658 #ifdef CONFIG_SCHED_MC
6659 *mask
= cpu_coregroup_map(cpu
);
6660 cpus_and(*mask
, *mask
, *cpu_map
);
6661 group
= first_cpu(*mask
);
6662 #elif defined(CONFIG_SCHED_SMT)
6663 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6664 cpus_and(*mask
, *mask
, *cpu_map
);
6665 group
= first_cpu(*mask
);
6670 *sg
= &per_cpu(sched_group_phys
, group
);
6676 * The init_sched_build_groups can't handle what we want to do with node
6677 * groups, so roll our own. Now each node has its own list of groups which
6678 * gets dynamically allocated.
6680 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6681 static struct sched_group
***sched_group_nodes_bycpu
;
6683 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6684 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6686 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6687 struct sched_group
**sg
, cpumask_t
*nodemask
)
6691 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6692 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6693 group
= first_cpu(*nodemask
);
6696 *sg
= &per_cpu(sched_group_allnodes
, group
);
6700 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6702 struct sched_group
*sg
= group_head
;
6708 for_each_cpu_mask(j
, sg
->cpumask
) {
6709 struct sched_domain
*sd
;
6711 sd
= &per_cpu(phys_domains
, j
);
6712 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6714 * Only add "power" once for each
6720 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6723 } while (sg
!= group_head
);
6728 /* Free memory allocated for various sched_group structures */
6729 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6733 for_each_cpu_mask(cpu
, *cpu_map
) {
6734 struct sched_group
**sched_group_nodes
6735 = sched_group_nodes_bycpu
[cpu
];
6737 if (!sched_group_nodes
)
6740 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6741 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6743 *nodemask
= node_to_cpumask(i
);
6744 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6745 if (cpus_empty(*nodemask
))
6755 if (oldsg
!= sched_group_nodes
[i
])
6758 kfree(sched_group_nodes
);
6759 sched_group_nodes_bycpu
[cpu
] = NULL
;
6763 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6769 * Initialize sched groups cpu_power.
6771 * cpu_power indicates the capacity of sched group, which is used while
6772 * distributing the load between different sched groups in a sched domain.
6773 * Typically cpu_power for all the groups in a sched domain will be same unless
6774 * there are asymmetries in the topology. If there are asymmetries, group
6775 * having more cpu_power will pickup more load compared to the group having
6778 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6779 * the maximum number of tasks a group can handle in the presence of other idle
6780 * or lightly loaded groups in the same sched domain.
6782 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6784 struct sched_domain
*child
;
6785 struct sched_group
*group
;
6787 WARN_ON(!sd
|| !sd
->groups
);
6789 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6794 sd
->groups
->__cpu_power
= 0;
6797 * For perf policy, if the groups in child domain share resources
6798 * (for example cores sharing some portions of the cache hierarchy
6799 * or SMT), then set this domain groups cpu_power such that each group
6800 * can handle only one task, when there are other idle groups in the
6801 * same sched domain.
6803 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6805 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6806 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6811 * add cpu_power of each child group to this groups cpu_power
6813 group
= child
->groups
;
6815 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6816 group
= group
->next
;
6817 } while (group
!= child
->groups
);
6821 * Initializers for schedule domains
6822 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6825 #define SD_INIT(sd, type) sd_init_##type(sd)
6826 #define SD_INIT_FUNC(type) \
6827 static noinline void sd_init_##type(struct sched_domain *sd) \
6829 memset(sd, 0, sizeof(*sd)); \
6830 *sd = SD_##type##_INIT; \
6831 sd->level = SD_LV_##type; \
6836 SD_INIT_FUNC(ALLNODES
)
6839 #ifdef CONFIG_SCHED_SMT
6840 SD_INIT_FUNC(SIBLING
)
6842 #ifdef CONFIG_SCHED_MC
6847 * To minimize stack usage kmalloc room for cpumasks and share the
6848 * space as the usage in build_sched_domains() dictates. Used only
6849 * if the amount of space is significant.
6852 cpumask_t tmpmask
; /* make this one first */
6855 cpumask_t this_sibling_map
;
6856 cpumask_t this_core_map
;
6858 cpumask_t send_covered
;
6861 cpumask_t domainspan
;
6863 cpumask_t notcovered
;
6868 #define SCHED_CPUMASK_ALLOC 1
6869 #define SCHED_CPUMASK_FREE(v) kfree(v)
6870 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6872 #define SCHED_CPUMASK_ALLOC 0
6873 #define SCHED_CPUMASK_FREE(v)
6874 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6877 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6878 ((unsigned long)(a) + offsetof(struct allmasks, v))
6880 static int default_relax_domain_level
= -1;
6882 static int __init
setup_relax_domain_level(char *str
)
6884 default_relax_domain_level
= simple_strtoul(str
, NULL
, 0);
6887 __setup("relax_domain_level=", setup_relax_domain_level
);
6889 static void set_domain_attribute(struct sched_domain
*sd
,
6890 struct sched_domain_attr
*attr
)
6894 if (!attr
|| attr
->relax_domain_level
< 0) {
6895 if (default_relax_domain_level
< 0)
6898 request
= default_relax_domain_level
;
6900 request
= attr
->relax_domain_level
;
6901 if (request
< sd
->level
) {
6902 /* turn off idle balance on this domain */
6903 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
6905 /* turn on idle balance on this domain */
6906 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
6911 * Build sched domains for a given set of cpus and attach the sched domains
6912 * to the individual cpus
6914 static int __build_sched_domains(const cpumask_t
*cpu_map
,
6915 struct sched_domain_attr
*attr
)
6918 struct root_domain
*rd
;
6919 SCHED_CPUMASK_DECLARE(allmasks
);
6922 struct sched_group
**sched_group_nodes
= NULL
;
6923 int sd_allnodes
= 0;
6926 * Allocate the per-node list of sched groups
6928 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6930 if (!sched_group_nodes
) {
6931 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6936 rd
= alloc_rootdomain();
6938 printk(KERN_WARNING
"Cannot alloc root domain\n");
6940 kfree(sched_group_nodes
);
6945 #if SCHED_CPUMASK_ALLOC
6946 /* get space for all scratch cpumask variables */
6947 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6949 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6952 kfree(sched_group_nodes
);
6957 tmpmask
= (cpumask_t
*)allmasks
;
6961 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6965 * Set up domains for cpus specified by the cpu_map.
6967 for_each_cpu_mask(i
, *cpu_map
) {
6968 struct sched_domain
*sd
= NULL
, *p
;
6969 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6971 *nodemask
= node_to_cpumask(cpu_to_node(i
));
6972 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6975 if (cpus_weight(*cpu_map
) >
6976 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
6977 sd
= &per_cpu(allnodes_domains
, i
);
6978 SD_INIT(sd
, ALLNODES
);
6979 set_domain_attribute(sd
, attr
);
6980 sd
->span
= *cpu_map
;
6981 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6987 sd
= &per_cpu(node_domains
, i
);
6989 set_domain_attribute(sd
, attr
);
6990 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
6994 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6998 sd
= &per_cpu(phys_domains
, i
);
7000 set_domain_attribute(sd
, attr
);
7001 sd
->span
= *nodemask
;
7005 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7007 #ifdef CONFIG_SCHED_MC
7009 sd
= &per_cpu(core_domains
, i
);
7011 set_domain_attribute(sd
, attr
);
7012 sd
->span
= cpu_coregroup_map(i
);
7013 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7016 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7019 #ifdef CONFIG_SCHED_SMT
7021 sd
= &per_cpu(cpu_domains
, i
);
7022 SD_INIT(sd
, SIBLING
);
7023 set_domain_attribute(sd
, attr
);
7024 sd
->span
= per_cpu(cpu_sibling_map
, i
);
7025 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7028 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7032 #ifdef CONFIG_SCHED_SMT
7033 /* Set up CPU (sibling) groups */
7034 for_each_cpu_mask(i
, *cpu_map
) {
7035 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
7036 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7038 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
7039 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
7040 if (i
!= first_cpu(*this_sibling_map
))
7043 init_sched_build_groups(this_sibling_map
, cpu_map
,
7045 send_covered
, tmpmask
);
7049 #ifdef CONFIG_SCHED_MC
7050 /* Set up multi-core groups */
7051 for_each_cpu_mask(i
, *cpu_map
) {
7052 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
7053 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7055 *this_core_map
= cpu_coregroup_map(i
);
7056 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
7057 if (i
!= first_cpu(*this_core_map
))
7060 init_sched_build_groups(this_core_map
, cpu_map
,
7062 send_covered
, tmpmask
);
7066 /* Set up physical groups */
7067 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7068 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7069 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7071 *nodemask
= node_to_cpumask(i
);
7072 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7073 if (cpus_empty(*nodemask
))
7076 init_sched_build_groups(nodemask
, cpu_map
,
7078 send_covered
, tmpmask
);
7082 /* Set up node groups */
7084 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7086 init_sched_build_groups(cpu_map
, cpu_map
,
7087 &cpu_to_allnodes_group
,
7088 send_covered
, tmpmask
);
7091 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7092 /* Set up node groups */
7093 struct sched_group
*sg
, *prev
;
7094 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7095 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
7096 SCHED_CPUMASK_VAR(covered
, allmasks
);
7099 *nodemask
= node_to_cpumask(i
);
7100 cpus_clear(*covered
);
7102 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7103 if (cpus_empty(*nodemask
)) {
7104 sched_group_nodes
[i
] = NULL
;
7108 sched_domain_node_span(i
, domainspan
);
7109 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7111 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7113 printk(KERN_WARNING
"Can not alloc domain group for "
7117 sched_group_nodes
[i
] = sg
;
7118 for_each_cpu_mask(j
, *nodemask
) {
7119 struct sched_domain
*sd
;
7121 sd
= &per_cpu(node_domains
, j
);
7124 sg
->__cpu_power
= 0;
7125 sg
->cpumask
= *nodemask
;
7127 cpus_or(*covered
, *covered
, *nodemask
);
7130 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7131 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7132 int n
= (i
+ j
) % MAX_NUMNODES
;
7133 node_to_cpumask_ptr(pnodemask
, n
);
7135 cpus_complement(*notcovered
, *covered
);
7136 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7137 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7138 if (cpus_empty(*tmpmask
))
7141 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7142 if (cpus_empty(*tmpmask
))
7145 sg
= kmalloc_node(sizeof(struct sched_group
),
7149 "Can not alloc domain group for node %d\n", j
);
7152 sg
->__cpu_power
= 0;
7153 sg
->cpumask
= *tmpmask
;
7154 sg
->next
= prev
->next
;
7155 cpus_or(*covered
, *covered
, *tmpmask
);
7162 /* Calculate CPU power for physical packages and nodes */
7163 #ifdef CONFIG_SCHED_SMT
7164 for_each_cpu_mask(i
, *cpu_map
) {
7165 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7167 init_sched_groups_power(i
, sd
);
7170 #ifdef CONFIG_SCHED_MC
7171 for_each_cpu_mask(i
, *cpu_map
) {
7172 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7174 init_sched_groups_power(i
, sd
);
7178 for_each_cpu_mask(i
, *cpu_map
) {
7179 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7181 init_sched_groups_power(i
, sd
);
7185 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7186 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7189 struct sched_group
*sg
;
7191 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7193 init_numa_sched_groups_power(sg
);
7197 /* Attach the domains */
7198 for_each_cpu_mask(i
, *cpu_map
) {
7199 struct sched_domain
*sd
;
7200 #ifdef CONFIG_SCHED_SMT
7201 sd
= &per_cpu(cpu_domains
, i
);
7202 #elif defined(CONFIG_SCHED_MC)
7203 sd
= &per_cpu(core_domains
, i
);
7205 sd
= &per_cpu(phys_domains
, i
);
7207 cpu_attach_domain(sd
, rd
, i
);
7210 SCHED_CPUMASK_FREE((void *)allmasks
);
7215 free_sched_groups(cpu_map
, tmpmask
);
7216 SCHED_CPUMASK_FREE((void *)allmasks
);
7221 static int build_sched_domains(const cpumask_t
*cpu_map
)
7223 return __build_sched_domains(cpu_map
, NULL
);
7226 static cpumask_t
*doms_cur
; /* current sched domains */
7227 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7228 static struct sched_domain_attr
*dattr_cur
;
7229 /* attribues of custom domains in 'doms_cur' */
7232 * Special case: If a kmalloc of a doms_cur partition (array of
7233 * cpumask_t) fails, then fallback to a single sched domain,
7234 * as determined by the single cpumask_t fallback_doms.
7236 static cpumask_t fallback_doms
;
7238 void __attribute__((weak
)) arch_update_cpu_topology(void)
7243 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7244 * For now this just excludes isolated cpus, but could be used to
7245 * exclude other special cases in the future.
7247 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7251 arch_update_cpu_topology();
7253 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7255 doms_cur
= &fallback_doms
;
7256 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7258 err
= build_sched_domains(doms_cur
);
7259 register_sched_domain_sysctl();
7264 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7267 free_sched_groups(cpu_map
, tmpmask
);
7271 * Detach sched domains from a group of cpus specified in cpu_map
7272 * These cpus will now be attached to the NULL domain
7274 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7279 unregister_sched_domain_sysctl();
7281 for_each_cpu_mask(i
, *cpu_map
)
7282 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7283 synchronize_sched();
7284 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7287 /* handle null as "default" */
7288 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7289 struct sched_domain_attr
*new, int idx_new
)
7291 struct sched_domain_attr tmp
;
7298 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7299 new ? (new + idx_new
) : &tmp
,
7300 sizeof(struct sched_domain_attr
));
7304 * Partition sched domains as specified by the 'ndoms_new'
7305 * cpumasks in the array doms_new[] of cpumasks. This compares
7306 * doms_new[] to the current sched domain partitioning, doms_cur[].
7307 * It destroys each deleted domain and builds each new domain.
7309 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7310 * The masks don't intersect (don't overlap.) We should setup one
7311 * sched domain for each mask. CPUs not in any of the cpumasks will
7312 * not be load balanced. If the same cpumask appears both in the
7313 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7316 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7317 * ownership of it and will kfree it when done with it. If the caller
7318 * failed the kmalloc call, then it can pass in doms_new == NULL,
7319 * and partition_sched_domains() will fallback to the single partition
7322 * Call with hotplug lock held
7324 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
,
7325 struct sched_domain_attr
*dattr_new
)
7329 mutex_lock(&sched_domains_mutex
);
7331 /* always unregister in case we don't destroy any domains */
7332 unregister_sched_domain_sysctl();
7334 if (doms_new
== NULL
) {
7336 doms_new
= &fallback_doms
;
7337 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7341 /* Destroy deleted domains */
7342 for (i
= 0; i
< ndoms_cur
; i
++) {
7343 for (j
= 0; j
< ndoms_new
; j
++) {
7344 if (cpus_equal(doms_cur
[i
], doms_new
[j
])
7345 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7348 /* no match - a current sched domain not in new doms_new[] */
7349 detach_destroy_domains(doms_cur
+ i
);
7354 /* Build new domains */
7355 for (i
= 0; i
< ndoms_new
; i
++) {
7356 for (j
= 0; j
< ndoms_cur
; j
++) {
7357 if (cpus_equal(doms_new
[i
], doms_cur
[j
])
7358 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7361 /* no match - add a new doms_new */
7362 __build_sched_domains(doms_new
+ i
,
7363 dattr_new
? dattr_new
+ i
: NULL
);
7368 /* Remember the new sched domains */
7369 if (doms_cur
!= &fallback_doms
)
7371 kfree(dattr_cur
); /* kfree(NULL) is safe */
7372 doms_cur
= doms_new
;
7373 dattr_cur
= dattr_new
;
7374 ndoms_cur
= ndoms_new
;
7376 register_sched_domain_sysctl();
7378 mutex_unlock(&sched_domains_mutex
);
7381 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7382 int arch_reinit_sched_domains(void)
7387 mutex_lock(&sched_domains_mutex
);
7388 detach_destroy_domains(&cpu_online_map
);
7389 err
= arch_init_sched_domains(&cpu_online_map
);
7390 mutex_unlock(&sched_domains_mutex
);
7396 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7400 if (buf
[0] != '0' && buf
[0] != '1')
7404 sched_smt_power_savings
= (buf
[0] == '1');
7406 sched_mc_power_savings
= (buf
[0] == '1');
7408 ret
= arch_reinit_sched_domains();
7410 return ret
? ret
: count
;
7413 #ifdef CONFIG_SCHED_MC
7414 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7416 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7418 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7419 const char *buf
, size_t count
)
7421 return sched_power_savings_store(buf
, count
, 0);
7423 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7424 sched_mc_power_savings_store
);
7427 #ifdef CONFIG_SCHED_SMT
7428 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7430 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7432 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7433 const char *buf
, size_t count
)
7435 return sched_power_savings_store(buf
, count
, 1);
7437 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7438 sched_smt_power_savings_store
);
7441 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7445 #ifdef CONFIG_SCHED_SMT
7447 err
= sysfs_create_file(&cls
->kset
.kobj
,
7448 &attr_sched_smt_power_savings
.attr
);
7450 #ifdef CONFIG_SCHED_MC
7451 if (!err
&& mc_capable())
7452 err
= sysfs_create_file(&cls
->kset
.kobj
,
7453 &attr_sched_mc_power_savings
.attr
);
7460 * Force a reinitialization of the sched domains hierarchy. The domains
7461 * and groups cannot be updated in place without racing with the balancing
7462 * code, so we temporarily attach all running cpus to the NULL domain
7463 * which will prevent rebalancing while the sched domains are recalculated.
7465 static int update_sched_domains(struct notifier_block
*nfb
,
7466 unsigned long action
, void *hcpu
)
7469 case CPU_UP_PREPARE
:
7470 case CPU_UP_PREPARE_FROZEN
:
7471 case CPU_DOWN_PREPARE
:
7472 case CPU_DOWN_PREPARE_FROZEN
:
7473 detach_destroy_domains(&cpu_online_map
);
7476 case CPU_UP_CANCELED
:
7477 case CPU_UP_CANCELED_FROZEN
:
7478 case CPU_DOWN_FAILED
:
7479 case CPU_DOWN_FAILED_FROZEN
:
7481 case CPU_ONLINE_FROZEN
:
7483 case CPU_DEAD_FROZEN
:
7485 * Fall through and re-initialise the domains.
7492 /* The hotplug lock is already held by cpu_up/cpu_down */
7493 arch_init_sched_domains(&cpu_online_map
);
7498 void __init
sched_init_smp(void)
7500 cpumask_t non_isolated_cpus
;
7502 #if defined(CONFIG_NUMA)
7503 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7505 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7508 mutex_lock(&sched_domains_mutex
);
7509 arch_init_sched_domains(&cpu_online_map
);
7510 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7511 if (cpus_empty(non_isolated_cpus
))
7512 cpu_set(smp_processor_id(), non_isolated_cpus
);
7513 mutex_unlock(&sched_domains_mutex
);
7515 /* XXX: Theoretical race here - CPU may be hotplugged now */
7516 hotcpu_notifier(update_sched_domains
, 0);
7519 /* Move init over to a non-isolated CPU */
7520 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7522 sched_init_granularity();
7525 void __init
sched_init_smp(void)
7527 sched_init_granularity();
7529 #endif /* CONFIG_SMP */
7531 int in_sched_functions(unsigned long addr
)
7533 return in_lock_functions(addr
) ||
7534 (addr
>= (unsigned long)__sched_text_start
7535 && addr
< (unsigned long)__sched_text_end
);
7538 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7540 cfs_rq
->tasks_timeline
= RB_ROOT
;
7541 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7542 #ifdef CONFIG_FAIR_GROUP_SCHED
7545 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7548 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7550 struct rt_prio_array
*array
;
7553 array
= &rt_rq
->active
;
7554 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7555 INIT_LIST_HEAD(array
->xqueue
+ i
);
7556 INIT_LIST_HEAD(array
->squeue
+ i
);
7557 __clear_bit(i
, array
->bitmap
);
7559 /* delimiter for bitsearch: */
7560 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7562 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7563 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7566 rt_rq
->rt_nr_migratory
= 0;
7567 rt_rq
->overloaded
= 0;
7571 rt_rq
->rt_throttled
= 0;
7572 rt_rq
->rt_runtime
= 0;
7573 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7575 #ifdef CONFIG_RT_GROUP_SCHED
7576 rt_rq
->rt_nr_boosted
= 0;
7581 #ifdef CONFIG_FAIR_GROUP_SCHED
7582 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7583 struct sched_entity
*se
, int cpu
, int add
,
7584 struct sched_entity
*parent
)
7586 struct rq
*rq
= cpu_rq(cpu
);
7587 tg
->cfs_rq
[cpu
] = cfs_rq
;
7588 init_cfs_rq(cfs_rq
, rq
);
7591 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7594 /* se could be NULL for init_task_group */
7599 se
->cfs_rq
= &rq
->cfs
;
7601 se
->cfs_rq
= parent
->my_q
;
7604 se
->load
.weight
= tg
->shares
;
7605 se
->load
.inv_weight
= 0;
7606 se
->parent
= parent
;
7610 #ifdef CONFIG_RT_GROUP_SCHED
7611 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7612 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7613 struct sched_rt_entity
*parent
)
7615 struct rq
*rq
= cpu_rq(cpu
);
7617 tg
->rt_rq
[cpu
] = rt_rq
;
7618 init_rt_rq(rt_rq
, rq
);
7620 rt_rq
->rt_se
= rt_se
;
7621 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7623 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7625 tg
->rt_se
[cpu
] = rt_se
;
7630 rt_se
->rt_rq
= &rq
->rt
;
7632 rt_se
->rt_rq
= parent
->my_q
;
7634 rt_se
->rt_rq
= &rq
->rt
;
7635 rt_se
->my_q
= rt_rq
;
7636 rt_se
->parent
= parent
;
7637 INIT_LIST_HEAD(&rt_se
->run_list
);
7641 void __init
sched_init(void)
7644 unsigned long alloc_size
= 0, ptr
;
7646 #ifdef CONFIG_FAIR_GROUP_SCHED
7647 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7649 #ifdef CONFIG_RT_GROUP_SCHED
7650 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7652 #ifdef CONFIG_USER_SCHED
7656 * As sched_init() is called before page_alloc is setup,
7657 * we use alloc_bootmem().
7660 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
7662 #ifdef CONFIG_FAIR_GROUP_SCHED
7663 init_task_group
.se
= (struct sched_entity
**)ptr
;
7664 ptr
+= nr_cpu_ids
* sizeof(void **);
7666 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7667 ptr
+= nr_cpu_ids
* sizeof(void **);
7669 #ifdef CONFIG_USER_SCHED
7670 root_task_group
.se
= (struct sched_entity
**)ptr
;
7671 ptr
+= nr_cpu_ids
* sizeof(void **);
7673 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7674 ptr
+= nr_cpu_ids
* sizeof(void **);
7677 #ifdef CONFIG_RT_GROUP_SCHED
7678 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7679 ptr
+= nr_cpu_ids
* sizeof(void **);
7681 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7682 ptr
+= nr_cpu_ids
* sizeof(void **);
7684 #ifdef CONFIG_USER_SCHED
7685 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7686 ptr
+= nr_cpu_ids
* sizeof(void **);
7688 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7689 ptr
+= nr_cpu_ids
* sizeof(void **);
7695 init_defrootdomain();
7698 init_rt_bandwidth(&def_rt_bandwidth
,
7699 global_rt_period(), global_rt_runtime());
7701 #ifdef CONFIG_RT_GROUP_SCHED
7702 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7703 global_rt_period(), global_rt_runtime());
7704 #ifdef CONFIG_USER_SCHED
7705 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7706 global_rt_period(), RUNTIME_INF
);
7710 #ifdef CONFIG_GROUP_SCHED
7711 list_add(&init_task_group
.list
, &task_groups
);
7712 INIT_LIST_HEAD(&init_task_group
.children
);
7714 #ifdef CONFIG_USER_SCHED
7715 INIT_LIST_HEAD(&root_task_group
.children
);
7716 init_task_group
.parent
= &root_task_group
;
7717 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
7721 for_each_possible_cpu(i
) {
7725 spin_lock_init(&rq
->lock
);
7726 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7728 init_cfs_rq(&rq
->cfs
, rq
);
7729 init_rt_rq(&rq
->rt
, rq
);
7730 #ifdef CONFIG_FAIR_GROUP_SCHED
7731 init_task_group
.shares
= init_task_group_load
;
7732 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7733 #ifdef CONFIG_CGROUP_SCHED
7735 * How much cpu bandwidth does init_task_group get?
7737 * In case of task-groups formed thr' the cgroup filesystem, it
7738 * gets 100% of the cpu resources in the system. This overall
7739 * system cpu resource is divided among the tasks of
7740 * init_task_group and its child task-groups in a fair manner,
7741 * based on each entity's (task or task-group's) weight
7742 * (se->load.weight).
7744 * In other words, if init_task_group has 10 tasks of weight
7745 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7746 * then A0's share of the cpu resource is:
7748 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7750 * We achieve this by letting init_task_group's tasks sit
7751 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7753 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7754 #elif defined CONFIG_USER_SCHED
7755 root_task_group
.shares
= NICE_0_LOAD
;
7756 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
7758 * In case of task-groups formed thr' the user id of tasks,
7759 * init_task_group represents tasks belonging to root user.
7760 * Hence it forms a sibling of all subsequent groups formed.
7761 * In this case, init_task_group gets only a fraction of overall
7762 * system cpu resource, based on the weight assigned to root
7763 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7764 * by letting tasks of init_task_group sit in a separate cfs_rq
7765 * (init_cfs_rq) and having one entity represent this group of
7766 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7768 init_tg_cfs_entry(&init_task_group
,
7769 &per_cpu(init_cfs_rq
, i
),
7770 &per_cpu(init_sched_entity
, i
), i
, 1,
7771 root_task_group
.se
[i
]);
7774 #endif /* CONFIG_FAIR_GROUP_SCHED */
7776 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7777 #ifdef CONFIG_RT_GROUP_SCHED
7778 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7779 #ifdef CONFIG_CGROUP_SCHED
7780 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7781 #elif defined CONFIG_USER_SCHED
7782 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
7783 init_tg_rt_entry(&init_task_group
,
7784 &per_cpu(init_rt_rq
, i
),
7785 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
7786 root_task_group
.rt_se
[i
]);
7790 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7791 rq
->cpu_load
[j
] = 0;
7795 rq
->active_balance
= 0;
7796 rq
->next_balance
= jiffies
;
7799 rq
->migration_thread
= NULL
;
7800 INIT_LIST_HEAD(&rq
->migration_queue
);
7801 rq_attach_root(rq
, &def_root_domain
);
7804 atomic_set(&rq
->nr_iowait
, 0);
7807 set_load_weight(&init_task
);
7809 #ifdef CONFIG_PREEMPT_NOTIFIERS
7810 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7814 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7817 #ifdef CONFIG_RT_MUTEXES
7818 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7822 * The boot idle thread does lazy MMU switching as well:
7824 atomic_inc(&init_mm
.mm_count
);
7825 enter_lazy_tlb(&init_mm
, current
);
7828 * Make us the idle thread. Technically, schedule() should not be
7829 * called from this thread, however somewhere below it might be,
7830 * but because we are the idle thread, we just pick up running again
7831 * when this runqueue becomes "idle".
7833 init_idle(current
, smp_processor_id());
7835 * During early bootup we pretend to be a normal task:
7837 current
->sched_class
= &fair_sched_class
;
7839 scheduler_running
= 1;
7842 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7843 void __might_sleep(char *file
, int line
)
7846 static unsigned long prev_jiffy
; /* ratelimiting */
7848 if ((in_atomic() || irqs_disabled()) &&
7849 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7850 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7852 prev_jiffy
= jiffies
;
7853 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7854 " context at %s:%d\n", file
, line
);
7855 printk("in_atomic():%d, irqs_disabled():%d\n",
7856 in_atomic(), irqs_disabled());
7857 debug_show_held_locks(current
);
7858 if (irqs_disabled())
7859 print_irqtrace_events(current
);
7864 EXPORT_SYMBOL(__might_sleep
);
7867 #ifdef CONFIG_MAGIC_SYSRQ
7868 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7872 update_rq_clock(rq
);
7873 on_rq
= p
->se
.on_rq
;
7875 deactivate_task(rq
, p
, 0);
7876 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7878 activate_task(rq
, p
, 0);
7879 resched_task(rq
->curr
);
7883 void normalize_rt_tasks(void)
7885 struct task_struct
*g
, *p
;
7886 unsigned long flags
;
7889 read_lock_irqsave(&tasklist_lock
, flags
);
7890 do_each_thread(g
, p
) {
7892 * Only normalize user tasks:
7897 p
->se
.exec_start
= 0;
7898 #ifdef CONFIG_SCHEDSTATS
7899 p
->se
.wait_start
= 0;
7900 p
->se
.sleep_start
= 0;
7901 p
->se
.block_start
= 0;
7906 * Renice negative nice level userspace
7909 if (TASK_NICE(p
) < 0 && p
->mm
)
7910 set_user_nice(p
, 0);
7914 spin_lock(&p
->pi_lock
);
7915 rq
= __task_rq_lock(p
);
7917 normalize_task(rq
, p
);
7919 __task_rq_unlock(rq
);
7920 spin_unlock(&p
->pi_lock
);
7921 } while_each_thread(g
, p
);
7923 read_unlock_irqrestore(&tasklist_lock
, flags
);
7926 #endif /* CONFIG_MAGIC_SYSRQ */
7930 * These functions are only useful for the IA64 MCA handling.
7932 * They can only be called when the whole system has been
7933 * stopped - every CPU needs to be quiescent, and no scheduling
7934 * activity can take place. Using them for anything else would
7935 * be a serious bug, and as a result, they aren't even visible
7936 * under any other configuration.
7940 * curr_task - return the current task for a given cpu.
7941 * @cpu: the processor in question.
7943 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7945 struct task_struct
*curr_task(int cpu
)
7947 return cpu_curr(cpu
);
7951 * set_curr_task - set the current task for a given cpu.
7952 * @cpu: the processor in question.
7953 * @p: the task pointer to set.
7955 * Description: This function must only be used when non-maskable interrupts
7956 * are serviced on a separate stack. It allows the architecture to switch the
7957 * notion of the current task on a cpu in a non-blocking manner. This function
7958 * must be called with all CPU's synchronized, and interrupts disabled, the
7959 * and caller must save the original value of the current task (see
7960 * curr_task() above) and restore that value before reenabling interrupts and
7961 * re-starting the system.
7963 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7965 void set_curr_task(int cpu
, struct task_struct
*p
)
7972 #ifdef CONFIG_FAIR_GROUP_SCHED
7973 static void free_fair_sched_group(struct task_group
*tg
)
7977 for_each_possible_cpu(i
) {
7979 kfree(tg
->cfs_rq
[i
]);
7989 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7991 struct cfs_rq
*cfs_rq
;
7992 struct sched_entity
*se
, *parent_se
;
7996 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7999 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8003 tg
->shares
= NICE_0_LOAD
;
8005 for_each_possible_cpu(i
) {
8008 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
8009 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8013 se
= kmalloc_node(sizeof(struct sched_entity
),
8014 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8018 parent_se
= parent
? parent
->se
[i
] : NULL
;
8019 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
8028 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8030 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8031 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8034 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8036 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8039 static inline void free_fair_sched_group(struct task_group
*tg
)
8044 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8049 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8053 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8058 #ifdef CONFIG_RT_GROUP_SCHED
8059 static void free_rt_sched_group(struct task_group
*tg
)
8063 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8065 for_each_possible_cpu(i
) {
8067 kfree(tg
->rt_rq
[i
]);
8069 kfree(tg
->rt_se
[i
]);
8077 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8079 struct rt_rq
*rt_rq
;
8080 struct sched_rt_entity
*rt_se
, *parent_se
;
8084 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8087 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8091 init_rt_bandwidth(&tg
->rt_bandwidth
,
8092 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8094 for_each_possible_cpu(i
) {
8097 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
8098 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8102 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
8103 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8107 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
8108 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
8117 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8119 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8120 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8123 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8125 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8128 static inline void free_rt_sched_group(struct task_group
*tg
)
8133 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8138 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8142 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8147 #ifdef CONFIG_GROUP_SCHED
8148 static void free_sched_group(struct task_group
*tg
)
8150 free_fair_sched_group(tg
);
8151 free_rt_sched_group(tg
);
8155 /* allocate runqueue etc for a new task group */
8156 struct task_group
*sched_create_group(struct task_group
*parent
)
8158 struct task_group
*tg
;
8159 unsigned long flags
;
8162 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8164 return ERR_PTR(-ENOMEM
);
8166 if (!alloc_fair_sched_group(tg
, parent
))
8169 if (!alloc_rt_sched_group(tg
, parent
))
8172 spin_lock_irqsave(&task_group_lock
, flags
);
8173 for_each_possible_cpu(i
) {
8174 register_fair_sched_group(tg
, i
);
8175 register_rt_sched_group(tg
, i
);
8177 list_add_rcu(&tg
->list
, &task_groups
);
8179 WARN_ON(!parent
); /* root should already exist */
8181 tg
->parent
= parent
;
8182 list_add_rcu(&tg
->siblings
, &parent
->children
);
8183 INIT_LIST_HEAD(&tg
->children
);
8184 spin_unlock_irqrestore(&task_group_lock
, flags
);
8189 free_sched_group(tg
);
8190 return ERR_PTR(-ENOMEM
);
8193 /* rcu callback to free various structures associated with a task group */
8194 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8196 /* now it should be safe to free those cfs_rqs */
8197 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8200 /* Destroy runqueue etc associated with a task group */
8201 void sched_destroy_group(struct task_group
*tg
)
8203 unsigned long flags
;
8206 spin_lock_irqsave(&task_group_lock
, flags
);
8207 for_each_possible_cpu(i
) {
8208 unregister_fair_sched_group(tg
, i
);
8209 unregister_rt_sched_group(tg
, i
);
8211 list_del_rcu(&tg
->list
);
8212 list_del_rcu(&tg
->siblings
);
8213 spin_unlock_irqrestore(&task_group_lock
, flags
);
8215 /* wait for possible concurrent references to cfs_rqs complete */
8216 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8219 /* change task's runqueue when it moves between groups.
8220 * The caller of this function should have put the task in its new group
8221 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8222 * reflect its new group.
8224 void sched_move_task(struct task_struct
*tsk
)
8227 unsigned long flags
;
8230 rq
= task_rq_lock(tsk
, &flags
);
8232 update_rq_clock(rq
);
8234 running
= task_current(rq
, tsk
);
8235 on_rq
= tsk
->se
.on_rq
;
8238 dequeue_task(rq
, tsk
, 0);
8239 if (unlikely(running
))
8240 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8242 set_task_rq(tsk
, task_cpu(tsk
));
8244 #ifdef CONFIG_FAIR_GROUP_SCHED
8245 if (tsk
->sched_class
->moved_group
)
8246 tsk
->sched_class
->moved_group(tsk
);
8249 if (unlikely(running
))
8250 tsk
->sched_class
->set_curr_task(rq
);
8252 enqueue_task(rq
, tsk
, 0);
8254 task_rq_unlock(rq
, &flags
);
8258 #ifdef CONFIG_FAIR_GROUP_SCHED
8259 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8261 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8262 struct rq
*rq
= cfs_rq
->rq
;
8265 spin_lock_irq(&rq
->lock
);
8269 dequeue_entity(cfs_rq
, se
, 0);
8271 se
->load
.weight
= shares
;
8272 se
->load
.inv_weight
= 0;
8275 enqueue_entity(cfs_rq
, se
, 0);
8277 spin_unlock_irq(&rq
->lock
);
8280 static DEFINE_MUTEX(shares_mutex
);
8282 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8285 unsigned long flags
;
8288 * We can't change the weight of the root cgroup.
8293 if (shares
< MIN_SHARES
)
8294 shares
= MIN_SHARES
;
8295 else if (shares
> MAX_SHARES
)
8296 shares
= MAX_SHARES
;
8298 mutex_lock(&shares_mutex
);
8299 if (tg
->shares
== shares
)
8302 spin_lock_irqsave(&task_group_lock
, flags
);
8303 for_each_possible_cpu(i
)
8304 unregister_fair_sched_group(tg
, i
);
8305 list_del_rcu(&tg
->siblings
);
8306 spin_unlock_irqrestore(&task_group_lock
, flags
);
8308 /* wait for any ongoing reference to this group to finish */
8309 synchronize_sched();
8312 * Now we are free to modify the group's share on each cpu
8313 * w/o tripping rebalance_share or load_balance_fair.
8315 tg
->shares
= shares
;
8316 for_each_possible_cpu(i
)
8317 set_se_shares(tg
->se
[i
], shares
);
8320 * Enable load balance activity on this group, by inserting it back on
8321 * each cpu's rq->leaf_cfs_rq_list.
8323 spin_lock_irqsave(&task_group_lock
, flags
);
8324 for_each_possible_cpu(i
)
8325 register_fair_sched_group(tg
, i
);
8326 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8327 spin_unlock_irqrestore(&task_group_lock
, flags
);
8329 mutex_unlock(&shares_mutex
);
8333 unsigned long sched_group_shares(struct task_group
*tg
)
8339 #ifdef CONFIG_RT_GROUP_SCHED
8341 * Ensure that the real time constraints are schedulable.
8343 static DEFINE_MUTEX(rt_constraints_mutex
);
8345 static unsigned long to_ratio(u64 period
, u64 runtime
)
8347 if (runtime
== RUNTIME_INF
)
8350 return div64_u64(runtime
<< 16, period
);
8353 #ifdef CONFIG_CGROUP_SCHED
8354 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8356 struct task_group
*tgi
, *parent
= tg
->parent
;
8357 unsigned long total
= 0;
8360 if (global_rt_period() < period
)
8363 return to_ratio(period
, runtime
) <
8364 to_ratio(global_rt_period(), global_rt_runtime());
8367 if (ktime_to_ns(parent
->rt_bandwidth
.rt_period
) < period
)
8371 list_for_each_entry_rcu(tgi
, &parent
->children
, siblings
) {
8375 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8376 tgi
->rt_bandwidth
.rt_runtime
);
8380 return total
+ to_ratio(period
, runtime
) <
8381 to_ratio(ktime_to_ns(parent
->rt_bandwidth
.rt_period
),
8382 parent
->rt_bandwidth
.rt_runtime
);
8384 #elif defined CONFIG_USER_SCHED
8385 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8387 struct task_group
*tgi
;
8388 unsigned long total
= 0;
8389 unsigned long global_ratio
=
8390 to_ratio(global_rt_period(), global_rt_runtime());
8393 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8397 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8398 tgi
->rt_bandwidth
.rt_runtime
);
8402 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8406 /* Must be called with tasklist_lock held */
8407 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8409 struct task_struct
*g
, *p
;
8410 do_each_thread(g
, p
) {
8411 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8413 } while_each_thread(g
, p
);
8417 static int tg_set_bandwidth(struct task_group
*tg
,
8418 u64 rt_period
, u64 rt_runtime
)
8422 mutex_lock(&rt_constraints_mutex
);
8423 read_lock(&tasklist_lock
);
8424 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8428 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8433 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8434 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8435 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8437 for_each_possible_cpu(i
) {
8438 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8440 spin_lock(&rt_rq
->rt_runtime_lock
);
8441 rt_rq
->rt_runtime
= rt_runtime
;
8442 spin_unlock(&rt_rq
->rt_runtime_lock
);
8444 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8446 read_unlock(&tasklist_lock
);
8447 mutex_unlock(&rt_constraints_mutex
);
8452 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8454 u64 rt_runtime
, rt_period
;
8456 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8457 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8458 if (rt_runtime_us
< 0)
8459 rt_runtime
= RUNTIME_INF
;
8461 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8464 long sched_group_rt_runtime(struct task_group
*tg
)
8468 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8471 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8472 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8473 return rt_runtime_us
;
8476 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8478 u64 rt_runtime
, rt_period
;
8480 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8481 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8483 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8486 long sched_group_rt_period(struct task_group
*tg
)
8490 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8491 do_div(rt_period_us
, NSEC_PER_USEC
);
8492 return rt_period_us
;
8495 static int sched_rt_global_constraints(void)
8499 mutex_lock(&rt_constraints_mutex
);
8500 if (!__rt_schedulable(NULL
, 1, 0))
8502 mutex_unlock(&rt_constraints_mutex
);
8507 static int sched_rt_global_constraints(void)
8509 unsigned long flags
;
8512 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8513 for_each_possible_cpu(i
) {
8514 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8516 spin_lock(&rt_rq
->rt_runtime_lock
);
8517 rt_rq
->rt_runtime
= global_rt_runtime();
8518 spin_unlock(&rt_rq
->rt_runtime_lock
);
8520 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8526 int sched_rt_handler(struct ctl_table
*table
, int write
,
8527 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8531 int old_period
, old_runtime
;
8532 static DEFINE_MUTEX(mutex
);
8535 old_period
= sysctl_sched_rt_period
;
8536 old_runtime
= sysctl_sched_rt_runtime
;
8538 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8540 if (!ret
&& write
) {
8541 ret
= sched_rt_global_constraints();
8543 sysctl_sched_rt_period
= old_period
;
8544 sysctl_sched_rt_runtime
= old_runtime
;
8546 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8547 def_rt_bandwidth
.rt_period
=
8548 ns_to_ktime(global_rt_period());
8551 mutex_unlock(&mutex
);
8556 #ifdef CONFIG_CGROUP_SCHED
8558 /* return corresponding task_group object of a cgroup */
8559 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8561 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8562 struct task_group
, css
);
8565 static struct cgroup_subsys_state
*
8566 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8568 struct task_group
*tg
, *parent
;
8570 if (!cgrp
->parent
) {
8571 /* This is early initialization for the top cgroup */
8572 init_task_group
.css
.cgroup
= cgrp
;
8573 return &init_task_group
.css
;
8576 parent
= cgroup_tg(cgrp
->parent
);
8577 tg
= sched_create_group(parent
);
8579 return ERR_PTR(-ENOMEM
);
8581 /* Bind the cgroup to task_group object we just created */
8582 tg
->css
.cgroup
= cgrp
;
8588 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8590 struct task_group
*tg
= cgroup_tg(cgrp
);
8592 sched_destroy_group(tg
);
8596 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8597 struct task_struct
*tsk
)
8599 #ifdef CONFIG_RT_GROUP_SCHED
8600 /* Don't accept realtime tasks when there is no way for them to run */
8601 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8604 /* We don't support RT-tasks being in separate groups */
8605 if (tsk
->sched_class
!= &fair_sched_class
)
8613 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8614 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8616 sched_move_task(tsk
);
8619 #ifdef CONFIG_FAIR_GROUP_SCHED
8620 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8623 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8626 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8628 struct task_group
*tg
= cgroup_tg(cgrp
);
8630 return (u64
) tg
->shares
;
8634 #ifdef CONFIG_RT_GROUP_SCHED
8635 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8638 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8641 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8643 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8646 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8649 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8652 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8654 return sched_group_rt_period(cgroup_tg(cgrp
));
8658 static struct cftype cpu_files
[] = {
8659 #ifdef CONFIG_FAIR_GROUP_SCHED
8662 .read_u64
= cpu_shares_read_u64
,
8663 .write_u64
= cpu_shares_write_u64
,
8666 #ifdef CONFIG_RT_GROUP_SCHED
8668 .name
= "rt_runtime_us",
8669 .read_s64
= cpu_rt_runtime_read
,
8670 .write_s64
= cpu_rt_runtime_write
,
8673 .name
= "rt_period_us",
8674 .read_u64
= cpu_rt_period_read_uint
,
8675 .write_u64
= cpu_rt_period_write_uint
,
8680 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8682 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8685 struct cgroup_subsys cpu_cgroup_subsys
= {
8687 .create
= cpu_cgroup_create
,
8688 .destroy
= cpu_cgroup_destroy
,
8689 .can_attach
= cpu_cgroup_can_attach
,
8690 .attach
= cpu_cgroup_attach
,
8691 .populate
= cpu_cgroup_populate
,
8692 .subsys_id
= cpu_cgroup_subsys_id
,
8696 #endif /* CONFIG_CGROUP_SCHED */
8698 #ifdef CONFIG_CGROUP_CPUACCT
8701 * CPU accounting code for task groups.
8703 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8704 * (balbir@in.ibm.com).
8707 /* track cpu usage of a group of tasks */
8709 struct cgroup_subsys_state css
;
8710 /* cpuusage holds pointer to a u64-type object on every cpu */
8714 struct cgroup_subsys cpuacct_subsys
;
8716 /* return cpu accounting group corresponding to this container */
8717 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8719 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8720 struct cpuacct
, css
);
8723 /* return cpu accounting group to which this task belongs */
8724 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8726 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8727 struct cpuacct
, css
);
8730 /* create a new cpu accounting group */
8731 static struct cgroup_subsys_state
*cpuacct_create(
8732 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8734 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8737 return ERR_PTR(-ENOMEM
);
8739 ca
->cpuusage
= alloc_percpu(u64
);
8740 if (!ca
->cpuusage
) {
8742 return ERR_PTR(-ENOMEM
);
8748 /* destroy an existing cpu accounting group */
8750 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8752 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8754 free_percpu(ca
->cpuusage
);
8758 /* return total cpu usage (in nanoseconds) of a group */
8759 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8761 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8762 u64 totalcpuusage
= 0;
8765 for_each_possible_cpu(i
) {
8766 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8769 * Take rq->lock to make 64-bit addition safe on 32-bit
8772 spin_lock_irq(&cpu_rq(i
)->lock
);
8773 totalcpuusage
+= *cpuusage
;
8774 spin_unlock_irq(&cpu_rq(i
)->lock
);
8777 return totalcpuusage
;
8780 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8783 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8792 for_each_possible_cpu(i
) {
8793 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8795 spin_lock_irq(&cpu_rq(i
)->lock
);
8797 spin_unlock_irq(&cpu_rq(i
)->lock
);
8803 static struct cftype files
[] = {
8806 .read_u64
= cpuusage_read
,
8807 .write_u64
= cpuusage_write
,
8811 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8813 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8817 * charge this task's execution time to its accounting group.
8819 * called with rq->lock held.
8821 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8825 if (!cpuacct_subsys
.active
)
8830 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8832 *cpuusage
+= cputime
;
8836 struct cgroup_subsys cpuacct_subsys
= {
8838 .create
= cpuacct_create
,
8839 .destroy
= cpuacct_destroy
,
8840 .populate
= cpuacct_populate
,
8841 .subsys_id
= cpuacct_subsys_id
,
8843 #endif /* CONFIG_CGROUP_CPUACCT */