2 * (C) 2001, 2002, 2003, 2004 Rusty Russell
4 * This code is licenced under the GPL.
6 #include <linux/proc_fs.h>
8 #include <linux/init.h>
9 #include <linux/notifier.h>
10 #include <linux/sched.h>
11 #include <linux/unistd.h>
12 #include <linux/cpu.h>
13 #include <linux/oom.h>
14 #include <linux/rcupdate.h>
15 #include <linux/export.h>
16 #include <linux/bug.h>
17 #include <linux/kthread.h>
18 #include <linux/stop_machine.h>
19 #include <linux/mutex.h>
20 #include <linux/gfp.h>
21 #include <linux/suspend.h>
22 /*******************************************************************************
23 * 20131225 marc.huang *
24 * CPU Hotplug debug mechanism *
25 *******************************************************************************/
26 #include <linux/kallsyms.h>
27 /******************************************************************************/
28 #ifdef CONFIG_MT_LOAD_BALANCE_PROFILER
29 #include <mtlbprof/mtlbprof.h>
34 /*******************************************************************************
35 * 20131225 marc.huang *
36 * CPU Hotplug and idle integration *
37 *******************************************************************************/
38 atomic_t is_in_hotplug
= ATOMIC_INIT(0);
39 void __attribute__((weak
)) spm_mcdi_wakeup_all_cores(void) {}
40 /******************************************************************************/
43 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
44 static DEFINE_MUTEX(cpu_add_remove_lock
);
47 * The following two API's must be used when attempting
48 * to serialize the updates to cpu_online_mask, cpu_present_mask.
50 void cpu_maps_update_begin(void)
52 mutex_lock(&cpu_add_remove_lock
);
55 void cpu_maps_update_done(void)
57 mutex_unlock(&cpu_add_remove_lock
);
60 /*******************************************************************************
61 * 20131225 marc.huang *
62 * CPU Hotplug debug mechanism *
63 *******************************************************************************/
64 #if defined(MTK_CPU_HOTPLUG_DEBUG_1) || defined(MTK_CPU_HOTPLUG_DEBUG_2)
65 RAW_NOTIFIER_HEAD(cpu_chain
);
67 static RAW_NOTIFIER_HEAD(cpu_chain
);
69 /******************************************************************************/
71 /* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
72 * Should always be manipulated under cpu_add_remove_lock
74 static int cpu_hotplug_disabled
;
76 #ifdef CONFIG_HOTPLUG_CPU
79 struct task_struct
*active_writer
;
80 struct mutex lock
; /* Synchronizes accesses to refcount, */
82 * Also blocks the new readers during
83 * an ongoing cpu hotplug operation.
87 .active_writer
= NULL
,
88 .lock
= __MUTEX_INITIALIZER(cpu_hotplug
.lock
),
92 void get_online_cpus(void)
95 if (cpu_hotplug
.active_writer
== current
)
97 mutex_lock(&cpu_hotplug
.lock
);
98 cpu_hotplug
.refcount
++;
99 mutex_unlock(&cpu_hotplug
.lock
);
102 EXPORT_SYMBOL_GPL(get_online_cpus
);
104 void put_online_cpus(void)
106 if (cpu_hotplug
.active_writer
== current
)
108 mutex_lock(&cpu_hotplug
.lock
);
110 if (WARN_ON(!cpu_hotplug
.refcount
))
111 cpu_hotplug
.refcount
++; /* try to fix things up */
113 if (!--cpu_hotplug
.refcount
&& unlikely(cpu_hotplug
.active_writer
))
114 wake_up_process(cpu_hotplug
.active_writer
);
115 mutex_unlock(&cpu_hotplug
.lock
);
118 EXPORT_SYMBOL_GPL(put_online_cpus
);
121 * This ensures that the hotplug operation can begin only when the
122 * refcount goes to zero.
124 * Note that during a cpu-hotplug operation, the new readers, if any,
125 * will be blocked by the cpu_hotplug.lock
127 * Since cpu_hotplug_begin() is always called after invoking
128 * cpu_maps_update_begin(), we can be sure that only one writer is active.
130 * Note that theoretically, there is a possibility of a livelock:
131 * - Refcount goes to zero, last reader wakes up the sleeping
133 * - Last reader unlocks the cpu_hotplug.lock.
134 * - A new reader arrives at this moment, bumps up the refcount.
135 * - The writer acquires the cpu_hotplug.lock finds the refcount
136 * non zero and goes to sleep again.
138 * However, this is very difficult to achieve in practice since
139 * get_online_cpus() not an api which is called all that often.
142 static void cpu_hotplug_begin(void)
144 cpu_hotplug
.active_writer
= current
;
147 mutex_lock(&cpu_hotplug
.lock
);
148 if (likely(!cpu_hotplug
.refcount
))
150 __set_current_state(TASK_UNINTERRUPTIBLE
);
151 mutex_unlock(&cpu_hotplug
.lock
);
155 /*******************************************************************************
156 * 20131225 marc.huang *
157 * CPU Hotplug and idle integration *
158 *******************************************************************************/
159 atomic_inc(&is_in_hotplug
);
160 spm_mcdi_wakeup_all_cores();
161 /******************************************************************************/
164 static void cpu_hotplug_done(void)
166 /*******************************************************************************
167 * 20131225 marc.huang *
168 * CPU Hotplug and idle integration *
169 *******************************************************************************/
170 atomic_dec(&is_in_hotplug
);
171 /******************************************************************************/
173 cpu_hotplug
.active_writer
= NULL
;
174 mutex_unlock(&cpu_hotplug
.lock
);
178 * Wait for currently running CPU hotplug operations to complete (if any) and
179 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
180 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
181 * hotplug path before performing hotplug operations. So acquiring that lock
182 * guarantees mutual exclusion from any currently running hotplug operations.
184 void cpu_hotplug_disable(void)
186 cpu_maps_update_begin();
187 cpu_hotplug_disabled
= 1;
188 cpu_maps_update_done();
191 void cpu_hotplug_enable(void)
193 cpu_maps_update_begin();
194 cpu_hotplug_disabled
= 0;
195 cpu_maps_update_done();
198 #else /* #if CONFIG_HOTPLUG_CPU */
199 static void cpu_hotplug_begin(void) {}
200 static void cpu_hotplug_done(void) {}
201 #endif /* #else #if CONFIG_HOTPLUG_CPU */
203 /* Need to know about CPUs going up/down? */
204 int __ref
register_cpu_notifier(struct notifier_block
*nb
)
208 /*******************************************************************************
209 * 20131225 marc.huang *
210 * CPU Hotplug debug mechanism *
211 *******************************************************************************/
212 #ifdef MTK_CPU_HOTPLUG_DEBUG_0
213 static int index
= 0;
214 #ifdef CONFIG_KALLSYMS
215 char namebuf
[128] = {0};
218 symname
= kallsyms_lookup((unsigned long)nb
->notifier_call
, NULL
, NULL
, NULL
, namebuf
);
220 printk("[cpu_ntf] <%02d>%08lx (%s)\n", index
++, (unsigned long)nb
->notifier_call
, symname
);
222 printk("[cpu_ntf] <%02d>%08lx\n", index
++, (unsigned long)nb
->notifier_call
);
223 #else //#ifdef CONFIG_KALLSYMS
224 printk("[cpu_ntf] <%02d>%08lx\n", index
++, (unsigned long)nb
->notifier_call
);
225 #endif //#ifdef CONFIG_KALLSYMS
226 #endif //#ifdef MTK_CPU_HOTPLUG_DEBUG_0
227 /******************************************************************************/
229 cpu_maps_update_begin();
230 ret
= raw_notifier_chain_register(&cpu_chain
, nb
);
231 cpu_maps_update_done();
235 static int __cpu_notify(unsigned long val
, void *v
, int nr_to_call
,
240 ret
= __raw_notifier_call_chain(&cpu_chain
, val
, v
, nr_to_call
,
243 return notifier_to_errno(ret
);
246 static int cpu_notify(unsigned long val
, void *v
)
248 return __cpu_notify(val
, v
, -1, NULL
);
251 #ifdef CONFIG_HOTPLUG_CPU
253 static void cpu_notify_nofail(unsigned long val
, void *v
)
255 BUG_ON(cpu_notify(val
, v
));
257 EXPORT_SYMBOL(register_cpu_notifier
);
259 void __ref
unregister_cpu_notifier(struct notifier_block
*nb
)
261 cpu_maps_update_begin();
262 raw_notifier_chain_unregister(&cpu_chain
, nb
);
263 cpu_maps_update_done();
265 EXPORT_SYMBOL(unregister_cpu_notifier
);
268 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
271 * This function walks all processes, finds a valid mm struct for each one and
272 * then clears a corresponding bit in mm's cpumask. While this all sounds
273 * trivial, there are various non-obvious corner cases, which this function
274 * tries to solve in a safe manner.
276 * Also note that the function uses a somewhat relaxed locking scheme, so it may
277 * be called only for an already offlined CPU.
279 void clear_tasks_mm_cpumask(int cpu
)
281 struct task_struct
*p
;
284 * This function is called after the cpu is taken down and marked
285 * offline, so its not like new tasks will ever get this cpu set in
286 * their mm mask. -- Peter Zijlstra
287 * Thus, we may use rcu_read_lock() here, instead of grabbing
288 * full-fledged tasklist_lock.
290 WARN_ON(cpu_online(cpu
));
292 for_each_process(p
) {
293 struct task_struct
*t
;
296 * Main thread might exit, but other threads may still have
297 * a valid mm. Find one.
299 t
= find_lock_task_mm(p
);
302 cpumask_clear_cpu(cpu
, mm_cpumask(t
->mm
));
308 static inline void check_for_tasks(int cpu
)
310 struct task_struct
*p
;
311 cputime_t utime
, stime
;
313 write_lock_irq(&tasklist_lock
);
314 for_each_process(p
) {
315 task_cputime(p
, &utime
, &stime
);
316 if (task_cpu(p
) == cpu
&& p
->state
== TASK_RUNNING
&&
318 printk(KERN_WARNING
"Task %s (pid = %d) is on cpu %d "
319 "(state = %ld, flags = %x)\n",
320 p
->comm
, task_pid_nr(p
), cpu
,
323 write_unlock_irq(&tasklist_lock
);
326 struct take_cpu_down_param
{
331 /* Take this CPU down. */
332 static int __ref
take_cpu_down(void *_param
)
334 struct take_cpu_down_param
*param
= _param
;
337 /* Ensure this CPU doesn't handle any more interrupts. */
338 err
= __cpu_disable();
342 cpu_notify(CPU_DYING
| param
->mod
, param
->hcpu
);
343 /* Park the stopper thread */
344 kthread_park(current
);
348 /* Requires cpu_add_remove_lock to be held */
349 static int __ref
_cpu_down(unsigned int cpu
, int tasks_frozen
)
351 int err
, nr_calls
= 0;
352 void *hcpu
= (void *)(long)cpu
;
353 unsigned long mod
= tasks_frozen
? CPU_TASKS_FROZEN
: 0;
354 struct take_cpu_down_param tcd_param
= {
359 if (num_online_cpus() == 1)
362 if (!cpu_online(cpu
))
367 err
= __cpu_notify(CPU_DOWN_PREPARE
| mod
, hcpu
, -1, &nr_calls
);
370 __cpu_notify(CPU_DOWN_FAILED
| mod
, hcpu
, nr_calls
, NULL
);
371 printk("%s: attempt to take down CPU %u failed\n",
375 smpboot_park_threads(cpu
);
377 err
= __stop_machine(take_cpu_down
, &tcd_param
, cpumask_of(cpu
));
379 /* CPU didn't die: tell everyone. Can't complain. */
380 smpboot_unpark_threads(cpu
);
381 cpu_notify_nofail(CPU_DOWN_FAILED
| mod
, hcpu
);
384 BUG_ON(cpu_online(cpu
));
387 * The migration_call() CPU_DYING callback will have removed all
388 * runnable tasks from the cpu, there's only the idle task left now
389 * that the migration thread is done doing the stop_machine thing.
391 * Wait for the stop thread to go away.
393 while (!idle_cpu(cpu
))
396 #ifdef CONFIG_MT_LOAD_BALANCE_PROFILER
397 mt_lbprof_update_state(cpu
, MT_LBPROF_HOTPLUG_STATE
);
400 /* This actually kills the CPU. */
403 /* CPU is completely dead: tell everyone. Too late to complain. */
404 cpu_notify_nofail(CPU_DEAD
| mod
, hcpu
);
406 check_for_tasks(cpu
);
411 cpu_notify_nofail(CPU_POST_DEAD
| mod
, hcpu
);
415 int __ref
cpu_down(unsigned int cpu
)
419 cpu_maps_update_begin();
421 if (cpu_hotplug_disabled
) {
426 err
= _cpu_down(cpu
, 0);
429 cpu_maps_update_done();
432 EXPORT_SYMBOL(cpu_down
);
433 #endif /*CONFIG_HOTPLUG_CPU*/
435 /* Requires cpu_add_remove_lock to be held */
436 static int __cpuinit
_cpu_up(unsigned int cpu
, int tasks_frozen
)
438 int ret
, nr_calls
= 0;
439 void *hcpu
= (void *)(long)cpu
;
440 unsigned long mod
= tasks_frozen
? CPU_TASKS_FROZEN
: 0;
441 struct task_struct
*idle
;
445 if (cpu_online(cpu
) || !cpu_present(cpu
)) {
450 idle
= idle_thread_get(cpu
);
456 ret
= smpboot_create_threads(cpu
);
460 ret
= __cpu_notify(CPU_UP_PREPARE
| mod
, hcpu
, -1, &nr_calls
);
463 printk(KERN_WARNING
"%s: attempt to bring up CPU %u failed\n",
468 /* Arch-specific enabling code. */
469 ret
= __cpu_up(cpu
, idle
);
472 BUG_ON(!cpu_online(cpu
));
474 /* Wake the per cpu threads */
475 smpboot_unpark_threads(cpu
);
477 /* Now call notifier in preparation. */
478 cpu_notify(CPU_ONLINE
| mod
, hcpu
);
482 __cpu_notify(CPU_UP_CANCELED
| mod
, hcpu
, nr_calls
, NULL
);
489 int __cpuinit
cpu_up(unsigned int cpu
)
493 #ifdef CONFIG_MEMORY_HOTPLUG
498 if (!cpu_possible(cpu
)) {
499 printk(KERN_ERR
"can't online cpu %d because it is not "
500 "configured as may-hotadd at boot time\n", cpu
);
501 #if defined(CONFIG_IA64)
502 printk(KERN_ERR
"please check additional_cpus= boot "
508 #ifdef CONFIG_MEMORY_HOTPLUG
509 nid
= cpu_to_node(cpu
);
510 if (!node_online(nid
)) {
511 err
= mem_online_node(nid
);
516 pgdat
= NODE_DATA(nid
);
519 "Can't online cpu %d due to NULL pgdat\n", cpu
);
523 if (pgdat
->node_zonelists
->_zonerefs
->zone
== NULL
) {
524 mutex_lock(&zonelists_mutex
);
525 build_all_zonelists(NULL
, NULL
);
526 mutex_unlock(&zonelists_mutex
);
530 cpu_maps_update_begin();
532 if (cpu_hotplug_disabled
) {
537 err
= _cpu_up(cpu
, 0);
540 cpu_maps_update_done();
543 EXPORT_SYMBOL_GPL(cpu_up
);
545 #ifdef CONFIG_PM_SLEEP_SMP
546 static cpumask_var_t frozen_cpus
;
548 int disable_nonboot_cpus(void)
550 int cpu
, first_cpu
, error
= 0;
552 cpu_maps_update_begin();
553 first_cpu
= cpumask_first(cpu_online_mask
);
555 * We take down all of the non-boot CPUs in one shot to avoid races
556 * with the userspace trying to use the CPU hotplug at the same time
558 cpumask_clear(frozen_cpus
);
560 printk("Disabling non-boot CPUs ...\n");
561 for_each_online_cpu(cpu
) {
562 if (cpu
== first_cpu
)
564 error
= _cpu_down(cpu
, 1);
566 cpumask_set_cpu(cpu
, frozen_cpus
);
568 printk(KERN_ERR
"Error taking CPU%d down: %d\n",
575 BUG_ON(num_online_cpus() > 1);
576 /* Make sure the CPUs won't be enabled by someone else */
577 cpu_hotplug_disabled
= 1;
579 printk(KERN_ERR
"Non-boot CPUs are not disabled\n");
581 cpu_maps_update_done();
584 EXPORT_SYMBOL_GPL(disable_nonboot_cpus
);
586 void __weak
arch_enable_nonboot_cpus_begin(void)
590 void __weak
arch_enable_nonboot_cpus_end(void)
594 void __ref
enable_nonboot_cpus(void)
598 /* Allow everyone to use the CPU hotplug again */
599 cpu_maps_update_begin();
600 cpu_hotplug_disabled
= 0;
601 if (cpumask_empty(frozen_cpus
))
604 printk(KERN_INFO
"Enabling non-boot CPUs ...\n");
606 arch_enable_nonboot_cpus_begin();
608 for_each_cpu(cpu
, frozen_cpus
) {
609 error
= _cpu_up(cpu
, 1);
611 printk(KERN_INFO
"CPU%d is up\n", cpu
);
614 printk(KERN_WARNING
"Error taking CPU%d up: %d\n", cpu
, error
);
617 arch_enable_nonboot_cpus_end();
619 cpumask_clear(frozen_cpus
);
621 cpu_maps_update_done();
623 EXPORT_SYMBOL_GPL(enable_nonboot_cpus
);
625 static int __init
alloc_frozen_cpus(void)
627 if (!alloc_cpumask_var(&frozen_cpus
, GFP_KERNEL
|__GFP_ZERO
))
631 core_initcall(alloc_frozen_cpus
);
634 * When callbacks for CPU hotplug notifications are being executed, we must
635 * ensure that the state of the system with respect to the tasks being frozen
636 * or not, as reported by the notification, remains unchanged *throughout the
637 * duration* of the execution of the callbacks.
638 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
640 * This synchronization is implemented by mutually excluding regular CPU
641 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
642 * Hibernate notifications.
645 cpu_hotplug_pm_callback(struct notifier_block
*nb
,
646 unsigned long action
, void *ptr
)
650 case PM_SUSPEND_PREPARE
:
651 case PM_HIBERNATION_PREPARE
:
652 cpu_hotplug_disable();
655 case PM_POST_SUSPEND
:
656 case PM_POST_HIBERNATION
:
657 cpu_hotplug_enable();
668 static int __init
cpu_hotplug_pm_sync_init(void)
671 * cpu_hotplug_pm_callback has higher priority than x86
672 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
673 * to disable cpu hotplug to avoid cpu hotplug race.
675 pm_notifier(cpu_hotplug_pm_callback
, 0);
678 core_initcall(cpu_hotplug_pm_sync_init
);
680 #endif /* CONFIG_PM_SLEEP_SMP */
683 * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
684 * @cpu: cpu that just started
686 * This function calls the cpu_chain notifiers with CPU_STARTING.
687 * It must be called by the arch code on the new cpu, before the new cpu
688 * enables interrupts and before the "boot" cpu returns from __cpu_up().
690 void __cpuinit
notify_cpu_starting(unsigned int cpu
)
692 unsigned long val
= CPU_STARTING
;
694 #ifdef CONFIG_PM_SLEEP_SMP
695 if (frozen_cpus
!= NULL
&& cpumask_test_cpu(cpu
, frozen_cpus
))
696 val
= CPU_STARTING_FROZEN
;
697 #endif /* CONFIG_PM_SLEEP_SMP */
698 cpu_notify(val
, (void *)(long)cpu
);
701 #endif /* CONFIG_SMP */
704 * cpu_bit_bitmap[] is a special, "compressed" data structure that
705 * represents all NR_CPUS bits binary values of 1<<nr.
707 * It is used by cpumask_of() to get a constant address to a CPU
708 * mask value that has a single bit set only.
711 /* cpu_bit_bitmap[0] is empty - so we can back into it */
712 #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
713 #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
714 #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
715 #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
717 const unsigned long cpu_bit_bitmap
[BITS_PER_LONG
+1][BITS_TO_LONGS(NR_CPUS
)] = {
719 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
720 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
721 #if BITS_PER_LONG > 32
722 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
723 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
726 EXPORT_SYMBOL_GPL(cpu_bit_bitmap
);
728 const DECLARE_BITMAP(cpu_all_bits
, NR_CPUS
) = CPU_BITS_ALL
;
729 EXPORT_SYMBOL(cpu_all_bits
);
731 #ifdef CONFIG_INIT_ALL_POSSIBLE
732 static DECLARE_BITMAP(cpu_possible_bits
, CONFIG_NR_CPUS
) __read_mostly
735 static DECLARE_BITMAP(cpu_possible_bits
, CONFIG_NR_CPUS
) __read_mostly
;
737 const struct cpumask
*const cpu_possible_mask
= to_cpumask(cpu_possible_bits
);
738 EXPORT_SYMBOL(cpu_possible_mask
);
740 static DECLARE_BITMAP(cpu_online_bits
, CONFIG_NR_CPUS
) __read_mostly
;
741 const struct cpumask
*const cpu_online_mask
= to_cpumask(cpu_online_bits
);
742 EXPORT_SYMBOL(cpu_online_mask
);
744 static DECLARE_BITMAP(cpu_present_bits
, CONFIG_NR_CPUS
) __read_mostly
;
745 const struct cpumask
*const cpu_present_mask
= to_cpumask(cpu_present_bits
);
746 EXPORT_SYMBOL(cpu_present_mask
);
748 static DECLARE_BITMAP(cpu_active_bits
, CONFIG_NR_CPUS
) __read_mostly
;
749 const struct cpumask
*const cpu_active_mask
= to_cpumask(cpu_active_bits
);
750 EXPORT_SYMBOL(cpu_active_mask
);
752 void set_cpu_possible(unsigned int cpu
, bool possible
)
755 cpumask_set_cpu(cpu
, to_cpumask(cpu_possible_bits
));
757 cpumask_clear_cpu(cpu
, to_cpumask(cpu_possible_bits
));
760 void set_cpu_present(unsigned int cpu
, bool present
)
763 cpumask_set_cpu(cpu
, to_cpumask(cpu_present_bits
));
765 cpumask_clear_cpu(cpu
, to_cpumask(cpu_present_bits
));
768 void set_cpu_online(unsigned int cpu
, bool online
)
771 cpumask_set_cpu(cpu
, to_cpumask(cpu_online_bits
));
772 cpumask_set_cpu(cpu
, to_cpumask(cpu_active_bits
));
774 cpumask_clear_cpu(cpu
, to_cpumask(cpu_online_bits
));
778 void set_cpu_active(unsigned int cpu
, bool active
)
781 cpumask_set_cpu(cpu
, to_cpumask(cpu_active_bits
));
783 cpumask_clear_cpu(cpu
, to_cpumask(cpu_active_bits
));
786 void init_cpu_present(const struct cpumask
*src
)
788 cpumask_copy(to_cpumask(cpu_present_bits
), src
);
791 void init_cpu_possible(const struct cpumask
*src
)
793 cpumask_copy(to_cpumask(cpu_possible_bits
), src
);
796 void init_cpu_online(const struct cpumask
*src
)
798 cpumask_copy(to_cpumask(cpu_online_bits
), src
);
801 static ATOMIC_NOTIFIER_HEAD(idle_notifier
);
803 void idle_notifier_register(struct notifier_block
*n
)
805 atomic_notifier_chain_register(&idle_notifier
, n
);
807 EXPORT_SYMBOL_GPL(idle_notifier_register
);
809 void idle_notifier_unregister(struct notifier_block
*n
)
811 atomic_notifier_chain_unregister(&idle_notifier
, n
);
813 EXPORT_SYMBOL_GPL(idle_notifier_unregister
);
815 void idle_notifier_call_chain(unsigned long val
)
817 atomic_notifier_call_chain(&idle_notifier
, val
, NULL
);
819 EXPORT_SYMBOL_GPL(idle_notifier_call_chain
);