2 * linux/kernel/workqueue.c
4 * Generic mechanism for defining kernel helper threads for running
5 * arbitrary tasks in process context.
7 * Started by Ingo Molnar, Copyright (C) 2002
9 * Derived from the taskqueue/keventd code by:
11 * David Woodhouse <dwmw2@infradead.org>
12 * Andrew Morton <andrewm@uow.edu.au>
13 * Kai Petzke <wpp@marie.physik.tu-berlin.de>
14 * Theodore Ts'o <tytso@mit.edu>
16 * Made to use alloc_percpu by Christoph Lameter.
19 #include <linux/module.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/init.h>
23 #include <linux/signal.h>
24 #include <linux/completion.h>
25 #include <linux/workqueue.h>
26 #include <linux/slab.h>
27 #include <linux/cpu.h>
28 #include <linux/notifier.h>
29 #include <linux/kthread.h>
30 #include <linux/hardirq.h>
31 #include <linux/mempolicy.h>
32 #include <linux/freezer.h>
33 #include <linux/kallsyms.h>
34 #include <linux/debug_locks.h>
35 #include <linux/lockdep.h>
38 * The per-CPU workqueue (if single thread, we always use the first
41 struct cpu_workqueue_struct {
45 struct list_head worklist;
46 wait_queue_head_t more_work;
47 struct work_struct *current_work;
49 struct workqueue_struct *wq;
50 struct task_struct *thread;
52 int run_depth; /* Detect run_workqueue() recursion depth */
53 } ____cacheline_aligned;
56 * The externally visible workqueue abstraction is an array of
59 struct workqueue_struct {
60 struct cpu_workqueue_struct *cpu_wq;
61 struct list_head list;
64 int freezeable; /* Freeze threads during suspend */
66 struct lockdep_map lockdep_map;
70 /* Serializes the accesses to the list of workqueues. */
71 static DEFINE_SPINLOCK(workqueue_lock);
72 static LIST_HEAD(workqueues);
74 static int singlethread_cpu __read_mostly;
75 static cpumask_t cpu_singlethread_map __read_mostly;
77 * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
78 * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
79 * which comes in between can't use for_each_online_cpu(). We could
80 * use cpu_possible_map, the cpumask below is more a documentation
83 static cpumask_t cpu_populated_map __read_mostly;
85 /* If it's single threaded, it isn't in the list of workqueues. */
86 static inline int is_single_threaded(struct workqueue_struct *wq)
88 return wq->singlethread;
91 static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
93 return is_single_threaded(wq)
94 ? &cpu_singlethread_map : &cpu_populated_map;
98 struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
100 if (unlikely(is_single_threaded(wq)))
101 cpu = singlethread_cpu;
102 return per_cpu_ptr(wq->cpu_wq, cpu);
106 * Set the workqueue on which a work item is to be run
107 * - Must *only* be called if the pending flag is set
109 static inline void set_wq_data(struct work_struct *work,
110 struct cpu_workqueue_struct *cwq)
114 BUG_ON(!work_pending(work));
116 new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
117 new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
118 atomic_long_set(&work->data, new);
122 struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
124 return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
127 static void insert_work(struct cpu_workqueue_struct *cwq,
128 struct work_struct *work, struct list_head *head)
130 set_wq_data(work, cwq);
132 * Ensure that we get the right work->data if we see the
133 * result of list_add() below, see try_to_grab_pending().
136 list_add_tail(&work->entry, head);
137 wake_up(&cwq->more_work);
140 static void __queue_work(struct cpu_workqueue_struct *cwq,
141 struct work_struct *work)
145 spin_lock_irqsave(&cwq->lock, flags);
146 insert_work(cwq, work, &cwq->worklist);
147 spin_unlock_irqrestore(&cwq->lock, flags);
151 * queue_work - queue work on a workqueue
152 * @wq: workqueue to use
153 * @work: work to queue
155 * Returns 0 if @work was already on a queue, non-zero otherwise.
157 * We queue the work to the CPU on which it was submitted, but if the CPU dies
158 * it can be processed by another CPU.
160 int queue_work(struct workqueue_struct *wq, struct work_struct *work)
164 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
165 BUG_ON(!list_empty(&work->entry));
166 __queue_work(wq_per_cpu(wq, get_cpu()), work);
172 EXPORT_SYMBOL_GPL(queue_work);
175 * queue_work_on - queue work on specific cpu
176 * @cpu: CPU number to execute work on
177 * @wq: workqueue to use
178 * @work: work to queue
180 * Returns 0 if @work was already on a queue, non-zero otherwise.
182 * We queue the work to a specific CPU, the caller must ensure it
186 queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
190 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
191 BUG_ON(!list_empty(&work->entry));
192 __queue_work(wq_per_cpu(wq, cpu), work);
197 EXPORT_SYMBOL_GPL(queue_work_on);
199 static void delayed_work_timer_fn(unsigned long __data)
201 struct delayed_work *dwork = (struct delayed_work *)__data;
202 struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
203 struct workqueue_struct *wq = cwq->wq;
205 __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work);
209 * queue_delayed_work - queue work on a workqueue after delay
210 * @wq: workqueue to use
211 * @dwork: delayable work to queue
212 * @delay: number of jiffies to wait before queueing
214 * Returns 0 if @work was already on a queue, non-zero otherwise.
216 int queue_delayed_work(struct workqueue_struct *wq,
217 struct delayed_work *dwork, unsigned long delay)
220 return queue_work(wq, &dwork->work);
222 return queue_delayed_work_on(-1, wq, dwork, delay);
224 EXPORT_SYMBOL_GPL(queue_delayed_work);
227 * queue_delayed_work_on - queue work on specific CPU after delay
228 * @cpu: CPU number to execute work on
229 * @wq: workqueue to use
230 * @dwork: work to queue
231 * @delay: number of jiffies to wait before queueing
233 * Returns 0 if @work was already on a queue, non-zero otherwise.
235 int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
236 struct delayed_work *dwork, unsigned long delay)
239 struct timer_list *timer = &dwork->timer;
240 struct work_struct *work = &dwork->work;
242 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
243 BUG_ON(timer_pending(timer));
244 BUG_ON(!list_empty(&work->entry));
246 timer_stats_timer_set_start_info(&dwork->timer);
248 /* This stores cwq for the moment, for the timer_fn */
249 set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
250 timer->expires = jiffies + delay;
251 timer->data = (unsigned long)dwork;
252 timer->function = delayed_work_timer_fn;
254 if (unlikely(cpu >= 0))
255 add_timer_on(timer, cpu);
262 EXPORT_SYMBOL_GPL(queue_delayed_work_on);
264 static void run_workqueue(struct cpu_workqueue_struct *cwq)
266 spin_lock_irq(&cwq->lock);
268 if (cwq->run_depth > 3) {
269 /* morton gets to eat his hat */
270 printk("%s: recursion depth exceeded: %d\n",
271 __func__, cwq->run_depth);
274 while (!list_empty(&cwq->worklist)) {
275 struct work_struct *work = list_entry(cwq->worklist.next,
276 struct work_struct, entry);
277 work_func_t f = work->func;
278 #ifdef CONFIG_LOCKDEP
280 * It is permissible to free the struct work_struct
281 * from inside the function that is called from it,
282 * this we need to take into account for lockdep too.
283 * To avoid bogus "held lock freed" warnings as well
284 * as problems when looking into work->lockdep_map,
285 * make a copy and use that here.
287 struct lockdep_map lockdep_map = work->lockdep_map;
290 cwq->current_work = work;
291 list_del_init(cwq->worklist.next);
292 spin_unlock_irq(&cwq->lock);
294 BUG_ON(get_wq_data(work) != cwq);
295 work_clear_pending(work);
296 lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
297 lock_acquire(&lockdep_map, 0, 0, 0, 2, _THIS_IP_);
299 lock_release(&lockdep_map, 1, _THIS_IP_);
300 lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
302 if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
303 printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
305 current->comm, preempt_count(),
306 task_pid_nr(current));
307 printk(KERN_ERR " last function: ");
308 print_symbol("%s\n", (unsigned long)f);
309 debug_show_held_locks(current);
313 spin_lock_irq(&cwq->lock);
314 cwq->current_work = NULL;
317 spin_unlock_irq(&cwq->lock);
320 static int worker_thread(void *__cwq)
322 struct cpu_workqueue_struct *cwq = __cwq;
325 if (cwq->wq->freezeable)
328 set_user_nice(current, -5);
331 prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
332 if (!freezing(current) &&
333 !kthread_should_stop() &&
334 list_empty(&cwq->worklist))
336 finish_wait(&cwq->more_work, &wait);
340 if (kthread_should_stop())
350 struct work_struct work;
351 struct completion done;
354 static void wq_barrier_func(struct work_struct *work)
356 struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
357 complete(&barr->done);
360 static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
361 struct wq_barrier *barr, struct list_head *head)
363 INIT_WORK(&barr->work, wq_barrier_func);
364 __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work));
366 init_completion(&barr->done);
368 insert_work(cwq, &barr->work, head);
371 static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
375 if (cwq->thread == current) {
377 * Probably keventd trying to flush its own queue. So simply run
378 * it by hand rather than deadlocking.
383 struct wq_barrier barr;
386 spin_lock_irq(&cwq->lock);
387 if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
388 insert_wq_barrier(cwq, &barr, &cwq->worklist);
391 spin_unlock_irq(&cwq->lock);
394 wait_for_completion(&barr.done);
401 * flush_workqueue - ensure that any scheduled work has run to completion.
402 * @wq: workqueue to flush
404 * Forces execution of the workqueue and blocks until its completion.
405 * This is typically used in driver shutdown handlers.
407 * We sleep until all works which were queued on entry have been handled,
408 * but we are not livelocked by new incoming ones.
410 * This function used to run the workqueues itself. Now we just wait for the
411 * helper threads to do it.
413 void flush_workqueue(struct workqueue_struct *wq)
415 const cpumask_t *cpu_map = wq_cpu_map(wq);
419 lock_acquire(&wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
420 lock_release(&wq->lockdep_map, 1, _THIS_IP_);
421 for_each_cpu_mask_nr(cpu, *cpu_map)
422 flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
424 EXPORT_SYMBOL_GPL(flush_workqueue);
427 * flush_work - block until a work_struct's callback has terminated
428 * @work: the work which is to be flushed
430 * It is expected that, prior to calling flush_work(), the caller has
431 * arranged for the work to not be requeued, otherwise it doesn't make
432 * sense to use this function.
434 int flush_work(struct work_struct *work)
436 struct cpu_workqueue_struct *cwq;
437 struct list_head *prev;
438 struct wq_barrier barr;
441 cwq = get_wq_data(work);
446 spin_lock_irq(&cwq->lock);
447 if (!list_empty(&work->entry)) {
449 * See the comment near try_to_grab_pending()->smp_rmb().
450 * If it was re-queued under us we are not going to wait.
453 if (unlikely(cwq != get_wq_data(work)))
457 if (cwq->current_work != work)
459 prev = &cwq->worklist;
461 insert_wq_barrier(cwq, &barr, prev->next);
463 spin_unlock_irq(&cwq->lock);
467 wait_for_completion(&barr.done);
470 EXPORT_SYMBOL_GPL(flush_work);
473 * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
474 * so this work can't be re-armed in any way.
476 static int try_to_grab_pending(struct work_struct *work)
478 struct cpu_workqueue_struct *cwq;
481 if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work)))
485 * The queueing is in progress, or it is already queued. Try to
486 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
489 cwq = get_wq_data(work);
493 spin_lock_irq(&cwq->lock);
494 if (!list_empty(&work->entry)) {
496 * This work is queued, but perhaps we locked the wrong cwq.
497 * In that case we must see the new value after rmb(), see
498 * insert_work()->wmb().
501 if (cwq == get_wq_data(work)) {
502 list_del_init(&work->entry);
506 spin_unlock_irq(&cwq->lock);
511 static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
512 struct work_struct *work)
514 struct wq_barrier barr;
517 spin_lock_irq(&cwq->lock);
518 if (unlikely(cwq->current_work == work)) {
519 insert_wq_barrier(cwq, &barr, cwq->worklist.next);
522 spin_unlock_irq(&cwq->lock);
524 if (unlikely(running))
525 wait_for_completion(&barr.done);
528 static void wait_on_work(struct work_struct *work)
530 struct cpu_workqueue_struct *cwq;
531 struct workqueue_struct *wq;
532 const cpumask_t *cpu_map;
537 lock_acquire(&work->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
538 lock_release(&work->lockdep_map, 1, _THIS_IP_);
540 cwq = get_wq_data(work);
545 cpu_map = wq_cpu_map(wq);
547 for_each_cpu_mask_nr(cpu, *cpu_map)
548 wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
551 static int __cancel_work_timer(struct work_struct *work,
552 struct timer_list* timer)
557 ret = (timer && likely(del_timer(timer)));
559 ret = try_to_grab_pending(work);
561 } while (unlikely(ret < 0));
563 work_clear_pending(work);
568 * cancel_work_sync - block until a work_struct's callback has terminated
569 * @work: the work which is to be flushed
571 * Returns true if @work was pending.
573 * cancel_work_sync() will cancel the work if it is queued. If the work's
574 * callback appears to be running, cancel_work_sync() will block until it
577 * It is possible to use this function if the work re-queues itself. It can
578 * cancel the work even if it migrates to another workqueue, however in that
579 * case it only guarantees that work->func() has completed on the last queued
582 * cancel_work_sync(&delayed_work->work) should be used only if ->timer is not
583 * pending, otherwise it goes into a busy-wait loop until the timer expires.
585 * The caller must ensure that workqueue_struct on which this work was last
586 * queued can't be destroyed before this function returns.
588 int cancel_work_sync(struct work_struct *work)
590 return __cancel_work_timer(work, NULL);
592 EXPORT_SYMBOL_GPL(cancel_work_sync);
595 * cancel_delayed_work_sync - reliably kill off a delayed work.
596 * @dwork: the delayed work struct
598 * Returns true if @dwork was pending.
600 * It is possible to use this function if @dwork rearms itself via queue_work()
601 * or queue_delayed_work(). See also the comment for cancel_work_sync().
603 int cancel_delayed_work_sync(struct delayed_work *dwork)
605 return __cancel_work_timer(&dwork->work, &dwork->timer);
607 EXPORT_SYMBOL(cancel_delayed_work_sync);
609 static struct workqueue_struct *keventd_wq __read_mostly;
612 * schedule_work - put work task in global workqueue
613 * @work: job to be done
615 * This puts a job in the kernel-global workqueue.
617 int schedule_work(struct work_struct *work)
619 return queue_work(keventd_wq, work);
621 EXPORT_SYMBOL(schedule_work);
624 * schedule_work_on - put work task on a specific cpu
625 * @cpu: cpu to put the work task on
626 * @work: job to be done
628 * This puts a job on a specific cpu
630 int schedule_work_on(int cpu, struct work_struct *work)
632 return queue_work_on(cpu, keventd_wq, work);
634 EXPORT_SYMBOL(schedule_work_on);
637 * schedule_delayed_work - put work task in global workqueue after delay
638 * @dwork: job to be done
639 * @delay: number of jiffies to wait or 0 for immediate execution
641 * After waiting for a given time this puts a job in the kernel-global
644 int schedule_delayed_work(struct delayed_work *dwork,
647 return queue_delayed_work(keventd_wq, dwork, delay);
649 EXPORT_SYMBOL(schedule_delayed_work);
652 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
654 * @dwork: job to be done
655 * @delay: number of jiffies to wait
657 * After waiting for a given time this puts a job in the kernel-global
658 * workqueue on the specified CPU.
660 int schedule_delayed_work_on(int cpu,
661 struct delayed_work *dwork, unsigned long delay)
663 return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
665 EXPORT_SYMBOL(schedule_delayed_work_on);
668 * schedule_on_each_cpu - call a function on each online CPU from keventd
669 * @func: the function to call
671 * Returns zero on success.
672 * Returns -ve errno on failure.
674 * schedule_on_each_cpu() is very slow.
676 int schedule_on_each_cpu(work_func_t func)
679 struct work_struct *works;
681 works = alloc_percpu(struct work_struct);
686 for_each_online_cpu(cpu) {
687 struct work_struct *work = per_cpu_ptr(works, cpu);
689 INIT_WORK(work, func);
690 set_bit(WORK_STRUCT_PENDING, work_data_bits(work));
691 __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work);
693 for_each_online_cpu(cpu)
694 flush_work(per_cpu_ptr(works, cpu));
700 void flush_scheduled_work(void)
702 flush_workqueue(keventd_wq);
704 EXPORT_SYMBOL(flush_scheduled_work);
707 * execute_in_process_context - reliably execute the routine with user context
708 * @fn: the function to execute
709 * @ew: guaranteed storage for the execute work structure (must
710 * be available when the work executes)
712 * Executes the function immediately if process context is available,
713 * otherwise schedules the function for delayed execution.
715 * Returns: 0 - function was executed
716 * 1 - function was scheduled for execution
718 int execute_in_process_context(work_func_t fn, struct execute_work *ew)
720 if (!in_interrupt()) {
725 INIT_WORK(&ew->work, fn);
726 schedule_work(&ew->work);
730 EXPORT_SYMBOL_GPL(execute_in_process_context);
734 return keventd_wq != NULL;
737 int current_is_keventd(void)
739 struct cpu_workqueue_struct *cwq;
740 int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */
745 cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
746 if (current == cwq->thread)
753 static struct cpu_workqueue_struct *
754 init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
756 struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
759 spin_lock_init(&cwq->lock);
760 INIT_LIST_HEAD(&cwq->worklist);
761 init_waitqueue_head(&cwq->more_work);
766 static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
768 struct workqueue_struct *wq = cwq->wq;
769 const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
770 struct task_struct *p;
772 p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
774 * Nobody can add the work_struct to this cwq,
775 * if (caller is __create_workqueue)
776 * nobody should see this wq
777 * else // caller is CPU_UP_PREPARE
778 * cpu is not on cpu_online_map
779 * so we can abort safely.
789 static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
791 struct task_struct *p = cwq->thread;
795 kthread_bind(p, cpu);
800 struct workqueue_struct *__create_workqueue_key(const char *name,
803 struct lock_class_key *key,
804 const char *lock_name)
806 struct workqueue_struct *wq;
807 struct cpu_workqueue_struct *cwq;
810 wq = kzalloc(sizeof(*wq), GFP_KERNEL);
814 wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
821 lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
822 wq->singlethread = singlethread;
823 wq->freezeable = freezeable;
824 INIT_LIST_HEAD(&wq->list);
827 cwq = init_cpu_workqueue(wq, singlethread_cpu);
828 err = create_workqueue_thread(cwq, singlethread_cpu);
829 start_workqueue_thread(cwq, -1);
831 cpu_maps_update_begin();
832 spin_lock(&workqueue_lock);
833 list_add(&wq->list, &workqueues);
834 spin_unlock(&workqueue_lock);
836 for_each_possible_cpu(cpu) {
837 cwq = init_cpu_workqueue(wq, cpu);
838 if (err || !cpu_online(cpu))
840 err = create_workqueue_thread(cwq, cpu);
841 start_workqueue_thread(cwq, cpu);
843 cpu_maps_update_done();
847 destroy_workqueue(wq);
852 EXPORT_SYMBOL_GPL(__create_workqueue_key);
854 static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
857 * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
858 * cpu_add_remove_lock protects cwq->thread.
860 if (cwq->thread == NULL)
863 lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
864 lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
866 flush_cpu_workqueue(cwq);
868 * If the caller is CPU_POST_DEAD and cwq->worklist was not empty,
869 * a concurrent flush_workqueue() can insert a barrier after us.
870 * However, in that case run_workqueue() won't return and check
871 * kthread_should_stop() until it flushes all work_struct's.
872 * When ->worklist becomes empty it is safe to exit because no
873 * more work_structs can be queued on this cwq: flush_workqueue
874 * checks list_empty(), and a "normal" queue_work() can't use
877 kthread_stop(cwq->thread);
882 * destroy_workqueue - safely terminate a workqueue
883 * @wq: target workqueue
885 * Safely destroy a workqueue. All work currently pending will be done first.
887 void destroy_workqueue(struct workqueue_struct *wq)
889 const cpumask_t *cpu_map = wq_cpu_map(wq);
892 cpu_maps_update_begin();
893 spin_lock(&workqueue_lock);
895 spin_unlock(&workqueue_lock);
897 for_each_cpu_mask_nr(cpu, *cpu_map)
898 cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
899 cpu_maps_update_done();
901 free_percpu(wq->cpu_wq);
904 EXPORT_SYMBOL_GPL(destroy_workqueue);
906 static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
907 unsigned long action,
910 unsigned int cpu = (unsigned long)hcpu;
911 struct cpu_workqueue_struct *cwq;
912 struct workqueue_struct *wq;
914 action &= ~CPU_TASKS_FROZEN;
918 cpu_set(cpu, cpu_populated_map);
921 list_for_each_entry(wq, &workqueues, list) {
922 cwq = per_cpu_ptr(wq->cpu_wq, cpu);
926 if (!create_workqueue_thread(cwq, cpu))
928 printk(KERN_ERR "workqueue [%s] for %i failed\n",
933 start_workqueue_thread(cwq, cpu);
936 case CPU_UP_CANCELED:
937 start_workqueue_thread(cwq, -1);
939 cleanup_workqueue_thread(cwq);
945 case CPU_UP_CANCELED:
947 cpu_clear(cpu, cpu_populated_map);
953 void __init init_workqueues(void)
955 cpu_populated_map = cpu_online_map;
956 singlethread_cpu = first_cpu(cpu_possible_map);
957 cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu);
958 hotcpu_notifier(workqueue_cpu_callback, 0);
959 keventd_wq = create_workqueue("events");