Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/workqueue.c | |
3 | * | |
4 | * Generic mechanism for defining kernel helper threads for running | |
5 | * arbitrary tasks in process context. | |
6 | * | |
7 | * Started by Ingo Molnar, Copyright (C) 2002 | |
8 | * | |
9 | * Derived from the taskqueue/keventd code by: | |
10 | * | |
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> | |
89ada679 CL |
15 | * |
16 | * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. | |
1da177e4 LT |
17 | */ |
18 | ||
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> | |
1fa44eca | 30 | #include <linux/hardirq.h> |
1da177e4 LT |
31 | |
32 | /* | |
f756d5e2 NL |
33 | * The per-CPU workqueue (if single thread, we always use the first |
34 | * possible cpu). | |
1da177e4 LT |
35 | * |
36 | * The sequence counters are for flush_scheduled_work(). It wants to wait | |
37 | * until until all currently-scheduled works are completed, but it doesn't | |
38 | * want to be livelocked by new, incoming ones. So it waits until | |
39 | * remove_sequence is >= the insert_sequence which pertained when | |
40 | * flush_scheduled_work() was called. | |
41 | */ | |
42 | struct cpu_workqueue_struct { | |
43 | ||
44 | spinlock_t lock; | |
45 | ||
46 | long remove_sequence; /* Least-recently added (next to run) */ | |
47 | long insert_sequence; /* Next to add */ | |
48 | ||
49 | struct list_head worklist; | |
50 | wait_queue_head_t more_work; | |
51 | wait_queue_head_t work_done; | |
52 | ||
53 | struct workqueue_struct *wq; | |
54 | task_t *thread; | |
55 | ||
56 | int run_depth; /* Detect run_workqueue() recursion depth */ | |
57 | } ____cacheline_aligned; | |
58 | ||
59 | /* | |
60 | * The externally visible workqueue abstraction is an array of | |
61 | * per-CPU workqueues: | |
62 | */ | |
63 | struct workqueue_struct { | |
89ada679 | 64 | struct cpu_workqueue_struct *cpu_wq; |
1da177e4 LT |
65 | const char *name; |
66 | struct list_head list; /* Empty if single thread */ | |
67 | }; | |
68 | ||
69 | /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove | |
70 | threads to each one as cpus come/go. */ | |
71 | static DEFINE_SPINLOCK(workqueue_lock); | |
72 | static LIST_HEAD(workqueues); | |
73 | ||
f756d5e2 NL |
74 | static int singlethread_cpu; |
75 | ||
1da177e4 LT |
76 | /* If it's single threaded, it isn't in the list of workqueues. */ |
77 | static inline int is_single_threaded(struct workqueue_struct *wq) | |
78 | { | |
79 | return list_empty(&wq->list); | |
80 | } | |
81 | ||
82 | /* Preempt must be disabled. */ | |
83 | static void __queue_work(struct cpu_workqueue_struct *cwq, | |
84 | struct work_struct *work) | |
85 | { | |
86 | unsigned long flags; | |
87 | ||
88 | spin_lock_irqsave(&cwq->lock, flags); | |
89 | work->wq_data = cwq; | |
90 | list_add_tail(&work->entry, &cwq->worklist); | |
91 | cwq->insert_sequence++; | |
92 | wake_up(&cwq->more_work); | |
93 | spin_unlock_irqrestore(&cwq->lock, flags); | |
94 | } | |
95 | ||
96 | /* | |
97 | * Queue work on a workqueue. Return non-zero if it was successfully | |
98 | * added. | |
99 | * | |
100 | * We queue the work to the CPU it was submitted, but there is no | |
101 | * guarantee that it will be processed by that CPU. | |
102 | */ | |
103 | int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) | |
104 | { | |
105 | int ret = 0, cpu = get_cpu(); | |
106 | ||
107 | if (!test_and_set_bit(0, &work->pending)) { | |
108 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 109 | cpu = singlethread_cpu; |
1da177e4 | 110 | BUG_ON(!list_empty(&work->entry)); |
89ada679 | 111 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
112 | ret = 1; |
113 | } | |
114 | put_cpu(); | |
115 | return ret; | |
116 | } | |
ae90dd5d | 117 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 LT |
118 | |
119 | static void delayed_work_timer_fn(unsigned long __data) | |
120 | { | |
121 | struct work_struct *work = (struct work_struct *)__data; | |
122 | struct workqueue_struct *wq = work->wq_data; | |
123 | int cpu = smp_processor_id(); | |
124 | ||
125 | if (unlikely(is_single_threaded(wq))) | |
f756d5e2 | 126 | cpu = singlethread_cpu; |
1da177e4 | 127 | |
89ada679 | 128 | __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); |
1da177e4 LT |
129 | } |
130 | ||
131 | int fastcall queue_delayed_work(struct workqueue_struct *wq, | |
132 | struct work_struct *work, unsigned long delay) | |
133 | { | |
134 | int ret = 0; | |
135 | struct timer_list *timer = &work->timer; | |
136 | ||
137 | if (!test_and_set_bit(0, &work->pending)) { | |
138 | BUG_ON(timer_pending(timer)); | |
139 | BUG_ON(!list_empty(&work->entry)); | |
140 | ||
141 | /* This stores wq for the moment, for the timer_fn */ | |
142 | work->wq_data = wq; | |
143 | timer->expires = jiffies + delay; | |
144 | timer->data = (unsigned long)work; | |
145 | timer->function = delayed_work_timer_fn; | |
146 | add_timer(timer); | |
147 | ret = 1; | |
148 | } | |
149 | return ret; | |
150 | } | |
ae90dd5d | 151 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 152 | |
7a6bc1cd VP |
153 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
154 | struct work_struct *work, unsigned long delay) | |
155 | { | |
156 | int ret = 0; | |
157 | struct timer_list *timer = &work->timer; | |
158 | ||
159 | if (!test_and_set_bit(0, &work->pending)) { | |
160 | BUG_ON(timer_pending(timer)); | |
161 | BUG_ON(!list_empty(&work->entry)); | |
162 | ||
163 | /* This stores wq for the moment, for the timer_fn */ | |
164 | work->wq_data = wq; | |
165 | timer->expires = jiffies + delay; | |
166 | timer->data = (unsigned long)work; | |
167 | timer->function = delayed_work_timer_fn; | |
168 | add_timer_on(timer, cpu); | |
169 | ret = 1; | |
170 | } | |
171 | return ret; | |
172 | } | |
ae90dd5d | 173 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
7a6bc1cd | 174 | |
858119e1 | 175 | static void run_workqueue(struct cpu_workqueue_struct *cwq) |
1da177e4 LT |
176 | { |
177 | unsigned long flags; | |
178 | ||
179 | /* | |
180 | * Keep taking off work from the queue until | |
181 | * done. | |
182 | */ | |
183 | spin_lock_irqsave(&cwq->lock, flags); | |
184 | cwq->run_depth++; | |
185 | if (cwq->run_depth > 3) { | |
186 | /* morton gets to eat his hat */ | |
187 | printk("%s: recursion depth exceeded: %d\n", | |
188 | __FUNCTION__, cwq->run_depth); | |
189 | dump_stack(); | |
190 | } | |
191 | while (!list_empty(&cwq->worklist)) { | |
192 | struct work_struct *work = list_entry(cwq->worklist.next, | |
193 | struct work_struct, entry); | |
194 | void (*f) (void *) = work->func; | |
195 | void *data = work->data; | |
196 | ||
197 | list_del_init(cwq->worklist.next); | |
198 | spin_unlock_irqrestore(&cwq->lock, flags); | |
199 | ||
200 | BUG_ON(work->wq_data != cwq); | |
201 | clear_bit(0, &work->pending); | |
202 | f(data); | |
203 | ||
204 | spin_lock_irqsave(&cwq->lock, flags); | |
205 | cwq->remove_sequence++; | |
206 | wake_up(&cwq->work_done); | |
207 | } | |
208 | cwq->run_depth--; | |
209 | spin_unlock_irqrestore(&cwq->lock, flags); | |
210 | } | |
211 | ||
212 | static int worker_thread(void *__cwq) | |
213 | { | |
214 | struct cpu_workqueue_struct *cwq = __cwq; | |
215 | DECLARE_WAITQUEUE(wait, current); | |
216 | struct k_sigaction sa; | |
217 | sigset_t blocked; | |
218 | ||
219 | current->flags |= PF_NOFREEZE; | |
220 | ||
221 | set_user_nice(current, -5); | |
222 | ||
223 | /* Block and flush all signals */ | |
224 | sigfillset(&blocked); | |
225 | sigprocmask(SIG_BLOCK, &blocked, NULL); | |
226 | flush_signals(current); | |
227 | ||
228 | /* SIG_IGN makes children autoreap: see do_notify_parent(). */ | |
229 | sa.sa.sa_handler = SIG_IGN; | |
230 | sa.sa.sa_flags = 0; | |
231 | siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); | |
232 | do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); | |
233 | ||
234 | set_current_state(TASK_INTERRUPTIBLE); | |
235 | while (!kthread_should_stop()) { | |
236 | add_wait_queue(&cwq->more_work, &wait); | |
237 | if (list_empty(&cwq->worklist)) | |
238 | schedule(); | |
239 | else | |
240 | __set_current_state(TASK_RUNNING); | |
241 | remove_wait_queue(&cwq->more_work, &wait); | |
242 | ||
243 | if (!list_empty(&cwq->worklist)) | |
244 | run_workqueue(cwq); | |
245 | set_current_state(TASK_INTERRUPTIBLE); | |
246 | } | |
247 | __set_current_state(TASK_RUNNING); | |
248 | return 0; | |
249 | } | |
250 | ||
251 | static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | |
252 | { | |
253 | if (cwq->thread == current) { | |
254 | /* | |
255 | * Probably keventd trying to flush its own queue. So simply run | |
256 | * it by hand rather than deadlocking. | |
257 | */ | |
258 | run_workqueue(cwq); | |
259 | } else { | |
260 | DEFINE_WAIT(wait); | |
261 | long sequence_needed; | |
262 | ||
263 | spin_lock_irq(&cwq->lock); | |
264 | sequence_needed = cwq->insert_sequence; | |
265 | ||
266 | while (sequence_needed - cwq->remove_sequence > 0) { | |
267 | prepare_to_wait(&cwq->work_done, &wait, | |
268 | TASK_UNINTERRUPTIBLE); | |
269 | spin_unlock_irq(&cwq->lock); | |
270 | schedule(); | |
271 | spin_lock_irq(&cwq->lock); | |
272 | } | |
273 | finish_wait(&cwq->work_done, &wait); | |
274 | spin_unlock_irq(&cwq->lock); | |
275 | } | |
276 | } | |
277 | ||
278 | /* | |
279 | * flush_workqueue - ensure that any scheduled work has run to completion. | |
280 | * | |
281 | * Forces execution of the workqueue and blocks until its completion. | |
282 | * This is typically used in driver shutdown handlers. | |
283 | * | |
284 | * This function will sample each workqueue's current insert_sequence number and | |
285 | * will sleep until the head sequence is greater than or equal to that. This | |
286 | * means that we sleep until all works which were queued on entry have been | |
287 | * handled, but we are not livelocked by new incoming ones. | |
288 | * | |
289 | * This function used to run the workqueues itself. Now we just wait for the | |
290 | * helper threads to do it. | |
291 | */ | |
292 | void fastcall flush_workqueue(struct workqueue_struct *wq) | |
293 | { | |
294 | might_sleep(); | |
295 | ||
296 | if (is_single_threaded(wq)) { | |
bce61dd4 | 297 | /* Always use first cpu's area. */ |
f756d5e2 | 298 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); |
1da177e4 LT |
299 | } else { |
300 | int cpu; | |
301 | ||
302 | lock_cpu_hotplug(); | |
303 | for_each_online_cpu(cpu) | |
89ada679 | 304 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); |
1da177e4 LT |
305 | unlock_cpu_hotplug(); |
306 | } | |
307 | } | |
ae90dd5d | 308 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 LT |
309 | |
310 | static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, | |
311 | int cpu) | |
312 | { | |
89ada679 | 313 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
314 | struct task_struct *p; |
315 | ||
316 | spin_lock_init(&cwq->lock); | |
317 | cwq->wq = wq; | |
318 | cwq->thread = NULL; | |
319 | cwq->insert_sequence = 0; | |
320 | cwq->remove_sequence = 0; | |
321 | INIT_LIST_HEAD(&cwq->worklist); | |
322 | init_waitqueue_head(&cwq->more_work); | |
323 | init_waitqueue_head(&cwq->work_done); | |
324 | ||
325 | if (is_single_threaded(wq)) | |
326 | p = kthread_create(worker_thread, cwq, "%s", wq->name); | |
327 | else | |
328 | p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); | |
329 | if (IS_ERR(p)) | |
330 | return NULL; | |
331 | cwq->thread = p; | |
332 | return p; | |
333 | } | |
334 | ||
335 | struct workqueue_struct *__create_workqueue(const char *name, | |
336 | int singlethread) | |
337 | { | |
338 | int cpu, destroy = 0; | |
339 | struct workqueue_struct *wq; | |
340 | struct task_struct *p; | |
341 | ||
dd392710 | 342 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
1da177e4 LT |
343 | if (!wq) |
344 | return NULL; | |
1da177e4 | 345 | |
89ada679 | 346 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); |
676121fc BC |
347 | if (!wq->cpu_wq) { |
348 | kfree(wq); | |
349 | return NULL; | |
350 | } | |
351 | ||
1da177e4 LT |
352 | wq->name = name; |
353 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
354 | lock_cpu_hotplug(); | |
355 | if (singlethread) { | |
356 | INIT_LIST_HEAD(&wq->list); | |
f756d5e2 | 357 | p = create_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
358 | if (!p) |
359 | destroy = 1; | |
360 | else | |
361 | wake_up_process(p); | |
362 | } else { | |
363 | spin_lock(&workqueue_lock); | |
364 | list_add(&wq->list, &workqueues); | |
365 | spin_unlock(&workqueue_lock); | |
366 | for_each_online_cpu(cpu) { | |
367 | p = create_workqueue_thread(wq, cpu); | |
368 | if (p) { | |
369 | kthread_bind(p, cpu); | |
370 | wake_up_process(p); | |
371 | } else | |
372 | destroy = 1; | |
373 | } | |
374 | } | |
375 | unlock_cpu_hotplug(); | |
376 | ||
377 | /* | |
378 | * Was there any error during startup? If yes then clean up: | |
379 | */ | |
380 | if (destroy) { | |
381 | destroy_workqueue(wq); | |
382 | wq = NULL; | |
383 | } | |
384 | return wq; | |
385 | } | |
ae90dd5d | 386 | EXPORT_SYMBOL_GPL(__create_workqueue); |
1da177e4 LT |
387 | |
388 | static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) | |
389 | { | |
390 | struct cpu_workqueue_struct *cwq; | |
391 | unsigned long flags; | |
392 | struct task_struct *p; | |
393 | ||
89ada679 | 394 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
1da177e4 LT |
395 | spin_lock_irqsave(&cwq->lock, flags); |
396 | p = cwq->thread; | |
397 | cwq->thread = NULL; | |
398 | spin_unlock_irqrestore(&cwq->lock, flags); | |
399 | if (p) | |
400 | kthread_stop(p); | |
401 | } | |
402 | ||
403 | void destroy_workqueue(struct workqueue_struct *wq) | |
404 | { | |
405 | int cpu; | |
406 | ||
407 | flush_workqueue(wq); | |
408 | ||
409 | /* We don't need the distraction of CPUs appearing and vanishing. */ | |
410 | lock_cpu_hotplug(); | |
411 | if (is_single_threaded(wq)) | |
f756d5e2 | 412 | cleanup_workqueue_thread(wq, singlethread_cpu); |
1da177e4 LT |
413 | else { |
414 | for_each_online_cpu(cpu) | |
415 | cleanup_workqueue_thread(wq, cpu); | |
416 | spin_lock(&workqueue_lock); | |
417 | list_del(&wq->list); | |
418 | spin_unlock(&workqueue_lock); | |
419 | } | |
420 | unlock_cpu_hotplug(); | |
89ada679 | 421 | free_percpu(wq->cpu_wq); |
1da177e4 LT |
422 | kfree(wq); |
423 | } | |
ae90dd5d | 424 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
1da177e4 LT |
425 | |
426 | static struct workqueue_struct *keventd_wq; | |
427 | ||
428 | int fastcall schedule_work(struct work_struct *work) | |
429 | { | |
430 | return queue_work(keventd_wq, work); | |
431 | } | |
ae90dd5d | 432 | EXPORT_SYMBOL(schedule_work); |
1da177e4 LT |
433 | |
434 | int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay) | |
435 | { | |
436 | return queue_delayed_work(keventd_wq, work, delay); | |
437 | } | |
ae90dd5d | 438 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 LT |
439 | |
440 | int schedule_delayed_work_on(int cpu, | |
441 | struct work_struct *work, unsigned long delay) | |
442 | { | |
7a6bc1cd | 443 | return queue_delayed_work_on(cpu, keventd_wq, work, delay); |
1da177e4 | 444 | } |
ae90dd5d | 445 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 446 | |
b6136773 AM |
447 | /** |
448 | * schedule_on_each_cpu - call a function on each online CPU from keventd | |
449 | * @func: the function to call | |
450 | * @info: a pointer to pass to func() | |
451 | * | |
452 | * Returns zero on success. | |
453 | * Returns -ve errno on failure. | |
454 | * | |
455 | * Appears to be racy against CPU hotplug. | |
456 | * | |
457 | * schedule_on_each_cpu() is very slow. | |
458 | */ | |
459 | int schedule_on_each_cpu(void (*func)(void *info), void *info) | |
15316ba8 CL |
460 | { |
461 | int cpu; | |
b6136773 | 462 | struct work_struct *works; |
15316ba8 | 463 | |
b6136773 AM |
464 | works = alloc_percpu(struct work_struct); |
465 | if (!works) | |
15316ba8 | 466 | return -ENOMEM; |
b6136773 | 467 | |
15316ba8 | 468 | for_each_online_cpu(cpu) { |
b6136773 | 469 | INIT_WORK(per_cpu_ptr(works, cpu), func, info); |
15316ba8 | 470 | __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), |
b6136773 | 471 | per_cpu_ptr(works, cpu)); |
15316ba8 CL |
472 | } |
473 | flush_workqueue(keventd_wq); | |
b6136773 | 474 | free_percpu(works); |
15316ba8 CL |
475 | return 0; |
476 | } | |
477 | ||
1da177e4 LT |
478 | void flush_scheduled_work(void) |
479 | { | |
480 | flush_workqueue(keventd_wq); | |
481 | } | |
ae90dd5d | 482 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 LT |
483 | |
484 | /** | |
485 | * cancel_rearming_delayed_workqueue - reliably kill off a delayed | |
486 | * work whose handler rearms the delayed work. | |
487 | * @wq: the controlling workqueue structure | |
488 | * @work: the delayed work struct | |
489 | */ | |
81ddef77 JB |
490 | void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, |
491 | struct work_struct *work) | |
1da177e4 LT |
492 | { |
493 | while (!cancel_delayed_work(work)) | |
494 | flush_workqueue(wq); | |
495 | } | |
81ddef77 | 496 | EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); |
1da177e4 LT |
497 | |
498 | /** | |
499 | * cancel_rearming_delayed_work - reliably kill off a delayed keventd | |
500 | * work whose handler rearms the delayed work. | |
501 | * @work: the delayed work struct | |
502 | */ | |
503 | void cancel_rearming_delayed_work(struct work_struct *work) | |
504 | { | |
505 | cancel_rearming_delayed_workqueue(keventd_wq, work); | |
506 | } | |
507 | EXPORT_SYMBOL(cancel_rearming_delayed_work); | |
508 | ||
1fa44eca JB |
509 | /** |
510 | * execute_in_process_context - reliably execute the routine with user context | |
511 | * @fn: the function to execute | |
512 | * @data: data to pass to the function | |
513 | * @ew: guaranteed storage for the execute work structure (must | |
514 | * be available when the work executes) | |
515 | * | |
516 | * Executes the function immediately if process context is available, | |
517 | * otherwise schedules the function for delayed execution. | |
518 | * | |
519 | * Returns: 0 - function was executed | |
520 | * 1 - function was scheduled for execution | |
521 | */ | |
522 | int execute_in_process_context(void (*fn)(void *data), void *data, | |
523 | struct execute_work *ew) | |
524 | { | |
525 | if (!in_interrupt()) { | |
526 | fn(data); | |
527 | return 0; | |
528 | } | |
529 | ||
530 | INIT_WORK(&ew->work, fn, data); | |
531 | schedule_work(&ew->work); | |
532 | ||
533 | return 1; | |
534 | } | |
535 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
536 | ||
1da177e4 LT |
537 | int keventd_up(void) |
538 | { | |
539 | return keventd_wq != NULL; | |
540 | } | |
541 | ||
542 | int current_is_keventd(void) | |
543 | { | |
544 | struct cpu_workqueue_struct *cwq; | |
545 | int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | |
546 | int ret = 0; | |
547 | ||
548 | BUG_ON(!keventd_wq); | |
549 | ||
89ada679 | 550 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); |
1da177e4 LT |
551 | if (current == cwq->thread) |
552 | ret = 1; | |
553 | ||
554 | return ret; | |
555 | ||
556 | } | |
557 | ||
558 | #ifdef CONFIG_HOTPLUG_CPU | |
559 | /* Take the work from this (downed) CPU. */ | |
560 | static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) | |
561 | { | |
89ada679 | 562 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); |
626ab0e6 | 563 | struct list_head list; |
1da177e4 LT |
564 | struct work_struct *work; |
565 | ||
566 | spin_lock_irq(&cwq->lock); | |
626ab0e6 | 567 | list_replace_init(&cwq->worklist, &list); |
1da177e4 LT |
568 | |
569 | while (!list_empty(&list)) { | |
570 | printk("Taking work for %s\n", wq->name); | |
571 | work = list_entry(list.next,struct work_struct,entry); | |
572 | list_del(&work->entry); | |
89ada679 | 573 | __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); |
1da177e4 LT |
574 | } |
575 | spin_unlock_irq(&cwq->lock); | |
576 | } | |
577 | ||
578 | /* We're holding the cpucontrol mutex here */ | |
9c7b216d | 579 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
1da177e4 LT |
580 | unsigned long action, |
581 | void *hcpu) | |
582 | { | |
583 | unsigned int hotcpu = (unsigned long)hcpu; | |
584 | struct workqueue_struct *wq; | |
585 | ||
586 | switch (action) { | |
587 | case CPU_UP_PREPARE: | |
588 | /* Create a new workqueue thread for it. */ | |
589 | list_for_each_entry(wq, &workqueues, list) { | |
230649da | 590 | if (!create_workqueue_thread(wq, hotcpu)) { |
1da177e4 LT |
591 | printk("workqueue for %i failed\n", hotcpu); |
592 | return NOTIFY_BAD; | |
593 | } | |
594 | } | |
595 | break; | |
596 | ||
597 | case CPU_ONLINE: | |
598 | /* Kick off worker threads. */ | |
599 | list_for_each_entry(wq, &workqueues, list) { | |
89ada679 CL |
600 | struct cpu_workqueue_struct *cwq; |
601 | ||
602 | cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); | |
603 | kthread_bind(cwq->thread, hotcpu); | |
604 | wake_up_process(cwq->thread); | |
1da177e4 LT |
605 | } |
606 | break; | |
607 | ||
608 | case CPU_UP_CANCELED: | |
609 | list_for_each_entry(wq, &workqueues, list) { | |
fc75cdfa HC |
610 | if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) |
611 | continue; | |
1da177e4 | 612 | /* Unbind so it can run. */ |
89ada679 | 613 | kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, |
a4c4af7c | 614 | any_online_cpu(cpu_online_map)); |
1da177e4 LT |
615 | cleanup_workqueue_thread(wq, hotcpu); |
616 | } | |
617 | break; | |
618 | ||
619 | case CPU_DEAD: | |
620 | list_for_each_entry(wq, &workqueues, list) | |
621 | cleanup_workqueue_thread(wq, hotcpu); | |
622 | list_for_each_entry(wq, &workqueues, list) | |
623 | take_over_work(wq, hotcpu); | |
624 | break; | |
625 | } | |
626 | ||
627 | return NOTIFY_OK; | |
628 | } | |
629 | #endif | |
630 | ||
631 | void init_workqueues(void) | |
632 | { | |
f756d5e2 | 633 | singlethread_cpu = first_cpu(cpu_possible_map); |
1da177e4 LT |
634 | hotcpu_notifier(workqueue_cpu_callback, 0); |
635 | keventd_wq = create_workqueue("events"); | |
636 | BUG_ON(!keventd_wq); | |
637 | } | |
638 |