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07fe7cb7 DH |
1 | /* Worker thread pool for slow items, such as filesystem lookups or mkdirs |
2 | * | |
3 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
8f0aa2f2 DH |
10 | * |
11 | * See Documentation/slow-work.txt | |
07fe7cb7 DH |
12 | */ |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/slow-work.h> | |
16 | #include <linux/kthread.h> | |
17 | #include <linux/freezer.h> | |
18 | #include <linux/wait.h> | |
8fba10a4 DH |
19 | #include <linux/proc_fs.h> |
20 | #include "slow-work.h" | |
3d7a641e | 21 | |
109d9272 DH |
22 | static void slow_work_cull_timeout(unsigned long); |
23 | static void slow_work_oom_timeout(unsigned long); | |
24 | ||
12e22c5e | 25 | #ifdef CONFIG_SYSCTL |
8d65af78 | 26 | static int slow_work_min_threads_sysctl(struct ctl_table *, int, |
12e22c5e DH |
27 | void __user *, size_t *, loff_t *); |
28 | ||
8d65af78 | 29 | static int slow_work_max_threads_sysctl(struct ctl_table *, int , |
12e22c5e DH |
30 | void __user *, size_t *, loff_t *); |
31 | #endif | |
32 | ||
07fe7cb7 DH |
33 | /* |
34 | * The pool of threads has at least min threads in it as long as someone is | |
35 | * using the facility, and may have as many as max. | |
36 | * | |
37 | * A portion of the pool may be processing very slow operations. | |
38 | */ | |
39 | static unsigned slow_work_min_threads = 2; | |
40 | static unsigned slow_work_max_threads = 4; | |
41 | static unsigned vslow_work_proportion = 50; /* % of threads that may process | |
42 | * very slow work */ | |
12e22c5e DH |
43 | |
44 | #ifdef CONFIG_SYSCTL | |
45 | static const int slow_work_min_min_threads = 2; | |
3d7a641e | 46 | static int slow_work_max_max_threads = SLOW_WORK_THREAD_LIMIT; |
12e22c5e DH |
47 | static const int slow_work_min_vslow = 1; |
48 | static const int slow_work_max_vslow = 99; | |
49 | ||
50 | ctl_table slow_work_sysctls[] = { | |
51 | { | |
52 | .ctl_name = CTL_UNNUMBERED, | |
53 | .procname = "min-threads", | |
54 | .data = &slow_work_min_threads, | |
55 | .maxlen = sizeof(unsigned), | |
56 | .mode = 0644, | |
57 | .proc_handler = slow_work_min_threads_sysctl, | |
58 | .extra1 = (void *) &slow_work_min_min_threads, | |
59 | .extra2 = &slow_work_max_threads, | |
60 | }, | |
61 | { | |
62 | .ctl_name = CTL_UNNUMBERED, | |
63 | .procname = "max-threads", | |
64 | .data = &slow_work_max_threads, | |
65 | .maxlen = sizeof(unsigned), | |
66 | .mode = 0644, | |
67 | .proc_handler = slow_work_max_threads_sysctl, | |
68 | .extra1 = &slow_work_min_threads, | |
69 | .extra2 = (void *) &slow_work_max_max_threads, | |
70 | }, | |
71 | { | |
72 | .ctl_name = CTL_UNNUMBERED, | |
73 | .procname = "vslow-percentage", | |
74 | .data = &vslow_work_proportion, | |
75 | .maxlen = sizeof(unsigned), | |
76 | .mode = 0644, | |
77 | .proc_handler = &proc_dointvec_minmax, | |
78 | .extra1 = (void *) &slow_work_min_vslow, | |
79 | .extra2 = (void *) &slow_work_max_vslow, | |
80 | }, | |
81 | { .ctl_name = 0 } | |
82 | }; | |
83 | #endif | |
84 | ||
85 | /* | |
86 | * The active state of the thread pool | |
87 | */ | |
07fe7cb7 DH |
88 | static atomic_t slow_work_thread_count; |
89 | static atomic_t vslow_work_executing_count; | |
90 | ||
109d9272 DH |
91 | static bool slow_work_may_not_start_new_thread; |
92 | static bool slow_work_cull; /* cull a thread due to lack of activity */ | |
93 | static DEFINE_TIMER(slow_work_cull_timer, slow_work_cull_timeout, 0, 0); | |
94 | static DEFINE_TIMER(slow_work_oom_timer, slow_work_oom_timeout, 0, 0); | |
95 | static struct slow_work slow_work_new_thread; /* new thread starter */ | |
96 | ||
3d7a641e DH |
97 | /* |
98 | * slow work ID allocation (use slow_work_queue_lock) | |
99 | */ | |
100 | static DECLARE_BITMAP(slow_work_ids, SLOW_WORK_THREAD_LIMIT); | |
101 | ||
102 | /* | |
103 | * Unregistration tracking to prevent put_ref() from disappearing during module | |
104 | * unload | |
105 | */ | |
106 | #ifdef CONFIG_MODULES | |
107 | static struct module *slow_work_thread_processing[SLOW_WORK_THREAD_LIMIT]; | |
108 | static struct module *slow_work_unreg_module; | |
109 | static struct slow_work *slow_work_unreg_work_item; | |
110 | static DECLARE_WAIT_QUEUE_HEAD(slow_work_unreg_wq); | |
111 | static DEFINE_MUTEX(slow_work_unreg_sync_lock); | |
112 | #endif | |
113 | ||
8fba10a4 DH |
114 | /* |
115 | * Data for tracking currently executing items for indication through /proc | |
116 | */ | |
117 | #ifdef CONFIG_SLOW_WORK_PROC | |
118 | struct slow_work *slow_work_execs[SLOW_WORK_THREAD_LIMIT]; | |
119 | pid_t slow_work_pids[SLOW_WORK_THREAD_LIMIT]; | |
120 | DEFINE_RWLOCK(slow_work_execs_lock); | |
121 | #endif | |
122 | ||
07fe7cb7 DH |
123 | /* |
124 | * The queues of work items and the lock governing access to them. These are | |
125 | * shared between all the CPUs. It doesn't make sense to have per-CPU queues | |
126 | * as the number of threads bears no relation to the number of CPUs. | |
127 | * | |
128 | * There are two queues of work items: one for slow work items, and one for | |
129 | * very slow work items. | |
130 | */ | |
8fba10a4 DH |
131 | LIST_HEAD(slow_work_queue); |
132 | LIST_HEAD(vslow_work_queue); | |
133 | DEFINE_SPINLOCK(slow_work_queue_lock); | |
07fe7cb7 | 134 | |
3bde31a4 DH |
135 | /* |
136 | * The following are two wait queues that get pinged when a work item is placed | |
137 | * on an empty queue. These allow work items that are hogging a thread by | |
138 | * sleeping in a way that could be deferred to yield their thread and enqueue | |
139 | * themselves. | |
140 | */ | |
141 | static DECLARE_WAIT_QUEUE_HEAD(slow_work_queue_waits_for_occupation); | |
142 | static DECLARE_WAIT_QUEUE_HEAD(vslow_work_queue_waits_for_occupation); | |
143 | ||
07fe7cb7 DH |
144 | /* |
145 | * The thread controls. A variable used to signal to the threads that they | |
146 | * should exit when the queue is empty, a waitqueue used by the threads to wait | |
147 | * for signals, and a completion set by the last thread to exit. | |
148 | */ | |
149 | static bool slow_work_threads_should_exit; | |
150 | static DECLARE_WAIT_QUEUE_HEAD(slow_work_thread_wq); | |
151 | static DECLARE_COMPLETION(slow_work_last_thread_exited); | |
152 | ||
153 | /* | |
154 | * The number of users of the thread pool and its lock. Whilst this is zero we | |
155 | * have no threads hanging around, and when this reaches zero, we wait for all | |
156 | * active or queued work items to complete and kill all the threads we do have. | |
157 | */ | |
158 | static int slow_work_user_count; | |
159 | static DEFINE_MUTEX(slow_work_user_lock); | |
160 | ||
4d8bb2cb JA |
161 | static inline int slow_work_get_ref(struct slow_work *work) |
162 | { | |
163 | if (work->ops->get_ref) | |
164 | return work->ops->get_ref(work); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | static inline void slow_work_put_ref(struct slow_work *work) | |
170 | { | |
171 | if (work->ops->put_ref) | |
172 | work->ops->put_ref(work); | |
173 | } | |
174 | ||
07fe7cb7 DH |
175 | /* |
176 | * Calculate the maximum number of active threads in the pool that are | |
177 | * permitted to process very slow work items. | |
178 | * | |
179 | * The answer is rounded up to at least 1, but may not equal or exceed the | |
180 | * maximum number of the threads in the pool. This means we always have at | |
181 | * least one thread that can process slow work items, and we always have at | |
182 | * least one thread that won't get tied up doing so. | |
183 | */ | |
184 | static unsigned slow_work_calc_vsmax(void) | |
185 | { | |
186 | unsigned vsmax; | |
187 | ||
188 | vsmax = atomic_read(&slow_work_thread_count) * vslow_work_proportion; | |
189 | vsmax /= 100; | |
190 | vsmax = max(vsmax, 1U); | |
191 | return min(vsmax, slow_work_max_threads - 1); | |
192 | } | |
193 | ||
194 | /* | |
195 | * Attempt to execute stuff queued on a slow thread. Return true if we managed | |
196 | * it, false if there was nothing to do. | |
197 | */ | |
8fba10a4 | 198 | static noinline bool slow_work_execute(int id) |
07fe7cb7 | 199 | { |
3d7a641e DH |
200 | #ifdef CONFIG_MODULES |
201 | struct module *module; | |
202 | #endif | |
07fe7cb7 DH |
203 | struct slow_work *work = NULL; |
204 | unsigned vsmax; | |
205 | bool very_slow; | |
206 | ||
207 | vsmax = slow_work_calc_vsmax(); | |
208 | ||
109d9272 DH |
209 | /* see if we can schedule a new thread to be started if we're not |
210 | * keeping up with the work */ | |
211 | if (!waitqueue_active(&slow_work_thread_wq) && | |
212 | (!list_empty(&slow_work_queue) || !list_empty(&vslow_work_queue)) && | |
213 | atomic_read(&slow_work_thread_count) < slow_work_max_threads && | |
214 | !slow_work_may_not_start_new_thread) | |
215 | slow_work_enqueue(&slow_work_new_thread); | |
216 | ||
07fe7cb7 DH |
217 | /* find something to execute */ |
218 | spin_lock_irq(&slow_work_queue_lock); | |
219 | if (!list_empty(&vslow_work_queue) && | |
220 | atomic_read(&vslow_work_executing_count) < vsmax) { | |
221 | work = list_entry(vslow_work_queue.next, | |
222 | struct slow_work, link); | |
223 | if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags)) | |
224 | BUG(); | |
225 | list_del_init(&work->link); | |
226 | atomic_inc(&vslow_work_executing_count); | |
227 | very_slow = true; | |
228 | } else if (!list_empty(&slow_work_queue)) { | |
229 | work = list_entry(slow_work_queue.next, | |
230 | struct slow_work, link); | |
231 | if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags)) | |
232 | BUG(); | |
233 | list_del_init(&work->link); | |
234 | very_slow = false; | |
235 | } else { | |
236 | very_slow = false; /* avoid the compiler warning */ | |
237 | } | |
3d7a641e DH |
238 | |
239 | #ifdef CONFIG_MODULES | |
240 | if (work) | |
241 | slow_work_thread_processing[id] = work->owner; | |
242 | #endif | |
8fba10a4 DH |
243 | if (work) { |
244 | slow_work_mark_time(work); | |
245 | slow_work_begin_exec(id, work); | |
246 | } | |
3d7a641e | 247 | |
07fe7cb7 DH |
248 | spin_unlock_irq(&slow_work_queue_lock); |
249 | ||
250 | if (!work) | |
251 | return false; | |
252 | ||
253 | if (!test_and_clear_bit(SLOW_WORK_PENDING, &work->flags)) | |
254 | BUG(); | |
255 | ||
01609502 JA |
256 | /* don't execute if the work is in the process of being cancelled */ |
257 | if (!test_bit(SLOW_WORK_CANCELLING, &work->flags)) | |
258 | work->ops->execute(work); | |
07fe7cb7 DH |
259 | |
260 | if (very_slow) | |
261 | atomic_dec(&vslow_work_executing_count); | |
262 | clear_bit_unlock(SLOW_WORK_EXECUTING, &work->flags); | |
263 | ||
01609502 JA |
264 | /* wake up anyone waiting for this work to be complete */ |
265 | wake_up_bit(&work->flags, SLOW_WORK_EXECUTING); | |
266 | ||
8fba10a4 DH |
267 | slow_work_end_exec(id, work); |
268 | ||
07fe7cb7 DH |
269 | /* if someone tried to enqueue the item whilst we were executing it, |
270 | * then it'll be left unenqueued to avoid multiple threads trying to | |
271 | * execute it simultaneously | |
272 | * | |
273 | * there is, however, a race between us testing the pending flag and | |
274 | * getting the spinlock, and between the enqueuer setting the pending | |
275 | * flag and getting the spinlock, so we use a deferral bit to tell us | |
276 | * if the enqueuer got there first | |
277 | */ | |
278 | if (test_bit(SLOW_WORK_PENDING, &work->flags)) { | |
279 | spin_lock_irq(&slow_work_queue_lock); | |
280 | ||
281 | if (!test_bit(SLOW_WORK_EXECUTING, &work->flags) && | |
282 | test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags)) | |
283 | goto auto_requeue; | |
284 | ||
285 | spin_unlock_irq(&slow_work_queue_lock); | |
286 | } | |
287 | ||
3d7a641e | 288 | /* sort out the race between module unloading and put_ref() */ |
4d8bb2cb | 289 | slow_work_put_ref(work); |
3d7a641e DH |
290 | |
291 | #ifdef CONFIG_MODULES | |
292 | module = slow_work_thread_processing[id]; | |
293 | slow_work_thread_processing[id] = NULL; | |
294 | smp_mb(); | |
295 | if (slow_work_unreg_work_item == work || | |
296 | slow_work_unreg_module == module) | |
297 | wake_up_all(&slow_work_unreg_wq); | |
298 | #endif | |
299 | ||
07fe7cb7 DH |
300 | return true; |
301 | ||
302 | auto_requeue: | |
303 | /* we must complete the enqueue operation | |
304 | * - we transfer our ref on the item back to the appropriate queue | |
305 | * - don't wake another thread up as we're awake already | |
306 | */ | |
8fba10a4 | 307 | slow_work_mark_time(work); |
07fe7cb7 DH |
308 | if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) |
309 | list_add_tail(&work->link, &vslow_work_queue); | |
310 | else | |
311 | list_add_tail(&work->link, &slow_work_queue); | |
312 | spin_unlock_irq(&slow_work_queue_lock); | |
3d7a641e | 313 | slow_work_thread_processing[id] = NULL; |
07fe7cb7 DH |
314 | return true; |
315 | } | |
316 | ||
3bde31a4 DH |
317 | /** |
318 | * slow_work_sleep_till_thread_needed - Sleep till thread needed by other work | |
319 | * work: The work item under execution that wants to sleep | |
320 | * _timeout: Scheduler sleep timeout | |
321 | * | |
322 | * Allow a requeueable work item to sleep on a slow-work processor thread until | |
323 | * that thread is needed to do some other work or the sleep is interrupted by | |
324 | * some other event. | |
325 | * | |
326 | * The caller must set up a wake up event before calling this and must have set | |
327 | * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own | |
328 | * condition before calling this function as no test is made here. | |
329 | * | |
330 | * False is returned if there is nothing on the queue; true is returned if the | |
331 | * work item should be requeued | |
332 | */ | |
333 | bool slow_work_sleep_till_thread_needed(struct slow_work *work, | |
334 | signed long *_timeout) | |
335 | { | |
336 | wait_queue_head_t *wfo_wq; | |
337 | struct list_head *queue; | |
338 | ||
339 | DEFINE_WAIT(wait); | |
340 | ||
341 | if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { | |
342 | wfo_wq = &vslow_work_queue_waits_for_occupation; | |
343 | queue = &vslow_work_queue; | |
344 | } else { | |
345 | wfo_wq = &slow_work_queue_waits_for_occupation; | |
346 | queue = &slow_work_queue; | |
347 | } | |
348 | ||
349 | if (!list_empty(queue)) | |
350 | return true; | |
351 | ||
352 | add_wait_queue_exclusive(wfo_wq, &wait); | |
353 | if (list_empty(queue)) | |
354 | *_timeout = schedule_timeout(*_timeout); | |
355 | finish_wait(wfo_wq, &wait); | |
356 | ||
357 | return !list_empty(queue); | |
358 | } | |
359 | EXPORT_SYMBOL(slow_work_sleep_till_thread_needed); | |
360 | ||
07fe7cb7 DH |
361 | /** |
362 | * slow_work_enqueue - Schedule a slow work item for processing | |
363 | * @work: The work item to queue | |
364 | * | |
365 | * Schedule a slow work item for processing. If the item is already undergoing | |
366 | * execution, this guarantees not to re-enter the execution routine until the | |
367 | * first execution finishes. | |
368 | * | |
369 | * The item is pinned by this function as it retains a reference to it, managed | |
370 | * through the item operations. The item is unpinned once it has been | |
371 | * executed. | |
372 | * | |
373 | * An item may hog the thread that is running it for a relatively large amount | |
374 | * of time, sufficient, for example, to perform several lookup, mkdir, create | |
375 | * and setxattr operations. It may sleep on I/O and may sleep to obtain locks. | |
376 | * | |
377 | * Conversely, if a number of items are awaiting processing, it may take some | |
378 | * time before any given item is given attention. The number of threads in the | |
379 | * pool may be increased to deal with demand, but only up to a limit. | |
380 | * | |
381 | * If SLOW_WORK_VERY_SLOW is set on the work item, then it will be placed in | |
382 | * the very slow queue, from which only a portion of the threads will be | |
383 | * allowed to pick items to execute. This ensures that very slow items won't | |
384 | * overly block ones that are just ordinarily slow. | |
385 | * | |
01609502 JA |
386 | * Returns 0 if successful, -EAGAIN if not (or -ECANCELED if cancelled work is |
387 | * attempted queued) | |
07fe7cb7 DH |
388 | */ |
389 | int slow_work_enqueue(struct slow_work *work) | |
390 | { | |
3bde31a4 DH |
391 | wait_queue_head_t *wfo_wq; |
392 | struct list_head *queue; | |
07fe7cb7 | 393 | unsigned long flags; |
01609502 JA |
394 | int ret; |
395 | ||
396 | if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) | |
397 | return -ECANCELED; | |
07fe7cb7 DH |
398 | |
399 | BUG_ON(slow_work_user_count <= 0); | |
400 | BUG_ON(!work); | |
401 | BUG_ON(!work->ops); | |
07fe7cb7 DH |
402 | |
403 | /* when honouring an enqueue request, we only promise that we will run | |
404 | * the work function in the future; we do not promise to run it once | |
405 | * per enqueue request | |
406 | * | |
407 | * we use the PENDING bit to merge together repeat requests without | |
408 | * having to disable IRQs and take the spinlock, whilst still | |
409 | * maintaining our promise | |
410 | */ | |
411 | if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) { | |
3bde31a4 DH |
412 | if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { |
413 | wfo_wq = &vslow_work_queue_waits_for_occupation; | |
414 | queue = &vslow_work_queue; | |
415 | } else { | |
416 | wfo_wq = &slow_work_queue_waits_for_occupation; | |
417 | queue = &slow_work_queue; | |
418 | } | |
419 | ||
07fe7cb7 DH |
420 | spin_lock_irqsave(&slow_work_queue_lock, flags); |
421 | ||
01609502 JA |
422 | if (unlikely(test_bit(SLOW_WORK_CANCELLING, &work->flags))) |
423 | goto cancelled; | |
424 | ||
07fe7cb7 DH |
425 | /* we promise that we will not attempt to execute the work |
426 | * function in more than one thread simultaneously | |
427 | * | |
428 | * this, however, leaves us with a problem if we're asked to | |
429 | * enqueue the work whilst someone is executing the work | |
430 | * function as simply queueing the work immediately means that | |
431 | * another thread may try executing it whilst it is already | |
432 | * under execution | |
433 | * | |
434 | * to deal with this, we set the ENQ_DEFERRED bit instead of | |
435 | * enqueueing, and the thread currently executing the work | |
436 | * function will enqueue the work item when the work function | |
437 | * returns and it has cleared the EXECUTING bit | |
438 | */ | |
439 | if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) { | |
440 | set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags); | |
441 | } else { | |
01609502 JA |
442 | ret = slow_work_get_ref(work); |
443 | if (ret < 0) | |
444 | goto failed; | |
8fba10a4 | 445 | slow_work_mark_time(work); |
3bde31a4 | 446 | list_add_tail(&work->link, queue); |
07fe7cb7 | 447 | wake_up(&slow_work_thread_wq); |
3bde31a4 DH |
448 | |
449 | /* if someone who could be requeued is sleeping on a | |
450 | * thread, then ask them to yield their thread */ | |
451 | if (work->link.prev == queue) | |
452 | wake_up(wfo_wq); | |
07fe7cb7 DH |
453 | } |
454 | ||
455 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); | |
456 | } | |
457 | return 0; | |
458 | ||
01609502 JA |
459 | cancelled: |
460 | ret = -ECANCELED; | |
461 | failed: | |
07fe7cb7 | 462 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); |
01609502 | 463 | return ret; |
07fe7cb7 DH |
464 | } |
465 | EXPORT_SYMBOL(slow_work_enqueue); | |
466 | ||
01609502 JA |
467 | static int slow_work_wait(void *word) |
468 | { | |
469 | schedule(); | |
470 | return 0; | |
471 | } | |
472 | ||
473 | /** | |
474 | * slow_work_cancel - Cancel a slow work item | |
475 | * @work: The work item to cancel | |
476 | * | |
477 | * This function will cancel a previously enqueued work item. If we cannot | |
478 | * cancel the work item, it is guarenteed to have run when this function | |
479 | * returns. | |
480 | */ | |
481 | void slow_work_cancel(struct slow_work *work) | |
482 | { | |
483 | bool wait = true, put = false; | |
484 | ||
485 | set_bit(SLOW_WORK_CANCELLING, &work->flags); | |
6b8268b1 JA |
486 | smp_mb(); |
487 | ||
488 | /* if the work item is a delayed work item with an active timer, we | |
489 | * need to wait for the timer to finish _before_ getting the spinlock, | |
490 | * lest we deadlock against the timer routine | |
491 | * | |
492 | * the timer routine will leave DELAYED set if it notices the | |
493 | * CANCELLING flag in time | |
494 | */ | |
495 | if (test_bit(SLOW_WORK_DELAYED, &work->flags)) { | |
496 | struct delayed_slow_work *dwork = | |
497 | container_of(work, struct delayed_slow_work, work); | |
498 | del_timer_sync(&dwork->timer); | |
499 | } | |
01609502 JA |
500 | |
501 | spin_lock_irq(&slow_work_queue_lock); | |
502 | ||
6b8268b1 JA |
503 | if (test_bit(SLOW_WORK_DELAYED, &work->flags)) { |
504 | /* the timer routine aborted or never happened, so we are left | |
505 | * holding the timer's reference on the item and should just | |
506 | * drop the pending flag and wait for any ongoing execution to | |
507 | * finish */ | |
508 | struct delayed_slow_work *dwork = | |
509 | container_of(work, struct delayed_slow_work, work); | |
510 | ||
511 | BUG_ON(timer_pending(&dwork->timer)); | |
512 | BUG_ON(!list_empty(&work->link)); | |
513 | ||
514 | clear_bit(SLOW_WORK_DELAYED, &work->flags); | |
515 | put = true; | |
516 | clear_bit(SLOW_WORK_PENDING, &work->flags); | |
517 | ||
518 | } else if (test_bit(SLOW_WORK_PENDING, &work->flags) && | |
519 | !list_empty(&work->link)) { | |
01609502 JA |
520 | /* the link in the pending queue holds a reference on the item |
521 | * that we will need to release */ | |
522 | list_del_init(&work->link); | |
523 | wait = false; | |
524 | put = true; | |
525 | clear_bit(SLOW_WORK_PENDING, &work->flags); | |
526 | ||
527 | } else if (test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags)) { | |
528 | /* the executor is holding our only reference on the item, so | |
529 | * we merely need to wait for it to finish executing */ | |
530 | clear_bit(SLOW_WORK_PENDING, &work->flags); | |
531 | } | |
532 | ||
533 | spin_unlock_irq(&slow_work_queue_lock); | |
534 | ||
535 | /* the EXECUTING flag is set by the executor whilst the spinlock is set | |
536 | * and before the item is dequeued - so assuming the above doesn't | |
537 | * actually dequeue it, simply waiting for the EXECUTING flag to be | |
538 | * released here should be sufficient */ | |
539 | if (wait) | |
540 | wait_on_bit(&work->flags, SLOW_WORK_EXECUTING, slow_work_wait, | |
541 | TASK_UNINTERRUPTIBLE); | |
542 | ||
543 | clear_bit(SLOW_WORK_CANCELLING, &work->flags); | |
544 | if (put) | |
545 | slow_work_put_ref(work); | |
546 | } | |
547 | EXPORT_SYMBOL(slow_work_cancel); | |
548 | ||
6b8268b1 JA |
549 | /* |
550 | * Handle expiry of the delay timer, indicating that a delayed slow work item | |
551 | * should now be queued if not cancelled | |
552 | */ | |
553 | static void delayed_slow_work_timer(unsigned long data) | |
554 | { | |
3bde31a4 DH |
555 | wait_queue_head_t *wfo_wq; |
556 | struct list_head *queue; | |
6b8268b1 JA |
557 | struct slow_work *work = (struct slow_work *) data; |
558 | unsigned long flags; | |
3bde31a4 DH |
559 | bool queued = false, put = false, first = false; |
560 | ||
561 | if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) { | |
562 | wfo_wq = &vslow_work_queue_waits_for_occupation; | |
563 | queue = &vslow_work_queue; | |
564 | } else { | |
565 | wfo_wq = &slow_work_queue_waits_for_occupation; | |
566 | queue = &slow_work_queue; | |
567 | } | |
6b8268b1 JA |
568 | |
569 | spin_lock_irqsave(&slow_work_queue_lock, flags); | |
570 | if (likely(!test_bit(SLOW_WORK_CANCELLING, &work->flags))) { | |
571 | clear_bit(SLOW_WORK_DELAYED, &work->flags); | |
572 | ||
573 | if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) { | |
574 | /* we discard the reference the timer was holding in | |
575 | * favour of the one the executor holds */ | |
576 | set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags); | |
577 | put = true; | |
578 | } else { | |
8fba10a4 | 579 | slow_work_mark_time(work); |
3bde31a4 | 580 | list_add_tail(&work->link, queue); |
6b8268b1 | 581 | queued = true; |
3bde31a4 DH |
582 | if (work->link.prev == queue) |
583 | first = true; | |
6b8268b1 JA |
584 | } |
585 | } | |
586 | ||
587 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); | |
588 | if (put) | |
589 | slow_work_put_ref(work); | |
3bde31a4 DH |
590 | if (first) |
591 | wake_up(wfo_wq); | |
6b8268b1 JA |
592 | if (queued) |
593 | wake_up(&slow_work_thread_wq); | |
594 | } | |
595 | ||
596 | /** | |
597 | * delayed_slow_work_enqueue - Schedule a delayed slow work item for processing | |
598 | * @dwork: The delayed work item to queue | |
599 | * @delay: When to start executing the work, in jiffies from now | |
600 | * | |
601 | * This is similar to slow_work_enqueue(), but it adds a delay before the work | |
602 | * is actually queued for processing. | |
603 | * | |
604 | * The item can have delayed processing requested on it whilst it is being | |
605 | * executed. The delay will begin immediately, and if it expires before the | |
606 | * item finishes executing, the item will be placed back on the queue when it | |
607 | * has done executing. | |
608 | */ | |
609 | int delayed_slow_work_enqueue(struct delayed_slow_work *dwork, | |
610 | unsigned long delay) | |
611 | { | |
612 | struct slow_work *work = &dwork->work; | |
613 | unsigned long flags; | |
614 | int ret; | |
615 | ||
616 | if (delay == 0) | |
617 | return slow_work_enqueue(&dwork->work); | |
618 | ||
619 | BUG_ON(slow_work_user_count <= 0); | |
620 | BUG_ON(!work); | |
621 | BUG_ON(!work->ops); | |
622 | ||
623 | if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) | |
624 | return -ECANCELED; | |
625 | ||
626 | if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) { | |
627 | spin_lock_irqsave(&slow_work_queue_lock, flags); | |
628 | ||
629 | if (test_bit(SLOW_WORK_CANCELLING, &work->flags)) | |
630 | goto cancelled; | |
631 | ||
632 | /* the timer holds a reference whilst it is pending */ | |
633 | ret = work->ops->get_ref(work); | |
634 | if (ret < 0) | |
635 | goto cant_get_ref; | |
636 | ||
637 | if (test_and_set_bit(SLOW_WORK_DELAYED, &work->flags)) | |
638 | BUG(); | |
639 | dwork->timer.expires = jiffies + delay; | |
640 | dwork->timer.data = (unsigned long) work; | |
641 | dwork->timer.function = delayed_slow_work_timer; | |
642 | add_timer(&dwork->timer); | |
643 | ||
644 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); | |
645 | } | |
646 | ||
647 | return 0; | |
648 | ||
649 | cancelled: | |
650 | ret = -ECANCELED; | |
651 | cant_get_ref: | |
652 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); | |
653 | return ret; | |
654 | } | |
655 | EXPORT_SYMBOL(delayed_slow_work_enqueue); | |
656 | ||
009789f0 CP |
657 | /* |
658 | * Schedule a cull of the thread pool at some time in the near future | |
659 | */ | |
660 | static void slow_work_schedule_cull(void) | |
661 | { | |
662 | mod_timer(&slow_work_cull_timer, | |
663 | round_jiffies(jiffies + SLOW_WORK_CULL_TIMEOUT)); | |
664 | } | |
665 | ||
109d9272 DH |
666 | /* |
667 | * Worker thread culling algorithm | |
668 | */ | |
669 | static bool slow_work_cull_thread(void) | |
670 | { | |
671 | unsigned long flags; | |
672 | bool do_cull = false; | |
673 | ||
674 | spin_lock_irqsave(&slow_work_queue_lock, flags); | |
675 | ||
676 | if (slow_work_cull) { | |
677 | slow_work_cull = false; | |
678 | ||
679 | if (list_empty(&slow_work_queue) && | |
680 | list_empty(&vslow_work_queue) && | |
681 | atomic_read(&slow_work_thread_count) > | |
682 | slow_work_min_threads) { | |
009789f0 | 683 | slow_work_schedule_cull(); |
109d9272 DH |
684 | do_cull = true; |
685 | } | |
686 | } | |
687 | ||
688 | spin_unlock_irqrestore(&slow_work_queue_lock, flags); | |
689 | return do_cull; | |
690 | } | |
691 | ||
07fe7cb7 DH |
692 | /* |
693 | * Determine if there is slow work available for dispatch | |
694 | */ | |
695 | static inline bool slow_work_available(int vsmax) | |
696 | { | |
697 | return !list_empty(&slow_work_queue) || | |
698 | (!list_empty(&vslow_work_queue) && | |
699 | atomic_read(&vslow_work_executing_count) < vsmax); | |
700 | } | |
701 | ||
702 | /* | |
703 | * Worker thread dispatcher | |
704 | */ | |
705 | static int slow_work_thread(void *_data) | |
706 | { | |
3d7a641e | 707 | int vsmax, id; |
07fe7cb7 DH |
708 | |
709 | DEFINE_WAIT(wait); | |
710 | ||
711 | set_freezable(); | |
712 | set_user_nice(current, -5); | |
713 | ||
3d7a641e DH |
714 | /* allocate ourselves an ID */ |
715 | spin_lock_irq(&slow_work_queue_lock); | |
716 | id = find_first_zero_bit(slow_work_ids, SLOW_WORK_THREAD_LIMIT); | |
717 | BUG_ON(id < 0 || id >= SLOW_WORK_THREAD_LIMIT); | |
718 | __set_bit(id, slow_work_ids); | |
8fba10a4 | 719 | slow_work_set_thread_pid(id, current->pid); |
3d7a641e DH |
720 | spin_unlock_irq(&slow_work_queue_lock); |
721 | ||
722 | sprintf(current->comm, "kslowd%03u", id); | |
723 | ||
07fe7cb7 DH |
724 | for (;;) { |
725 | vsmax = vslow_work_proportion; | |
726 | vsmax *= atomic_read(&slow_work_thread_count); | |
727 | vsmax /= 100; | |
728 | ||
b415c49a ON |
729 | prepare_to_wait_exclusive(&slow_work_thread_wq, &wait, |
730 | TASK_INTERRUPTIBLE); | |
07fe7cb7 DH |
731 | if (!freezing(current) && |
732 | !slow_work_threads_should_exit && | |
109d9272 DH |
733 | !slow_work_available(vsmax) && |
734 | !slow_work_cull) | |
07fe7cb7 DH |
735 | schedule(); |
736 | finish_wait(&slow_work_thread_wq, &wait); | |
737 | ||
738 | try_to_freeze(); | |
739 | ||
740 | vsmax = vslow_work_proportion; | |
741 | vsmax *= atomic_read(&slow_work_thread_count); | |
742 | vsmax /= 100; | |
743 | ||
3d7a641e | 744 | if (slow_work_available(vsmax) && slow_work_execute(id)) { |
07fe7cb7 | 745 | cond_resched(); |
109d9272 DH |
746 | if (list_empty(&slow_work_queue) && |
747 | list_empty(&vslow_work_queue) && | |
748 | atomic_read(&slow_work_thread_count) > | |
749 | slow_work_min_threads) | |
009789f0 | 750 | slow_work_schedule_cull(); |
07fe7cb7 DH |
751 | continue; |
752 | } | |
753 | ||
754 | if (slow_work_threads_should_exit) | |
755 | break; | |
109d9272 DH |
756 | |
757 | if (slow_work_cull && slow_work_cull_thread()) | |
758 | break; | |
07fe7cb7 DH |
759 | } |
760 | ||
3d7a641e | 761 | spin_lock_irq(&slow_work_queue_lock); |
8fba10a4 | 762 | slow_work_set_thread_pid(id, 0); |
3d7a641e DH |
763 | __clear_bit(id, slow_work_ids); |
764 | spin_unlock_irq(&slow_work_queue_lock); | |
765 | ||
07fe7cb7 DH |
766 | if (atomic_dec_and_test(&slow_work_thread_count)) |
767 | complete_and_exit(&slow_work_last_thread_exited, 0); | |
768 | return 0; | |
769 | } | |
770 | ||
109d9272 DH |
771 | /* |
772 | * Handle thread cull timer expiration | |
773 | */ | |
774 | static void slow_work_cull_timeout(unsigned long data) | |
775 | { | |
776 | slow_work_cull = true; | |
777 | wake_up(&slow_work_thread_wq); | |
778 | } | |
779 | ||
109d9272 DH |
780 | /* |
781 | * Start a new slow work thread | |
782 | */ | |
783 | static void slow_work_new_thread_execute(struct slow_work *work) | |
784 | { | |
785 | struct task_struct *p; | |
786 | ||
787 | if (slow_work_threads_should_exit) | |
788 | return; | |
789 | ||
790 | if (atomic_read(&slow_work_thread_count) >= slow_work_max_threads) | |
791 | return; | |
792 | ||
793 | if (!mutex_trylock(&slow_work_user_lock)) | |
794 | return; | |
795 | ||
796 | slow_work_may_not_start_new_thread = true; | |
797 | atomic_inc(&slow_work_thread_count); | |
798 | p = kthread_run(slow_work_thread, NULL, "kslowd"); | |
799 | if (IS_ERR(p)) { | |
800 | printk(KERN_DEBUG "Slow work thread pool: OOM\n"); | |
801 | if (atomic_dec_and_test(&slow_work_thread_count)) | |
802 | BUG(); /* we're running on a slow work thread... */ | |
803 | mod_timer(&slow_work_oom_timer, | |
009789f0 | 804 | round_jiffies(jiffies + SLOW_WORK_OOM_TIMEOUT)); |
109d9272 DH |
805 | } else { |
806 | /* ratelimit the starting of new threads */ | |
807 | mod_timer(&slow_work_oom_timer, jiffies + 1); | |
808 | } | |
809 | ||
810 | mutex_unlock(&slow_work_user_lock); | |
811 | } | |
812 | ||
813 | static const struct slow_work_ops slow_work_new_thread_ops = { | |
3d7a641e | 814 | .owner = THIS_MODULE, |
109d9272 | 815 | .execute = slow_work_new_thread_execute, |
8fba10a4 DH |
816 | #ifdef CONFIG_SLOW_WORK_PROC |
817 | .desc = slow_work_new_thread_desc, | |
818 | #endif | |
109d9272 DH |
819 | }; |
820 | ||
821 | /* | |
822 | * post-OOM new thread start suppression expiration | |
823 | */ | |
824 | static void slow_work_oom_timeout(unsigned long data) | |
825 | { | |
826 | slow_work_may_not_start_new_thread = false; | |
827 | } | |
828 | ||
12e22c5e DH |
829 | #ifdef CONFIG_SYSCTL |
830 | /* | |
831 | * Handle adjustment of the minimum number of threads | |
832 | */ | |
833 | static int slow_work_min_threads_sysctl(struct ctl_table *table, int write, | |
8d65af78 | 834 | void __user *buffer, |
12e22c5e DH |
835 | size_t *lenp, loff_t *ppos) |
836 | { | |
8d65af78 | 837 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
12e22c5e DH |
838 | int n; |
839 | ||
840 | if (ret == 0) { | |
841 | mutex_lock(&slow_work_user_lock); | |
842 | if (slow_work_user_count > 0) { | |
843 | /* see if we need to start or stop threads */ | |
844 | n = atomic_read(&slow_work_thread_count) - | |
845 | slow_work_min_threads; | |
846 | ||
847 | if (n < 0 && !slow_work_may_not_start_new_thread) | |
848 | slow_work_enqueue(&slow_work_new_thread); | |
849 | else if (n > 0) | |
009789f0 | 850 | slow_work_schedule_cull(); |
12e22c5e DH |
851 | } |
852 | mutex_unlock(&slow_work_user_lock); | |
853 | } | |
854 | ||
855 | return ret; | |
856 | } | |
857 | ||
858 | /* | |
859 | * Handle adjustment of the maximum number of threads | |
860 | */ | |
861 | static int slow_work_max_threads_sysctl(struct ctl_table *table, int write, | |
8d65af78 | 862 | void __user *buffer, |
12e22c5e DH |
863 | size_t *lenp, loff_t *ppos) |
864 | { | |
8d65af78 | 865 | int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
12e22c5e DH |
866 | int n; |
867 | ||
868 | if (ret == 0) { | |
869 | mutex_lock(&slow_work_user_lock); | |
870 | if (slow_work_user_count > 0) { | |
871 | /* see if we need to stop threads */ | |
872 | n = slow_work_max_threads - | |
873 | atomic_read(&slow_work_thread_count); | |
874 | ||
875 | if (n < 0) | |
009789f0 | 876 | slow_work_schedule_cull(); |
12e22c5e DH |
877 | } |
878 | mutex_unlock(&slow_work_user_lock); | |
879 | } | |
880 | ||
881 | return ret; | |
882 | } | |
883 | #endif /* CONFIG_SYSCTL */ | |
884 | ||
07fe7cb7 DH |
885 | /** |
886 | * slow_work_register_user - Register a user of the facility | |
3d7a641e | 887 | * @module: The module about to make use of the facility |
07fe7cb7 DH |
888 | * |
889 | * Register a user of the facility, starting up the initial threads if there | |
890 | * aren't any other users at this point. This will return 0 if successful, or | |
891 | * an error if not. | |
892 | */ | |
3d7a641e | 893 | int slow_work_register_user(struct module *module) |
07fe7cb7 DH |
894 | { |
895 | struct task_struct *p; | |
896 | int loop; | |
897 | ||
898 | mutex_lock(&slow_work_user_lock); | |
899 | ||
900 | if (slow_work_user_count == 0) { | |
901 | printk(KERN_NOTICE "Slow work thread pool: Starting up\n"); | |
902 | init_completion(&slow_work_last_thread_exited); | |
903 | ||
904 | slow_work_threads_should_exit = false; | |
109d9272 DH |
905 | slow_work_init(&slow_work_new_thread, |
906 | &slow_work_new_thread_ops); | |
907 | slow_work_may_not_start_new_thread = false; | |
908 | slow_work_cull = false; | |
07fe7cb7 DH |
909 | |
910 | /* start the minimum number of threads */ | |
911 | for (loop = 0; loop < slow_work_min_threads; loop++) { | |
912 | atomic_inc(&slow_work_thread_count); | |
913 | p = kthread_run(slow_work_thread, NULL, "kslowd"); | |
914 | if (IS_ERR(p)) | |
915 | goto error; | |
916 | } | |
917 | printk(KERN_NOTICE "Slow work thread pool: Ready\n"); | |
918 | } | |
919 | ||
920 | slow_work_user_count++; | |
921 | mutex_unlock(&slow_work_user_lock); | |
922 | return 0; | |
923 | ||
924 | error: | |
925 | if (atomic_dec_and_test(&slow_work_thread_count)) | |
926 | complete(&slow_work_last_thread_exited); | |
927 | if (loop > 0) { | |
928 | printk(KERN_ERR "Slow work thread pool:" | |
929 | " Aborting startup on ENOMEM\n"); | |
930 | slow_work_threads_should_exit = true; | |
931 | wake_up_all(&slow_work_thread_wq); | |
932 | wait_for_completion(&slow_work_last_thread_exited); | |
933 | printk(KERN_ERR "Slow work thread pool: Aborted\n"); | |
934 | } | |
935 | mutex_unlock(&slow_work_user_lock); | |
936 | return PTR_ERR(p); | |
937 | } | |
938 | EXPORT_SYMBOL(slow_work_register_user); | |
939 | ||
3d7a641e DH |
940 | /* |
941 | * wait for all outstanding items from the calling module to complete | |
942 | * - note that more items may be queued whilst we're waiting | |
943 | */ | |
944 | static void slow_work_wait_for_items(struct module *module) | |
945 | { | |
946 | DECLARE_WAITQUEUE(myself, current); | |
947 | struct slow_work *work; | |
948 | int loop; | |
949 | ||
950 | mutex_lock(&slow_work_unreg_sync_lock); | |
951 | add_wait_queue(&slow_work_unreg_wq, &myself); | |
952 | ||
953 | for (;;) { | |
954 | spin_lock_irq(&slow_work_queue_lock); | |
955 | ||
956 | /* first of all, we wait for the last queued item in each list | |
957 | * to be processed */ | |
958 | list_for_each_entry_reverse(work, &vslow_work_queue, link) { | |
959 | if (work->owner == module) { | |
960 | set_current_state(TASK_UNINTERRUPTIBLE); | |
961 | slow_work_unreg_work_item = work; | |
962 | goto do_wait; | |
963 | } | |
964 | } | |
965 | list_for_each_entry_reverse(work, &slow_work_queue, link) { | |
966 | if (work->owner == module) { | |
967 | set_current_state(TASK_UNINTERRUPTIBLE); | |
968 | slow_work_unreg_work_item = work; | |
969 | goto do_wait; | |
970 | } | |
971 | } | |
972 | ||
973 | /* then we wait for the items being processed to finish */ | |
974 | slow_work_unreg_module = module; | |
975 | smp_mb(); | |
976 | for (loop = 0; loop < SLOW_WORK_THREAD_LIMIT; loop++) { | |
977 | if (slow_work_thread_processing[loop] == module) | |
978 | goto do_wait; | |
979 | } | |
980 | spin_unlock_irq(&slow_work_queue_lock); | |
981 | break; /* okay, we're done */ | |
982 | ||
983 | do_wait: | |
984 | spin_unlock_irq(&slow_work_queue_lock); | |
985 | schedule(); | |
986 | slow_work_unreg_work_item = NULL; | |
987 | slow_work_unreg_module = NULL; | |
988 | } | |
989 | ||
990 | remove_wait_queue(&slow_work_unreg_wq, &myself); | |
991 | mutex_unlock(&slow_work_unreg_sync_lock); | |
992 | } | |
993 | ||
07fe7cb7 DH |
994 | /** |
995 | * slow_work_unregister_user - Unregister a user of the facility | |
3d7a641e | 996 | * @module: The module whose items should be cleared |
07fe7cb7 DH |
997 | * |
998 | * Unregister a user of the facility, killing all the threads if this was the | |
999 | * last one. | |
3d7a641e DH |
1000 | * |
1001 | * This waits for all the work items belonging to the nominated module to go | |
1002 | * away before proceeding. | |
07fe7cb7 | 1003 | */ |
3d7a641e | 1004 | void slow_work_unregister_user(struct module *module) |
07fe7cb7 | 1005 | { |
3d7a641e DH |
1006 | /* first of all, wait for all outstanding items from the calling module |
1007 | * to complete */ | |
1008 | if (module) | |
1009 | slow_work_wait_for_items(module); | |
1010 | ||
1011 | /* then we can actually go about shutting down the facility if need | |
1012 | * be */ | |
07fe7cb7 DH |
1013 | mutex_lock(&slow_work_user_lock); |
1014 | ||
1015 | BUG_ON(slow_work_user_count <= 0); | |
1016 | ||
1017 | slow_work_user_count--; | |
1018 | if (slow_work_user_count == 0) { | |
1019 | printk(KERN_NOTICE "Slow work thread pool: Shutting down\n"); | |
1020 | slow_work_threads_should_exit = true; | |
418df63c JC |
1021 | del_timer_sync(&slow_work_cull_timer); |
1022 | del_timer_sync(&slow_work_oom_timer); | |
07fe7cb7 DH |
1023 | wake_up_all(&slow_work_thread_wq); |
1024 | wait_for_completion(&slow_work_last_thread_exited); | |
1025 | printk(KERN_NOTICE "Slow work thread pool:" | |
1026 | " Shut down complete\n"); | |
1027 | } | |
1028 | ||
1029 | mutex_unlock(&slow_work_user_lock); | |
1030 | } | |
1031 | EXPORT_SYMBOL(slow_work_unregister_user); | |
1032 | ||
1033 | /* | |
1034 | * Initialise the slow work facility | |
1035 | */ | |
1036 | static int __init init_slow_work(void) | |
1037 | { | |
1038 | unsigned nr_cpus = num_possible_cpus(); | |
1039 | ||
12e22c5e | 1040 | if (slow_work_max_threads < nr_cpus) |
07fe7cb7 | 1041 | slow_work_max_threads = nr_cpus; |
12e22c5e DH |
1042 | #ifdef CONFIG_SYSCTL |
1043 | if (slow_work_max_max_threads < nr_cpus * 2) | |
1044 | slow_work_max_max_threads = nr_cpus * 2; | |
8fba10a4 DH |
1045 | #endif |
1046 | #ifdef CONFIG_SLOW_WORK_PROC | |
1047 | proc_create("slow_work_rq", S_IFREG | 0400, NULL, | |
1048 | &slow_work_runqueue_fops); | |
12e22c5e | 1049 | #endif |
07fe7cb7 DH |
1050 | return 0; |
1051 | } | |
1052 | ||
1053 | subsys_initcall(init_slow_work); |