Commit | Line | Data |
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8b712842 CM |
1 | /* |
2 | * Copyright (C) 2007 Oracle. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/kthread.h> | |
20 | #include <linux/list.h> | |
21 | #include <linux/spinlock.h> | |
b51912c9 | 22 | #include <linux/freezer.h> |
8b712842 CM |
23 | #include "async-thread.h" |
24 | ||
4a69a410 CM |
25 | #define WORK_QUEUED_BIT 0 |
26 | #define WORK_DONE_BIT 1 | |
27 | #define WORK_ORDER_DONE_BIT 2 | |
d313d7a3 | 28 | #define WORK_HIGH_PRIO_BIT 3 |
4a69a410 | 29 | |
8b712842 CM |
30 | /* |
31 | * container for the kthread task pointer and the list of pending work | |
32 | * One of these is allocated per thread. | |
33 | */ | |
34 | struct btrfs_worker_thread { | |
35d8ba66 CM |
35 | /* pool we belong to */ |
36 | struct btrfs_workers *workers; | |
37 | ||
8b712842 CM |
38 | /* list of struct btrfs_work that are waiting for service */ |
39 | struct list_head pending; | |
d313d7a3 | 40 | struct list_head prio_pending; |
8b712842 CM |
41 | |
42 | /* list of worker threads from struct btrfs_workers */ | |
43 | struct list_head worker_list; | |
44 | ||
45 | /* kthread */ | |
46 | struct task_struct *task; | |
47 | ||
48 | /* number of things on the pending list */ | |
49 | atomic_t num_pending; | |
53863232 | 50 | |
9042846b CM |
51 | /* reference counter for this struct */ |
52 | atomic_t refs; | |
53 | ||
4854ddd0 | 54 | unsigned long sequence; |
8b712842 CM |
55 | |
56 | /* protects the pending list. */ | |
57 | spinlock_t lock; | |
58 | ||
59 | /* set to non-zero when this thread is already awake and kicking */ | |
60 | int working; | |
35d8ba66 CM |
61 | |
62 | /* are we currently idle */ | |
63 | int idle; | |
8b712842 CM |
64 | }; |
65 | ||
35d8ba66 CM |
66 | /* |
67 | * helper function to move a thread onto the idle list after it | |
68 | * has finished some requests. | |
69 | */ | |
70 | static void check_idle_worker(struct btrfs_worker_thread *worker) | |
71 | { | |
72 | if (!worker->idle && atomic_read(&worker->num_pending) < | |
73 | worker->workers->idle_thresh / 2) { | |
74 | unsigned long flags; | |
75 | spin_lock_irqsave(&worker->workers->lock, flags); | |
76 | worker->idle = 1; | |
3e99d8eb CM |
77 | |
78 | /* the list may be empty if the worker is just starting */ | |
79 | if (!list_empty(&worker->worker_list)) { | |
80 | list_move(&worker->worker_list, | |
81 | &worker->workers->idle_list); | |
82 | } | |
35d8ba66 CM |
83 | spin_unlock_irqrestore(&worker->workers->lock, flags); |
84 | } | |
85 | } | |
86 | ||
87 | /* | |
88 | * helper function to move a thread off the idle list after new | |
89 | * pending work is added. | |
90 | */ | |
91 | static void check_busy_worker(struct btrfs_worker_thread *worker) | |
92 | { | |
93 | if (worker->idle && atomic_read(&worker->num_pending) >= | |
94 | worker->workers->idle_thresh) { | |
95 | unsigned long flags; | |
96 | spin_lock_irqsave(&worker->workers->lock, flags); | |
97 | worker->idle = 0; | |
3e99d8eb CM |
98 | |
99 | if (!list_empty(&worker->worker_list)) { | |
100 | list_move_tail(&worker->worker_list, | |
101 | &worker->workers->worker_list); | |
102 | } | |
35d8ba66 CM |
103 | spin_unlock_irqrestore(&worker->workers->lock, flags); |
104 | } | |
105 | } | |
106 | ||
9042846b CM |
107 | static void check_pending_worker_creates(struct btrfs_worker_thread *worker) |
108 | { | |
109 | struct btrfs_workers *workers = worker->workers; | |
110 | unsigned long flags; | |
111 | ||
112 | rmb(); | |
113 | if (!workers->atomic_start_pending) | |
114 | return; | |
115 | ||
116 | spin_lock_irqsave(&workers->lock, flags); | |
117 | if (!workers->atomic_start_pending) | |
118 | goto out; | |
119 | ||
120 | workers->atomic_start_pending = 0; | |
121 | if (workers->num_workers >= workers->max_workers) | |
122 | goto out; | |
123 | ||
124 | spin_unlock_irqrestore(&workers->lock, flags); | |
125 | btrfs_start_workers(workers, 1); | |
126 | return; | |
127 | ||
128 | out: | |
129 | spin_unlock_irqrestore(&workers->lock, flags); | |
130 | } | |
131 | ||
4a69a410 CM |
132 | static noinline int run_ordered_completions(struct btrfs_workers *workers, |
133 | struct btrfs_work *work) | |
134 | { | |
4a69a410 CM |
135 | if (!workers->ordered) |
136 | return 0; | |
137 | ||
138 | set_bit(WORK_DONE_BIT, &work->flags); | |
139 | ||
4e3f9c50 | 140 | spin_lock(&workers->order_lock); |
4a69a410 | 141 | |
d313d7a3 CM |
142 | while (1) { |
143 | if (!list_empty(&workers->prio_order_list)) { | |
144 | work = list_entry(workers->prio_order_list.next, | |
145 | struct btrfs_work, order_list); | |
146 | } else if (!list_empty(&workers->order_list)) { | |
147 | work = list_entry(workers->order_list.next, | |
148 | struct btrfs_work, order_list); | |
149 | } else { | |
150 | break; | |
151 | } | |
4a69a410 CM |
152 | if (!test_bit(WORK_DONE_BIT, &work->flags)) |
153 | break; | |
154 | ||
155 | /* we are going to call the ordered done function, but | |
156 | * we leave the work item on the list as a barrier so | |
157 | * that later work items that are done don't have their | |
158 | * functions called before this one returns | |
159 | */ | |
160 | if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags)) | |
161 | break; | |
162 | ||
4e3f9c50 | 163 | spin_unlock(&workers->order_lock); |
4a69a410 CM |
164 | |
165 | work->ordered_func(work); | |
166 | ||
167 | /* now take the lock again and call the freeing code */ | |
4e3f9c50 | 168 | spin_lock(&workers->order_lock); |
4a69a410 CM |
169 | list_del(&work->order_list); |
170 | work->ordered_free(work); | |
171 | } | |
172 | ||
4e3f9c50 | 173 | spin_unlock(&workers->order_lock); |
4a69a410 CM |
174 | return 0; |
175 | } | |
176 | ||
9042846b CM |
177 | static void put_worker(struct btrfs_worker_thread *worker) |
178 | { | |
179 | if (atomic_dec_and_test(&worker->refs)) | |
180 | kfree(worker); | |
181 | } | |
182 | ||
183 | static int try_worker_shutdown(struct btrfs_worker_thread *worker) | |
184 | { | |
185 | int freeit = 0; | |
186 | ||
187 | spin_lock_irq(&worker->lock); | |
188 | spin_lock_irq(&worker->workers->lock); | |
189 | if (worker->workers->num_workers > 1 && | |
190 | worker->idle && | |
191 | !worker->working && | |
192 | !list_empty(&worker->worker_list) && | |
193 | list_empty(&worker->prio_pending) && | |
194 | list_empty(&worker->pending)) { | |
195 | freeit = 1; | |
196 | list_del_init(&worker->worker_list); | |
197 | worker->workers->num_workers--; | |
198 | } | |
199 | spin_unlock_irq(&worker->workers->lock); | |
200 | spin_unlock_irq(&worker->lock); | |
201 | ||
202 | if (freeit) | |
203 | put_worker(worker); | |
204 | return freeit; | |
205 | } | |
206 | ||
4f878e84 CM |
207 | static struct btrfs_work *get_next_work(struct btrfs_worker_thread *worker, |
208 | struct list_head *prio_head, | |
209 | struct list_head *head) | |
210 | { | |
211 | struct btrfs_work *work = NULL; | |
212 | struct list_head *cur = NULL; | |
213 | ||
214 | if(!list_empty(prio_head)) | |
215 | cur = prio_head->next; | |
216 | ||
217 | smp_mb(); | |
218 | if (!list_empty(&worker->prio_pending)) | |
219 | goto refill; | |
220 | ||
221 | if (!list_empty(head)) | |
222 | cur = head->next; | |
223 | ||
224 | if (cur) | |
225 | goto out; | |
226 | ||
227 | refill: | |
228 | spin_lock_irq(&worker->lock); | |
229 | list_splice_tail_init(&worker->prio_pending, prio_head); | |
230 | list_splice_tail_init(&worker->pending, head); | |
231 | ||
232 | if (!list_empty(prio_head)) | |
233 | cur = prio_head->next; | |
234 | else if (!list_empty(head)) | |
235 | cur = head->next; | |
236 | spin_unlock_irq(&worker->lock); | |
237 | ||
238 | if (!cur) | |
239 | goto out_fail; | |
240 | ||
241 | out: | |
242 | work = list_entry(cur, struct btrfs_work, list); | |
243 | ||
244 | out_fail: | |
245 | return work; | |
246 | } | |
247 | ||
8b712842 CM |
248 | /* |
249 | * main loop for servicing work items | |
250 | */ | |
251 | static int worker_loop(void *arg) | |
252 | { | |
253 | struct btrfs_worker_thread *worker = arg; | |
4f878e84 CM |
254 | struct list_head head; |
255 | struct list_head prio_head; | |
8b712842 | 256 | struct btrfs_work *work; |
4f878e84 CM |
257 | |
258 | INIT_LIST_HEAD(&head); | |
259 | INIT_LIST_HEAD(&prio_head); | |
260 | ||
8b712842 | 261 | do { |
4f878e84 | 262 | again: |
d313d7a3 | 263 | while (1) { |
4f878e84 CM |
264 | |
265 | ||
266 | work = get_next_work(worker, &prio_head, &head); | |
267 | if (!work) | |
d313d7a3 CM |
268 | break; |
269 | ||
8b712842 | 270 | list_del(&work->list); |
4a69a410 | 271 | clear_bit(WORK_QUEUED_BIT, &work->flags); |
8b712842 CM |
272 | |
273 | work->worker = worker; | |
8b712842 CM |
274 | |
275 | work->func(work); | |
276 | ||
277 | atomic_dec(&worker->num_pending); | |
4a69a410 CM |
278 | /* |
279 | * unless this is an ordered work queue, | |
280 | * 'work' was probably freed by func above. | |
281 | */ | |
282 | run_ordered_completions(worker->workers, work); | |
283 | ||
9042846b CM |
284 | check_pending_worker_creates(worker); |
285 | ||
8b712842 | 286 | } |
4f878e84 CM |
287 | |
288 | spin_lock_irq(&worker->lock); | |
289 | check_idle_worker(worker); | |
290 | ||
8b712842 | 291 | if (freezing(current)) { |
b51912c9 CM |
292 | worker->working = 0; |
293 | spin_unlock_irq(&worker->lock); | |
8b712842 CM |
294 | refrigerator(); |
295 | } else { | |
8b712842 | 296 | spin_unlock_irq(&worker->lock); |
b51912c9 CM |
297 | if (!kthread_should_stop()) { |
298 | cpu_relax(); | |
299 | /* | |
300 | * we've dropped the lock, did someone else | |
301 | * jump_in? | |
302 | */ | |
303 | smp_mb(); | |
d313d7a3 CM |
304 | if (!list_empty(&worker->pending) || |
305 | !list_empty(&worker->prio_pending)) | |
b51912c9 CM |
306 | continue; |
307 | ||
308 | /* | |
309 | * this short schedule allows more work to | |
310 | * come in without the queue functions | |
311 | * needing to go through wake_up_process() | |
312 | * | |
313 | * worker->working is still 1, so nobody | |
314 | * is going to try and wake us up | |
315 | */ | |
316 | schedule_timeout(1); | |
317 | smp_mb(); | |
d313d7a3 CM |
318 | if (!list_empty(&worker->pending) || |
319 | !list_empty(&worker->prio_pending)) | |
b51912c9 CM |
320 | continue; |
321 | ||
b5555f77 AG |
322 | if (kthread_should_stop()) |
323 | break; | |
324 | ||
b51912c9 CM |
325 | /* still no more work?, sleep for real */ |
326 | spin_lock_irq(&worker->lock); | |
327 | set_current_state(TASK_INTERRUPTIBLE); | |
d313d7a3 | 328 | if (!list_empty(&worker->pending) || |
4f878e84 CM |
329 | !list_empty(&worker->prio_pending)) { |
330 | spin_unlock_irq(&worker->lock); | |
331 | goto again; | |
332 | } | |
b51912c9 CM |
333 | |
334 | /* | |
335 | * this makes sure we get a wakeup when someone | |
336 | * adds something new to the queue | |
337 | */ | |
338 | worker->working = 0; | |
339 | spin_unlock_irq(&worker->lock); | |
340 | ||
9042846b CM |
341 | if (!kthread_should_stop()) { |
342 | schedule_timeout(HZ * 120); | |
343 | if (!worker->working && | |
344 | try_worker_shutdown(worker)) { | |
345 | return 0; | |
346 | } | |
347 | } | |
b51912c9 | 348 | } |
8b712842 CM |
349 | __set_current_state(TASK_RUNNING); |
350 | } | |
351 | } while (!kthread_should_stop()); | |
352 | return 0; | |
353 | } | |
354 | ||
355 | /* | |
356 | * this will wait for all the worker threads to shutdown | |
357 | */ | |
358 | int btrfs_stop_workers(struct btrfs_workers *workers) | |
359 | { | |
360 | struct list_head *cur; | |
361 | struct btrfs_worker_thread *worker; | |
9042846b | 362 | int can_stop; |
8b712842 | 363 | |
9042846b | 364 | spin_lock_irq(&workers->lock); |
35d8ba66 | 365 | list_splice_init(&workers->idle_list, &workers->worker_list); |
d397712b | 366 | while (!list_empty(&workers->worker_list)) { |
8b712842 CM |
367 | cur = workers->worker_list.next; |
368 | worker = list_entry(cur, struct btrfs_worker_thread, | |
369 | worker_list); | |
9042846b CM |
370 | |
371 | atomic_inc(&worker->refs); | |
372 | workers->num_workers -= 1; | |
373 | if (!list_empty(&worker->worker_list)) { | |
374 | list_del_init(&worker->worker_list); | |
375 | put_worker(worker); | |
376 | can_stop = 1; | |
377 | } else | |
378 | can_stop = 0; | |
379 | spin_unlock_irq(&workers->lock); | |
380 | if (can_stop) | |
381 | kthread_stop(worker->task); | |
382 | spin_lock_irq(&workers->lock); | |
383 | put_worker(worker); | |
8b712842 | 384 | } |
9042846b | 385 | spin_unlock_irq(&workers->lock); |
8b712842 CM |
386 | return 0; |
387 | } | |
388 | ||
389 | /* | |
390 | * simple init on struct btrfs_workers | |
391 | */ | |
5443be45 | 392 | void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max) |
8b712842 CM |
393 | { |
394 | workers->num_workers = 0; | |
395 | INIT_LIST_HEAD(&workers->worker_list); | |
35d8ba66 | 396 | INIT_LIST_HEAD(&workers->idle_list); |
4a69a410 | 397 | INIT_LIST_HEAD(&workers->order_list); |
d313d7a3 | 398 | INIT_LIST_HEAD(&workers->prio_order_list); |
8b712842 | 399 | spin_lock_init(&workers->lock); |
4e3f9c50 | 400 | spin_lock_init(&workers->order_lock); |
8b712842 | 401 | workers->max_workers = max; |
61b49440 | 402 | workers->idle_thresh = 32; |
5443be45 | 403 | workers->name = name; |
4a69a410 | 404 | workers->ordered = 0; |
9042846b CM |
405 | workers->atomic_start_pending = 0; |
406 | workers->atomic_worker_start = 0; | |
8b712842 CM |
407 | } |
408 | ||
409 | /* | |
410 | * starts new worker threads. This does not enforce the max worker | |
411 | * count in case you need to temporarily go past it. | |
412 | */ | |
413 | int btrfs_start_workers(struct btrfs_workers *workers, int num_workers) | |
414 | { | |
415 | struct btrfs_worker_thread *worker; | |
416 | int ret = 0; | |
417 | int i; | |
418 | ||
419 | for (i = 0; i < num_workers; i++) { | |
420 | worker = kzalloc(sizeof(*worker), GFP_NOFS); | |
421 | if (!worker) { | |
422 | ret = -ENOMEM; | |
423 | goto fail; | |
424 | } | |
425 | ||
426 | INIT_LIST_HEAD(&worker->pending); | |
d313d7a3 | 427 | INIT_LIST_HEAD(&worker->prio_pending); |
8b712842 CM |
428 | INIT_LIST_HEAD(&worker->worker_list); |
429 | spin_lock_init(&worker->lock); | |
4e3f9c50 | 430 | |
8b712842 | 431 | atomic_set(&worker->num_pending, 0); |
9042846b | 432 | atomic_set(&worker->refs, 1); |
fd0fb038 | 433 | worker->workers = workers; |
5443be45 CM |
434 | worker->task = kthread_run(worker_loop, worker, |
435 | "btrfs-%s-%d", workers->name, | |
436 | workers->num_workers + i); | |
8b712842 CM |
437 | if (IS_ERR(worker->task)) { |
438 | ret = PTR_ERR(worker->task); | |
9b627e9b | 439 | kfree(worker); |
8b712842 CM |
440 | goto fail; |
441 | } | |
8b712842 | 442 | spin_lock_irq(&workers->lock); |
35d8ba66 | 443 | list_add_tail(&worker->worker_list, &workers->idle_list); |
4854ddd0 | 444 | worker->idle = 1; |
8b712842 CM |
445 | workers->num_workers++; |
446 | spin_unlock_irq(&workers->lock); | |
447 | } | |
448 | return 0; | |
449 | fail: | |
450 | btrfs_stop_workers(workers); | |
451 | return ret; | |
452 | } | |
453 | ||
454 | /* | |
455 | * run through the list and find a worker thread that doesn't have a lot | |
456 | * to do right now. This can return null if we aren't yet at the thread | |
457 | * count limit and all of the threads are busy. | |
458 | */ | |
459 | static struct btrfs_worker_thread *next_worker(struct btrfs_workers *workers) | |
460 | { | |
461 | struct btrfs_worker_thread *worker; | |
462 | struct list_head *next; | |
8b712842 CM |
463 | int enforce_min = workers->num_workers < workers->max_workers; |
464 | ||
8b712842 | 465 | /* |
35d8ba66 CM |
466 | * if we find an idle thread, don't move it to the end of the |
467 | * idle list. This improves the chance that the next submission | |
468 | * will reuse the same thread, and maybe catch it while it is still | |
469 | * working | |
8b712842 | 470 | */ |
35d8ba66 CM |
471 | if (!list_empty(&workers->idle_list)) { |
472 | next = workers->idle_list.next; | |
8b712842 CM |
473 | worker = list_entry(next, struct btrfs_worker_thread, |
474 | worker_list); | |
35d8ba66 | 475 | return worker; |
8b712842 | 476 | } |
35d8ba66 CM |
477 | if (enforce_min || list_empty(&workers->worker_list)) |
478 | return NULL; | |
479 | ||
8b712842 | 480 | /* |
35d8ba66 | 481 | * if we pick a busy task, move the task to the end of the list. |
d352ac68 CM |
482 | * hopefully this will keep things somewhat evenly balanced. |
483 | * Do the move in batches based on the sequence number. This groups | |
484 | * requests submitted at roughly the same time onto the same worker. | |
8b712842 | 485 | */ |
35d8ba66 CM |
486 | next = workers->worker_list.next; |
487 | worker = list_entry(next, struct btrfs_worker_thread, worker_list); | |
4854ddd0 CM |
488 | atomic_inc(&worker->num_pending); |
489 | worker->sequence++; | |
d352ac68 | 490 | |
53863232 | 491 | if (worker->sequence % workers->idle_thresh == 0) |
4854ddd0 | 492 | list_move_tail(next, &workers->worker_list); |
8b712842 CM |
493 | return worker; |
494 | } | |
495 | ||
d352ac68 CM |
496 | /* |
497 | * selects a worker thread to take the next job. This will either find | |
498 | * an idle worker, start a new worker up to the max count, or just return | |
499 | * one of the existing busy workers. | |
500 | */ | |
8b712842 CM |
501 | static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers) |
502 | { | |
503 | struct btrfs_worker_thread *worker; | |
504 | unsigned long flags; | |
9042846b | 505 | struct list_head *fallback; |
8b712842 CM |
506 | |
507 | again: | |
508 | spin_lock_irqsave(&workers->lock, flags); | |
509 | worker = next_worker(workers); | |
8b712842 CM |
510 | |
511 | if (!worker) { | |
8b712842 | 512 | if (workers->num_workers >= workers->max_workers) { |
9042846b CM |
513 | goto fallback; |
514 | } else if (workers->atomic_worker_start) { | |
515 | workers->atomic_start_pending = 1; | |
516 | goto fallback; | |
8b712842 CM |
517 | } else { |
518 | spin_unlock_irqrestore(&workers->lock, flags); | |
519 | /* we're below the limit, start another worker */ | |
520 | btrfs_start_workers(workers, 1); | |
521 | goto again; | |
522 | } | |
523 | } | |
4e3f9c50 | 524 | spin_unlock_irqrestore(&workers->lock, flags); |
8b712842 | 525 | return worker; |
9042846b CM |
526 | |
527 | fallback: | |
528 | fallback = NULL; | |
529 | /* | |
530 | * we have failed to find any workers, just | |
531 | * return the first one we can find. | |
532 | */ | |
533 | if (!list_empty(&workers->worker_list)) | |
534 | fallback = workers->worker_list.next; | |
535 | if (!list_empty(&workers->idle_list)) | |
536 | fallback = workers->idle_list.next; | |
537 | BUG_ON(!fallback); | |
538 | worker = list_entry(fallback, | |
539 | struct btrfs_worker_thread, worker_list); | |
540 | spin_unlock_irqrestore(&workers->lock, flags); | |
541 | return worker; | |
8b712842 CM |
542 | } |
543 | ||
544 | /* | |
545 | * btrfs_requeue_work just puts the work item back on the tail of the list | |
546 | * it was taken from. It is intended for use with long running work functions | |
547 | * that make some progress and want to give the cpu up for others. | |
548 | */ | |
549 | int btrfs_requeue_work(struct btrfs_work *work) | |
550 | { | |
551 | struct btrfs_worker_thread *worker = work->worker; | |
552 | unsigned long flags; | |
a6837051 | 553 | int wake = 0; |
8b712842 | 554 | |
4a69a410 | 555 | if (test_and_set_bit(WORK_QUEUED_BIT, &work->flags)) |
8b712842 CM |
556 | goto out; |
557 | ||
558 | spin_lock_irqsave(&worker->lock, flags); | |
d313d7a3 CM |
559 | if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) |
560 | list_add_tail(&work->list, &worker->prio_pending); | |
561 | else | |
562 | list_add_tail(&work->list, &worker->pending); | |
b51912c9 | 563 | atomic_inc(&worker->num_pending); |
75ccf47d CM |
564 | |
565 | /* by definition we're busy, take ourselves off the idle | |
566 | * list | |
567 | */ | |
568 | if (worker->idle) { | |
29c5e8ce | 569 | spin_lock(&worker->workers->lock); |
75ccf47d CM |
570 | worker->idle = 0; |
571 | list_move_tail(&worker->worker_list, | |
572 | &worker->workers->worker_list); | |
29c5e8ce | 573 | spin_unlock(&worker->workers->lock); |
75ccf47d | 574 | } |
a6837051 CM |
575 | if (!worker->working) { |
576 | wake = 1; | |
577 | worker->working = 1; | |
578 | } | |
75ccf47d | 579 | |
a6837051 CM |
580 | if (wake) |
581 | wake_up_process(worker->task); | |
9042846b | 582 | spin_unlock_irqrestore(&worker->lock, flags); |
8b712842 | 583 | out: |
a6837051 | 584 | |
8b712842 CM |
585 | return 0; |
586 | } | |
587 | ||
d313d7a3 CM |
588 | void btrfs_set_work_high_prio(struct btrfs_work *work) |
589 | { | |
590 | set_bit(WORK_HIGH_PRIO_BIT, &work->flags); | |
591 | } | |
592 | ||
8b712842 CM |
593 | /* |
594 | * places a struct btrfs_work into the pending queue of one of the kthreads | |
595 | */ | |
596 | int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work) | |
597 | { | |
598 | struct btrfs_worker_thread *worker; | |
599 | unsigned long flags; | |
600 | int wake = 0; | |
601 | ||
602 | /* don't requeue something already on a list */ | |
4a69a410 | 603 | if (test_and_set_bit(WORK_QUEUED_BIT, &work->flags)) |
8b712842 CM |
604 | goto out; |
605 | ||
606 | worker = find_worker(workers); | |
4a69a410 | 607 | if (workers->ordered) { |
4e3f9c50 CM |
608 | /* |
609 | * you're not allowed to do ordered queues from an | |
610 | * interrupt handler | |
611 | */ | |
612 | spin_lock(&workers->order_lock); | |
d313d7a3 CM |
613 | if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) { |
614 | list_add_tail(&work->order_list, | |
615 | &workers->prio_order_list); | |
616 | } else { | |
617 | list_add_tail(&work->order_list, &workers->order_list); | |
618 | } | |
4e3f9c50 | 619 | spin_unlock(&workers->order_lock); |
4a69a410 CM |
620 | } else { |
621 | INIT_LIST_HEAD(&work->order_list); | |
622 | } | |
8b712842 CM |
623 | |
624 | spin_lock_irqsave(&worker->lock, flags); | |
a6837051 | 625 | |
d313d7a3 CM |
626 | if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) |
627 | list_add_tail(&work->list, &worker->prio_pending); | |
628 | else | |
629 | list_add_tail(&work->list, &worker->pending); | |
8b712842 | 630 | atomic_inc(&worker->num_pending); |
35d8ba66 | 631 | check_busy_worker(worker); |
8b712842 CM |
632 | |
633 | /* | |
634 | * avoid calling into wake_up_process if this thread has already | |
635 | * been kicked | |
636 | */ | |
637 | if (!worker->working) | |
638 | wake = 1; | |
639 | worker->working = 1; | |
640 | ||
8b712842 CM |
641 | if (wake) |
642 | wake_up_process(worker->task); | |
9042846b CM |
643 | spin_unlock_irqrestore(&worker->lock, flags); |
644 | ||
8b712842 CM |
645 | out: |
646 | return 0; | |
647 | } |