Commit | Line | Data |
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1da177e4 | 1 | /* |
c54fce6e | 2 | * kernel/workqueue.c - generic async execution with shared worker pool |
1da177e4 | 3 | * |
c54fce6e | 4 | * Copyright (C) 2002 Ingo Molnar |
1da177e4 | 5 | * |
c54fce6e TH |
6 | * Derived from the taskqueue/keventd code by: |
7 | * David Woodhouse <dwmw2@infradead.org> | |
8 | * Andrew Morton | |
9 | * Kai Petzke <wpp@marie.physik.tu-berlin.de> | |
10 | * Theodore Ts'o <tytso@mit.edu> | |
1da177e4 | 11 | * |
c54fce6e | 12 | * Made to use alloc_percpu by Christoph Lameter. |
1da177e4 | 13 | * |
c54fce6e TH |
14 | * Copyright (C) 2010 SUSE Linux Products GmbH |
15 | * Copyright (C) 2010 Tejun Heo <tj@kernel.org> | |
89ada679 | 16 | * |
c54fce6e TH |
17 | * This is the generic async execution mechanism. Work items as are |
18 | * executed in process context. The worker pool is shared and | |
19 | * automatically managed. There is one worker pool for each CPU and | |
20 | * one extra for works which are better served by workers which are | |
21 | * not bound to any specific CPU. | |
22 | * | |
23 | * Please read Documentation/workqueue.txt for details. | |
1da177e4 LT |
24 | */ |
25 | ||
9984de1a | 26 | #include <linux/export.h> |
1da177e4 LT |
27 | #include <linux/kernel.h> |
28 | #include <linux/sched.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/signal.h> | |
31 | #include <linux/completion.h> | |
32 | #include <linux/workqueue.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/cpu.h> | |
35 | #include <linux/notifier.h> | |
36 | #include <linux/kthread.h> | |
1fa44eca | 37 | #include <linux/hardirq.h> |
46934023 | 38 | #include <linux/mempolicy.h> |
341a5958 | 39 | #include <linux/freezer.h> |
d5abe669 PZ |
40 | #include <linux/kallsyms.h> |
41 | #include <linux/debug_locks.h> | |
4e6045f1 | 42 | #include <linux/lockdep.h> |
c34056a3 | 43 | #include <linux/idr.h> |
e22bee78 TH |
44 | |
45 | #include "workqueue_sched.h" | |
1da177e4 | 46 | |
c8e55f36 | 47 | enum { |
bc2ae0f5 TH |
48 | /* |
49 | * global_cwq flags | |
50 | * | |
51 | * A bound gcwq is either associated or disassociated with its CPU. | |
52 | * While associated (!DISASSOCIATED), all workers are bound to the | |
53 | * CPU and none has %WORKER_UNBOUND set and concurrency management | |
54 | * is in effect. | |
55 | * | |
56 | * While DISASSOCIATED, the cpu may be offline and all workers have | |
57 | * %WORKER_UNBOUND set and concurrency management disabled, and may | |
58 | * be executing on any CPU. The gcwq behaves as an unbound one. | |
59 | * | |
60 | * Note that DISASSOCIATED can be flipped only while holding | |
61 | * managership of all pools on the gcwq to avoid changing binding | |
62 | * state while create_worker() is in progress. | |
63 | */ | |
11ebea50 TH |
64 | GCWQ_DISASSOCIATED = 1 << 0, /* cpu can't serve workers */ |
65 | GCWQ_FREEZING = 1 << 1, /* freeze in progress */ | |
66 | ||
67 | /* pool flags */ | |
68 | POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ | |
552a37e9 | 69 | POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */ |
db7bccf4 | 70 | |
c8e55f36 TH |
71 | /* worker flags */ |
72 | WORKER_STARTED = 1 << 0, /* started */ | |
73 | WORKER_DIE = 1 << 1, /* die die die */ | |
74 | WORKER_IDLE = 1 << 2, /* is idle */ | |
e22bee78 | 75 | WORKER_PREP = 1 << 3, /* preparing to run works */ |
e22bee78 | 76 | WORKER_REBIND = 1 << 5, /* mom is home, come back */ |
fb0e7beb | 77 | WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ |
f3421797 | 78 | WORKER_UNBOUND = 1 << 7, /* worker is unbound */ |
e22bee78 | 79 | |
403c821d TH |
80 | WORKER_NOT_RUNNING = WORKER_PREP | WORKER_REBIND | WORKER_UNBOUND | |
81 | WORKER_CPU_INTENSIVE, | |
db7bccf4 | 82 | |
3270476a | 83 | NR_WORKER_POOLS = 2, /* # worker pools per gcwq */ |
4ce62e9e | 84 | |
c8e55f36 TH |
85 | BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ |
86 | BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER, | |
87 | BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1, | |
db7bccf4 | 88 | |
e22bee78 TH |
89 | MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ |
90 | IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ | |
91 | ||
3233cdbd TH |
92 | MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, |
93 | /* call for help after 10ms | |
94 | (min two ticks) */ | |
e22bee78 TH |
95 | MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ |
96 | CREATE_COOLDOWN = HZ, /* time to breath after fail */ | |
e22bee78 TH |
97 | |
98 | /* | |
99 | * Rescue workers are used only on emergencies and shared by | |
100 | * all cpus. Give -20. | |
101 | */ | |
102 | RESCUER_NICE_LEVEL = -20, | |
3270476a | 103 | HIGHPRI_NICE_LEVEL = -20, |
c8e55f36 | 104 | }; |
1da177e4 LT |
105 | |
106 | /* | |
4690c4ab TH |
107 | * Structure fields follow one of the following exclusion rules. |
108 | * | |
e41e704b TH |
109 | * I: Modifiable by initialization/destruction paths and read-only for |
110 | * everyone else. | |
4690c4ab | 111 | * |
e22bee78 TH |
112 | * P: Preemption protected. Disabling preemption is enough and should |
113 | * only be modified and accessed from the local cpu. | |
114 | * | |
8b03ae3c | 115 | * L: gcwq->lock protected. Access with gcwq->lock held. |
4690c4ab | 116 | * |
e22bee78 TH |
117 | * X: During normal operation, modification requires gcwq->lock and |
118 | * should be done only from local cpu. Either disabling preemption | |
119 | * on local cpu or grabbing gcwq->lock is enough for read access. | |
f3421797 | 120 | * If GCWQ_DISASSOCIATED is set, it's identical to L. |
e22bee78 | 121 | * |
73f53c4a TH |
122 | * F: wq->flush_mutex protected. |
123 | * | |
4690c4ab | 124 | * W: workqueue_lock protected. |
1da177e4 | 125 | */ |
1da177e4 | 126 | |
8b03ae3c | 127 | struct global_cwq; |
bd7bdd43 | 128 | struct worker_pool; |
25511a47 | 129 | struct idle_rebind; |
1da177e4 | 130 | |
e22bee78 TH |
131 | /* |
132 | * The poor guys doing the actual heavy lifting. All on-duty workers | |
133 | * are either serving the manager role, on idle list or on busy hash. | |
134 | */ | |
c34056a3 | 135 | struct worker { |
c8e55f36 TH |
136 | /* on idle list while idle, on busy hash table while busy */ |
137 | union { | |
138 | struct list_head entry; /* L: while idle */ | |
139 | struct hlist_node hentry; /* L: while busy */ | |
140 | }; | |
1da177e4 | 141 | |
c34056a3 | 142 | struct work_struct *current_work; /* L: work being processed */ |
8cca0eea | 143 | struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ |
affee4b2 | 144 | struct list_head scheduled; /* L: scheduled works */ |
c34056a3 | 145 | struct task_struct *task; /* I: worker task */ |
bd7bdd43 | 146 | struct worker_pool *pool; /* I: the associated pool */ |
e22bee78 TH |
147 | /* 64 bytes boundary on 64bit, 32 on 32bit */ |
148 | unsigned long last_active; /* L: last active timestamp */ | |
149 | unsigned int flags; /* X: flags */ | |
c34056a3 | 150 | int id; /* I: worker id */ |
25511a47 TH |
151 | |
152 | /* for rebinding worker to CPU */ | |
153 | struct idle_rebind *idle_rebind; /* L: for idle worker */ | |
154 | struct work_struct rebind_work; /* L: for busy worker */ | |
c34056a3 TH |
155 | }; |
156 | ||
bd7bdd43 TH |
157 | struct worker_pool { |
158 | struct global_cwq *gcwq; /* I: the owning gcwq */ | |
11ebea50 | 159 | unsigned int flags; /* X: flags */ |
bd7bdd43 TH |
160 | |
161 | struct list_head worklist; /* L: list of pending works */ | |
162 | int nr_workers; /* L: total number of workers */ | |
163 | int nr_idle; /* L: currently idle ones */ | |
164 | ||
165 | struct list_head idle_list; /* X: list of idle workers */ | |
166 | struct timer_list idle_timer; /* L: worker idle timeout */ | |
167 | struct timer_list mayday_timer; /* L: SOS timer for workers */ | |
168 | ||
60373152 | 169 | struct mutex manager_mutex; /* mutex manager should hold */ |
bd7bdd43 | 170 | struct ida worker_ida; /* L: for worker IDs */ |
bd7bdd43 TH |
171 | }; |
172 | ||
8b03ae3c | 173 | /* |
e22bee78 TH |
174 | * Global per-cpu workqueue. There's one and only one for each cpu |
175 | * and all works are queued and processed here regardless of their | |
176 | * target workqueues. | |
8b03ae3c TH |
177 | */ |
178 | struct global_cwq { | |
179 | spinlock_t lock; /* the gcwq lock */ | |
180 | unsigned int cpu; /* I: the associated cpu */ | |
db7bccf4 | 181 | unsigned int flags; /* L: GCWQ_* flags */ |
c8e55f36 | 182 | |
bd7bdd43 | 183 | /* workers are chained either in busy_hash or pool idle_list */ |
c8e55f36 TH |
184 | struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE]; |
185 | /* L: hash of busy workers */ | |
186 | ||
3270476a | 187 | struct worker_pool pools[2]; /* normal and highpri pools */ |
db7bccf4 | 188 | |
25511a47 | 189 | wait_queue_head_t rebind_hold; /* rebind hold wait */ |
8b03ae3c TH |
190 | } ____cacheline_aligned_in_smp; |
191 | ||
1da177e4 | 192 | /* |
502ca9d8 | 193 | * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of |
0f900049 TH |
194 | * work_struct->data are used for flags and thus cwqs need to be |
195 | * aligned at two's power of the number of flag bits. | |
1da177e4 LT |
196 | */ |
197 | struct cpu_workqueue_struct { | |
bd7bdd43 | 198 | struct worker_pool *pool; /* I: the associated pool */ |
4690c4ab | 199 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
73f53c4a TH |
200 | int work_color; /* L: current color */ |
201 | int flush_color; /* L: flushing color */ | |
202 | int nr_in_flight[WORK_NR_COLORS]; | |
203 | /* L: nr of in_flight works */ | |
1e19ffc6 | 204 | int nr_active; /* L: nr of active works */ |
a0a1a5fd | 205 | int max_active; /* L: max active works */ |
1e19ffc6 | 206 | struct list_head delayed_works; /* L: delayed works */ |
0f900049 | 207 | }; |
1da177e4 | 208 | |
73f53c4a TH |
209 | /* |
210 | * Structure used to wait for workqueue flush. | |
211 | */ | |
212 | struct wq_flusher { | |
213 | struct list_head list; /* F: list of flushers */ | |
214 | int flush_color; /* F: flush color waiting for */ | |
215 | struct completion done; /* flush completion */ | |
216 | }; | |
217 | ||
f2e005aa TH |
218 | /* |
219 | * All cpumasks are assumed to be always set on UP and thus can't be | |
220 | * used to determine whether there's something to be done. | |
221 | */ | |
222 | #ifdef CONFIG_SMP | |
223 | typedef cpumask_var_t mayday_mask_t; | |
224 | #define mayday_test_and_set_cpu(cpu, mask) \ | |
225 | cpumask_test_and_set_cpu((cpu), (mask)) | |
226 | #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) | |
227 | #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) | |
9c37547a | 228 | #define alloc_mayday_mask(maskp, gfp) zalloc_cpumask_var((maskp), (gfp)) |
f2e005aa TH |
229 | #define free_mayday_mask(mask) free_cpumask_var((mask)) |
230 | #else | |
231 | typedef unsigned long mayday_mask_t; | |
232 | #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) | |
233 | #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) | |
234 | #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) | |
235 | #define alloc_mayday_mask(maskp, gfp) true | |
236 | #define free_mayday_mask(mask) do { } while (0) | |
237 | #endif | |
1da177e4 LT |
238 | |
239 | /* | |
240 | * The externally visible workqueue abstraction is an array of | |
241 | * per-CPU workqueues: | |
242 | */ | |
243 | struct workqueue_struct { | |
9c5a2ba7 | 244 | unsigned int flags; /* W: WQ_* flags */ |
bdbc5dd7 TH |
245 | union { |
246 | struct cpu_workqueue_struct __percpu *pcpu; | |
247 | struct cpu_workqueue_struct *single; | |
248 | unsigned long v; | |
249 | } cpu_wq; /* I: cwq's */ | |
4690c4ab | 250 | struct list_head list; /* W: list of all workqueues */ |
73f53c4a TH |
251 | |
252 | struct mutex flush_mutex; /* protects wq flushing */ | |
253 | int work_color; /* F: current work color */ | |
254 | int flush_color; /* F: current flush color */ | |
255 | atomic_t nr_cwqs_to_flush; /* flush in progress */ | |
256 | struct wq_flusher *first_flusher; /* F: first flusher */ | |
257 | struct list_head flusher_queue; /* F: flush waiters */ | |
258 | struct list_head flusher_overflow; /* F: flush overflow list */ | |
259 | ||
f2e005aa | 260 | mayday_mask_t mayday_mask; /* cpus requesting rescue */ |
e22bee78 TH |
261 | struct worker *rescuer; /* I: rescue worker */ |
262 | ||
9c5a2ba7 | 263 | int nr_drainers; /* W: drain in progress */ |
dcd989cb | 264 | int saved_max_active; /* W: saved cwq max_active */ |
4e6045f1 | 265 | #ifdef CONFIG_LOCKDEP |
4690c4ab | 266 | struct lockdep_map lockdep_map; |
4e6045f1 | 267 | #endif |
b196be89 | 268 | char name[]; /* I: workqueue name */ |
1da177e4 LT |
269 | }; |
270 | ||
d320c038 TH |
271 | struct workqueue_struct *system_wq __read_mostly; |
272 | struct workqueue_struct *system_long_wq __read_mostly; | |
273 | struct workqueue_struct *system_nrt_wq __read_mostly; | |
f3421797 | 274 | struct workqueue_struct *system_unbound_wq __read_mostly; |
24d51add | 275 | struct workqueue_struct *system_freezable_wq __read_mostly; |
62d3c543 | 276 | struct workqueue_struct *system_nrt_freezable_wq __read_mostly; |
d320c038 TH |
277 | EXPORT_SYMBOL_GPL(system_wq); |
278 | EXPORT_SYMBOL_GPL(system_long_wq); | |
279 | EXPORT_SYMBOL_GPL(system_nrt_wq); | |
f3421797 | 280 | EXPORT_SYMBOL_GPL(system_unbound_wq); |
24d51add | 281 | EXPORT_SYMBOL_GPL(system_freezable_wq); |
62d3c543 | 282 | EXPORT_SYMBOL_GPL(system_nrt_freezable_wq); |
d320c038 | 283 | |
97bd2347 TH |
284 | #define CREATE_TRACE_POINTS |
285 | #include <trace/events/workqueue.h> | |
286 | ||
4ce62e9e | 287 | #define for_each_worker_pool(pool, gcwq) \ |
3270476a TH |
288 | for ((pool) = &(gcwq)->pools[0]; \ |
289 | (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++) | |
4ce62e9e | 290 | |
db7bccf4 TH |
291 | #define for_each_busy_worker(worker, i, pos, gcwq) \ |
292 | for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \ | |
293 | hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry) | |
294 | ||
f3421797 TH |
295 | static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, |
296 | unsigned int sw) | |
297 | { | |
298 | if (cpu < nr_cpu_ids) { | |
299 | if (sw & 1) { | |
300 | cpu = cpumask_next(cpu, mask); | |
301 | if (cpu < nr_cpu_ids) | |
302 | return cpu; | |
303 | } | |
304 | if (sw & 2) | |
305 | return WORK_CPU_UNBOUND; | |
306 | } | |
307 | return WORK_CPU_NONE; | |
308 | } | |
309 | ||
310 | static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, | |
311 | struct workqueue_struct *wq) | |
312 | { | |
313 | return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); | |
314 | } | |
315 | ||
09884951 TH |
316 | /* |
317 | * CPU iterators | |
318 | * | |
319 | * An extra gcwq is defined for an invalid cpu number | |
320 | * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any | |
321 | * specific CPU. The following iterators are similar to | |
322 | * for_each_*_cpu() iterators but also considers the unbound gcwq. | |
323 | * | |
324 | * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND | |
325 | * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND | |
326 | * for_each_cwq_cpu() : possible CPUs for bound workqueues, | |
327 | * WORK_CPU_UNBOUND for unbound workqueues | |
328 | */ | |
f3421797 TH |
329 | #define for_each_gcwq_cpu(cpu) \ |
330 | for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ | |
331 | (cpu) < WORK_CPU_NONE; \ | |
332 | (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) | |
333 | ||
334 | #define for_each_online_gcwq_cpu(cpu) \ | |
335 | for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ | |
336 | (cpu) < WORK_CPU_NONE; \ | |
337 | (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) | |
338 | ||
339 | #define for_each_cwq_cpu(cpu, wq) \ | |
340 | for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ | |
341 | (cpu) < WORK_CPU_NONE; \ | |
342 | (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) | |
343 | ||
dc186ad7 TG |
344 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
345 | ||
346 | static struct debug_obj_descr work_debug_descr; | |
347 | ||
99777288 SG |
348 | static void *work_debug_hint(void *addr) |
349 | { | |
350 | return ((struct work_struct *) addr)->func; | |
351 | } | |
352 | ||
dc186ad7 TG |
353 | /* |
354 | * fixup_init is called when: | |
355 | * - an active object is initialized | |
356 | */ | |
357 | static int work_fixup_init(void *addr, enum debug_obj_state state) | |
358 | { | |
359 | struct work_struct *work = addr; | |
360 | ||
361 | switch (state) { | |
362 | case ODEBUG_STATE_ACTIVE: | |
363 | cancel_work_sync(work); | |
364 | debug_object_init(work, &work_debug_descr); | |
365 | return 1; | |
366 | default: | |
367 | return 0; | |
368 | } | |
369 | } | |
370 | ||
371 | /* | |
372 | * fixup_activate is called when: | |
373 | * - an active object is activated | |
374 | * - an unknown object is activated (might be a statically initialized object) | |
375 | */ | |
376 | static int work_fixup_activate(void *addr, enum debug_obj_state state) | |
377 | { | |
378 | struct work_struct *work = addr; | |
379 | ||
380 | switch (state) { | |
381 | ||
382 | case ODEBUG_STATE_NOTAVAILABLE: | |
383 | /* | |
384 | * This is not really a fixup. The work struct was | |
385 | * statically initialized. We just make sure that it | |
386 | * is tracked in the object tracker. | |
387 | */ | |
22df02bb | 388 | if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { |
dc186ad7 TG |
389 | debug_object_init(work, &work_debug_descr); |
390 | debug_object_activate(work, &work_debug_descr); | |
391 | return 0; | |
392 | } | |
393 | WARN_ON_ONCE(1); | |
394 | return 0; | |
395 | ||
396 | case ODEBUG_STATE_ACTIVE: | |
397 | WARN_ON(1); | |
398 | ||
399 | default: | |
400 | return 0; | |
401 | } | |
402 | } | |
403 | ||
404 | /* | |
405 | * fixup_free is called when: | |
406 | * - an active object is freed | |
407 | */ | |
408 | static int work_fixup_free(void *addr, enum debug_obj_state state) | |
409 | { | |
410 | struct work_struct *work = addr; | |
411 | ||
412 | switch (state) { | |
413 | case ODEBUG_STATE_ACTIVE: | |
414 | cancel_work_sync(work); | |
415 | debug_object_free(work, &work_debug_descr); | |
416 | return 1; | |
417 | default: | |
418 | return 0; | |
419 | } | |
420 | } | |
421 | ||
422 | static struct debug_obj_descr work_debug_descr = { | |
423 | .name = "work_struct", | |
99777288 | 424 | .debug_hint = work_debug_hint, |
dc186ad7 TG |
425 | .fixup_init = work_fixup_init, |
426 | .fixup_activate = work_fixup_activate, | |
427 | .fixup_free = work_fixup_free, | |
428 | }; | |
429 | ||
430 | static inline void debug_work_activate(struct work_struct *work) | |
431 | { | |
432 | debug_object_activate(work, &work_debug_descr); | |
433 | } | |
434 | ||
435 | static inline void debug_work_deactivate(struct work_struct *work) | |
436 | { | |
437 | debug_object_deactivate(work, &work_debug_descr); | |
438 | } | |
439 | ||
440 | void __init_work(struct work_struct *work, int onstack) | |
441 | { | |
442 | if (onstack) | |
443 | debug_object_init_on_stack(work, &work_debug_descr); | |
444 | else | |
445 | debug_object_init(work, &work_debug_descr); | |
446 | } | |
447 | EXPORT_SYMBOL_GPL(__init_work); | |
448 | ||
449 | void destroy_work_on_stack(struct work_struct *work) | |
450 | { | |
451 | debug_object_free(work, &work_debug_descr); | |
452 | } | |
453 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
454 | ||
455 | #else | |
456 | static inline void debug_work_activate(struct work_struct *work) { } | |
457 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
458 | #endif | |
459 | ||
95402b38 GS |
460 | /* Serializes the accesses to the list of workqueues. */ |
461 | static DEFINE_SPINLOCK(workqueue_lock); | |
1da177e4 | 462 | static LIST_HEAD(workqueues); |
a0a1a5fd | 463 | static bool workqueue_freezing; /* W: have wqs started freezing? */ |
c34056a3 | 464 | |
e22bee78 TH |
465 | /* |
466 | * The almighty global cpu workqueues. nr_running is the only field | |
467 | * which is expected to be used frequently by other cpus via | |
468 | * try_to_wake_up(). Put it in a separate cacheline. | |
469 | */ | |
8b03ae3c | 470 | static DEFINE_PER_CPU(struct global_cwq, global_cwq); |
4ce62e9e | 471 | static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_WORKER_POOLS]); |
8b03ae3c | 472 | |
f3421797 TH |
473 | /* |
474 | * Global cpu workqueue and nr_running counter for unbound gcwq. The | |
475 | * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its | |
476 | * workers have WORKER_UNBOUND set. | |
477 | */ | |
478 | static struct global_cwq unbound_global_cwq; | |
4ce62e9e TH |
479 | static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = { |
480 | [0 ... NR_WORKER_POOLS - 1] = ATOMIC_INIT(0), /* always 0 */ | |
481 | }; | |
f3421797 | 482 | |
c34056a3 | 483 | static int worker_thread(void *__worker); |
1da177e4 | 484 | |
3270476a TH |
485 | static int worker_pool_pri(struct worker_pool *pool) |
486 | { | |
487 | return pool - pool->gcwq->pools; | |
488 | } | |
489 | ||
8b03ae3c TH |
490 | static struct global_cwq *get_gcwq(unsigned int cpu) |
491 | { | |
f3421797 TH |
492 | if (cpu != WORK_CPU_UNBOUND) |
493 | return &per_cpu(global_cwq, cpu); | |
494 | else | |
495 | return &unbound_global_cwq; | |
8b03ae3c TH |
496 | } |
497 | ||
63d95a91 | 498 | static atomic_t *get_pool_nr_running(struct worker_pool *pool) |
e22bee78 | 499 | { |
63d95a91 | 500 | int cpu = pool->gcwq->cpu; |
3270476a | 501 | int idx = worker_pool_pri(pool); |
63d95a91 | 502 | |
f3421797 | 503 | if (cpu != WORK_CPU_UNBOUND) |
4ce62e9e | 504 | return &per_cpu(pool_nr_running, cpu)[idx]; |
f3421797 | 505 | else |
4ce62e9e | 506 | return &unbound_pool_nr_running[idx]; |
e22bee78 TH |
507 | } |
508 | ||
1537663f TH |
509 | static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, |
510 | struct workqueue_struct *wq) | |
b1f4ec17 | 511 | { |
f3421797 | 512 | if (!(wq->flags & WQ_UNBOUND)) { |
e06ffa1e | 513 | if (likely(cpu < nr_cpu_ids)) |
f3421797 | 514 | return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); |
f3421797 TH |
515 | } else if (likely(cpu == WORK_CPU_UNBOUND)) |
516 | return wq->cpu_wq.single; | |
517 | return NULL; | |
b1f4ec17 ON |
518 | } |
519 | ||
73f53c4a TH |
520 | static unsigned int work_color_to_flags(int color) |
521 | { | |
522 | return color << WORK_STRUCT_COLOR_SHIFT; | |
523 | } | |
524 | ||
525 | static int get_work_color(struct work_struct *work) | |
526 | { | |
527 | return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & | |
528 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); | |
529 | } | |
530 | ||
531 | static int work_next_color(int color) | |
532 | { | |
533 | return (color + 1) % WORK_NR_COLORS; | |
534 | } | |
1da177e4 | 535 | |
14441960 | 536 | /* |
e120153d TH |
537 | * A work's data points to the cwq with WORK_STRUCT_CWQ set while the |
538 | * work is on queue. Once execution starts, WORK_STRUCT_CWQ is | |
539 | * cleared and the work data contains the cpu number it was last on. | |
7a22ad75 TH |
540 | * |
541 | * set_work_{cwq|cpu}() and clear_work_data() can be used to set the | |
542 | * cwq, cpu or clear work->data. These functions should only be | |
543 | * called while the work is owned - ie. while the PENDING bit is set. | |
544 | * | |
545 | * get_work_[g]cwq() can be used to obtain the gcwq or cwq | |
546 | * corresponding to a work. gcwq is available once the work has been | |
547 | * queued anywhere after initialization. cwq is available only from | |
548 | * queueing until execution starts. | |
14441960 | 549 | */ |
7a22ad75 TH |
550 | static inline void set_work_data(struct work_struct *work, unsigned long data, |
551 | unsigned long flags) | |
365970a1 | 552 | { |
4594bf15 | 553 | BUG_ON(!work_pending(work)); |
7a22ad75 TH |
554 | atomic_long_set(&work->data, data | flags | work_static(work)); |
555 | } | |
365970a1 | 556 | |
7a22ad75 TH |
557 | static void set_work_cwq(struct work_struct *work, |
558 | struct cpu_workqueue_struct *cwq, | |
559 | unsigned long extra_flags) | |
560 | { | |
561 | set_work_data(work, (unsigned long)cwq, | |
e120153d | 562 | WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); |
365970a1 DH |
563 | } |
564 | ||
7a22ad75 TH |
565 | static void set_work_cpu(struct work_struct *work, unsigned int cpu) |
566 | { | |
567 | set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, WORK_STRUCT_PENDING); | |
568 | } | |
f756d5e2 | 569 | |
7a22ad75 | 570 | static void clear_work_data(struct work_struct *work) |
1da177e4 | 571 | { |
7a22ad75 | 572 | set_work_data(work, WORK_STRUCT_NO_CPU, 0); |
1da177e4 LT |
573 | } |
574 | ||
7a22ad75 | 575 | static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) |
b1f4ec17 | 576 | { |
e120153d | 577 | unsigned long data = atomic_long_read(&work->data); |
7a22ad75 | 578 | |
e120153d TH |
579 | if (data & WORK_STRUCT_CWQ) |
580 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); | |
581 | else | |
582 | return NULL; | |
4d707b9f ON |
583 | } |
584 | ||
7a22ad75 | 585 | static struct global_cwq *get_work_gcwq(struct work_struct *work) |
365970a1 | 586 | { |
e120153d | 587 | unsigned long data = atomic_long_read(&work->data); |
7a22ad75 TH |
588 | unsigned int cpu; |
589 | ||
e120153d TH |
590 | if (data & WORK_STRUCT_CWQ) |
591 | return ((struct cpu_workqueue_struct *) | |
bd7bdd43 | 592 | (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq; |
7a22ad75 TH |
593 | |
594 | cpu = data >> WORK_STRUCT_FLAG_BITS; | |
bdbc5dd7 | 595 | if (cpu == WORK_CPU_NONE) |
7a22ad75 TH |
596 | return NULL; |
597 | ||
f3421797 | 598 | BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND); |
7a22ad75 | 599 | return get_gcwq(cpu); |
b1f4ec17 ON |
600 | } |
601 | ||
e22bee78 | 602 | /* |
3270476a TH |
603 | * Policy functions. These define the policies on how the global worker |
604 | * pools are managed. Unless noted otherwise, these functions assume that | |
605 | * they're being called with gcwq->lock held. | |
e22bee78 TH |
606 | */ |
607 | ||
63d95a91 | 608 | static bool __need_more_worker(struct worker_pool *pool) |
a848e3b6 | 609 | { |
3270476a | 610 | return !atomic_read(get_pool_nr_running(pool)); |
a848e3b6 ON |
611 | } |
612 | ||
4594bf15 | 613 | /* |
e22bee78 TH |
614 | * Need to wake up a worker? Called from anything but currently |
615 | * running workers. | |
974271c4 TH |
616 | * |
617 | * Note that, because unbound workers never contribute to nr_running, this | |
618 | * function will always return %true for unbound gcwq as long as the | |
619 | * worklist isn't empty. | |
4594bf15 | 620 | */ |
63d95a91 | 621 | static bool need_more_worker(struct worker_pool *pool) |
365970a1 | 622 | { |
63d95a91 | 623 | return !list_empty(&pool->worklist) && __need_more_worker(pool); |
e22bee78 | 624 | } |
4594bf15 | 625 | |
e22bee78 | 626 | /* Can I start working? Called from busy but !running workers. */ |
63d95a91 | 627 | static bool may_start_working(struct worker_pool *pool) |
e22bee78 | 628 | { |
63d95a91 | 629 | return pool->nr_idle; |
e22bee78 TH |
630 | } |
631 | ||
632 | /* Do I need to keep working? Called from currently running workers. */ | |
63d95a91 | 633 | static bool keep_working(struct worker_pool *pool) |
e22bee78 | 634 | { |
63d95a91 | 635 | atomic_t *nr_running = get_pool_nr_running(pool); |
e22bee78 | 636 | |
3270476a | 637 | return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1; |
e22bee78 TH |
638 | } |
639 | ||
640 | /* Do we need a new worker? Called from manager. */ | |
63d95a91 | 641 | static bool need_to_create_worker(struct worker_pool *pool) |
e22bee78 | 642 | { |
63d95a91 | 643 | return need_more_worker(pool) && !may_start_working(pool); |
e22bee78 | 644 | } |
365970a1 | 645 | |
e22bee78 | 646 | /* Do I need to be the manager? */ |
63d95a91 | 647 | static bool need_to_manage_workers(struct worker_pool *pool) |
e22bee78 | 648 | { |
63d95a91 | 649 | return need_to_create_worker(pool) || |
11ebea50 | 650 | (pool->flags & POOL_MANAGE_WORKERS); |
e22bee78 TH |
651 | } |
652 | ||
653 | /* Do we have too many workers and should some go away? */ | |
63d95a91 | 654 | static bool too_many_workers(struct worker_pool *pool) |
e22bee78 | 655 | { |
552a37e9 | 656 | bool managing = pool->flags & POOL_MANAGING_WORKERS; |
63d95a91 TH |
657 | int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ |
658 | int nr_busy = pool->nr_workers - nr_idle; | |
e22bee78 TH |
659 | |
660 | return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; | |
365970a1 DH |
661 | } |
662 | ||
4d707b9f | 663 | /* |
e22bee78 TH |
664 | * Wake up functions. |
665 | */ | |
666 | ||
7e11629d | 667 | /* Return the first worker. Safe with preemption disabled */ |
63d95a91 | 668 | static struct worker *first_worker(struct worker_pool *pool) |
7e11629d | 669 | { |
63d95a91 | 670 | if (unlikely(list_empty(&pool->idle_list))) |
7e11629d TH |
671 | return NULL; |
672 | ||
63d95a91 | 673 | return list_first_entry(&pool->idle_list, struct worker, entry); |
7e11629d TH |
674 | } |
675 | ||
676 | /** | |
677 | * wake_up_worker - wake up an idle worker | |
63d95a91 | 678 | * @pool: worker pool to wake worker from |
7e11629d | 679 | * |
63d95a91 | 680 | * Wake up the first idle worker of @pool. |
7e11629d TH |
681 | * |
682 | * CONTEXT: | |
683 | * spin_lock_irq(gcwq->lock). | |
684 | */ | |
63d95a91 | 685 | static void wake_up_worker(struct worker_pool *pool) |
7e11629d | 686 | { |
63d95a91 | 687 | struct worker *worker = first_worker(pool); |
7e11629d TH |
688 | |
689 | if (likely(worker)) | |
690 | wake_up_process(worker->task); | |
691 | } | |
692 | ||
d302f017 | 693 | /** |
e22bee78 TH |
694 | * wq_worker_waking_up - a worker is waking up |
695 | * @task: task waking up | |
696 | * @cpu: CPU @task is waking up to | |
697 | * | |
698 | * This function is called during try_to_wake_up() when a worker is | |
699 | * being awoken. | |
700 | * | |
701 | * CONTEXT: | |
702 | * spin_lock_irq(rq->lock) | |
703 | */ | |
704 | void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) | |
705 | { | |
706 | struct worker *worker = kthread_data(task); | |
707 | ||
2d64672e | 708 | if (!(worker->flags & WORKER_NOT_RUNNING)) |
63d95a91 | 709 | atomic_inc(get_pool_nr_running(worker->pool)); |
e22bee78 TH |
710 | } |
711 | ||
712 | /** | |
713 | * wq_worker_sleeping - a worker is going to sleep | |
714 | * @task: task going to sleep | |
715 | * @cpu: CPU in question, must be the current CPU number | |
716 | * | |
717 | * This function is called during schedule() when a busy worker is | |
718 | * going to sleep. Worker on the same cpu can be woken up by | |
719 | * returning pointer to its task. | |
720 | * | |
721 | * CONTEXT: | |
722 | * spin_lock_irq(rq->lock) | |
723 | * | |
724 | * RETURNS: | |
725 | * Worker task on @cpu to wake up, %NULL if none. | |
726 | */ | |
727 | struct task_struct *wq_worker_sleeping(struct task_struct *task, | |
728 | unsigned int cpu) | |
729 | { | |
730 | struct worker *worker = kthread_data(task), *to_wakeup = NULL; | |
bd7bdd43 | 731 | struct worker_pool *pool = worker->pool; |
63d95a91 | 732 | atomic_t *nr_running = get_pool_nr_running(pool); |
e22bee78 | 733 | |
2d64672e | 734 | if (worker->flags & WORKER_NOT_RUNNING) |
e22bee78 TH |
735 | return NULL; |
736 | ||
737 | /* this can only happen on the local cpu */ | |
738 | BUG_ON(cpu != raw_smp_processor_id()); | |
739 | ||
740 | /* | |
741 | * The counterpart of the following dec_and_test, implied mb, | |
742 | * worklist not empty test sequence is in insert_work(). | |
743 | * Please read comment there. | |
744 | * | |
628c78e7 TH |
745 | * NOT_RUNNING is clear. This means that we're bound to and |
746 | * running on the local cpu w/ rq lock held and preemption | |
747 | * disabled, which in turn means that none else could be | |
748 | * manipulating idle_list, so dereferencing idle_list without gcwq | |
749 | * lock is safe. | |
e22bee78 | 750 | */ |
bd7bdd43 | 751 | if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist)) |
63d95a91 | 752 | to_wakeup = first_worker(pool); |
e22bee78 TH |
753 | return to_wakeup ? to_wakeup->task : NULL; |
754 | } | |
755 | ||
756 | /** | |
757 | * worker_set_flags - set worker flags and adjust nr_running accordingly | |
cb444766 | 758 | * @worker: self |
d302f017 TH |
759 | * @flags: flags to set |
760 | * @wakeup: wakeup an idle worker if necessary | |
761 | * | |
e22bee78 TH |
762 | * Set @flags in @worker->flags and adjust nr_running accordingly. If |
763 | * nr_running becomes zero and @wakeup is %true, an idle worker is | |
764 | * woken up. | |
d302f017 | 765 | * |
cb444766 TH |
766 | * CONTEXT: |
767 | * spin_lock_irq(gcwq->lock) | |
d302f017 TH |
768 | */ |
769 | static inline void worker_set_flags(struct worker *worker, unsigned int flags, | |
770 | bool wakeup) | |
771 | { | |
bd7bdd43 | 772 | struct worker_pool *pool = worker->pool; |
e22bee78 | 773 | |
cb444766 TH |
774 | WARN_ON_ONCE(worker->task != current); |
775 | ||
e22bee78 TH |
776 | /* |
777 | * If transitioning into NOT_RUNNING, adjust nr_running and | |
778 | * wake up an idle worker as necessary if requested by | |
779 | * @wakeup. | |
780 | */ | |
781 | if ((flags & WORKER_NOT_RUNNING) && | |
782 | !(worker->flags & WORKER_NOT_RUNNING)) { | |
63d95a91 | 783 | atomic_t *nr_running = get_pool_nr_running(pool); |
e22bee78 TH |
784 | |
785 | if (wakeup) { | |
786 | if (atomic_dec_and_test(nr_running) && | |
bd7bdd43 | 787 | !list_empty(&pool->worklist)) |
63d95a91 | 788 | wake_up_worker(pool); |
e22bee78 TH |
789 | } else |
790 | atomic_dec(nr_running); | |
791 | } | |
792 | ||
d302f017 TH |
793 | worker->flags |= flags; |
794 | } | |
795 | ||
796 | /** | |
e22bee78 | 797 | * worker_clr_flags - clear worker flags and adjust nr_running accordingly |
cb444766 | 798 | * @worker: self |
d302f017 TH |
799 | * @flags: flags to clear |
800 | * | |
e22bee78 | 801 | * Clear @flags in @worker->flags and adjust nr_running accordingly. |
d302f017 | 802 | * |
cb444766 TH |
803 | * CONTEXT: |
804 | * spin_lock_irq(gcwq->lock) | |
d302f017 TH |
805 | */ |
806 | static inline void worker_clr_flags(struct worker *worker, unsigned int flags) | |
807 | { | |
63d95a91 | 808 | struct worker_pool *pool = worker->pool; |
e22bee78 TH |
809 | unsigned int oflags = worker->flags; |
810 | ||
cb444766 TH |
811 | WARN_ON_ONCE(worker->task != current); |
812 | ||
d302f017 | 813 | worker->flags &= ~flags; |
e22bee78 | 814 | |
42c025f3 TH |
815 | /* |
816 | * If transitioning out of NOT_RUNNING, increment nr_running. Note | |
817 | * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask | |
818 | * of multiple flags, not a single flag. | |
819 | */ | |
e22bee78 TH |
820 | if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) |
821 | if (!(worker->flags & WORKER_NOT_RUNNING)) | |
63d95a91 | 822 | atomic_inc(get_pool_nr_running(pool)); |
d302f017 TH |
823 | } |
824 | ||
c8e55f36 TH |
825 | /** |
826 | * busy_worker_head - return the busy hash head for a work | |
827 | * @gcwq: gcwq of interest | |
828 | * @work: work to be hashed | |
829 | * | |
830 | * Return hash head of @gcwq for @work. | |
831 | * | |
832 | * CONTEXT: | |
833 | * spin_lock_irq(gcwq->lock). | |
834 | * | |
835 | * RETURNS: | |
836 | * Pointer to the hash head. | |
837 | */ | |
838 | static struct hlist_head *busy_worker_head(struct global_cwq *gcwq, | |
839 | struct work_struct *work) | |
840 | { | |
841 | const int base_shift = ilog2(sizeof(struct work_struct)); | |
842 | unsigned long v = (unsigned long)work; | |
843 | ||
844 | /* simple shift and fold hash, do we need something better? */ | |
845 | v >>= base_shift; | |
846 | v += v >> BUSY_WORKER_HASH_ORDER; | |
847 | v &= BUSY_WORKER_HASH_MASK; | |
848 | ||
849 | return &gcwq->busy_hash[v]; | |
850 | } | |
851 | ||
8cca0eea TH |
852 | /** |
853 | * __find_worker_executing_work - find worker which is executing a work | |
854 | * @gcwq: gcwq of interest | |
855 | * @bwh: hash head as returned by busy_worker_head() | |
856 | * @work: work to find worker for | |
857 | * | |
858 | * Find a worker which is executing @work on @gcwq. @bwh should be | |
859 | * the hash head obtained by calling busy_worker_head() with the same | |
860 | * work. | |
861 | * | |
862 | * CONTEXT: | |
863 | * spin_lock_irq(gcwq->lock). | |
864 | * | |
865 | * RETURNS: | |
866 | * Pointer to worker which is executing @work if found, NULL | |
867 | * otherwise. | |
868 | */ | |
869 | static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, | |
870 | struct hlist_head *bwh, | |
871 | struct work_struct *work) | |
872 | { | |
873 | struct worker *worker; | |
874 | struct hlist_node *tmp; | |
875 | ||
876 | hlist_for_each_entry(worker, tmp, bwh, hentry) | |
877 | if (worker->current_work == work) | |
878 | return worker; | |
879 | return NULL; | |
880 | } | |
881 | ||
882 | /** | |
883 | * find_worker_executing_work - find worker which is executing a work | |
884 | * @gcwq: gcwq of interest | |
885 | * @work: work to find worker for | |
886 | * | |
887 | * Find a worker which is executing @work on @gcwq. This function is | |
888 | * identical to __find_worker_executing_work() except that this | |
889 | * function calculates @bwh itself. | |
890 | * | |
891 | * CONTEXT: | |
892 | * spin_lock_irq(gcwq->lock). | |
893 | * | |
894 | * RETURNS: | |
895 | * Pointer to worker which is executing @work if found, NULL | |
896 | * otherwise. | |
4d707b9f | 897 | */ |
8cca0eea TH |
898 | static struct worker *find_worker_executing_work(struct global_cwq *gcwq, |
899 | struct work_struct *work) | |
4d707b9f | 900 | { |
8cca0eea TH |
901 | return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work), |
902 | work); | |
4d707b9f ON |
903 | } |
904 | ||
4690c4ab | 905 | /** |
7e11629d | 906 | * insert_work - insert a work into gcwq |
4690c4ab TH |
907 | * @cwq: cwq @work belongs to |
908 | * @work: work to insert | |
909 | * @head: insertion point | |
910 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
911 | * | |
7e11629d TH |
912 | * Insert @work which belongs to @cwq into @gcwq after @head. |
913 | * @extra_flags is or'd to work_struct flags. | |
4690c4ab TH |
914 | * |
915 | * CONTEXT: | |
8b03ae3c | 916 | * spin_lock_irq(gcwq->lock). |
4690c4ab | 917 | */ |
b89deed3 | 918 | static void insert_work(struct cpu_workqueue_struct *cwq, |
4690c4ab TH |
919 | struct work_struct *work, struct list_head *head, |
920 | unsigned int extra_flags) | |
b89deed3 | 921 | { |
63d95a91 | 922 | struct worker_pool *pool = cwq->pool; |
e22bee78 | 923 | |
4690c4ab | 924 | /* we own @work, set data and link */ |
7a22ad75 | 925 | set_work_cwq(work, cwq, extra_flags); |
e1d8aa9f | 926 | |
6e84d644 ON |
927 | /* |
928 | * Ensure that we get the right work->data if we see the | |
929 | * result of list_add() below, see try_to_grab_pending(). | |
930 | */ | |
931 | smp_wmb(); | |
4690c4ab | 932 | |
1a4d9b0a | 933 | list_add_tail(&work->entry, head); |
e22bee78 TH |
934 | |
935 | /* | |
936 | * Ensure either worker_sched_deactivated() sees the above | |
937 | * list_add_tail() or we see zero nr_running to avoid workers | |
938 | * lying around lazily while there are works to be processed. | |
939 | */ | |
940 | smp_mb(); | |
941 | ||
63d95a91 TH |
942 | if (__need_more_worker(pool)) |
943 | wake_up_worker(pool); | |
b89deed3 ON |
944 | } |
945 | ||
c8efcc25 TH |
946 | /* |
947 | * Test whether @work is being queued from another work executing on the | |
948 | * same workqueue. This is rather expensive and should only be used from | |
949 | * cold paths. | |
950 | */ | |
951 | static bool is_chained_work(struct workqueue_struct *wq) | |
952 | { | |
953 | unsigned long flags; | |
954 | unsigned int cpu; | |
955 | ||
956 | for_each_gcwq_cpu(cpu) { | |
957 | struct global_cwq *gcwq = get_gcwq(cpu); | |
958 | struct worker *worker; | |
959 | struct hlist_node *pos; | |
960 | int i; | |
961 | ||
962 | spin_lock_irqsave(&gcwq->lock, flags); | |
963 | for_each_busy_worker(worker, i, pos, gcwq) { | |
964 | if (worker->task != current) | |
965 | continue; | |
966 | spin_unlock_irqrestore(&gcwq->lock, flags); | |
967 | /* | |
968 | * I'm @worker, no locking necessary. See if @work | |
969 | * is headed to the same workqueue. | |
970 | */ | |
971 | return worker->current_cwq->wq == wq; | |
972 | } | |
973 | spin_unlock_irqrestore(&gcwq->lock, flags); | |
974 | } | |
975 | return false; | |
976 | } | |
977 | ||
4690c4ab | 978 | static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
979 | struct work_struct *work) |
980 | { | |
502ca9d8 TH |
981 | struct global_cwq *gcwq; |
982 | struct cpu_workqueue_struct *cwq; | |
1e19ffc6 | 983 | struct list_head *worklist; |
8a2e8e5d | 984 | unsigned int work_flags; |
1da177e4 LT |
985 | unsigned long flags; |
986 | ||
dc186ad7 | 987 | debug_work_activate(work); |
1e19ffc6 | 988 | |
c8efcc25 | 989 | /* if dying, only works from the same workqueue are allowed */ |
9c5a2ba7 | 990 | if (unlikely(wq->flags & WQ_DRAINING) && |
c8efcc25 | 991 | WARN_ON_ONCE(!is_chained_work(wq))) |
e41e704b TH |
992 | return; |
993 | ||
c7fc77f7 TH |
994 | /* determine gcwq to use */ |
995 | if (!(wq->flags & WQ_UNBOUND)) { | |
18aa9eff TH |
996 | struct global_cwq *last_gcwq; |
997 | ||
c7fc77f7 TH |
998 | if (unlikely(cpu == WORK_CPU_UNBOUND)) |
999 | cpu = raw_smp_processor_id(); | |
1000 | ||
18aa9eff TH |
1001 | /* |
1002 | * It's multi cpu. If @wq is non-reentrant and @work | |
1003 | * was previously on a different cpu, it might still | |
1004 | * be running there, in which case the work needs to | |
1005 | * be queued on that cpu to guarantee non-reentrance. | |
1006 | */ | |
502ca9d8 | 1007 | gcwq = get_gcwq(cpu); |
18aa9eff TH |
1008 | if (wq->flags & WQ_NON_REENTRANT && |
1009 | (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) { | |
1010 | struct worker *worker; | |
1011 | ||
1012 | spin_lock_irqsave(&last_gcwq->lock, flags); | |
1013 | ||
1014 | worker = find_worker_executing_work(last_gcwq, work); | |
1015 | ||
1016 | if (worker && worker->current_cwq->wq == wq) | |
1017 | gcwq = last_gcwq; | |
1018 | else { | |
1019 | /* meh... not running there, queue here */ | |
1020 | spin_unlock_irqrestore(&last_gcwq->lock, flags); | |
1021 | spin_lock_irqsave(&gcwq->lock, flags); | |
1022 | } | |
1023 | } else | |
1024 | spin_lock_irqsave(&gcwq->lock, flags); | |
f3421797 TH |
1025 | } else { |
1026 | gcwq = get_gcwq(WORK_CPU_UNBOUND); | |
1027 | spin_lock_irqsave(&gcwq->lock, flags); | |
502ca9d8 TH |
1028 | } |
1029 | ||
1030 | /* gcwq determined, get cwq and queue */ | |
1031 | cwq = get_cwq(gcwq->cpu, wq); | |
cdadf009 | 1032 | trace_workqueue_queue_work(cpu, cwq, work); |
502ca9d8 | 1033 | |
f5b2552b DC |
1034 | if (WARN_ON(!list_empty(&work->entry))) { |
1035 | spin_unlock_irqrestore(&gcwq->lock, flags); | |
1036 | return; | |
1037 | } | |
1e19ffc6 | 1038 | |
73f53c4a | 1039 | cwq->nr_in_flight[cwq->work_color]++; |
8a2e8e5d | 1040 | work_flags = work_color_to_flags(cwq->work_color); |
1e19ffc6 TH |
1041 | |
1042 | if (likely(cwq->nr_active < cwq->max_active)) { | |
cdadf009 | 1043 | trace_workqueue_activate_work(work); |
1e19ffc6 | 1044 | cwq->nr_active++; |
3270476a | 1045 | worklist = &cwq->pool->worklist; |
8a2e8e5d TH |
1046 | } else { |
1047 | work_flags |= WORK_STRUCT_DELAYED; | |
1e19ffc6 | 1048 | worklist = &cwq->delayed_works; |
8a2e8e5d | 1049 | } |
1e19ffc6 | 1050 | |
8a2e8e5d | 1051 | insert_work(cwq, work, worklist, work_flags); |
1e19ffc6 | 1052 | |
8b03ae3c | 1053 | spin_unlock_irqrestore(&gcwq->lock, flags); |
1da177e4 LT |
1054 | } |
1055 | ||
0fcb78c2 REB |
1056 | /** |
1057 | * queue_work - queue work on a workqueue | |
1058 | * @wq: workqueue to use | |
1059 | * @work: work to queue | |
1060 | * | |
057647fc | 1061 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
1da177e4 | 1062 | * |
00dfcaf7 ON |
1063 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
1064 | * it can be processed by another CPU. | |
1da177e4 | 1065 | */ |
7ad5b3a5 | 1066 | int queue_work(struct workqueue_struct *wq, struct work_struct *work) |
1da177e4 | 1067 | { |
ef1ca236 ON |
1068 | int ret; |
1069 | ||
1070 | ret = queue_work_on(get_cpu(), wq, work); | |
1071 | put_cpu(); | |
1072 | ||
1da177e4 LT |
1073 | return ret; |
1074 | } | |
ae90dd5d | 1075 | EXPORT_SYMBOL_GPL(queue_work); |
1da177e4 | 1076 | |
c1a220e7 ZR |
1077 | /** |
1078 | * queue_work_on - queue work on specific cpu | |
1079 | * @cpu: CPU number to execute work on | |
1080 | * @wq: workqueue to use | |
1081 | * @work: work to queue | |
1082 | * | |
1083 | * Returns 0 if @work was already on a queue, non-zero otherwise. | |
1084 | * | |
1085 | * We queue the work to a specific CPU, the caller must ensure it | |
1086 | * can't go away. | |
1087 | */ | |
1088 | int | |
1089 | queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |
1090 | { | |
1091 | int ret = 0; | |
1092 | ||
22df02bb | 1093 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 1094 | __queue_work(cpu, wq, work); |
c1a220e7 ZR |
1095 | ret = 1; |
1096 | } | |
1097 | return ret; | |
1098 | } | |
1099 | EXPORT_SYMBOL_GPL(queue_work_on); | |
1100 | ||
6d141c3f | 1101 | static void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 1102 | { |
52bad64d | 1103 | struct delayed_work *dwork = (struct delayed_work *)__data; |
7a22ad75 | 1104 | struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work); |
1da177e4 | 1105 | |
4690c4ab | 1106 | __queue_work(smp_processor_id(), cwq->wq, &dwork->work); |
1da177e4 LT |
1107 | } |
1108 | ||
0fcb78c2 REB |
1109 | /** |
1110 | * queue_delayed_work - queue work on a workqueue after delay | |
1111 | * @wq: workqueue to use | |
af9997e4 | 1112 | * @dwork: delayable work to queue |
0fcb78c2 REB |
1113 | * @delay: number of jiffies to wait before queueing |
1114 | * | |
057647fc | 1115 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 1116 | */ |
7ad5b3a5 | 1117 | int queue_delayed_work(struct workqueue_struct *wq, |
52bad64d | 1118 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 1119 | { |
52bad64d | 1120 | if (delay == 0) |
63bc0362 | 1121 | return queue_work(wq, &dwork->work); |
1da177e4 | 1122 | |
63bc0362 | 1123 | return queue_delayed_work_on(-1, wq, dwork, delay); |
1da177e4 | 1124 | } |
ae90dd5d | 1125 | EXPORT_SYMBOL_GPL(queue_delayed_work); |
1da177e4 | 1126 | |
0fcb78c2 REB |
1127 | /** |
1128 | * queue_delayed_work_on - queue work on specific CPU after delay | |
1129 | * @cpu: CPU number to execute work on | |
1130 | * @wq: workqueue to use | |
af9997e4 | 1131 | * @dwork: work to queue |
0fcb78c2 REB |
1132 | * @delay: number of jiffies to wait before queueing |
1133 | * | |
057647fc | 1134 | * Returns 0 if @work was already on a queue, non-zero otherwise. |
0fcb78c2 | 1135 | */ |
7a6bc1cd | 1136 | int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
52bad64d | 1137 | struct delayed_work *dwork, unsigned long delay) |
7a6bc1cd VP |
1138 | { |
1139 | int ret = 0; | |
52bad64d DH |
1140 | struct timer_list *timer = &dwork->timer; |
1141 | struct work_struct *work = &dwork->work; | |
7a6bc1cd | 1142 | |
22df02bb | 1143 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
c7fc77f7 | 1144 | unsigned int lcpu; |
7a22ad75 | 1145 | |
7a6bc1cd VP |
1146 | BUG_ON(timer_pending(timer)); |
1147 | BUG_ON(!list_empty(&work->entry)); | |
1148 | ||
8a3e77cc AL |
1149 | timer_stats_timer_set_start_info(&dwork->timer); |
1150 | ||
7a22ad75 TH |
1151 | /* |
1152 | * This stores cwq for the moment, for the timer_fn. | |
1153 | * Note that the work's gcwq is preserved to allow | |
1154 | * reentrance detection for delayed works. | |
1155 | */ | |
c7fc77f7 TH |
1156 | if (!(wq->flags & WQ_UNBOUND)) { |
1157 | struct global_cwq *gcwq = get_work_gcwq(work); | |
1158 | ||
1159 | if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND) | |
1160 | lcpu = gcwq->cpu; | |
1161 | else | |
1162 | lcpu = raw_smp_processor_id(); | |
1163 | } else | |
1164 | lcpu = WORK_CPU_UNBOUND; | |
1165 | ||
7a22ad75 | 1166 | set_work_cwq(work, get_cwq(lcpu, wq), 0); |
c7fc77f7 | 1167 | |
7a6bc1cd | 1168 | timer->expires = jiffies + delay; |
52bad64d | 1169 | timer->data = (unsigned long)dwork; |
7a6bc1cd | 1170 | timer->function = delayed_work_timer_fn; |
63bc0362 ON |
1171 | |
1172 | if (unlikely(cpu >= 0)) | |
1173 | add_timer_on(timer, cpu); | |
1174 | else | |
1175 | add_timer(timer); | |
7a6bc1cd VP |
1176 | ret = 1; |
1177 | } | |
1178 | return ret; | |
1179 | } | |
ae90dd5d | 1180 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
1da177e4 | 1181 | |
c8e55f36 TH |
1182 | /** |
1183 | * worker_enter_idle - enter idle state | |
1184 | * @worker: worker which is entering idle state | |
1185 | * | |
1186 | * @worker is entering idle state. Update stats and idle timer if | |
1187 | * necessary. | |
1188 | * | |
1189 | * LOCKING: | |
1190 | * spin_lock_irq(gcwq->lock). | |
1191 | */ | |
1192 | static void worker_enter_idle(struct worker *worker) | |
1da177e4 | 1193 | { |
bd7bdd43 TH |
1194 | struct worker_pool *pool = worker->pool; |
1195 | struct global_cwq *gcwq = pool->gcwq; | |
c8e55f36 TH |
1196 | |
1197 | BUG_ON(worker->flags & WORKER_IDLE); | |
1198 | BUG_ON(!list_empty(&worker->entry) && | |
1199 | (worker->hentry.next || worker->hentry.pprev)); | |
1200 | ||
cb444766 TH |
1201 | /* can't use worker_set_flags(), also called from start_worker() */ |
1202 | worker->flags |= WORKER_IDLE; | |
bd7bdd43 | 1203 | pool->nr_idle++; |
e22bee78 | 1204 | worker->last_active = jiffies; |
c8e55f36 TH |
1205 | |
1206 | /* idle_list is LIFO */ | |
bd7bdd43 | 1207 | list_add(&worker->entry, &pool->idle_list); |
db7bccf4 | 1208 | |
628c78e7 TH |
1209 | if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) |
1210 | mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); | |
cb444766 | 1211 | |
544ecf31 | 1212 | /* |
628c78e7 TH |
1213 | * Sanity check nr_running. Because gcwq_unbind_fn() releases |
1214 | * gcwq->lock between setting %WORKER_UNBOUND and zapping | |
1215 | * nr_running, the warning may trigger spuriously. Check iff | |
1216 | * unbind is not in progress. | |
544ecf31 | 1217 | */ |
628c78e7 | 1218 | WARN_ON_ONCE(!(gcwq->flags & GCWQ_DISASSOCIATED) && |
bd7bdd43 | 1219 | pool->nr_workers == pool->nr_idle && |
63d95a91 | 1220 | atomic_read(get_pool_nr_running(pool))); |
c8e55f36 TH |
1221 | } |
1222 | ||
1223 | /** | |
1224 | * worker_leave_idle - leave idle state | |
1225 | * @worker: worker which is leaving idle state | |
1226 | * | |
1227 | * @worker is leaving idle state. Update stats. | |
1228 | * | |
1229 | * LOCKING: | |
1230 | * spin_lock_irq(gcwq->lock). | |
1231 | */ | |
1232 | static void worker_leave_idle(struct worker *worker) | |
1233 | { | |
bd7bdd43 | 1234 | struct worker_pool *pool = worker->pool; |
c8e55f36 TH |
1235 | |
1236 | BUG_ON(!(worker->flags & WORKER_IDLE)); | |
d302f017 | 1237 | worker_clr_flags(worker, WORKER_IDLE); |
bd7bdd43 | 1238 | pool->nr_idle--; |
c8e55f36 TH |
1239 | list_del_init(&worker->entry); |
1240 | } | |
1241 | ||
e22bee78 TH |
1242 | /** |
1243 | * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq | |
1244 | * @worker: self | |
1245 | * | |
1246 | * Works which are scheduled while the cpu is online must at least be | |
1247 | * scheduled to a worker which is bound to the cpu so that if they are | |
1248 | * flushed from cpu callbacks while cpu is going down, they are | |
1249 | * guaranteed to execute on the cpu. | |
1250 | * | |
1251 | * This function is to be used by rogue workers and rescuers to bind | |
1252 | * themselves to the target cpu and may race with cpu going down or | |
1253 | * coming online. kthread_bind() can't be used because it may put the | |
1254 | * worker to already dead cpu and set_cpus_allowed_ptr() can't be used | |
1255 | * verbatim as it's best effort and blocking and gcwq may be | |
1256 | * [dis]associated in the meantime. | |
1257 | * | |
f2d5a0ee TH |
1258 | * This function tries set_cpus_allowed() and locks gcwq and verifies the |
1259 | * binding against %GCWQ_DISASSOCIATED which is set during | |
1260 | * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker | |
1261 | * enters idle state or fetches works without dropping lock, it can | |
1262 | * guarantee the scheduling requirement described in the first paragraph. | |
e22bee78 TH |
1263 | * |
1264 | * CONTEXT: | |
1265 | * Might sleep. Called without any lock but returns with gcwq->lock | |
1266 | * held. | |
1267 | * | |
1268 | * RETURNS: | |
1269 | * %true if the associated gcwq is online (@worker is successfully | |
1270 | * bound), %false if offline. | |
1271 | */ | |
1272 | static bool worker_maybe_bind_and_lock(struct worker *worker) | |
972fa1c5 | 1273 | __acquires(&gcwq->lock) |
e22bee78 | 1274 | { |
bd7bdd43 | 1275 | struct global_cwq *gcwq = worker->pool->gcwq; |
e22bee78 TH |
1276 | struct task_struct *task = worker->task; |
1277 | ||
1278 | while (true) { | |
4e6045f1 | 1279 | /* |
e22bee78 TH |
1280 | * The following call may fail, succeed or succeed |
1281 | * without actually migrating the task to the cpu if | |
1282 | * it races with cpu hotunplug operation. Verify | |
1283 | * against GCWQ_DISASSOCIATED. | |
4e6045f1 | 1284 | */ |
f3421797 TH |
1285 | if (!(gcwq->flags & GCWQ_DISASSOCIATED)) |
1286 | set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); | |
e22bee78 TH |
1287 | |
1288 | spin_lock_irq(&gcwq->lock); | |
1289 | if (gcwq->flags & GCWQ_DISASSOCIATED) | |
1290 | return false; | |
1291 | if (task_cpu(task) == gcwq->cpu && | |
1292 | cpumask_equal(¤t->cpus_allowed, | |
1293 | get_cpu_mask(gcwq->cpu))) | |
1294 | return true; | |
1295 | spin_unlock_irq(&gcwq->lock); | |
1296 | ||
5035b20f TH |
1297 | /* |
1298 | * We've raced with CPU hot[un]plug. Give it a breather | |
1299 | * and retry migration. cond_resched() is required here; | |
1300 | * otherwise, we might deadlock against cpu_stop trying to | |
1301 | * bring down the CPU on non-preemptive kernel. | |
1302 | */ | |
e22bee78 | 1303 | cpu_relax(); |
5035b20f | 1304 | cond_resched(); |
e22bee78 TH |
1305 | } |
1306 | } | |
1307 | ||
25511a47 TH |
1308 | struct idle_rebind { |
1309 | int cnt; /* # workers to be rebound */ | |
1310 | struct completion done; /* all workers rebound */ | |
1311 | }; | |
1312 | ||
1313 | /* | |
1314 | * Rebind an idle @worker to its CPU. During CPU onlining, this has to | |
1315 | * happen synchronously for idle workers. worker_thread() will test | |
1316 | * %WORKER_REBIND before leaving idle and call this function. | |
1317 | */ | |
1318 | static void idle_worker_rebind(struct worker *worker) | |
1319 | { | |
1320 | struct global_cwq *gcwq = worker->pool->gcwq; | |
1321 | ||
1322 | /* CPU must be online at this point */ | |
1323 | WARN_ON(!worker_maybe_bind_and_lock(worker)); | |
1324 | if (!--worker->idle_rebind->cnt) | |
1325 | complete(&worker->idle_rebind->done); | |
1326 | spin_unlock_irq(&worker->pool->gcwq->lock); | |
1327 | ||
1328 | /* we did our part, wait for rebind_workers() to finish up */ | |
1329 | wait_event(gcwq->rebind_hold, !(worker->flags & WORKER_REBIND)); | |
ec58815a TH |
1330 | |
1331 | /* | |
1332 | * rebind_workers() shouldn't finish until all workers passed the | |
1333 | * above WORKER_REBIND wait. Tell it when done. | |
1334 | */ | |
1335 | spin_lock_irq(&worker->pool->gcwq->lock); | |
1336 | if (!--worker->idle_rebind->cnt) | |
1337 | complete(&worker->idle_rebind->done); | |
1338 | spin_unlock_irq(&worker->pool->gcwq->lock); | |
25511a47 TH |
1339 | } |
1340 | ||
e22bee78 | 1341 | /* |
25511a47 | 1342 | * Function for @worker->rebind.work used to rebind unbound busy workers to |
403c821d TH |
1343 | * the associated cpu which is coming back online. This is scheduled by |
1344 | * cpu up but can race with other cpu hotplug operations and may be | |
1345 | * executed twice without intervening cpu down. | |
e22bee78 | 1346 | */ |
25511a47 | 1347 | static void busy_worker_rebind_fn(struct work_struct *work) |
e22bee78 TH |
1348 | { |
1349 | struct worker *worker = container_of(work, struct worker, rebind_work); | |
bd7bdd43 | 1350 | struct global_cwq *gcwq = worker->pool->gcwq; |
e22bee78 | 1351 | |
960bd11b LJ |
1352 | worker_maybe_bind_and_lock(worker); |
1353 | ||
1354 | /* | |
1355 | * %WORKER_REBIND must be cleared even if the above binding failed; | |
1356 | * otherwise, we may confuse the next CPU_UP cycle or oops / get | |
1357 | * stuck by calling idle_worker_rebind() prematurely. If CPU went | |
1358 | * down again inbetween, %WORKER_UNBOUND would be set, so clearing | |
1359 | * %WORKER_REBIND is always safe. | |
1360 | */ | |
1361 | worker_clr_flags(worker, WORKER_REBIND); | |
e22bee78 TH |
1362 | |
1363 | spin_unlock_irq(&gcwq->lock); | |
1364 | } | |
1365 | ||
25511a47 TH |
1366 | /** |
1367 | * rebind_workers - rebind all workers of a gcwq to the associated CPU | |
1368 | * @gcwq: gcwq of interest | |
1369 | * | |
1370 | * @gcwq->cpu is coming online. Rebind all workers to the CPU. Rebinding | |
1371 | * is different for idle and busy ones. | |
1372 | * | |
1373 | * The idle ones should be rebound synchronously and idle rebinding should | |
1374 | * be complete before any worker starts executing work items with | |
1375 | * concurrency management enabled; otherwise, scheduler may oops trying to | |
1376 | * wake up non-local idle worker from wq_worker_sleeping(). | |
1377 | * | |
1378 | * This is achieved by repeatedly requesting rebinding until all idle | |
1379 | * workers are known to have been rebound under @gcwq->lock and holding all | |
1380 | * idle workers from becoming busy until idle rebinding is complete. | |
1381 | * | |
1382 | * Once idle workers are rebound, busy workers can be rebound as they | |
1383 | * finish executing their current work items. Queueing the rebind work at | |
1384 | * the head of their scheduled lists is enough. Note that nr_running will | |
1385 | * be properbly bumped as busy workers rebind. | |
1386 | * | |
1387 | * On return, all workers are guaranteed to either be bound or have rebind | |
1388 | * work item scheduled. | |
1389 | */ | |
1390 | static void rebind_workers(struct global_cwq *gcwq) | |
1391 | __releases(&gcwq->lock) __acquires(&gcwq->lock) | |
1392 | { | |
1393 | struct idle_rebind idle_rebind; | |
1394 | struct worker_pool *pool; | |
1395 | struct worker *worker; | |
1396 | struct hlist_node *pos; | |
1397 | int i; | |
1398 | ||
1399 | lockdep_assert_held(&gcwq->lock); | |
1400 | ||
1401 | for_each_worker_pool(pool, gcwq) | |
1402 | lockdep_assert_held(&pool->manager_mutex); | |
1403 | ||
1404 | /* | |
1405 | * Rebind idle workers. Interlocked both ways. We wait for | |
1406 | * workers to rebind via @idle_rebind.done. Workers will wait for | |
1407 | * us to finish up by watching %WORKER_REBIND. | |
1408 | */ | |
1409 | init_completion(&idle_rebind.done); | |
1410 | retry: | |
1411 | idle_rebind.cnt = 1; | |
1412 | INIT_COMPLETION(idle_rebind.done); | |
1413 | ||
1414 | /* set REBIND and kick idle ones, we'll wait for these later */ | |
1415 | for_each_worker_pool(pool, gcwq) { | |
1416 | list_for_each_entry(worker, &pool->idle_list, entry) { | |
96e65306 LJ |
1417 | unsigned long worker_flags = worker->flags; |
1418 | ||
25511a47 TH |
1419 | if (worker->flags & WORKER_REBIND) |
1420 | continue; | |
1421 | ||
96e65306 LJ |
1422 | /* morph UNBOUND to REBIND atomically */ |
1423 | worker_flags &= ~WORKER_UNBOUND; | |
1424 | worker_flags |= WORKER_REBIND; | |
1425 | ACCESS_ONCE(worker->flags) = worker_flags; | |
25511a47 TH |
1426 | |
1427 | idle_rebind.cnt++; | |
1428 | worker->idle_rebind = &idle_rebind; | |
1429 | ||
1430 | /* worker_thread() will call idle_worker_rebind() */ | |
1431 | wake_up_process(worker->task); | |
1432 | } | |
1433 | } | |
1434 | ||
1435 | if (--idle_rebind.cnt) { | |
1436 | spin_unlock_irq(&gcwq->lock); | |
1437 | wait_for_completion(&idle_rebind.done); | |
1438 | spin_lock_irq(&gcwq->lock); | |
1439 | /* busy ones might have become idle while waiting, retry */ | |
1440 | goto retry; | |
1441 | } | |
1442 | ||
90beca5d | 1443 | /* all idle workers are rebound, rebind busy workers */ |
25511a47 TH |
1444 | for_each_busy_worker(worker, i, pos, gcwq) { |
1445 | struct work_struct *rebind_work = &worker->rebind_work; | |
96e65306 | 1446 | unsigned long worker_flags = worker->flags; |
25511a47 | 1447 | |
96e65306 LJ |
1448 | /* morph UNBOUND to REBIND atomically */ |
1449 | worker_flags &= ~WORKER_UNBOUND; | |
1450 | worker_flags |= WORKER_REBIND; | |
1451 | ACCESS_ONCE(worker->flags) = worker_flags; | |
25511a47 TH |
1452 | |
1453 | if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, | |
1454 | work_data_bits(rebind_work))) | |
1455 | continue; | |
1456 | ||
1457 | /* wq doesn't matter, use the default one */ | |
1458 | debug_work_activate(rebind_work); | |
1459 | insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work, | |
1460 | worker->scheduled.next, | |
1461 | work_color_to_flags(WORK_NO_COLOR)); | |
1462 | } | |
90beca5d TH |
1463 | |
1464 | /* | |
1465 | * All idle workers are rebound and waiting for %WORKER_REBIND to | |
1466 | * be cleared inside idle_worker_rebind(). Clear and release. | |
1467 | * Clearing %WORKER_REBIND from this foreign context is safe | |
1468 | * because these workers are still guaranteed to be idle. | |
ec58815a TH |
1469 | * |
1470 | * We need to make sure all idle workers passed WORKER_REBIND wait | |
1471 | * in idle_worker_rebind() before returning; otherwise, workers can | |
1472 | * get stuck at the wait if hotplug cycle repeats. | |
90beca5d | 1473 | */ |
ec58815a TH |
1474 | idle_rebind.cnt = 1; |
1475 | INIT_COMPLETION(idle_rebind.done); | |
1476 | ||
1477 | for_each_worker_pool(pool, gcwq) { | |
1478 | list_for_each_entry(worker, &pool->idle_list, entry) { | |
90beca5d | 1479 | worker->flags &= ~WORKER_REBIND; |
ec58815a TH |
1480 | idle_rebind.cnt++; |
1481 | } | |
1482 | } | |
90beca5d TH |
1483 | |
1484 | wake_up_all(&gcwq->rebind_hold); | |
ec58815a TH |
1485 | |
1486 | if (--idle_rebind.cnt) { | |
1487 | spin_unlock_irq(&gcwq->lock); | |
1488 | wait_for_completion(&idle_rebind.done); | |
1489 | spin_lock_irq(&gcwq->lock); | |
1490 | } | |
25511a47 TH |
1491 | } |
1492 | ||
c34056a3 TH |
1493 | static struct worker *alloc_worker(void) |
1494 | { | |
1495 | struct worker *worker; | |
1496 | ||
1497 | worker = kzalloc(sizeof(*worker), GFP_KERNEL); | |
c8e55f36 TH |
1498 | if (worker) { |
1499 | INIT_LIST_HEAD(&worker->entry); | |
affee4b2 | 1500 | INIT_LIST_HEAD(&worker->scheduled); |
25511a47 | 1501 | INIT_WORK(&worker->rebind_work, busy_worker_rebind_fn); |
e22bee78 TH |
1502 | /* on creation a worker is in !idle && prep state */ |
1503 | worker->flags = WORKER_PREP; | |
c8e55f36 | 1504 | } |
c34056a3 TH |
1505 | return worker; |
1506 | } | |
1507 | ||
1508 | /** | |
1509 | * create_worker - create a new workqueue worker | |
63d95a91 | 1510 | * @pool: pool the new worker will belong to |
c34056a3 | 1511 | * |
63d95a91 | 1512 | * Create a new worker which is bound to @pool. The returned worker |
c34056a3 TH |
1513 | * can be started by calling start_worker() or destroyed using |
1514 | * destroy_worker(). | |
1515 | * | |
1516 | * CONTEXT: | |
1517 | * Might sleep. Does GFP_KERNEL allocations. | |
1518 | * | |
1519 | * RETURNS: | |
1520 | * Pointer to the newly created worker. | |
1521 | */ | |
bc2ae0f5 | 1522 | static struct worker *create_worker(struct worker_pool *pool) |
c34056a3 | 1523 | { |
63d95a91 | 1524 | struct global_cwq *gcwq = pool->gcwq; |
3270476a | 1525 | const char *pri = worker_pool_pri(pool) ? "H" : ""; |
c34056a3 | 1526 | struct worker *worker = NULL; |
f3421797 | 1527 | int id = -1; |
c34056a3 | 1528 | |
8b03ae3c | 1529 | spin_lock_irq(&gcwq->lock); |
bd7bdd43 | 1530 | while (ida_get_new(&pool->worker_ida, &id)) { |
8b03ae3c | 1531 | spin_unlock_irq(&gcwq->lock); |
bd7bdd43 | 1532 | if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL)) |
c34056a3 | 1533 | goto fail; |
8b03ae3c | 1534 | spin_lock_irq(&gcwq->lock); |
c34056a3 | 1535 | } |
8b03ae3c | 1536 | spin_unlock_irq(&gcwq->lock); |
c34056a3 TH |
1537 | |
1538 | worker = alloc_worker(); | |
1539 | if (!worker) | |
1540 | goto fail; | |
1541 | ||
bd7bdd43 | 1542 | worker->pool = pool; |
c34056a3 TH |
1543 | worker->id = id; |
1544 | ||
bc2ae0f5 | 1545 | if (gcwq->cpu != WORK_CPU_UNBOUND) |
94dcf29a | 1546 | worker->task = kthread_create_on_node(worker_thread, |
3270476a TH |
1547 | worker, cpu_to_node(gcwq->cpu), |
1548 | "kworker/%u:%d%s", gcwq->cpu, id, pri); | |
f3421797 TH |
1549 | else |
1550 | worker->task = kthread_create(worker_thread, worker, | |
3270476a | 1551 | "kworker/u:%d%s", id, pri); |
c34056a3 TH |
1552 | if (IS_ERR(worker->task)) |
1553 | goto fail; | |
1554 | ||
3270476a TH |
1555 | if (worker_pool_pri(pool)) |
1556 | set_user_nice(worker->task, HIGHPRI_NICE_LEVEL); | |
1557 | ||
db7bccf4 | 1558 | /* |
bc2ae0f5 TH |
1559 | * Determine CPU binding of the new worker depending on |
1560 | * %GCWQ_DISASSOCIATED. The caller is responsible for ensuring the | |
1561 | * flag remains stable across this function. See the comments | |
1562 | * above the flag definition for details. | |
1563 | * | |
1564 | * As an unbound worker may later become a regular one if CPU comes | |
1565 | * online, make sure every worker has %PF_THREAD_BOUND set. | |
db7bccf4 | 1566 | */ |
bc2ae0f5 | 1567 | if (!(gcwq->flags & GCWQ_DISASSOCIATED)) { |
8b03ae3c | 1568 | kthread_bind(worker->task, gcwq->cpu); |
bc2ae0f5 | 1569 | } else { |
db7bccf4 | 1570 | worker->task->flags |= PF_THREAD_BOUND; |
bc2ae0f5 | 1571 | worker->flags |= WORKER_UNBOUND; |
f3421797 | 1572 | } |
c34056a3 TH |
1573 | |
1574 | return worker; | |
1575 | fail: | |
1576 | if (id >= 0) { | |
8b03ae3c | 1577 | spin_lock_irq(&gcwq->lock); |
bd7bdd43 | 1578 | ida_remove(&pool->worker_ida, id); |
8b03ae3c | 1579 | spin_unlock_irq(&gcwq->lock); |
c34056a3 TH |
1580 | } |
1581 | kfree(worker); | |
1582 | return NULL; | |
1583 | } | |
1584 | ||
1585 | /** | |
1586 | * start_worker - start a newly created worker | |
1587 | * @worker: worker to start | |
1588 | * | |
c8e55f36 | 1589 | * Make the gcwq aware of @worker and start it. |
c34056a3 TH |
1590 | * |
1591 | * CONTEXT: | |
8b03ae3c | 1592 | * spin_lock_irq(gcwq->lock). |
c34056a3 TH |
1593 | */ |
1594 | static void start_worker(struct worker *worker) | |
1595 | { | |
cb444766 | 1596 | worker->flags |= WORKER_STARTED; |
bd7bdd43 | 1597 | worker->pool->nr_workers++; |
c8e55f36 | 1598 | worker_enter_idle(worker); |
c34056a3 TH |
1599 | wake_up_process(worker->task); |
1600 | } | |
1601 | ||
1602 | /** | |
1603 | * destroy_worker - destroy a workqueue worker | |
1604 | * @worker: worker to be destroyed | |
1605 | * | |
c8e55f36 TH |
1606 | * Destroy @worker and adjust @gcwq stats accordingly. |
1607 | * | |
1608 | * CONTEXT: | |
1609 | * spin_lock_irq(gcwq->lock) which is released and regrabbed. | |
c34056a3 TH |
1610 | */ |
1611 | static void destroy_worker(struct worker *worker) | |
1612 | { | |
bd7bdd43 TH |
1613 | struct worker_pool *pool = worker->pool; |
1614 | struct global_cwq *gcwq = pool->gcwq; | |
c34056a3 TH |
1615 | int id = worker->id; |
1616 | ||
1617 | /* sanity check frenzy */ | |
1618 | BUG_ON(worker->current_work); | |
affee4b2 | 1619 | BUG_ON(!list_empty(&worker->scheduled)); |
c34056a3 | 1620 | |
c8e55f36 | 1621 | if (worker->flags & WORKER_STARTED) |
bd7bdd43 | 1622 | pool->nr_workers--; |
c8e55f36 | 1623 | if (worker->flags & WORKER_IDLE) |
bd7bdd43 | 1624 | pool->nr_idle--; |
c8e55f36 TH |
1625 | |
1626 | list_del_init(&worker->entry); | |
cb444766 | 1627 | worker->flags |= WORKER_DIE; |
c8e55f36 TH |
1628 | |
1629 | spin_unlock_irq(&gcwq->lock); | |
1630 | ||
c34056a3 TH |
1631 | kthread_stop(worker->task); |
1632 | kfree(worker); | |
1633 | ||
8b03ae3c | 1634 | spin_lock_irq(&gcwq->lock); |
bd7bdd43 | 1635 | ida_remove(&pool->worker_ida, id); |
c34056a3 TH |
1636 | } |
1637 | ||
63d95a91 | 1638 | static void idle_worker_timeout(unsigned long __pool) |
e22bee78 | 1639 | { |
63d95a91 TH |
1640 | struct worker_pool *pool = (void *)__pool; |
1641 | struct global_cwq *gcwq = pool->gcwq; | |
e22bee78 TH |
1642 | |
1643 | spin_lock_irq(&gcwq->lock); | |
1644 | ||
63d95a91 | 1645 | if (too_many_workers(pool)) { |
e22bee78 TH |
1646 | struct worker *worker; |
1647 | unsigned long expires; | |
1648 | ||
1649 | /* idle_list is kept in LIFO order, check the last one */ | |
63d95a91 | 1650 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 TH |
1651 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
1652 | ||
1653 | if (time_before(jiffies, expires)) | |
63d95a91 | 1654 | mod_timer(&pool->idle_timer, expires); |
e22bee78 TH |
1655 | else { |
1656 | /* it's been idle for too long, wake up manager */ | |
11ebea50 | 1657 | pool->flags |= POOL_MANAGE_WORKERS; |
63d95a91 | 1658 | wake_up_worker(pool); |
d5abe669 | 1659 | } |
e22bee78 TH |
1660 | } |
1661 | ||
1662 | spin_unlock_irq(&gcwq->lock); | |
1663 | } | |
d5abe669 | 1664 | |
e22bee78 TH |
1665 | static bool send_mayday(struct work_struct *work) |
1666 | { | |
1667 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); | |
1668 | struct workqueue_struct *wq = cwq->wq; | |
f3421797 | 1669 | unsigned int cpu; |
e22bee78 TH |
1670 | |
1671 | if (!(wq->flags & WQ_RESCUER)) | |
1672 | return false; | |
1673 | ||
1674 | /* mayday mayday mayday */ | |
bd7bdd43 | 1675 | cpu = cwq->pool->gcwq->cpu; |
f3421797 TH |
1676 | /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ |
1677 | if (cpu == WORK_CPU_UNBOUND) | |
1678 | cpu = 0; | |
f2e005aa | 1679 | if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) |
e22bee78 TH |
1680 | wake_up_process(wq->rescuer->task); |
1681 | return true; | |
1682 | } | |
1683 | ||
63d95a91 | 1684 | static void gcwq_mayday_timeout(unsigned long __pool) |
e22bee78 | 1685 | { |
63d95a91 TH |
1686 | struct worker_pool *pool = (void *)__pool; |
1687 | struct global_cwq *gcwq = pool->gcwq; | |
e22bee78 TH |
1688 | struct work_struct *work; |
1689 | ||
1690 | spin_lock_irq(&gcwq->lock); | |
1691 | ||
63d95a91 | 1692 | if (need_to_create_worker(pool)) { |
e22bee78 TH |
1693 | /* |
1694 | * We've been trying to create a new worker but | |
1695 | * haven't been successful. We might be hitting an | |
1696 | * allocation deadlock. Send distress signals to | |
1697 | * rescuers. | |
1698 | */ | |
63d95a91 | 1699 | list_for_each_entry(work, &pool->worklist, entry) |
e22bee78 | 1700 | send_mayday(work); |
1da177e4 | 1701 | } |
e22bee78 TH |
1702 | |
1703 | spin_unlock_irq(&gcwq->lock); | |
1704 | ||
63d95a91 | 1705 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); |
1da177e4 LT |
1706 | } |
1707 | ||
e22bee78 TH |
1708 | /** |
1709 | * maybe_create_worker - create a new worker if necessary | |
63d95a91 | 1710 | * @pool: pool to create a new worker for |
e22bee78 | 1711 | * |
63d95a91 | 1712 | * Create a new worker for @pool if necessary. @pool is guaranteed to |
e22bee78 TH |
1713 | * have at least one idle worker on return from this function. If |
1714 | * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is | |
63d95a91 | 1715 | * sent to all rescuers with works scheduled on @pool to resolve |
e22bee78 TH |
1716 | * possible allocation deadlock. |
1717 | * | |
1718 | * On return, need_to_create_worker() is guaranteed to be false and | |
1719 | * may_start_working() true. | |
1720 | * | |
1721 | * LOCKING: | |
1722 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | |
1723 | * multiple times. Does GFP_KERNEL allocations. Called only from | |
1724 | * manager. | |
1725 | * | |
1726 | * RETURNS: | |
1727 | * false if no action was taken and gcwq->lock stayed locked, true | |
1728 | * otherwise. | |
1729 | */ | |
63d95a91 | 1730 | static bool maybe_create_worker(struct worker_pool *pool) |
06bd6ebf NK |
1731 | __releases(&gcwq->lock) |
1732 | __acquires(&gcwq->lock) | |
1da177e4 | 1733 | { |
63d95a91 TH |
1734 | struct global_cwq *gcwq = pool->gcwq; |
1735 | ||
1736 | if (!need_to_create_worker(pool)) | |
e22bee78 TH |
1737 | return false; |
1738 | restart: | |
9f9c2364 TH |
1739 | spin_unlock_irq(&gcwq->lock); |
1740 | ||
e22bee78 | 1741 | /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ |
63d95a91 | 1742 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); |
e22bee78 TH |
1743 | |
1744 | while (true) { | |
1745 | struct worker *worker; | |
1746 | ||
bc2ae0f5 | 1747 | worker = create_worker(pool); |
e22bee78 | 1748 | if (worker) { |
63d95a91 | 1749 | del_timer_sync(&pool->mayday_timer); |
e22bee78 TH |
1750 | spin_lock_irq(&gcwq->lock); |
1751 | start_worker(worker); | |
63d95a91 | 1752 | BUG_ON(need_to_create_worker(pool)); |
e22bee78 TH |
1753 | return true; |
1754 | } | |
1755 | ||
63d95a91 | 1756 | if (!need_to_create_worker(pool)) |
e22bee78 | 1757 | break; |
1da177e4 | 1758 | |
e22bee78 TH |
1759 | __set_current_state(TASK_INTERRUPTIBLE); |
1760 | schedule_timeout(CREATE_COOLDOWN); | |
9f9c2364 | 1761 | |
63d95a91 | 1762 | if (!need_to_create_worker(pool)) |
e22bee78 TH |
1763 | break; |
1764 | } | |
1765 | ||
63d95a91 | 1766 | del_timer_sync(&pool->mayday_timer); |
e22bee78 | 1767 | spin_lock_irq(&gcwq->lock); |
63d95a91 | 1768 | if (need_to_create_worker(pool)) |
e22bee78 TH |
1769 | goto restart; |
1770 | return true; | |
1771 | } | |
1772 | ||
1773 | /** | |
1774 | * maybe_destroy_worker - destroy workers which have been idle for a while | |
63d95a91 | 1775 | * @pool: pool to destroy workers for |
e22bee78 | 1776 | * |
63d95a91 | 1777 | * Destroy @pool workers which have been idle for longer than |
e22bee78 TH |
1778 | * IDLE_WORKER_TIMEOUT. |
1779 | * | |
1780 | * LOCKING: | |
1781 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | |
1782 | * multiple times. Called only from manager. | |
1783 | * | |
1784 | * RETURNS: | |
1785 | * false if no action was taken and gcwq->lock stayed locked, true | |
1786 | * otherwise. | |
1787 | */ | |
63d95a91 | 1788 | static bool maybe_destroy_workers(struct worker_pool *pool) |
e22bee78 TH |
1789 | { |
1790 | bool ret = false; | |
1da177e4 | 1791 | |
63d95a91 | 1792 | while (too_many_workers(pool)) { |
e22bee78 TH |
1793 | struct worker *worker; |
1794 | unsigned long expires; | |
3af24433 | 1795 | |
63d95a91 | 1796 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 | 1797 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
85f4186a | 1798 | |
e22bee78 | 1799 | if (time_before(jiffies, expires)) { |
63d95a91 | 1800 | mod_timer(&pool->idle_timer, expires); |
3af24433 | 1801 | break; |
e22bee78 | 1802 | } |
1da177e4 | 1803 | |
e22bee78 TH |
1804 | destroy_worker(worker); |
1805 | ret = true; | |
1da177e4 | 1806 | } |
3af24433 | 1807 | |
e22bee78 TH |
1808 | return ret; |
1809 | } | |
1810 | ||
1811 | /** | |
1812 | * manage_workers - manage worker pool | |
1813 | * @worker: self | |
1814 | * | |
1815 | * Assume the manager role and manage gcwq worker pool @worker belongs | |
1816 | * to. At any given time, there can be only zero or one manager per | |
1817 | * gcwq. The exclusion is handled automatically by this function. | |
1818 | * | |
1819 | * The caller can safely start processing works on false return. On | |
1820 | * true return, it's guaranteed that need_to_create_worker() is false | |
1821 | * and may_start_working() is true. | |
1822 | * | |
1823 | * CONTEXT: | |
1824 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | |
1825 | * multiple times. Does GFP_KERNEL allocations. | |
1826 | * | |
1827 | * RETURNS: | |
1828 | * false if no action was taken and gcwq->lock stayed locked, true if | |
1829 | * some action was taken. | |
1830 | */ | |
1831 | static bool manage_workers(struct worker *worker) | |
1832 | { | |
63d95a91 | 1833 | struct worker_pool *pool = worker->pool; |
e22bee78 TH |
1834 | bool ret = false; |
1835 | ||
ee378aa4 | 1836 | if (pool->flags & POOL_MANAGING_WORKERS) |
e22bee78 TH |
1837 | return ret; |
1838 | ||
552a37e9 | 1839 | pool->flags |= POOL_MANAGING_WORKERS; |
ee378aa4 LJ |
1840 | |
1841 | /* | |
1842 | * To simplify both worker management and CPU hotplug, hold off | |
1843 | * management while hotplug is in progress. CPU hotplug path can't | |
1844 | * grab %POOL_MANAGING_WORKERS to achieve this because that can | |
1845 | * lead to idle worker depletion (all become busy thinking someone | |
1846 | * else is managing) which in turn can result in deadlock under | |
1847 | * extreme circumstances. Use @pool->manager_mutex to synchronize | |
1848 | * manager against CPU hotplug. | |
1849 | * | |
1850 | * manager_mutex would always be free unless CPU hotplug is in | |
1851 | * progress. trylock first without dropping @gcwq->lock. | |
1852 | */ | |
1853 | if (unlikely(!mutex_trylock(&pool->manager_mutex))) { | |
1854 | spin_unlock_irq(&pool->gcwq->lock); | |
1855 | mutex_lock(&pool->manager_mutex); | |
1856 | /* | |
1857 | * CPU hotplug could have happened while we were waiting | |
1858 | * for manager_mutex. Hotplug itself can't handle us | |
1859 | * because manager isn't either on idle or busy list, and | |
1860 | * @gcwq's state and ours could have deviated. | |
1861 | * | |
1862 | * As hotplug is now excluded via manager_mutex, we can | |
1863 | * simply try to bind. It will succeed or fail depending | |
1864 | * on @gcwq's current state. Try it and adjust | |
1865 | * %WORKER_UNBOUND accordingly. | |
1866 | */ | |
1867 | if (worker_maybe_bind_and_lock(worker)) | |
1868 | worker->flags &= ~WORKER_UNBOUND; | |
1869 | else | |
1870 | worker->flags |= WORKER_UNBOUND; | |
1871 | ||
1872 | ret = true; | |
1873 | } | |
1874 | ||
11ebea50 | 1875 | pool->flags &= ~POOL_MANAGE_WORKERS; |
e22bee78 TH |
1876 | |
1877 | /* | |
1878 | * Destroy and then create so that may_start_working() is true | |
1879 | * on return. | |
1880 | */ | |
63d95a91 TH |
1881 | ret |= maybe_destroy_workers(pool); |
1882 | ret |= maybe_create_worker(pool); | |
e22bee78 | 1883 | |
552a37e9 | 1884 | pool->flags &= ~POOL_MANAGING_WORKERS; |
60373152 | 1885 | mutex_unlock(&pool->manager_mutex); |
e22bee78 TH |
1886 | return ret; |
1887 | } | |
1888 | ||
affee4b2 TH |
1889 | /** |
1890 | * move_linked_works - move linked works to a list | |
1891 | * @work: start of series of works to be scheduled | |
1892 | * @head: target list to append @work to | |
1893 | * @nextp: out paramter for nested worklist walking | |
1894 | * | |
1895 | * Schedule linked works starting from @work to @head. Work series to | |
1896 | * be scheduled starts at @work and includes any consecutive work with | |
1897 | * WORK_STRUCT_LINKED set in its predecessor. | |
1898 | * | |
1899 | * If @nextp is not NULL, it's updated to point to the next work of | |
1900 | * the last scheduled work. This allows move_linked_works() to be | |
1901 | * nested inside outer list_for_each_entry_safe(). | |
1902 | * | |
1903 | * CONTEXT: | |
8b03ae3c | 1904 | * spin_lock_irq(gcwq->lock). |
affee4b2 TH |
1905 | */ |
1906 | static void move_linked_works(struct work_struct *work, struct list_head *head, | |
1907 | struct work_struct **nextp) | |
1908 | { | |
1909 | struct work_struct *n; | |
1910 | ||
1911 | /* | |
1912 | * Linked worklist will always end before the end of the list, | |
1913 | * use NULL for list head. | |
1914 | */ | |
1915 | list_for_each_entry_safe_from(work, n, NULL, entry) { | |
1916 | list_move_tail(&work->entry, head); | |
1917 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | |
1918 | break; | |
1919 | } | |
1920 | ||
1921 | /* | |
1922 | * If we're already inside safe list traversal and have moved | |
1923 | * multiple works to the scheduled queue, the next position | |
1924 | * needs to be updated. | |
1925 | */ | |
1926 | if (nextp) | |
1927 | *nextp = n; | |
1928 | } | |
1929 | ||
1e19ffc6 TH |
1930 | static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) |
1931 | { | |
1932 | struct work_struct *work = list_first_entry(&cwq->delayed_works, | |
1933 | struct work_struct, entry); | |
1934 | ||
cdadf009 | 1935 | trace_workqueue_activate_work(work); |
3270476a | 1936 | move_linked_works(work, &cwq->pool->worklist, NULL); |
8a2e8e5d | 1937 | __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); |
1e19ffc6 TH |
1938 | cwq->nr_active++; |
1939 | } | |
1940 | ||
73f53c4a TH |
1941 | /** |
1942 | * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight | |
1943 | * @cwq: cwq of interest | |
1944 | * @color: color of work which left the queue | |
8a2e8e5d | 1945 | * @delayed: for a delayed work |
73f53c4a TH |
1946 | * |
1947 | * A work either has completed or is removed from pending queue, | |
1948 | * decrement nr_in_flight of its cwq and handle workqueue flushing. | |
1949 | * | |
1950 | * CONTEXT: | |
8b03ae3c | 1951 | * spin_lock_irq(gcwq->lock). |
73f53c4a | 1952 | */ |
8a2e8e5d TH |
1953 | static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color, |
1954 | bool delayed) | |
73f53c4a TH |
1955 | { |
1956 | /* ignore uncolored works */ | |
1957 | if (color == WORK_NO_COLOR) | |
1958 | return; | |
1959 | ||
1960 | cwq->nr_in_flight[color]--; | |
1e19ffc6 | 1961 | |
8a2e8e5d TH |
1962 | if (!delayed) { |
1963 | cwq->nr_active--; | |
1964 | if (!list_empty(&cwq->delayed_works)) { | |
1965 | /* one down, submit a delayed one */ | |
1966 | if (cwq->nr_active < cwq->max_active) | |
1967 | cwq_activate_first_delayed(cwq); | |
1968 | } | |
502ca9d8 | 1969 | } |
73f53c4a TH |
1970 | |
1971 | /* is flush in progress and are we at the flushing tip? */ | |
1972 | if (likely(cwq->flush_color != color)) | |
1973 | return; | |
1974 | ||
1975 | /* are there still in-flight works? */ | |
1976 | if (cwq->nr_in_flight[color]) | |
1977 | return; | |
1978 | ||
1979 | /* this cwq is done, clear flush_color */ | |
1980 | cwq->flush_color = -1; | |
1981 | ||
1982 | /* | |
1983 | * If this was the last cwq, wake up the first flusher. It | |
1984 | * will handle the rest. | |
1985 | */ | |
1986 | if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) | |
1987 | complete(&cwq->wq->first_flusher->done); | |
1988 | } | |
1989 | ||
a62428c0 TH |
1990 | /** |
1991 | * process_one_work - process single work | |
c34056a3 | 1992 | * @worker: self |
a62428c0 TH |
1993 | * @work: work to process |
1994 | * | |
1995 | * Process @work. This function contains all the logics necessary to | |
1996 | * process a single work including synchronization against and | |
1997 | * interaction with other workers on the same cpu, queueing and | |
1998 | * flushing. As long as context requirement is met, any worker can | |
1999 | * call this function to process a work. | |
2000 | * | |
2001 | * CONTEXT: | |
8b03ae3c | 2002 | * spin_lock_irq(gcwq->lock) which is released and regrabbed. |
a62428c0 | 2003 | */ |
c34056a3 | 2004 | static void process_one_work(struct worker *worker, struct work_struct *work) |
06bd6ebf NK |
2005 | __releases(&gcwq->lock) |
2006 | __acquires(&gcwq->lock) | |
a62428c0 | 2007 | { |
7e11629d | 2008 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); |
bd7bdd43 TH |
2009 | struct worker_pool *pool = worker->pool; |
2010 | struct global_cwq *gcwq = pool->gcwq; | |
c8e55f36 | 2011 | struct hlist_head *bwh = busy_worker_head(gcwq, work); |
fb0e7beb | 2012 | bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; |
a62428c0 | 2013 | work_func_t f = work->func; |
73f53c4a | 2014 | int work_color; |
7e11629d | 2015 | struct worker *collision; |
a62428c0 TH |
2016 | #ifdef CONFIG_LOCKDEP |
2017 | /* | |
2018 | * It is permissible to free the struct work_struct from | |
2019 | * inside the function that is called from it, this we need to | |
2020 | * take into account for lockdep too. To avoid bogus "held | |
2021 | * lock freed" warnings as well as problems when looking into | |
2022 | * work->lockdep_map, make a copy and use that here. | |
2023 | */ | |
4d82a1de PZ |
2024 | struct lockdep_map lockdep_map; |
2025 | ||
2026 | lockdep_copy_map(&lockdep_map, &work->lockdep_map); | |
a62428c0 | 2027 | #endif |
6fec10a1 TH |
2028 | /* |
2029 | * Ensure we're on the correct CPU. DISASSOCIATED test is | |
2030 | * necessary to avoid spurious warnings from rescuers servicing the | |
2031 | * unbound or a disassociated gcwq. | |
2032 | */ | |
25511a47 | 2033 | WARN_ON_ONCE(!(worker->flags & (WORKER_UNBOUND | WORKER_REBIND)) && |
6fec10a1 | 2034 | !(gcwq->flags & GCWQ_DISASSOCIATED) && |
25511a47 TH |
2035 | raw_smp_processor_id() != gcwq->cpu); |
2036 | ||
7e11629d TH |
2037 | /* |
2038 | * A single work shouldn't be executed concurrently by | |
2039 | * multiple workers on a single cpu. Check whether anyone is | |
2040 | * already processing the work. If so, defer the work to the | |
2041 | * currently executing one. | |
2042 | */ | |
2043 | collision = __find_worker_executing_work(gcwq, bwh, work); | |
2044 | if (unlikely(collision)) { | |
2045 | move_linked_works(work, &collision->scheduled, NULL); | |
2046 | return; | |
2047 | } | |
2048 | ||
a62428c0 | 2049 | /* claim and process */ |
a62428c0 | 2050 | debug_work_deactivate(work); |
c8e55f36 | 2051 | hlist_add_head(&worker->hentry, bwh); |
c34056a3 | 2052 | worker->current_work = work; |
8cca0eea | 2053 | worker->current_cwq = cwq; |
73f53c4a | 2054 | work_color = get_work_color(work); |
7a22ad75 | 2055 | |
7a22ad75 TH |
2056 | /* record the current cpu number in the work data and dequeue */ |
2057 | set_work_cpu(work, gcwq->cpu); | |
a62428c0 TH |
2058 | list_del_init(&work->entry); |
2059 | ||
fb0e7beb TH |
2060 | /* |
2061 | * CPU intensive works don't participate in concurrency | |
2062 | * management. They're the scheduler's responsibility. | |
2063 | */ | |
2064 | if (unlikely(cpu_intensive)) | |
2065 | worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); | |
2066 | ||
974271c4 TH |
2067 | /* |
2068 | * Unbound gcwq isn't concurrency managed and work items should be | |
2069 | * executed ASAP. Wake up another worker if necessary. | |
2070 | */ | |
63d95a91 TH |
2071 | if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool)) |
2072 | wake_up_worker(pool); | |
974271c4 | 2073 | |
8b03ae3c | 2074 | spin_unlock_irq(&gcwq->lock); |
a62428c0 | 2075 | |
a62428c0 | 2076 | work_clear_pending(work); |
e159489b | 2077 | lock_map_acquire_read(&cwq->wq->lockdep_map); |
a62428c0 | 2078 | lock_map_acquire(&lockdep_map); |
e36c886a | 2079 | trace_workqueue_execute_start(work); |
a62428c0 | 2080 | f(work); |
e36c886a AV |
2081 | /* |
2082 | * While we must be careful to not use "work" after this, the trace | |
2083 | * point will only record its address. | |
2084 | */ | |
2085 | trace_workqueue_execute_end(work); | |
a62428c0 TH |
2086 | lock_map_release(&lockdep_map); |
2087 | lock_map_release(&cwq->wq->lockdep_map); | |
2088 | ||
2089 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
2090 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | |
2091 | "%s/0x%08x/%d\n", | |
2092 | current->comm, preempt_count(), task_pid_nr(current)); | |
2093 | printk(KERN_ERR " last function: "); | |
2094 | print_symbol("%s\n", (unsigned long)f); | |
2095 | debug_show_held_locks(current); | |
2096 | dump_stack(); | |
2097 | } | |
2098 | ||
8b03ae3c | 2099 | spin_lock_irq(&gcwq->lock); |
a62428c0 | 2100 | |
fb0e7beb TH |
2101 | /* clear cpu intensive status */ |
2102 | if (unlikely(cpu_intensive)) | |
2103 | worker_clr_flags(worker, WORKER_CPU_INTENSIVE); | |
2104 | ||
a62428c0 | 2105 | /* we're done with it, release */ |
c8e55f36 | 2106 | hlist_del_init(&worker->hentry); |
c34056a3 | 2107 | worker->current_work = NULL; |
8cca0eea | 2108 | worker->current_cwq = NULL; |
8a2e8e5d | 2109 | cwq_dec_nr_in_flight(cwq, work_color, false); |
a62428c0 TH |
2110 | } |
2111 | ||
affee4b2 TH |
2112 | /** |
2113 | * process_scheduled_works - process scheduled works | |
2114 | * @worker: self | |
2115 | * | |
2116 | * Process all scheduled works. Please note that the scheduled list | |
2117 | * may change while processing a work, so this function repeatedly | |
2118 | * fetches a work from the top and executes it. | |
2119 | * | |
2120 | * CONTEXT: | |
8b03ae3c | 2121 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed |
affee4b2 TH |
2122 | * multiple times. |
2123 | */ | |
2124 | static void process_scheduled_works(struct worker *worker) | |
1da177e4 | 2125 | { |
affee4b2 TH |
2126 | while (!list_empty(&worker->scheduled)) { |
2127 | struct work_struct *work = list_first_entry(&worker->scheduled, | |
1da177e4 | 2128 | struct work_struct, entry); |
c34056a3 | 2129 | process_one_work(worker, work); |
1da177e4 | 2130 | } |
1da177e4 LT |
2131 | } |
2132 | ||
4690c4ab TH |
2133 | /** |
2134 | * worker_thread - the worker thread function | |
c34056a3 | 2135 | * @__worker: self |
4690c4ab | 2136 | * |
e22bee78 TH |
2137 | * The gcwq worker thread function. There's a single dynamic pool of |
2138 | * these per each cpu. These workers process all works regardless of | |
2139 | * their specific target workqueue. The only exception is works which | |
2140 | * belong to workqueues with a rescuer which will be explained in | |
2141 | * rescuer_thread(). | |
4690c4ab | 2142 | */ |
c34056a3 | 2143 | static int worker_thread(void *__worker) |
1da177e4 | 2144 | { |
c34056a3 | 2145 | struct worker *worker = __worker; |
bd7bdd43 TH |
2146 | struct worker_pool *pool = worker->pool; |
2147 | struct global_cwq *gcwq = pool->gcwq; | |
1da177e4 | 2148 | |
e22bee78 TH |
2149 | /* tell the scheduler that this is a workqueue worker */ |
2150 | worker->task->flags |= PF_WQ_WORKER; | |
c8e55f36 | 2151 | woke_up: |
c8e55f36 | 2152 | spin_lock_irq(&gcwq->lock); |
1da177e4 | 2153 | |
25511a47 TH |
2154 | /* |
2155 | * DIE can be set only while idle and REBIND set while busy has | |
2156 | * @worker->rebind_work scheduled. Checking here is enough. | |
2157 | */ | |
2158 | if (unlikely(worker->flags & (WORKER_REBIND | WORKER_DIE))) { | |
c8e55f36 | 2159 | spin_unlock_irq(&gcwq->lock); |
25511a47 TH |
2160 | |
2161 | if (worker->flags & WORKER_DIE) { | |
2162 | worker->task->flags &= ~PF_WQ_WORKER; | |
2163 | return 0; | |
2164 | } | |
2165 | ||
2166 | idle_worker_rebind(worker); | |
2167 | goto woke_up; | |
c8e55f36 | 2168 | } |
affee4b2 | 2169 | |
c8e55f36 | 2170 | worker_leave_idle(worker); |
db7bccf4 | 2171 | recheck: |
e22bee78 | 2172 | /* no more worker necessary? */ |
63d95a91 | 2173 | if (!need_more_worker(pool)) |
e22bee78 TH |
2174 | goto sleep; |
2175 | ||
2176 | /* do we need to manage? */ | |
63d95a91 | 2177 | if (unlikely(!may_start_working(pool)) && manage_workers(worker)) |
e22bee78 TH |
2178 | goto recheck; |
2179 | ||
c8e55f36 TH |
2180 | /* |
2181 | * ->scheduled list can only be filled while a worker is | |
2182 | * preparing to process a work or actually processing it. | |
2183 | * Make sure nobody diddled with it while I was sleeping. | |
2184 | */ | |
2185 | BUG_ON(!list_empty(&worker->scheduled)); | |
2186 | ||
e22bee78 TH |
2187 | /* |
2188 | * When control reaches this point, we're guaranteed to have | |
2189 | * at least one idle worker or that someone else has already | |
2190 | * assumed the manager role. | |
2191 | */ | |
2192 | worker_clr_flags(worker, WORKER_PREP); | |
2193 | ||
2194 | do { | |
c8e55f36 | 2195 | struct work_struct *work = |
bd7bdd43 | 2196 | list_first_entry(&pool->worklist, |
c8e55f36 TH |
2197 | struct work_struct, entry); |
2198 | ||
2199 | if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { | |
2200 | /* optimization path, not strictly necessary */ | |
2201 | process_one_work(worker, work); | |
2202 | if (unlikely(!list_empty(&worker->scheduled))) | |
affee4b2 | 2203 | process_scheduled_works(worker); |
c8e55f36 TH |
2204 | } else { |
2205 | move_linked_works(work, &worker->scheduled, NULL); | |
2206 | process_scheduled_works(worker); | |
affee4b2 | 2207 | } |
63d95a91 | 2208 | } while (keep_working(pool)); |
e22bee78 TH |
2209 | |
2210 | worker_set_flags(worker, WORKER_PREP, false); | |
d313dd85 | 2211 | sleep: |
63d95a91 | 2212 | if (unlikely(need_to_manage_workers(pool)) && manage_workers(worker)) |
e22bee78 | 2213 | goto recheck; |
d313dd85 | 2214 | |
c8e55f36 | 2215 | /* |
e22bee78 TH |
2216 | * gcwq->lock is held and there's no work to process and no |
2217 | * need to manage, sleep. Workers are woken up only while | |
2218 | * holding gcwq->lock or from local cpu, so setting the | |
2219 | * current state before releasing gcwq->lock is enough to | |
2220 | * prevent losing any event. | |
c8e55f36 TH |
2221 | */ |
2222 | worker_enter_idle(worker); | |
2223 | __set_current_state(TASK_INTERRUPTIBLE); | |
2224 | spin_unlock_irq(&gcwq->lock); | |
2225 | schedule(); | |
2226 | goto woke_up; | |
1da177e4 LT |
2227 | } |
2228 | ||
e22bee78 TH |
2229 | /** |
2230 | * rescuer_thread - the rescuer thread function | |
2231 | * @__wq: the associated workqueue | |
2232 | * | |
2233 | * Workqueue rescuer thread function. There's one rescuer for each | |
2234 | * workqueue which has WQ_RESCUER set. | |
2235 | * | |
2236 | * Regular work processing on a gcwq may block trying to create a new | |
2237 | * worker which uses GFP_KERNEL allocation which has slight chance of | |
2238 | * developing into deadlock if some works currently on the same queue | |
2239 | * need to be processed to satisfy the GFP_KERNEL allocation. This is | |
2240 | * the problem rescuer solves. | |
2241 | * | |
2242 | * When such condition is possible, the gcwq summons rescuers of all | |
2243 | * workqueues which have works queued on the gcwq and let them process | |
2244 | * those works so that forward progress can be guaranteed. | |
2245 | * | |
2246 | * This should happen rarely. | |
2247 | */ | |
2248 | static int rescuer_thread(void *__wq) | |
2249 | { | |
2250 | struct workqueue_struct *wq = __wq; | |
2251 | struct worker *rescuer = wq->rescuer; | |
2252 | struct list_head *scheduled = &rescuer->scheduled; | |
f3421797 | 2253 | bool is_unbound = wq->flags & WQ_UNBOUND; |
e22bee78 TH |
2254 | unsigned int cpu; |
2255 | ||
2256 | set_user_nice(current, RESCUER_NICE_LEVEL); | |
2257 | repeat: | |
2258 | set_current_state(TASK_INTERRUPTIBLE); | |
2259 | ||
2260 | if (kthread_should_stop()) | |
2261 | return 0; | |
2262 | ||
f3421797 TH |
2263 | /* |
2264 | * See whether any cpu is asking for help. Unbounded | |
2265 | * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. | |
2266 | */ | |
f2e005aa | 2267 | for_each_mayday_cpu(cpu, wq->mayday_mask) { |
f3421797 TH |
2268 | unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; |
2269 | struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); | |
bd7bdd43 TH |
2270 | struct worker_pool *pool = cwq->pool; |
2271 | struct global_cwq *gcwq = pool->gcwq; | |
e22bee78 TH |
2272 | struct work_struct *work, *n; |
2273 | ||
2274 | __set_current_state(TASK_RUNNING); | |
f2e005aa | 2275 | mayday_clear_cpu(cpu, wq->mayday_mask); |
e22bee78 TH |
2276 | |
2277 | /* migrate to the target cpu if possible */ | |
bd7bdd43 | 2278 | rescuer->pool = pool; |
e22bee78 TH |
2279 | worker_maybe_bind_and_lock(rescuer); |
2280 | ||
2281 | /* | |
2282 | * Slurp in all works issued via this workqueue and | |
2283 | * process'em. | |
2284 | */ | |
2285 | BUG_ON(!list_empty(&rescuer->scheduled)); | |
bd7bdd43 | 2286 | list_for_each_entry_safe(work, n, &pool->worklist, entry) |
e22bee78 TH |
2287 | if (get_work_cwq(work) == cwq) |
2288 | move_linked_works(work, scheduled, &n); | |
2289 | ||
2290 | process_scheduled_works(rescuer); | |
7576958a TH |
2291 | |
2292 | /* | |
2293 | * Leave this gcwq. If keep_working() is %true, notify a | |
2294 | * regular worker; otherwise, we end up with 0 concurrency | |
2295 | * and stalling the execution. | |
2296 | */ | |
63d95a91 TH |
2297 | if (keep_working(pool)) |
2298 | wake_up_worker(pool); | |
7576958a | 2299 | |
e22bee78 TH |
2300 | spin_unlock_irq(&gcwq->lock); |
2301 | } | |
2302 | ||
2303 | schedule(); | |
2304 | goto repeat; | |
1da177e4 LT |
2305 | } |
2306 | ||
fc2e4d70 ON |
2307 | struct wq_barrier { |
2308 | struct work_struct work; | |
2309 | struct completion done; | |
2310 | }; | |
2311 | ||
2312 | static void wq_barrier_func(struct work_struct *work) | |
2313 | { | |
2314 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
2315 | complete(&barr->done); | |
2316 | } | |
2317 | ||
4690c4ab TH |
2318 | /** |
2319 | * insert_wq_barrier - insert a barrier work | |
2320 | * @cwq: cwq to insert barrier into | |
2321 | * @barr: wq_barrier to insert | |
affee4b2 TH |
2322 | * @target: target work to attach @barr to |
2323 | * @worker: worker currently executing @target, NULL if @target is not executing | |
4690c4ab | 2324 | * |
affee4b2 TH |
2325 | * @barr is linked to @target such that @barr is completed only after |
2326 | * @target finishes execution. Please note that the ordering | |
2327 | * guarantee is observed only with respect to @target and on the local | |
2328 | * cpu. | |
2329 | * | |
2330 | * Currently, a queued barrier can't be canceled. This is because | |
2331 | * try_to_grab_pending() can't determine whether the work to be | |
2332 | * grabbed is at the head of the queue and thus can't clear LINKED | |
2333 | * flag of the previous work while there must be a valid next work | |
2334 | * after a work with LINKED flag set. | |
2335 | * | |
2336 | * Note that when @worker is non-NULL, @target may be modified | |
2337 | * underneath us, so we can't reliably determine cwq from @target. | |
4690c4ab TH |
2338 | * |
2339 | * CONTEXT: | |
8b03ae3c | 2340 | * spin_lock_irq(gcwq->lock). |
4690c4ab | 2341 | */ |
83c22520 | 2342 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
affee4b2 TH |
2343 | struct wq_barrier *barr, |
2344 | struct work_struct *target, struct worker *worker) | |
fc2e4d70 | 2345 | { |
affee4b2 TH |
2346 | struct list_head *head; |
2347 | unsigned int linked = 0; | |
2348 | ||
dc186ad7 | 2349 | /* |
8b03ae3c | 2350 | * debugobject calls are safe here even with gcwq->lock locked |
dc186ad7 TG |
2351 | * as we know for sure that this will not trigger any of the |
2352 | * checks and call back into the fixup functions where we | |
2353 | * might deadlock. | |
2354 | */ | |
ca1cab37 | 2355 | INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); |
22df02bb | 2356 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
fc2e4d70 | 2357 | init_completion(&barr->done); |
83c22520 | 2358 | |
affee4b2 TH |
2359 | /* |
2360 | * If @target is currently being executed, schedule the | |
2361 | * barrier to the worker; otherwise, put it after @target. | |
2362 | */ | |
2363 | if (worker) | |
2364 | head = worker->scheduled.next; | |
2365 | else { | |
2366 | unsigned long *bits = work_data_bits(target); | |
2367 | ||
2368 | head = target->entry.next; | |
2369 | /* there can already be other linked works, inherit and set */ | |
2370 | linked = *bits & WORK_STRUCT_LINKED; | |
2371 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); | |
2372 | } | |
2373 | ||
dc186ad7 | 2374 | debug_work_activate(&barr->work); |
affee4b2 TH |
2375 | insert_work(cwq, &barr->work, head, |
2376 | work_color_to_flags(WORK_NO_COLOR) | linked); | |
fc2e4d70 ON |
2377 | } |
2378 | ||
73f53c4a TH |
2379 | /** |
2380 | * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing | |
2381 | * @wq: workqueue being flushed | |
2382 | * @flush_color: new flush color, < 0 for no-op | |
2383 | * @work_color: new work color, < 0 for no-op | |
2384 | * | |
2385 | * Prepare cwqs for workqueue flushing. | |
2386 | * | |
2387 | * If @flush_color is non-negative, flush_color on all cwqs should be | |
2388 | * -1. If no cwq has in-flight commands at the specified color, all | |
2389 | * cwq->flush_color's stay at -1 and %false is returned. If any cwq | |
2390 | * has in flight commands, its cwq->flush_color is set to | |
2391 | * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq | |
2392 | * wakeup logic is armed and %true is returned. | |
2393 | * | |
2394 | * The caller should have initialized @wq->first_flusher prior to | |
2395 | * calling this function with non-negative @flush_color. If | |
2396 | * @flush_color is negative, no flush color update is done and %false | |
2397 | * is returned. | |
2398 | * | |
2399 | * If @work_color is non-negative, all cwqs should have the same | |
2400 | * work_color which is previous to @work_color and all will be | |
2401 | * advanced to @work_color. | |
2402 | * | |
2403 | * CONTEXT: | |
2404 | * mutex_lock(wq->flush_mutex). | |
2405 | * | |
2406 | * RETURNS: | |
2407 | * %true if @flush_color >= 0 and there's something to flush. %false | |
2408 | * otherwise. | |
2409 | */ | |
2410 | static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, | |
2411 | int flush_color, int work_color) | |
1da177e4 | 2412 | { |
73f53c4a TH |
2413 | bool wait = false; |
2414 | unsigned int cpu; | |
1da177e4 | 2415 | |
73f53c4a TH |
2416 | if (flush_color >= 0) { |
2417 | BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); | |
2418 | atomic_set(&wq->nr_cwqs_to_flush, 1); | |
1da177e4 | 2419 | } |
2355b70f | 2420 | |
f3421797 | 2421 | for_each_cwq_cpu(cpu, wq) { |
73f53c4a | 2422 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
bd7bdd43 | 2423 | struct global_cwq *gcwq = cwq->pool->gcwq; |
fc2e4d70 | 2424 | |
8b03ae3c | 2425 | spin_lock_irq(&gcwq->lock); |
83c22520 | 2426 | |
73f53c4a TH |
2427 | if (flush_color >= 0) { |
2428 | BUG_ON(cwq->flush_color != -1); | |
fc2e4d70 | 2429 | |
73f53c4a TH |
2430 | if (cwq->nr_in_flight[flush_color]) { |
2431 | cwq->flush_color = flush_color; | |
2432 | atomic_inc(&wq->nr_cwqs_to_flush); | |
2433 | wait = true; | |
2434 | } | |
2435 | } | |
1da177e4 | 2436 | |
73f53c4a TH |
2437 | if (work_color >= 0) { |
2438 | BUG_ON(work_color != work_next_color(cwq->work_color)); | |
2439 | cwq->work_color = work_color; | |
2440 | } | |
1da177e4 | 2441 | |
8b03ae3c | 2442 | spin_unlock_irq(&gcwq->lock); |
1da177e4 | 2443 | } |
2355b70f | 2444 | |
73f53c4a TH |
2445 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) |
2446 | complete(&wq->first_flusher->done); | |
14441960 | 2447 | |
73f53c4a | 2448 | return wait; |
1da177e4 LT |
2449 | } |
2450 | ||
0fcb78c2 | 2451 | /** |
1da177e4 | 2452 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 2453 | * @wq: workqueue to flush |
1da177e4 LT |
2454 | * |
2455 | * Forces execution of the workqueue and blocks until its completion. | |
2456 | * This is typically used in driver shutdown handlers. | |
2457 | * | |
fc2e4d70 ON |
2458 | * We sleep until all works which were queued on entry have been handled, |
2459 | * but we are not livelocked by new incoming ones. | |
1da177e4 | 2460 | */ |
7ad5b3a5 | 2461 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 2462 | { |
73f53c4a TH |
2463 | struct wq_flusher this_flusher = { |
2464 | .list = LIST_HEAD_INIT(this_flusher.list), | |
2465 | .flush_color = -1, | |
2466 | .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), | |
2467 | }; | |
2468 | int next_color; | |
1da177e4 | 2469 | |
3295f0ef IM |
2470 | lock_map_acquire(&wq->lockdep_map); |
2471 | lock_map_release(&wq->lockdep_map); | |
73f53c4a TH |
2472 | |
2473 | mutex_lock(&wq->flush_mutex); | |
2474 | ||
2475 | /* | |
2476 | * Start-to-wait phase | |
2477 | */ | |
2478 | next_color = work_next_color(wq->work_color); | |
2479 | ||
2480 | if (next_color != wq->flush_color) { | |
2481 | /* | |
2482 | * Color space is not full. The current work_color | |
2483 | * becomes our flush_color and work_color is advanced | |
2484 | * by one. | |
2485 | */ | |
2486 | BUG_ON(!list_empty(&wq->flusher_overflow)); | |
2487 | this_flusher.flush_color = wq->work_color; | |
2488 | wq->work_color = next_color; | |
2489 | ||
2490 | if (!wq->first_flusher) { | |
2491 | /* no flush in progress, become the first flusher */ | |
2492 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
2493 | ||
2494 | wq->first_flusher = &this_flusher; | |
2495 | ||
2496 | if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, | |
2497 | wq->work_color)) { | |
2498 | /* nothing to flush, done */ | |
2499 | wq->flush_color = next_color; | |
2500 | wq->first_flusher = NULL; | |
2501 | goto out_unlock; | |
2502 | } | |
2503 | } else { | |
2504 | /* wait in queue */ | |
2505 | BUG_ON(wq->flush_color == this_flusher.flush_color); | |
2506 | list_add_tail(&this_flusher.list, &wq->flusher_queue); | |
2507 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
2508 | } | |
2509 | } else { | |
2510 | /* | |
2511 | * Oops, color space is full, wait on overflow queue. | |
2512 | * The next flush completion will assign us | |
2513 | * flush_color and transfer to flusher_queue. | |
2514 | */ | |
2515 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | |
2516 | } | |
2517 | ||
2518 | mutex_unlock(&wq->flush_mutex); | |
2519 | ||
2520 | wait_for_completion(&this_flusher.done); | |
2521 | ||
2522 | /* | |
2523 | * Wake-up-and-cascade phase | |
2524 | * | |
2525 | * First flushers are responsible for cascading flushes and | |
2526 | * handling overflow. Non-first flushers can simply return. | |
2527 | */ | |
2528 | if (wq->first_flusher != &this_flusher) | |
2529 | return; | |
2530 | ||
2531 | mutex_lock(&wq->flush_mutex); | |
2532 | ||
4ce48b37 TH |
2533 | /* we might have raced, check again with mutex held */ |
2534 | if (wq->first_flusher != &this_flusher) | |
2535 | goto out_unlock; | |
2536 | ||
73f53c4a TH |
2537 | wq->first_flusher = NULL; |
2538 | ||
2539 | BUG_ON(!list_empty(&this_flusher.list)); | |
2540 | BUG_ON(wq->flush_color != this_flusher.flush_color); | |
2541 | ||
2542 | while (true) { | |
2543 | struct wq_flusher *next, *tmp; | |
2544 | ||
2545 | /* complete all the flushers sharing the current flush color */ | |
2546 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | |
2547 | if (next->flush_color != wq->flush_color) | |
2548 | break; | |
2549 | list_del_init(&next->list); | |
2550 | complete(&next->done); | |
2551 | } | |
2552 | ||
2553 | BUG_ON(!list_empty(&wq->flusher_overflow) && | |
2554 | wq->flush_color != work_next_color(wq->work_color)); | |
2555 | ||
2556 | /* this flush_color is finished, advance by one */ | |
2557 | wq->flush_color = work_next_color(wq->flush_color); | |
2558 | ||
2559 | /* one color has been freed, handle overflow queue */ | |
2560 | if (!list_empty(&wq->flusher_overflow)) { | |
2561 | /* | |
2562 | * Assign the same color to all overflowed | |
2563 | * flushers, advance work_color and append to | |
2564 | * flusher_queue. This is the start-to-wait | |
2565 | * phase for these overflowed flushers. | |
2566 | */ | |
2567 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | |
2568 | tmp->flush_color = wq->work_color; | |
2569 | ||
2570 | wq->work_color = work_next_color(wq->work_color); | |
2571 | ||
2572 | list_splice_tail_init(&wq->flusher_overflow, | |
2573 | &wq->flusher_queue); | |
2574 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | |
2575 | } | |
2576 | ||
2577 | if (list_empty(&wq->flusher_queue)) { | |
2578 | BUG_ON(wq->flush_color != wq->work_color); | |
2579 | break; | |
2580 | } | |
2581 | ||
2582 | /* | |
2583 | * Need to flush more colors. Make the next flusher | |
2584 | * the new first flusher and arm cwqs. | |
2585 | */ | |
2586 | BUG_ON(wq->flush_color == wq->work_color); | |
2587 | BUG_ON(wq->flush_color != next->flush_color); | |
2588 | ||
2589 | list_del_init(&next->list); | |
2590 | wq->first_flusher = next; | |
2591 | ||
2592 | if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) | |
2593 | break; | |
2594 | ||
2595 | /* | |
2596 | * Meh... this color is already done, clear first | |
2597 | * flusher and repeat cascading. | |
2598 | */ | |
2599 | wq->first_flusher = NULL; | |
2600 | } | |
2601 | ||
2602 | out_unlock: | |
2603 | mutex_unlock(&wq->flush_mutex); | |
1da177e4 | 2604 | } |
ae90dd5d | 2605 | EXPORT_SYMBOL_GPL(flush_workqueue); |
1da177e4 | 2606 | |
9c5a2ba7 TH |
2607 | /** |
2608 | * drain_workqueue - drain a workqueue | |
2609 | * @wq: workqueue to drain | |
2610 | * | |
2611 | * Wait until the workqueue becomes empty. While draining is in progress, | |
2612 | * only chain queueing is allowed. IOW, only currently pending or running | |
2613 | * work items on @wq can queue further work items on it. @wq is flushed | |
2614 | * repeatedly until it becomes empty. The number of flushing is detemined | |
2615 | * by the depth of chaining and should be relatively short. Whine if it | |
2616 | * takes too long. | |
2617 | */ | |
2618 | void drain_workqueue(struct workqueue_struct *wq) | |
2619 | { | |
2620 | unsigned int flush_cnt = 0; | |
2621 | unsigned int cpu; | |
2622 | ||
2623 | /* | |
2624 | * __queue_work() needs to test whether there are drainers, is much | |
2625 | * hotter than drain_workqueue() and already looks at @wq->flags. | |
2626 | * Use WQ_DRAINING so that queue doesn't have to check nr_drainers. | |
2627 | */ | |
2628 | spin_lock(&workqueue_lock); | |
2629 | if (!wq->nr_drainers++) | |
2630 | wq->flags |= WQ_DRAINING; | |
2631 | spin_unlock(&workqueue_lock); | |
2632 | reflush: | |
2633 | flush_workqueue(wq); | |
2634 | ||
2635 | for_each_cwq_cpu(cpu, wq) { | |
2636 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
fa2563e4 | 2637 | bool drained; |
9c5a2ba7 | 2638 | |
bd7bdd43 | 2639 | spin_lock_irq(&cwq->pool->gcwq->lock); |
fa2563e4 | 2640 | drained = !cwq->nr_active && list_empty(&cwq->delayed_works); |
bd7bdd43 | 2641 | spin_unlock_irq(&cwq->pool->gcwq->lock); |
fa2563e4 TT |
2642 | |
2643 | if (drained) | |
9c5a2ba7 TH |
2644 | continue; |
2645 | ||
2646 | if (++flush_cnt == 10 || | |
2647 | (flush_cnt % 100 == 0 && flush_cnt <= 1000)) | |
2648 | pr_warning("workqueue %s: flush on destruction isn't complete after %u tries\n", | |
2649 | wq->name, flush_cnt); | |
2650 | goto reflush; | |
2651 | } | |
2652 | ||
2653 | spin_lock(&workqueue_lock); | |
2654 | if (!--wq->nr_drainers) | |
2655 | wq->flags &= ~WQ_DRAINING; | |
2656 | spin_unlock(&workqueue_lock); | |
2657 | } | |
2658 | EXPORT_SYMBOL_GPL(drain_workqueue); | |
2659 | ||
baf59022 TH |
2660 | static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, |
2661 | bool wait_executing) | |
db700897 | 2662 | { |
affee4b2 | 2663 | struct worker *worker = NULL; |
8b03ae3c | 2664 | struct global_cwq *gcwq; |
db700897 | 2665 | struct cpu_workqueue_struct *cwq; |
db700897 ON |
2666 | |
2667 | might_sleep(); | |
7a22ad75 TH |
2668 | gcwq = get_work_gcwq(work); |
2669 | if (!gcwq) | |
baf59022 | 2670 | return false; |
db700897 | 2671 | |
8b03ae3c | 2672 | spin_lock_irq(&gcwq->lock); |
db700897 ON |
2673 | if (!list_empty(&work->entry)) { |
2674 | /* | |
2675 | * See the comment near try_to_grab_pending()->smp_rmb(). | |
7a22ad75 TH |
2676 | * If it was re-queued to a different gcwq under us, we |
2677 | * are not going to wait. | |
db700897 ON |
2678 | */ |
2679 | smp_rmb(); | |
7a22ad75 | 2680 | cwq = get_work_cwq(work); |
bd7bdd43 | 2681 | if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) |
4690c4ab | 2682 | goto already_gone; |
baf59022 | 2683 | } else if (wait_executing) { |
7a22ad75 | 2684 | worker = find_worker_executing_work(gcwq, work); |
affee4b2 | 2685 | if (!worker) |
4690c4ab | 2686 | goto already_gone; |
7a22ad75 | 2687 | cwq = worker->current_cwq; |
baf59022 TH |
2688 | } else |
2689 | goto already_gone; | |
db700897 | 2690 | |
baf59022 | 2691 | insert_wq_barrier(cwq, barr, work, worker); |
8b03ae3c | 2692 | spin_unlock_irq(&gcwq->lock); |
7a22ad75 | 2693 | |
e159489b TH |
2694 | /* |
2695 | * If @max_active is 1 or rescuer is in use, flushing another work | |
2696 | * item on the same workqueue may lead to deadlock. Make sure the | |
2697 | * flusher is not running on the same workqueue by verifying write | |
2698 | * access. | |
2699 | */ | |
2700 | if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER) | |
2701 | lock_map_acquire(&cwq->wq->lockdep_map); | |
2702 | else | |
2703 | lock_map_acquire_read(&cwq->wq->lockdep_map); | |
7a22ad75 | 2704 | lock_map_release(&cwq->wq->lockdep_map); |
e159489b | 2705 | |
401a8d04 | 2706 | return true; |
4690c4ab | 2707 | already_gone: |
8b03ae3c | 2708 | spin_unlock_irq(&gcwq->lock); |
401a8d04 | 2709 | return false; |
db700897 | 2710 | } |
baf59022 TH |
2711 | |
2712 | /** | |
2713 | * flush_work - wait for a work to finish executing the last queueing instance | |
2714 | * @work: the work to flush | |
2715 | * | |
2716 | * Wait until @work has finished execution. This function considers | |
2717 | * only the last queueing instance of @work. If @work has been | |
2718 | * enqueued across different CPUs on a non-reentrant workqueue or on | |
2719 | * multiple workqueues, @work might still be executing on return on | |
2720 | * some of the CPUs from earlier queueing. | |
2721 | * | |
2722 | * If @work was queued only on a non-reentrant, ordered or unbound | |
2723 | * workqueue, @work is guaranteed to be idle on return if it hasn't | |
2724 | * been requeued since flush started. | |
2725 | * | |
2726 | * RETURNS: | |
2727 | * %true if flush_work() waited for the work to finish execution, | |
2728 | * %false if it was already idle. | |
2729 | */ | |
2730 | bool flush_work(struct work_struct *work) | |
2731 | { | |
2732 | struct wq_barrier barr; | |
2733 | ||
0976dfc1 SB |
2734 | lock_map_acquire(&work->lockdep_map); |
2735 | lock_map_release(&work->lockdep_map); | |
2736 | ||
baf59022 TH |
2737 | if (start_flush_work(work, &barr, true)) { |
2738 | wait_for_completion(&barr.done); | |
2739 | destroy_work_on_stack(&barr.work); | |
2740 | return true; | |
2741 | } else | |
2742 | return false; | |
2743 | } | |
db700897 ON |
2744 | EXPORT_SYMBOL_GPL(flush_work); |
2745 | ||
401a8d04 TH |
2746 | static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) |
2747 | { | |
2748 | struct wq_barrier barr; | |
2749 | struct worker *worker; | |
2750 | ||
2751 | spin_lock_irq(&gcwq->lock); | |
2752 | ||
2753 | worker = find_worker_executing_work(gcwq, work); | |
2754 | if (unlikely(worker)) | |
2755 | insert_wq_barrier(worker->current_cwq, &barr, work, worker); | |
2756 | ||
2757 | spin_unlock_irq(&gcwq->lock); | |
2758 | ||
2759 | if (unlikely(worker)) { | |
2760 | wait_for_completion(&barr.done); | |
2761 | destroy_work_on_stack(&barr.work); | |
2762 | return true; | |
2763 | } else | |
2764 | return false; | |
2765 | } | |
2766 | ||
2767 | static bool wait_on_work(struct work_struct *work) | |
2768 | { | |
2769 | bool ret = false; | |
2770 | int cpu; | |
2771 | ||
2772 | might_sleep(); | |
2773 | ||
2774 | lock_map_acquire(&work->lockdep_map); | |
2775 | lock_map_release(&work->lockdep_map); | |
2776 | ||
2777 | for_each_gcwq_cpu(cpu) | |
2778 | ret |= wait_on_cpu_work(get_gcwq(cpu), work); | |
2779 | return ret; | |
2780 | } | |
2781 | ||
09383498 TH |
2782 | /** |
2783 | * flush_work_sync - wait until a work has finished execution | |
2784 | * @work: the work to flush | |
2785 | * | |
2786 | * Wait until @work has finished execution. On return, it's | |
2787 | * guaranteed that all queueing instances of @work which happened | |
2788 | * before this function is called are finished. In other words, if | |
2789 | * @work hasn't been requeued since this function was called, @work is | |
2790 | * guaranteed to be idle on return. | |
2791 | * | |
2792 | * RETURNS: | |
2793 | * %true if flush_work_sync() waited for the work to finish execution, | |
2794 | * %false if it was already idle. | |
2795 | */ | |
2796 | bool flush_work_sync(struct work_struct *work) | |
2797 | { | |
2798 | struct wq_barrier barr; | |
2799 | bool pending, waited; | |
2800 | ||
2801 | /* we'll wait for executions separately, queue barr only if pending */ | |
2802 | pending = start_flush_work(work, &barr, false); | |
2803 | ||
2804 | /* wait for executions to finish */ | |
2805 | waited = wait_on_work(work); | |
2806 | ||
2807 | /* wait for the pending one */ | |
2808 | if (pending) { | |
2809 | wait_for_completion(&barr.done); | |
2810 | destroy_work_on_stack(&barr.work); | |
2811 | } | |
2812 | ||
2813 | return pending || waited; | |
2814 | } | |
2815 | EXPORT_SYMBOL_GPL(flush_work_sync); | |
2816 | ||
6e84d644 | 2817 | /* |
1f1f642e | 2818 | * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit, |
6e84d644 ON |
2819 | * so this work can't be re-armed in any way. |
2820 | */ | |
2821 | static int try_to_grab_pending(struct work_struct *work) | |
2822 | { | |
8b03ae3c | 2823 | struct global_cwq *gcwq; |
1f1f642e | 2824 | int ret = -1; |
6e84d644 | 2825 | |
22df02bb | 2826 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1f1f642e | 2827 | return 0; |
6e84d644 ON |
2828 | |
2829 | /* | |
2830 | * The queueing is in progress, or it is already queued. Try to | |
2831 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
2832 | */ | |
7a22ad75 TH |
2833 | gcwq = get_work_gcwq(work); |
2834 | if (!gcwq) | |
6e84d644 ON |
2835 | return ret; |
2836 | ||
8b03ae3c | 2837 | spin_lock_irq(&gcwq->lock); |
6e84d644 ON |
2838 | if (!list_empty(&work->entry)) { |
2839 | /* | |
7a22ad75 | 2840 | * This work is queued, but perhaps we locked the wrong gcwq. |
6e84d644 ON |
2841 | * In that case we must see the new value after rmb(), see |
2842 | * insert_work()->wmb(). | |
2843 | */ | |
2844 | smp_rmb(); | |
7a22ad75 | 2845 | if (gcwq == get_work_gcwq(work)) { |
dc186ad7 | 2846 | debug_work_deactivate(work); |
6e84d644 | 2847 | list_del_init(&work->entry); |
7a22ad75 | 2848 | cwq_dec_nr_in_flight(get_work_cwq(work), |
8a2e8e5d TH |
2849 | get_work_color(work), |
2850 | *work_data_bits(work) & WORK_STRUCT_DELAYED); | |
6e84d644 ON |
2851 | ret = 1; |
2852 | } | |
2853 | } | |
8b03ae3c | 2854 | spin_unlock_irq(&gcwq->lock); |
6e84d644 ON |
2855 | |
2856 | return ret; | |
2857 | } | |
2858 | ||
401a8d04 | 2859 | static bool __cancel_work_timer(struct work_struct *work, |
1f1f642e ON |
2860 | struct timer_list* timer) |
2861 | { | |
2862 | int ret; | |
2863 | ||
2864 | do { | |
2865 | ret = (timer && likely(del_timer(timer))); | |
2866 | if (!ret) | |
2867 | ret = try_to_grab_pending(work); | |
2868 | wait_on_work(work); | |
2869 | } while (unlikely(ret < 0)); | |
2870 | ||
7a22ad75 | 2871 | clear_work_data(work); |
1f1f642e ON |
2872 | return ret; |
2873 | } | |
2874 | ||
6e84d644 | 2875 | /** |
401a8d04 TH |
2876 | * cancel_work_sync - cancel a work and wait for it to finish |
2877 | * @work: the work to cancel | |
6e84d644 | 2878 | * |
401a8d04 TH |
2879 | * Cancel @work and wait for its execution to finish. This function |
2880 | * can be used even if the work re-queues itself or migrates to | |
2881 | * another workqueue. On return from this function, @work is | |
2882 | * guaranteed to be not pending or executing on any CPU. | |
1f1f642e | 2883 | * |
401a8d04 TH |
2884 | * cancel_work_sync(&delayed_work->work) must not be used for |
2885 | * delayed_work's. Use cancel_delayed_work_sync() instead. | |
6e84d644 | 2886 | * |
401a8d04 | 2887 | * The caller must ensure that the workqueue on which @work was last |
6e84d644 | 2888 | * queued can't be destroyed before this function returns. |
401a8d04 TH |
2889 | * |
2890 | * RETURNS: | |
2891 | * %true if @work was pending, %false otherwise. | |
6e84d644 | 2892 | */ |
401a8d04 | 2893 | bool cancel_work_sync(struct work_struct *work) |
6e84d644 | 2894 | { |
1f1f642e | 2895 | return __cancel_work_timer(work, NULL); |
b89deed3 | 2896 | } |
28e53bdd | 2897 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 2898 | |
6e84d644 | 2899 | /** |
401a8d04 TH |
2900 | * flush_delayed_work - wait for a dwork to finish executing the last queueing |
2901 | * @dwork: the delayed work to flush | |
6e84d644 | 2902 | * |
401a8d04 TH |
2903 | * Delayed timer is cancelled and the pending work is queued for |
2904 | * immediate execution. Like flush_work(), this function only | |
2905 | * considers the last queueing instance of @dwork. | |
1f1f642e | 2906 | * |
401a8d04 TH |
2907 | * RETURNS: |
2908 | * %true if flush_work() waited for the work to finish execution, | |
2909 | * %false if it was already idle. | |
6e84d644 | 2910 | */ |
401a8d04 TH |
2911 | bool flush_delayed_work(struct delayed_work *dwork) |
2912 | { | |
2913 | if (del_timer_sync(&dwork->timer)) | |
2914 | __queue_work(raw_smp_processor_id(), | |
2915 | get_work_cwq(&dwork->work)->wq, &dwork->work); | |
2916 | return flush_work(&dwork->work); | |
2917 | } | |
2918 | EXPORT_SYMBOL(flush_delayed_work); | |
2919 | ||
09383498 TH |
2920 | /** |
2921 | * flush_delayed_work_sync - wait for a dwork to finish | |
2922 | * @dwork: the delayed work to flush | |
2923 | * | |
2924 | * Delayed timer is cancelled and the pending work is queued for | |
2925 | * execution immediately. Other than timer handling, its behavior | |
2926 | * is identical to flush_work_sync(). | |
2927 | * | |
2928 | * RETURNS: | |
2929 | * %true if flush_work_sync() waited for the work to finish execution, | |
2930 | * %false if it was already idle. | |
2931 | */ | |
2932 | bool flush_delayed_work_sync(struct delayed_work *dwork) | |
2933 | { | |
2934 | if (del_timer_sync(&dwork->timer)) | |
2935 | __queue_work(raw_smp_processor_id(), | |
2936 | get_work_cwq(&dwork->work)->wq, &dwork->work); | |
2937 | return flush_work_sync(&dwork->work); | |
2938 | } | |
2939 | EXPORT_SYMBOL(flush_delayed_work_sync); | |
2940 | ||
401a8d04 TH |
2941 | /** |
2942 | * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish | |
2943 | * @dwork: the delayed work cancel | |
2944 | * | |
2945 | * This is cancel_work_sync() for delayed works. | |
2946 | * | |
2947 | * RETURNS: | |
2948 | * %true if @dwork was pending, %false otherwise. | |
2949 | */ | |
2950 | bool cancel_delayed_work_sync(struct delayed_work *dwork) | |
6e84d644 | 2951 | { |
1f1f642e | 2952 | return __cancel_work_timer(&dwork->work, &dwork->timer); |
6e84d644 | 2953 | } |
f5a421a4 | 2954 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 2955 | |
0fcb78c2 REB |
2956 | /** |
2957 | * schedule_work - put work task in global workqueue | |
2958 | * @work: job to be done | |
2959 | * | |
5b0f437d BVA |
2960 | * Returns zero if @work was already on the kernel-global workqueue and |
2961 | * non-zero otherwise. | |
2962 | * | |
2963 | * This puts a job in the kernel-global workqueue if it was not already | |
2964 | * queued and leaves it in the same position on the kernel-global | |
2965 | * workqueue otherwise. | |
0fcb78c2 | 2966 | */ |
7ad5b3a5 | 2967 | int schedule_work(struct work_struct *work) |
1da177e4 | 2968 | { |
d320c038 | 2969 | return queue_work(system_wq, work); |
1da177e4 | 2970 | } |
ae90dd5d | 2971 | EXPORT_SYMBOL(schedule_work); |
1da177e4 | 2972 | |
c1a220e7 ZR |
2973 | /* |
2974 | * schedule_work_on - put work task on a specific cpu | |
2975 | * @cpu: cpu to put the work task on | |
2976 | * @work: job to be done | |
2977 | * | |
2978 | * This puts a job on a specific cpu | |
2979 | */ | |
2980 | int schedule_work_on(int cpu, struct work_struct *work) | |
2981 | { | |
d320c038 | 2982 | return queue_work_on(cpu, system_wq, work); |
c1a220e7 ZR |
2983 | } |
2984 | EXPORT_SYMBOL(schedule_work_on); | |
2985 | ||
0fcb78c2 REB |
2986 | /** |
2987 | * schedule_delayed_work - put work task in global workqueue after delay | |
52bad64d DH |
2988 | * @dwork: job to be done |
2989 | * @delay: number of jiffies to wait or 0 for immediate execution | |
0fcb78c2 REB |
2990 | * |
2991 | * After waiting for a given time this puts a job in the kernel-global | |
2992 | * workqueue. | |
2993 | */ | |
7ad5b3a5 | 2994 | int schedule_delayed_work(struct delayed_work *dwork, |
82f67cd9 | 2995 | unsigned long delay) |
1da177e4 | 2996 | { |
d320c038 | 2997 | return queue_delayed_work(system_wq, dwork, delay); |
1da177e4 | 2998 | } |
ae90dd5d | 2999 | EXPORT_SYMBOL(schedule_delayed_work); |
1da177e4 | 3000 | |
0fcb78c2 REB |
3001 | /** |
3002 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay | |
3003 | * @cpu: cpu to use | |
52bad64d | 3004 | * @dwork: job to be done |
0fcb78c2 REB |
3005 | * @delay: number of jiffies to wait |
3006 | * | |
3007 | * After waiting for a given time this puts a job in the kernel-global | |
3008 | * workqueue on the specified CPU. | |
3009 | */ | |
1da177e4 | 3010 | int schedule_delayed_work_on(int cpu, |
52bad64d | 3011 | struct delayed_work *dwork, unsigned long delay) |
1da177e4 | 3012 | { |
d320c038 | 3013 | return queue_delayed_work_on(cpu, system_wq, dwork, delay); |
1da177e4 | 3014 | } |
ae90dd5d | 3015 | EXPORT_SYMBOL(schedule_delayed_work_on); |
1da177e4 | 3016 | |
b6136773 | 3017 | /** |
31ddd871 | 3018 | * schedule_on_each_cpu - execute a function synchronously on each online CPU |
b6136773 | 3019 | * @func: the function to call |
b6136773 | 3020 | * |
31ddd871 TH |
3021 | * schedule_on_each_cpu() executes @func on each online CPU using the |
3022 | * system workqueue and blocks until all CPUs have completed. | |
b6136773 | 3023 | * schedule_on_each_cpu() is very slow. |
31ddd871 TH |
3024 | * |
3025 | * RETURNS: | |
3026 | * 0 on success, -errno on failure. | |
b6136773 | 3027 | */ |
65f27f38 | 3028 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
3029 | { |
3030 | int cpu; | |
38f51568 | 3031 | struct work_struct __percpu *works; |
15316ba8 | 3032 | |
b6136773 AM |
3033 | works = alloc_percpu(struct work_struct); |
3034 | if (!works) | |
15316ba8 | 3035 | return -ENOMEM; |
b6136773 | 3036 | |
93981800 TH |
3037 | get_online_cpus(); |
3038 | ||
15316ba8 | 3039 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
3040 | struct work_struct *work = per_cpu_ptr(works, cpu); |
3041 | ||
3042 | INIT_WORK(work, func); | |
b71ab8c2 | 3043 | schedule_work_on(cpu, work); |
65a64464 | 3044 | } |
93981800 TH |
3045 | |
3046 | for_each_online_cpu(cpu) | |
3047 | flush_work(per_cpu_ptr(works, cpu)); | |
3048 | ||
95402b38 | 3049 | put_online_cpus(); |
b6136773 | 3050 | free_percpu(works); |
15316ba8 CL |
3051 | return 0; |
3052 | } | |
3053 | ||
eef6a7d5 AS |
3054 | /** |
3055 | * flush_scheduled_work - ensure that any scheduled work has run to completion. | |
3056 | * | |
3057 | * Forces execution of the kernel-global workqueue and blocks until its | |
3058 | * completion. | |
3059 | * | |
3060 | * Think twice before calling this function! It's very easy to get into | |
3061 | * trouble if you don't take great care. Either of the following situations | |
3062 | * will lead to deadlock: | |
3063 | * | |
3064 | * One of the work items currently on the workqueue needs to acquire | |
3065 | * a lock held by your code or its caller. | |
3066 | * | |
3067 | * Your code is running in the context of a work routine. | |
3068 | * | |
3069 | * They will be detected by lockdep when they occur, but the first might not | |
3070 | * occur very often. It depends on what work items are on the workqueue and | |
3071 | * what locks they need, which you have no control over. | |
3072 | * | |
3073 | * In most situations flushing the entire workqueue is overkill; you merely | |
3074 | * need to know that a particular work item isn't queued and isn't running. | |
3075 | * In such cases you should use cancel_delayed_work_sync() or | |
3076 | * cancel_work_sync() instead. | |
3077 | */ | |
1da177e4 LT |
3078 | void flush_scheduled_work(void) |
3079 | { | |
d320c038 | 3080 | flush_workqueue(system_wq); |
1da177e4 | 3081 | } |
ae90dd5d | 3082 | EXPORT_SYMBOL(flush_scheduled_work); |
1da177e4 | 3083 | |
1fa44eca JB |
3084 | /** |
3085 | * execute_in_process_context - reliably execute the routine with user context | |
3086 | * @fn: the function to execute | |
1fa44eca JB |
3087 | * @ew: guaranteed storage for the execute work structure (must |
3088 | * be available when the work executes) | |
3089 | * | |
3090 | * Executes the function immediately if process context is available, | |
3091 | * otherwise schedules the function for delayed execution. | |
3092 | * | |
3093 | * Returns: 0 - function was executed | |
3094 | * 1 - function was scheduled for execution | |
3095 | */ | |
65f27f38 | 3096 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
3097 | { |
3098 | if (!in_interrupt()) { | |
65f27f38 | 3099 | fn(&ew->work); |
1fa44eca JB |
3100 | return 0; |
3101 | } | |
3102 | ||
65f27f38 | 3103 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
3104 | schedule_work(&ew->work); |
3105 | ||
3106 | return 1; | |
3107 | } | |
3108 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
3109 | ||
1da177e4 LT |
3110 | int keventd_up(void) |
3111 | { | |
d320c038 | 3112 | return system_wq != NULL; |
1da177e4 LT |
3113 | } |
3114 | ||
bdbc5dd7 | 3115 | static int alloc_cwqs(struct workqueue_struct *wq) |
0f900049 | 3116 | { |
65a64464 | 3117 | /* |
0f900049 TH |
3118 | * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. |
3119 | * Make sure that the alignment isn't lower than that of | |
3120 | * unsigned long long. | |
65a64464 | 3121 | */ |
0f900049 TH |
3122 | const size_t size = sizeof(struct cpu_workqueue_struct); |
3123 | const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, | |
3124 | __alignof__(unsigned long long)); | |
65a64464 | 3125 | |
e06ffa1e | 3126 | if (!(wq->flags & WQ_UNBOUND)) |
f3421797 | 3127 | wq->cpu_wq.pcpu = __alloc_percpu(size, align); |
931ac77e | 3128 | else { |
f3421797 TH |
3129 | void *ptr; |
3130 | ||
3131 | /* | |
3132 | * Allocate enough room to align cwq and put an extra | |
3133 | * pointer at the end pointing back to the originally | |
3134 | * allocated pointer which will be used for free. | |
3135 | */ | |
3136 | ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); | |
3137 | if (ptr) { | |
3138 | wq->cpu_wq.single = PTR_ALIGN(ptr, align); | |
3139 | *(void **)(wq->cpu_wq.single + 1) = ptr; | |
3140 | } | |
bdbc5dd7 | 3141 | } |
f3421797 | 3142 | |
0415b00d | 3143 | /* just in case, make sure it's actually aligned */ |
bdbc5dd7 TH |
3144 | BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); |
3145 | return wq->cpu_wq.v ? 0 : -ENOMEM; | |
0f900049 TH |
3146 | } |
3147 | ||
bdbc5dd7 | 3148 | static void free_cwqs(struct workqueue_struct *wq) |
0f900049 | 3149 | { |
e06ffa1e | 3150 | if (!(wq->flags & WQ_UNBOUND)) |
f3421797 TH |
3151 | free_percpu(wq->cpu_wq.pcpu); |
3152 | else if (wq->cpu_wq.single) { | |
3153 | /* the pointer to free is stored right after the cwq */ | |
bdbc5dd7 | 3154 | kfree(*(void **)(wq->cpu_wq.single + 1)); |
f3421797 | 3155 | } |
0f900049 TH |
3156 | } |
3157 | ||
f3421797 TH |
3158 | static int wq_clamp_max_active(int max_active, unsigned int flags, |
3159 | const char *name) | |
b71ab8c2 | 3160 | { |
f3421797 TH |
3161 | int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; |
3162 | ||
3163 | if (max_active < 1 || max_active > lim) | |
b71ab8c2 TH |
3164 | printk(KERN_WARNING "workqueue: max_active %d requested for %s " |
3165 | "is out of range, clamping between %d and %d\n", | |
f3421797 | 3166 | max_active, name, 1, lim); |
b71ab8c2 | 3167 | |
f3421797 | 3168 | return clamp_val(max_active, 1, lim); |
b71ab8c2 TH |
3169 | } |
3170 | ||
b196be89 | 3171 | struct workqueue_struct *__alloc_workqueue_key(const char *fmt, |
d320c038 TH |
3172 | unsigned int flags, |
3173 | int max_active, | |
3174 | struct lock_class_key *key, | |
b196be89 | 3175 | const char *lock_name, ...) |
1da177e4 | 3176 | { |
b196be89 | 3177 | va_list args, args1; |
1da177e4 | 3178 | struct workqueue_struct *wq; |
c34056a3 | 3179 | unsigned int cpu; |
b196be89 TH |
3180 | size_t namelen; |
3181 | ||
3182 | /* determine namelen, allocate wq and format name */ | |
3183 | va_start(args, lock_name); | |
3184 | va_copy(args1, args); | |
3185 | namelen = vsnprintf(NULL, 0, fmt, args) + 1; | |
3186 | ||
3187 | wq = kzalloc(sizeof(*wq) + namelen, GFP_KERNEL); | |
3188 | if (!wq) | |
3189 | goto err; | |
3190 | ||
3191 | vsnprintf(wq->name, namelen, fmt, args1); | |
3192 | va_end(args); | |
3193 | va_end(args1); | |
1da177e4 | 3194 | |
6370a6ad TH |
3195 | /* |
3196 | * Workqueues which may be used during memory reclaim should | |
3197 | * have a rescuer to guarantee forward progress. | |
3198 | */ | |
3199 | if (flags & WQ_MEM_RECLAIM) | |
3200 | flags |= WQ_RESCUER; | |
3201 | ||
d320c038 | 3202 | max_active = max_active ?: WQ_DFL_ACTIVE; |
b196be89 | 3203 | max_active = wq_clamp_max_active(max_active, flags, wq->name); |
3af24433 | 3204 | |
b196be89 | 3205 | /* init wq */ |
97e37d7b | 3206 | wq->flags = flags; |
a0a1a5fd | 3207 | wq->saved_max_active = max_active; |
73f53c4a TH |
3208 | mutex_init(&wq->flush_mutex); |
3209 | atomic_set(&wq->nr_cwqs_to_flush, 0); | |
3210 | INIT_LIST_HEAD(&wq->flusher_queue); | |
3211 | INIT_LIST_HEAD(&wq->flusher_overflow); | |
502ca9d8 | 3212 | |
eb13ba87 | 3213 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 3214 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 3215 | |
bdbc5dd7 TH |
3216 | if (alloc_cwqs(wq) < 0) |
3217 | goto err; | |
3218 | ||
f3421797 | 3219 | for_each_cwq_cpu(cpu, wq) { |
1537663f | 3220 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
8b03ae3c | 3221 | struct global_cwq *gcwq = get_gcwq(cpu); |
3270476a | 3222 | int pool_idx = (bool)(flags & WQ_HIGHPRI); |
1537663f | 3223 | |
0f900049 | 3224 | BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); |
3270476a | 3225 | cwq->pool = &gcwq->pools[pool_idx]; |
c34056a3 | 3226 | cwq->wq = wq; |
73f53c4a | 3227 | cwq->flush_color = -1; |
1e19ffc6 | 3228 | cwq->max_active = max_active; |
1e19ffc6 | 3229 | INIT_LIST_HEAD(&cwq->delayed_works); |
e22bee78 | 3230 | } |
1537663f | 3231 | |
e22bee78 TH |
3232 | if (flags & WQ_RESCUER) { |
3233 | struct worker *rescuer; | |
3234 | ||
f2e005aa | 3235 | if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) |
e22bee78 TH |
3236 | goto err; |
3237 | ||
3238 | wq->rescuer = rescuer = alloc_worker(); | |
3239 | if (!rescuer) | |
3240 | goto err; | |
3241 | ||
b196be89 TH |
3242 | rescuer->task = kthread_create(rescuer_thread, wq, "%s", |
3243 | wq->name); | |
e22bee78 TH |
3244 | if (IS_ERR(rescuer->task)) |
3245 | goto err; | |
3246 | ||
e22bee78 TH |
3247 | rescuer->task->flags |= PF_THREAD_BOUND; |
3248 | wake_up_process(rescuer->task); | |
3af24433 ON |
3249 | } |
3250 | ||
a0a1a5fd TH |
3251 | /* |
3252 | * workqueue_lock protects global freeze state and workqueues | |
3253 | * list. Grab it, set max_active accordingly and add the new | |
3254 | * workqueue to workqueues list. | |
3255 | */ | |
1537663f | 3256 | spin_lock(&workqueue_lock); |
a0a1a5fd | 3257 | |
58a69cb4 | 3258 | if (workqueue_freezing && wq->flags & WQ_FREEZABLE) |
f3421797 | 3259 | for_each_cwq_cpu(cpu, wq) |
a0a1a5fd TH |
3260 | get_cwq(cpu, wq)->max_active = 0; |
3261 | ||
1537663f | 3262 | list_add(&wq->list, &workqueues); |
a0a1a5fd | 3263 | |
1537663f TH |
3264 | spin_unlock(&workqueue_lock); |
3265 | ||
3af24433 | 3266 | return wq; |
4690c4ab TH |
3267 | err: |
3268 | if (wq) { | |
bdbc5dd7 | 3269 | free_cwqs(wq); |
f2e005aa | 3270 | free_mayday_mask(wq->mayday_mask); |
e22bee78 | 3271 | kfree(wq->rescuer); |
4690c4ab TH |
3272 | kfree(wq); |
3273 | } | |
3274 | return NULL; | |
3af24433 | 3275 | } |
d320c038 | 3276 | EXPORT_SYMBOL_GPL(__alloc_workqueue_key); |
1da177e4 | 3277 | |
3af24433 ON |
3278 | /** |
3279 | * destroy_workqueue - safely terminate a workqueue | |
3280 | * @wq: target workqueue | |
3281 | * | |
3282 | * Safely destroy a workqueue. All work currently pending will be done first. | |
3283 | */ | |
3284 | void destroy_workqueue(struct workqueue_struct *wq) | |
3285 | { | |
c8e55f36 | 3286 | unsigned int cpu; |
3af24433 | 3287 | |
9c5a2ba7 TH |
3288 | /* drain it before proceeding with destruction */ |
3289 | drain_workqueue(wq); | |
c8efcc25 | 3290 | |
a0a1a5fd TH |
3291 | /* |
3292 | * wq list is used to freeze wq, remove from list after | |
3293 | * flushing is complete in case freeze races us. | |
3294 | */ | |
95402b38 | 3295 | spin_lock(&workqueue_lock); |
b1f4ec17 | 3296 | list_del(&wq->list); |
95402b38 | 3297 | spin_unlock(&workqueue_lock); |
3af24433 | 3298 | |
e22bee78 | 3299 | /* sanity check */ |
f3421797 | 3300 | for_each_cwq_cpu(cpu, wq) { |
73f53c4a TH |
3301 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3302 | int i; | |
3303 | ||
73f53c4a TH |
3304 | for (i = 0; i < WORK_NR_COLORS; i++) |
3305 | BUG_ON(cwq->nr_in_flight[i]); | |
1e19ffc6 TH |
3306 | BUG_ON(cwq->nr_active); |
3307 | BUG_ON(!list_empty(&cwq->delayed_works)); | |
73f53c4a | 3308 | } |
9b41ea72 | 3309 | |
e22bee78 TH |
3310 | if (wq->flags & WQ_RESCUER) { |
3311 | kthread_stop(wq->rescuer->task); | |
f2e005aa | 3312 | free_mayday_mask(wq->mayday_mask); |
8d9df9f0 | 3313 | kfree(wq->rescuer); |
e22bee78 TH |
3314 | } |
3315 | ||
bdbc5dd7 | 3316 | free_cwqs(wq); |
3af24433 ON |
3317 | kfree(wq); |
3318 | } | |
3319 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
3320 | ||
dcd989cb TH |
3321 | /** |
3322 | * workqueue_set_max_active - adjust max_active of a workqueue | |
3323 | * @wq: target workqueue | |
3324 | * @max_active: new max_active value. | |
3325 | * | |
3326 | * Set max_active of @wq to @max_active. | |
3327 | * | |
3328 | * CONTEXT: | |
3329 | * Don't call from IRQ context. | |
3330 | */ | |
3331 | void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) | |
3332 | { | |
3333 | unsigned int cpu; | |
3334 | ||
f3421797 | 3335 | max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); |
dcd989cb TH |
3336 | |
3337 | spin_lock(&workqueue_lock); | |
3338 | ||
3339 | wq->saved_max_active = max_active; | |
3340 | ||
f3421797 | 3341 | for_each_cwq_cpu(cpu, wq) { |
dcd989cb TH |
3342 | struct global_cwq *gcwq = get_gcwq(cpu); |
3343 | ||
3344 | spin_lock_irq(&gcwq->lock); | |
3345 | ||
58a69cb4 | 3346 | if (!(wq->flags & WQ_FREEZABLE) || |
dcd989cb TH |
3347 | !(gcwq->flags & GCWQ_FREEZING)) |
3348 | get_cwq(gcwq->cpu, wq)->max_active = max_active; | |
9bfb1839 | 3349 | |
dcd989cb | 3350 | spin_unlock_irq(&gcwq->lock); |
65a64464 | 3351 | } |
93981800 | 3352 | |
dcd989cb | 3353 | spin_unlock(&workqueue_lock); |
15316ba8 | 3354 | } |
dcd989cb | 3355 | EXPORT_SYMBOL_GPL(workqueue_set_max_active); |
15316ba8 | 3356 | |
eef6a7d5 | 3357 | /** |
dcd989cb TH |
3358 | * workqueue_congested - test whether a workqueue is congested |
3359 | * @cpu: CPU in question | |
3360 | * @wq: target workqueue | |
eef6a7d5 | 3361 | * |
dcd989cb TH |
3362 | * Test whether @wq's cpu workqueue for @cpu is congested. There is |
3363 | * no synchronization around this function and the test result is | |
3364 | * unreliable and only useful as advisory hints or for debugging. | |
eef6a7d5 | 3365 | * |
dcd989cb TH |
3366 | * RETURNS: |
3367 | * %true if congested, %false otherwise. | |
eef6a7d5 | 3368 | */ |
dcd989cb | 3369 | bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) |
1da177e4 | 3370 | { |
dcd989cb TH |
3371 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
3372 | ||
3373 | return !list_empty(&cwq->delayed_works); | |
1da177e4 | 3374 | } |
dcd989cb | 3375 | EXPORT_SYMBOL_GPL(workqueue_congested); |
1da177e4 | 3376 | |
1fa44eca | 3377 | /** |
dcd989cb TH |
3378 | * work_cpu - return the last known associated cpu for @work |
3379 | * @work: the work of interest | |
1fa44eca | 3380 | * |
dcd989cb | 3381 | * RETURNS: |
bdbc5dd7 | 3382 | * CPU number if @work was ever queued. WORK_CPU_NONE otherwise. |
1fa44eca | 3383 | */ |
dcd989cb | 3384 | unsigned int work_cpu(struct work_struct *work) |
1fa44eca | 3385 | { |
dcd989cb | 3386 | struct global_cwq *gcwq = get_work_gcwq(work); |
1fa44eca | 3387 | |
bdbc5dd7 | 3388 | return gcwq ? gcwq->cpu : WORK_CPU_NONE; |
1fa44eca | 3389 | } |
dcd989cb | 3390 | EXPORT_SYMBOL_GPL(work_cpu); |
1fa44eca | 3391 | |
dcd989cb TH |
3392 | /** |
3393 | * work_busy - test whether a work is currently pending or running | |
3394 | * @work: the work to be tested | |
3395 | * | |
3396 | * Test whether @work is currently pending or running. There is no | |
3397 | * synchronization around this function and the test result is | |
3398 | * unreliable and only useful as advisory hints or for debugging. | |
3399 | * Especially for reentrant wqs, the pending state might hide the | |
3400 | * running state. | |
3401 | * | |
3402 | * RETURNS: | |
3403 | * OR'd bitmask of WORK_BUSY_* bits. | |
3404 | */ | |
3405 | unsigned int work_busy(struct work_struct *work) | |
1da177e4 | 3406 | { |
dcd989cb TH |
3407 | struct global_cwq *gcwq = get_work_gcwq(work); |
3408 | unsigned long flags; | |
3409 | unsigned int ret = 0; | |
1da177e4 | 3410 | |
dcd989cb TH |
3411 | if (!gcwq) |
3412 | return false; | |
1da177e4 | 3413 | |
dcd989cb | 3414 | spin_lock_irqsave(&gcwq->lock, flags); |
1da177e4 | 3415 | |
dcd989cb TH |
3416 | if (work_pending(work)) |
3417 | ret |= WORK_BUSY_PENDING; | |
3418 | if (find_worker_executing_work(gcwq, work)) | |
3419 | ret |= WORK_BUSY_RUNNING; | |
1da177e4 | 3420 | |
dcd989cb | 3421 | spin_unlock_irqrestore(&gcwq->lock, flags); |
1da177e4 | 3422 | |
dcd989cb | 3423 | return ret; |
1da177e4 | 3424 | } |
dcd989cb | 3425 | EXPORT_SYMBOL_GPL(work_busy); |
1da177e4 | 3426 | |
db7bccf4 TH |
3427 | /* |
3428 | * CPU hotplug. | |
3429 | * | |
e22bee78 TH |
3430 | * There are two challenges in supporting CPU hotplug. Firstly, there |
3431 | * are a lot of assumptions on strong associations among work, cwq and | |
3432 | * gcwq which make migrating pending and scheduled works very | |
3433 | * difficult to implement without impacting hot paths. Secondly, | |
3434 | * gcwqs serve mix of short, long and very long running works making | |
3435 | * blocked draining impractical. | |
3436 | * | |
628c78e7 TH |
3437 | * This is solved by allowing a gcwq to be disassociated from the CPU |
3438 | * running as an unbound one and allowing it to be reattached later if the | |
3439 | * cpu comes back online. | |
db7bccf4 | 3440 | */ |
1da177e4 | 3441 | |
60373152 | 3442 | /* claim manager positions of all pools */ |
8db25e78 | 3443 | static void gcwq_claim_management_and_lock(struct global_cwq *gcwq) |
60373152 TH |
3444 | { |
3445 | struct worker_pool *pool; | |
3446 | ||
3447 | for_each_worker_pool(pool, gcwq) | |
3448 | mutex_lock_nested(&pool->manager_mutex, pool - gcwq->pools); | |
8db25e78 | 3449 | spin_lock_irq(&gcwq->lock); |
60373152 TH |
3450 | } |
3451 | ||
3452 | /* release manager positions */ | |
8db25e78 | 3453 | static void gcwq_release_management_and_unlock(struct global_cwq *gcwq) |
60373152 TH |
3454 | { |
3455 | struct worker_pool *pool; | |
3456 | ||
8db25e78 | 3457 | spin_unlock_irq(&gcwq->lock); |
60373152 TH |
3458 | for_each_worker_pool(pool, gcwq) |
3459 | mutex_unlock(&pool->manager_mutex); | |
3460 | } | |
3461 | ||
628c78e7 | 3462 | static void gcwq_unbind_fn(struct work_struct *work) |
3af24433 | 3463 | { |
628c78e7 | 3464 | struct global_cwq *gcwq = get_gcwq(smp_processor_id()); |
4ce62e9e | 3465 | struct worker_pool *pool; |
db7bccf4 TH |
3466 | struct worker *worker; |
3467 | struct hlist_node *pos; | |
3468 | int i; | |
3af24433 | 3469 | |
db7bccf4 TH |
3470 | BUG_ON(gcwq->cpu != smp_processor_id()); |
3471 | ||
8db25e78 | 3472 | gcwq_claim_management_and_lock(gcwq); |
3af24433 | 3473 | |
f2d5a0ee TH |
3474 | /* |
3475 | * We've claimed all manager positions. Make all workers unbound | |
3476 | * and set DISASSOCIATED. Before this, all workers except for the | |
3477 | * ones which are still executing works from before the last CPU | |
3478 | * down must be on the cpu. After this, they may become diasporas. | |
3479 | */ | |
60373152 | 3480 | for_each_worker_pool(pool, gcwq) |
4ce62e9e | 3481 | list_for_each_entry(worker, &pool->idle_list, entry) |
403c821d | 3482 | worker->flags |= WORKER_UNBOUND; |
3af24433 | 3483 | |
db7bccf4 | 3484 | for_each_busy_worker(worker, i, pos, gcwq) |
403c821d | 3485 | worker->flags |= WORKER_UNBOUND; |
06ba38a9 | 3486 | |
f2d5a0ee TH |
3487 | gcwq->flags |= GCWQ_DISASSOCIATED; |
3488 | ||
8db25e78 | 3489 | gcwq_release_management_and_unlock(gcwq); |
628c78e7 | 3490 | |
e22bee78 | 3491 | /* |
403c821d | 3492 | * Call schedule() so that we cross rq->lock and thus can guarantee |
628c78e7 TH |
3493 | * sched callbacks see the %WORKER_UNBOUND flag. This is necessary |
3494 | * as scheduler callbacks may be invoked from other cpus. | |
e22bee78 | 3495 | */ |
e22bee78 | 3496 | schedule(); |
06ba38a9 | 3497 | |
e22bee78 | 3498 | /* |
628c78e7 TH |
3499 | * Sched callbacks are disabled now. Zap nr_running. After this, |
3500 | * nr_running stays zero and need_more_worker() and keep_working() | |
3501 | * are always true as long as the worklist is not empty. @gcwq now | |
3502 | * behaves as unbound (in terms of concurrency management) gcwq | |
3503 | * which is served by workers tied to the CPU. | |
3504 | * | |
3505 | * On return from this function, the current worker would trigger | |
3506 | * unbound chain execution of pending work items if other workers | |
3507 | * didn't already. | |
e22bee78 | 3508 | */ |
4ce62e9e TH |
3509 | for_each_worker_pool(pool, gcwq) |
3510 | atomic_set(get_pool_nr_running(pool), 0); | |
3af24433 | 3511 | } |
3af24433 | 3512 | |
8db25e78 TH |
3513 | /* |
3514 | * Workqueues should be brought up before normal priority CPU notifiers. | |
3515 | * This will be registered high priority CPU notifier. | |
3516 | */ | |
3517 | static int __devinit workqueue_cpu_up_callback(struct notifier_block *nfb, | |
3518 | unsigned long action, | |
3519 | void *hcpu) | |
3af24433 ON |
3520 | { |
3521 | unsigned int cpu = (unsigned long)hcpu; | |
db7bccf4 | 3522 | struct global_cwq *gcwq = get_gcwq(cpu); |
4ce62e9e | 3523 | struct worker_pool *pool; |
3ce63377 | 3524 | |
8db25e78 | 3525 | switch (action & ~CPU_TASKS_FROZEN) { |
3af24433 | 3526 | case CPU_UP_PREPARE: |
4ce62e9e | 3527 | for_each_worker_pool(pool, gcwq) { |
3ce63377 TH |
3528 | struct worker *worker; |
3529 | ||
3530 | if (pool->nr_workers) | |
3531 | continue; | |
3532 | ||
3533 | worker = create_worker(pool); | |
3534 | if (!worker) | |
3535 | return NOTIFY_BAD; | |
3536 | ||
3537 | spin_lock_irq(&gcwq->lock); | |
3538 | start_worker(worker); | |
3539 | spin_unlock_irq(&gcwq->lock); | |
3af24433 | 3540 | } |
8db25e78 | 3541 | break; |
3af24433 | 3542 | |
db7bccf4 TH |
3543 | case CPU_DOWN_FAILED: |
3544 | case CPU_ONLINE: | |
8db25e78 | 3545 | gcwq_claim_management_and_lock(gcwq); |
bc2ae0f5 | 3546 | gcwq->flags &= ~GCWQ_DISASSOCIATED; |
25511a47 | 3547 | rebind_workers(gcwq); |
8db25e78 | 3548 | gcwq_release_management_and_unlock(gcwq); |
db7bccf4 | 3549 | break; |
00dfcaf7 | 3550 | } |
65758202 TH |
3551 | return NOTIFY_OK; |
3552 | } | |
3553 | ||
3554 | /* | |
3555 | * Workqueues should be brought down after normal priority CPU notifiers. | |
3556 | * This will be registered as low priority CPU notifier. | |
3557 | */ | |
3558 | static int __devinit workqueue_cpu_down_callback(struct notifier_block *nfb, | |
3559 | unsigned long action, | |
3560 | void *hcpu) | |
3561 | { | |
8db25e78 TH |
3562 | unsigned int cpu = (unsigned long)hcpu; |
3563 | struct work_struct unbind_work; | |
3564 | ||
65758202 TH |
3565 | switch (action & ~CPU_TASKS_FROZEN) { |
3566 | case CPU_DOWN_PREPARE: | |
8db25e78 TH |
3567 | /* unbinding should happen on the local CPU */ |
3568 | INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn); | |
3569 | schedule_work_on(cpu, &unbind_work); | |
3570 | flush_work(&unbind_work); | |
3571 | break; | |
65758202 TH |
3572 | } |
3573 | return NOTIFY_OK; | |
3574 | } | |
3575 | ||
2d3854a3 | 3576 | #ifdef CONFIG_SMP |
8ccad40d | 3577 | |
2d3854a3 | 3578 | struct work_for_cpu { |
ed48ece2 | 3579 | struct work_struct work; |
2d3854a3 RR |
3580 | long (*fn)(void *); |
3581 | void *arg; | |
3582 | long ret; | |
3583 | }; | |
3584 | ||
ed48ece2 | 3585 | static void work_for_cpu_fn(struct work_struct *work) |
2d3854a3 | 3586 | { |
ed48ece2 TH |
3587 | struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); |
3588 | ||
2d3854a3 RR |
3589 | wfc->ret = wfc->fn(wfc->arg); |
3590 | } | |
3591 | ||
3592 | /** | |
3593 | * work_on_cpu - run a function in user context on a particular cpu | |
3594 | * @cpu: the cpu to run on | |
3595 | * @fn: the function to run | |
3596 | * @arg: the function arg | |
3597 | * | |
31ad9081 RR |
3598 | * This will return the value @fn returns. |
3599 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
6b44003e | 3600 | * The caller must not hold any locks which would prevent @fn from completing. |
2d3854a3 RR |
3601 | */ |
3602 | long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |
3603 | { | |
ed48ece2 | 3604 | struct work_for_cpu wfc = { .fn = fn, .arg = arg }; |
6b44003e | 3605 | |
ed48ece2 TH |
3606 | INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); |
3607 | schedule_work_on(cpu, &wfc.work); | |
3608 | flush_work(&wfc.work); | |
2d3854a3 RR |
3609 | return wfc.ret; |
3610 | } | |
3611 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
3612 | #endif /* CONFIG_SMP */ | |
3613 | ||
a0a1a5fd TH |
3614 | #ifdef CONFIG_FREEZER |
3615 | ||
3616 | /** | |
3617 | * freeze_workqueues_begin - begin freezing workqueues | |
3618 | * | |
58a69cb4 TH |
3619 | * Start freezing workqueues. After this function returns, all freezable |
3620 | * workqueues will queue new works to their frozen_works list instead of | |
3621 | * gcwq->worklist. | |
a0a1a5fd TH |
3622 | * |
3623 | * CONTEXT: | |
8b03ae3c | 3624 | * Grabs and releases workqueue_lock and gcwq->lock's. |
a0a1a5fd TH |
3625 | */ |
3626 | void freeze_workqueues_begin(void) | |
3627 | { | |
a0a1a5fd TH |
3628 | unsigned int cpu; |
3629 | ||
3630 | spin_lock(&workqueue_lock); | |
3631 | ||
3632 | BUG_ON(workqueue_freezing); | |
3633 | workqueue_freezing = true; | |
3634 | ||
f3421797 | 3635 | for_each_gcwq_cpu(cpu) { |
8b03ae3c | 3636 | struct global_cwq *gcwq = get_gcwq(cpu); |
bdbc5dd7 | 3637 | struct workqueue_struct *wq; |
8b03ae3c TH |
3638 | |
3639 | spin_lock_irq(&gcwq->lock); | |
3640 | ||
db7bccf4 TH |
3641 | BUG_ON(gcwq->flags & GCWQ_FREEZING); |
3642 | gcwq->flags |= GCWQ_FREEZING; | |
3643 | ||
a0a1a5fd TH |
3644 | list_for_each_entry(wq, &workqueues, list) { |
3645 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
3646 | ||
58a69cb4 | 3647 | if (cwq && wq->flags & WQ_FREEZABLE) |
a0a1a5fd | 3648 | cwq->max_active = 0; |
a0a1a5fd | 3649 | } |
8b03ae3c TH |
3650 | |
3651 | spin_unlock_irq(&gcwq->lock); | |
a0a1a5fd TH |
3652 | } |
3653 | ||
3654 | spin_unlock(&workqueue_lock); | |
3655 | } | |
3656 | ||
3657 | /** | |
58a69cb4 | 3658 | * freeze_workqueues_busy - are freezable workqueues still busy? |
a0a1a5fd TH |
3659 | * |
3660 | * Check whether freezing is complete. This function must be called | |
3661 | * between freeze_workqueues_begin() and thaw_workqueues(). | |
3662 | * | |
3663 | * CONTEXT: | |
3664 | * Grabs and releases workqueue_lock. | |
3665 | * | |
3666 | * RETURNS: | |
58a69cb4 TH |
3667 | * %true if some freezable workqueues are still busy. %false if freezing |
3668 | * is complete. | |
a0a1a5fd TH |
3669 | */ |
3670 | bool freeze_workqueues_busy(void) | |
3671 | { | |
a0a1a5fd TH |
3672 | unsigned int cpu; |
3673 | bool busy = false; | |
3674 | ||
3675 | spin_lock(&workqueue_lock); | |
3676 | ||
3677 | BUG_ON(!workqueue_freezing); | |
3678 | ||
f3421797 | 3679 | for_each_gcwq_cpu(cpu) { |
bdbc5dd7 | 3680 | struct workqueue_struct *wq; |
a0a1a5fd TH |
3681 | /* |
3682 | * nr_active is monotonically decreasing. It's safe | |
3683 | * to peek without lock. | |
3684 | */ | |
3685 | list_for_each_entry(wq, &workqueues, list) { | |
3686 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
3687 | ||
58a69cb4 | 3688 | if (!cwq || !(wq->flags & WQ_FREEZABLE)) |
a0a1a5fd TH |
3689 | continue; |
3690 | ||
3691 | BUG_ON(cwq->nr_active < 0); | |
3692 | if (cwq->nr_active) { | |
3693 | busy = true; | |
3694 | goto out_unlock; | |
3695 | } | |
3696 | } | |
3697 | } | |
3698 | out_unlock: | |
3699 | spin_unlock(&workqueue_lock); | |
3700 | return busy; | |
3701 | } | |
3702 | ||
3703 | /** | |
3704 | * thaw_workqueues - thaw workqueues | |
3705 | * | |
3706 | * Thaw workqueues. Normal queueing is restored and all collected | |
7e11629d | 3707 | * frozen works are transferred to their respective gcwq worklists. |
a0a1a5fd TH |
3708 | * |
3709 | * CONTEXT: | |
8b03ae3c | 3710 | * Grabs and releases workqueue_lock and gcwq->lock's. |
a0a1a5fd TH |
3711 | */ |
3712 | void thaw_workqueues(void) | |
3713 | { | |
a0a1a5fd TH |
3714 | unsigned int cpu; |
3715 | ||
3716 | spin_lock(&workqueue_lock); | |
3717 | ||
3718 | if (!workqueue_freezing) | |
3719 | goto out_unlock; | |
3720 | ||
f3421797 | 3721 | for_each_gcwq_cpu(cpu) { |
8b03ae3c | 3722 | struct global_cwq *gcwq = get_gcwq(cpu); |
4ce62e9e | 3723 | struct worker_pool *pool; |
bdbc5dd7 | 3724 | struct workqueue_struct *wq; |
8b03ae3c TH |
3725 | |
3726 | spin_lock_irq(&gcwq->lock); | |
3727 | ||
db7bccf4 TH |
3728 | BUG_ON(!(gcwq->flags & GCWQ_FREEZING)); |
3729 | gcwq->flags &= ~GCWQ_FREEZING; | |
3730 | ||
a0a1a5fd TH |
3731 | list_for_each_entry(wq, &workqueues, list) { |
3732 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | |
3733 | ||
58a69cb4 | 3734 | if (!cwq || !(wq->flags & WQ_FREEZABLE)) |
a0a1a5fd TH |
3735 | continue; |
3736 | ||
a0a1a5fd TH |
3737 | /* restore max_active and repopulate worklist */ |
3738 | cwq->max_active = wq->saved_max_active; | |
3739 | ||
3740 | while (!list_empty(&cwq->delayed_works) && | |
3741 | cwq->nr_active < cwq->max_active) | |
3742 | cwq_activate_first_delayed(cwq); | |
a0a1a5fd | 3743 | } |
8b03ae3c | 3744 | |
4ce62e9e TH |
3745 | for_each_worker_pool(pool, gcwq) |
3746 | wake_up_worker(pool); | |
e22bee78 | 3747 | |
8b03ae3c | 3748 | spin_unlock_irq(&gcwq->lock); |
a0a1a5fd TH |
3749 | } |
3750 | ||
3751 | workqueue_freezing = false; | |
3752 | out_unlock: | |
3753 | spin_unlock(&workqueue_lock); | |
3754 | } | |
3755 | #endif /* CONFIG_FREEZER */ | |
3756 | ||
6ee0578b | 3757 | static int __init init_workqueues(void) |
1da177e4 | 3758 | { |
c34056a3 | 3759 | unsigned int cpu; |
c8e55f36 | 3760 | int i; |
c34056a3 | 3761 | |
65758202 TH |
3762 | cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); |
3763 | cpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN); | |
8b03ae3c TH |
3764 | |
3765 | /* initialize gcwqs */ | |
f3421797 | 3766 | for_each_gcwq_cpu(cpu) { |
8b03ae3c | 3767 | struct global_cwq *gcwq = get_gcwq(cpu); |
4ce62e9e | 3768 | struct worker_pool *pool; |
8b03ae3c TH |
3769 | |
3770 | spin_lock_init(&gcwq->lock); | |
3771 | gcwq->cpu = cpu; | |
477a3c33 | 3772 | gcwq->flags |= GCWQ_DISASSOCIATED; |
8b03ae3c | 3773 | |
c8e55f36 TH |
3774 | for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) |
3775 | INIT_HLIST_HEAD(&gcwq->busy_hash[i]); | |
3776 | ||
4ce62e9e TH |
3777 | for_each_worker_pool(pool, gcwq) { |
3778 | pool->gcwq = gcwq; | |
3779 | INIT_LIST_HEAD(&pool->worklist); | |
3780 | INIT_LIST_HEAD(&pool->idle_list); | |
e7577c50 | 3781 | |
4ce62e9e TH |
3782 | init_timer_deferrable(&pool->idle_timer); |
3783 | pool->idle_timer.function = idle_worker_timeout; | |
3784 | pool->idle_timer.data = (unsigned long)pool; | |
e22bee78 | 3785 | |
4ce62e9e TH |
3786 | setup_timer(&pool->mayday_timer, gcwq_mayday_timeout, |
3787 | (unsigned long)pool); | |
3788 | ||
60373152 | 3789 | mutex_init(&pool->manager_mutex); |
4ce62e9e TH |
3790 | ida_init(&pool->worker_ida); |
3791 | } | |
db7bccf4 | 3792 | |
25511a47 | 3793 | init_waitqueue_head(&gcwq->rebind_hold); |
8b03ae3c TH |
3794 | } |
3795 | ||
e22bee78 | 3796 | /* create the initial worker */ |
f3421797 | 3797 | for_each_online_gcwq_cpu(cpu) { |
e22bee78 | 3798 | struct global_cwq *gcwq = get_gcwq(cpu); |
4ce62e9e | 3799 | struct worker_pool *pool; |
e22bee78 | 3800 | |
477a3c33 TH |
3801 | if (cpu != WORK_CPU_UNBOUND) |
3802 | gcwq->flags &= ~GCWQ_DISASSOCIATED; | |
4ce62e9e TH |
3803 | |
3804 | for_each_worker_pool(pool, gcwq) { | |
3805 | struct worker *worker; | |
3806 | ||
bc2ae0f5 | 3807 | worker = create_worker(pool); |
4ce62e9e TH |
3808 | BUG_ON(!worker); |
3809 | spin_lock_irq(&gcwq->lock); | |
3810 | start_worker(worker); | |
3811 | spin_unlock_irq(&gcwq->lock); | |
3812 | } | |
e22bee78 TH |
3813 | } |
3814 | ||
d320c038 TH |
3815 | system_wq = alloc_workqueue("events", 0, 0); |
3816 | system_long_wq = alloc_workqueue("events_long", 0, 0); | |
3817 | system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0); | |
f3421797 TH |
3818 | system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, |
3819 | WQ_UNBOUND_MAX_ACTIVE); | |
24d51add TH |
3820 | system_freezable_wq = alloc_workqueue("events_freezable", |
3821 | WQ_FREEZABLE, 0); | |
62d3c543 AS |
3822 | system_nrt_freezable_wq = alloc_workqueue("events_nrt_freezable", |
3823 | WQ_NON_REENTRANT | WQ_FREEZABLE, 0); | |
e5cba24e | 3824 | BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq || |
62d3c543 AS |
3825 | !system_unbound_wq || !system_freezable_wq || |
3826 | !system_nrt_freezable_wq); | |
6ee0578b | 3827 | return 0; |
1da177e4 | 3828 | } |
6ee0578b | 3829 | early_initcall(init_workqueues); |