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 | |
b11895c4 L |
19 | * automatically managed. There are two worker pools for each CPU (one for |
20 | * normal work items and the other for high priority ones) and some extra | |
21 | * pools for workqueues which are not bound to any specific CPU - the | |
22 | * number of these backing pools is dynamic. | |
c54fce6e | 23 | * |
9a261491 | 24 | * Please read Documentation/core-api/workqueue.rst for details. |
1da177e4 LT |
25 | */ |
26 | ||
9984de1a | 27 | #include <linux/export.h> |
1da177e4 LT |
28 | #include <linux/kernel.h> |
29 | #include <linux/sched.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/signal.h> | |
32 | #include <linux/completion.h> | |
33 | #include <linux/workqueue.h> | |
34 | #include <linux/slab.h> | |
35 | #include <linux/cpu.h> | |
36 | #include <linux/notifier.h> | |
37 | #include <linux/kthread.h> | |
1fa44eca | 38 | #include <linux/hardirq.h> |
46934023 | 39 | #include <linux/mempolicy.h> |
341a5958 | 40 | #include <linux/freezer.h> |
d5abe669 PZ |
41 | #include <linux/kallsyms.h> |
42 | #include <linux/debug_locks.h> | |
4e6045f1 | 43 | #include <linux/lockdep.h> |
c34056a3 | 44 | #include <linux/idr.h> |
29c91e99 | 45 | #include <linux/jhash.h> |
42f8570f | 46 | #include <linux/hashtable.h> |
76af4d93 | 47 | #include <linux/rculist.h> |
bce90380 | 48 | #include <linux/nodemask.h> |
4c16bd32 | 49 | #include <linux/moduleparam.h> |
3d1cb205 | 50 | #include <linux/uaccess.h> |
e22bee78 | 51 | |
ea138446 | 52 | #include "workqueue_internal.h" |
1da177e4 | 53 | |
c8e55f36 | 54 | enum { |
24647570 TH |
55 | /* |
56 | * worker_pool flags | |
bc2ae0f5 | 57 | * |
24647570 | 58 | * A bound pool is either associated or disassociated with its CPU. |
bc2ae0f5 TH |
59 | * While associated (!DISASSOCIATED), all workers are bound to the |
60 | * CPU and none has %WORKER_UNBOUND set and concurrency management | |
61 | * is in effect. | |
62 | * | |
63 | * While DISASSOCIATED, the cpu may be offline and all workers have | |
64 | * %WORKER_UNBOUND set and concurrency management disabled, and may | |
24647570 | 65 | * be executing on any CPU. The pool behaves as an unbound one. |
bc2ae0f5 | 66 | * |
bc3a1afc | 67 | * Note that DISASSOCIATED should be flipped only while holding |
92f9c5c4 | 68 | * attach_mutex to avoid changing binding state while |
4736cbf7 | 69 | * worker_attach_to_pool() is in progress. |
bc2ae0f5 | 70 | */ |
692b4825 | 71 | POOL_MANAGER_ACTIVE = 1 << 0, /* being managed */ |
24647570 | 72 | POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ |
db7bccf4 | 73 | |
c8e55f36 | 74 | /* worker flags */ |
c8e55f36 TH |
75 | WORKER_DIE = 1 << 1, /* die die die */ |
76 | WORKER_IDLE = 1 << 2, /* is idle */ | |
e22bee78 | 77 | WORKER_PREP = 1 << 3, /* preparing to run works */ |
fb0e7beb | 78 | WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ |
f3421797 | 79 | WORKER_UNBOUND = 1 << 7, /* worker is unbound */ |
a9ab775b | 80 | WORKER_REBOUND = 1 << 8, /* worker was rebound */ |
e22bee78 | 81 | |
a9ab775b TH |
82 | WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE | |
83 | WORKER_UNBOUND | WORKER_REBOUND, | |
db7bccf4 | 84 | |
e34cdddb | 85 | NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */ |
4ce62e9e | 86 | |
29c91e99 | 87 | UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */ |
c8e55f36 | 88 | BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ |
db7bccf4 | 89 | |
e22bee78 TH |
90 | MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ |
91 | IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ | |
92 | ||
3233cdbd TH |
93 | MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, |
94 | /* call for help after 10ms | |
95 | (min two ticks) */ | |
e22bee78 TH |
96 | MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ |
97 | CREATE_COOLDOWN = HZ, /* time to breath after fail */ | |
e22bee78 TH |
98 | |
99 | /* | |
100 | * Rescue workers are used only on emergencies and shared by | |
8698a745 | 101 | * all cpus. Give MIN_NICE. |
e22bee78 | 102 | */ |
8698a745 DY |
103 | RESCUER_NICE_LEVEL = MIN_NICE, |
104 | HIGHPRI_NICE_LEVEL = MIN_NICE, | |
ecf6881f TH |
105 | |
106 | WQ_NAME_LEN = 24, | |
c8e55f36 | 107 | }; |
1da177e4 LT |
108 | |
109 | /* | |
4690c4ab TH |
110 | * Structure fields follow one of the following exclusion rules. |
111 | * | |
e41e704b TH |
112 | * I: Modifiable by initialization/destruction paths and read-only for |
113 | * everyone else. | |
4690c4ab | 114 | * |
e22bee78 TH |
115 | * P: Preemption protected. Disabling preemption is enough and should |
116 | * only be modified and accessed from the local cpu. | |
117 | * | |
d565ed63 | 118 | * L: pool->lock protected. Access with pool->lock held. |
4690c4ab | 119 | * |
d565ed63 TH |
120 | * X: During normal operation, modification requires pool->lock and should |
121 | * be done only from local cpu. Either disabling preemption on local | |
122 | * cpu or grabbing pool->lock is enough for read access. If | |
123 | * POOL_DISASSOCIATED is set, it's identical to L. | |
e22bee78 | 124 | * |
92f9c5c4 | 125 | * A: pool->attach_mutex protected. |
822d8405 | 126 | * |
68e13a67 | 127 | * PL: wq_pool_mutex protected. |
5bcab335 | 128 | * |
68e13a67 | 129 | * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads. |
76af4d93 | 130 | * |
5b95e1af LJ |
131 | * PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads. |
132 | * | |
133 | * PWR: wq_pool_mutex and wq->mutex protected for writes. Either or | |
134 | * sched-RCU for reads. | |
135 | * | |
3c25a55d LJ |
136 | * WQ: wq->mutex protected. |
137 | * | |
b5927605 | 138 | * WR: wq->mutex protected for writes. Sched-RCU protected for reads. |
2e109a28 TH |
139 | * |
140 | * MD: wq_mayday_lock protected. | |
1da177e4 | 141 | */ |
1da177e4 | 142 | |
2eaebdb3 | 143 | /* struct worker is defined in workqueue_internal.h */ |
c34056a3 | 144 | |
bd7bdd43 | 145 | struct worker_pool { |
d565ed63 | 146 | spinlock_t lock; /* the pool lock */ |
d84ff051 | 147 | int cpu; /* I: the associated cpu */ |
f3f90ad4 | 148 | int node; /* I: the associated node ID */ |
9daf9e67 | 149 | int id; /* I: pool ID */ |
11ebea50 | 150 | unsigned int flags; /* X: flags */ |
bd7bdd43 | 151 | |
82607adc TH |
152 | unsigned long watchdog_ts; /* L: watchdog timestamp */ |
153 | ||
bd7bdd43 TH |
154 | struct list_head worklist; /* L: list of pending works */ |
155 | int nr_workers; /* L: total number of workers */ | |
ea1abd61 LJ |
156 | |
157 | /* nr_idle includes the ones off idle_list for rebinding */ | |
bd7bdd43 TH |
158 | int nr_idle; /* L: currently idle ones */ |
159 | ||
160 | struct list_head idle_list; /* X: list of idle workers */ | |
161 | struct timer_list idle_timer; /* L: worker idle timeout */ | |
162 | struct timer_list mayday_timer; /* L: SOS timer for workers */ | |
163 | ||
c5aa87bb | 164 | /* a workers is either on busy_hash or idle_list, or the manager */ |
c9e7cf27 TH |
165 | DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER); |
166 | /* L: hash of busy workers */ | |
167 | ||
bc3a1afc | 168 | /* see manage_workers() for details on the two manager mutexes */ |
2607d7a6 | 169 | struct worker *manager; /* L: purely informational */ |
92f9c5c4 LJ |
170 | struct mutex attach_mutex; /* attach/detach exclusion */ |
171 | struct list_head workers; /* A: attached workers */ | |
60f5a4bc | 172 | struct completion *detach_completion; /* all workers detached */ |
e19e397a | 173 | |
7cda9aae | 174 | struct ida worker_ida; /* worker IDs for task name */ |
e19e397a | 175 | |
7a4e344c | 176 | struct workqueue_attrs *attrs; /* I: worker attributes */ |
68e13a67 LJ |
177 | struct hlist_node hash_node; /* PL: unbound_pool_hash node */ |
178 | int refcnt; /* PL: refcnt for unbound pools */ | |
7a4e344c | 179 | |
e19e397a TH |
180 | /* |
181 | * The current concurrency level. As it's likely to be accessed | |
182 | * from other CPUs during try_to_wake_up(), put it in a separate | |
183 | * cacheline. | |
184 | */ | |
185 | atomic_t nr_running ____cacheline_aligned_in_smp; | |
29c91e99 TH |
186 | |
187 | /* | |
188 | * Destruction of pool is sched-RCU protected to allow dereferences | |
189 | * from get_work_pool(). | |
190 | */ | |
191 | struct rcu_head rcu; | |
8b03ae3c TH |
192 | } ____cacheline_aligned_in_smp; |
193 | ||
1da177e4 | 194 | /* |
112202d9 TH |
195 | * The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS |
196 | * of work_struct->data are used for flags and the remaining high bits | |
197 | * point to the pwq; thus, pwqs need to be aligned at two's power of the | |
198 | * number of flag bits. | |
1da177e4 | 199 | */ |
112202d9 | 200 | struct pool_workqueue { |
bd7bdd43 | 201 | struct worker_pool *pool; /* I: the associated pool */ |
4690c4ab | 202 | struct workqueue_struct *wq; /* I: the owning workqueue */ |
73f53c4a TH |
203 | int work_color; /* L: current color */ |
204 | int flush_color; /* L: flushing color */ | |
8864b4e5 | 205 | int refcnt; /* L: reference count */ |
73f53c4a TH |
206 | int nr_in_flight[WORK_NR_COLORS]; |
207 | /* L: nr of in_flight works */ | |
1e19ffc6 | 208 | int nr_active; /* L: nr of active works */ |
a0a1a5fd | 209 | int max_active; /* L: max active works */ |
1e19ffc6 | 210 | struct list_head delayed_works; /* L: delayed works */ |
3c25a55d | 211 | struct list_head pwqs_node; /* WR: node on wq->pwqs */ |
2e109a28 | 212 | struct list_head mayday_node; /* MD: node on wq->maydays */ |
8864b4e5 TH |
213 | |
214 | /* | |
215 | * Release of unbound pwq is punted to system_wq. See put_pwq() | |
216 | * and pwq_unbound_release_workfn() for details. pool_workqueue | |
217 | * itself is also sched-RCU protected so that the first pwq can be | |
b09f4fd3 | 218 | * determined without grabbing wq->mutex. |
8864b4e5 TH |
219 | */ |
220 | struct work_struct unbound_release_work; | |
221 | struct rcu_head rcu; | |
e904e6c2 | 222 | } __aligned(1 << WORK_STRUCT_FLAG_BITS); |
1da177e4 | 223 | |
73f53c4a TH |
224 | /* |
225 | * Structure used to wait for workqueue flush. | |
226 | */ | |
227 | struct wq_flusher { | |
3c25a55d LJ |
228 | struct list_head list; /* WQ: list of flushers */ |
229 | int flush_color; /* WQ: flush color waiting for */ | |
73f53c4a TH |
230 | struct completion done; /* flush completion */ |
231 | }; | |
232 | ||
226223ab TH |
233 | struct wq_device; |
234 | ||
1da177e4 | 235 | /* |
c5aa87bb TH |
236 | * The externally visible workqueue. It relays the issued work items to |
237 | * the appropriate worker_pool through its pool_workqueues. | |
1da177e4 LT |
238 | */ |
239 | struct workqueue_struct { | |
3c25a55d | 240 | struct list_head pwqs; /* WR: all pwqs of this wq */ |
e2dca7ad | 241 | struct list_head list; /* PR: list of all workqueues */ |
73f53c4a | 242 | |
3c25a55d LJ |
243 | struct mutex mutex; /* protects this wq */ |
244 | int work_color; /* WQ: current work color */ | |
245 | int flush_color; /* WQ: current flush color */ | |
112202d9 | 246 | atomic_t nr_pwqs_to_flush; /* flush in progress */ |
3c25a55d LJ |
247 | struct wq_flusher *first_flusher; /* WQ: first flusher */ |
248 | struct list_head flusher_queue; /* WQ: flush waiters */ | |
249 | struct list_head flusher_overflow; /* WQ: flush overflow list */ | |
73f53c4a | 250 | |
2e109a28 | 251 | struct list_head maydays; /* MD: pwqs requesting rescue */ |
e22bee78 TH |
252 | struct worker *rescuer; /* I: rescue worker */ |
253 | ||
87fc741e | 254 | int nr_drainers; /* WQ: drain in progress */ |
a357fc03 | 255 | int saved_max_active; /* WQ: saved pwq max_active */ |
226223ab | 256 | |
5b95e1af LJ |
257 | struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */ |
258 | struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */ | |
6029a918 | 259 | |
226223ab TH |
260 | #ifdef CONFIG_SYSFS |
261 | struct wq_device *wq_dev; /* I: for sysfs interface */ | |
262 | #endif | |
4e6045f1 | 263 | #ifdef CONFIG_LOCKDEP |
4690c4ab | 264 | struct lockdep_map lockdep_map; |
4e6045f1 | 265 | #endif |
ecf6881f | 266 | char name[WQ_NAME_LEN]; /* I: workqueue name */ |
2728fd2f | 267 | |
e2dca7ad TH |
268 | /* |
269 | * Destruction of workqueue_struct is sched-RCU protected to allow | |
270 | * walking the workqueues list without grabbing wq_pool_mutex. | |
271 | * This is used to dump all workqueues from sysrq. | |
272 | */ | |
273 | struct rcu_head rcu; | |
274 | ||
2728fd2f TH |
275 | /* hot fields used during command issue, aligned to cacheline */ |
276 | unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */ | |
277 | struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */ | |
5b95e1af | 278 | struct pool_workqueue __rcu *numa_pwq_tbl[]; /* PWR: unbound pwqs indexed by node */ |
1da177e4 LT |
279 | }; |
280 | ||
e904e6c2 TH |
281 | static struct kmem_cache *pwq_cache; |
282 | ||
bce90380 TH |
283 | static cpumask_var_t *wq_numa_possible_cpumask; |
284 | /* possible CPUs of each node */ | |
285 | ||
d55262c4 TH |
286 | static bool wq_disable_numa; |
287 | module_param_named(disable_numa, wq_disable_numa, bool, 0444); | |
288 | ||
cee22a15 | 289 | /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
552f530c | 290 | static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT); |
cee22a15 VK |
291 | module_param_named(power_efficient, wq_power_efficient, bool, 0444); |
292 | ||
863b710b | 293 | static bool wq_online; /* can kworkers be created yet? */ |
3347fa09 | 294 | |
bce90380 TH |
295 | static bool wq_numa_enabled; /* unbound NUMA affinity enabled */ |
296 | ||
4c16bd32 TH |
297 | /* buf for wq_update_unbound_numa_attrs(), protected by CPU hotplug exclusion */ |
298 | static struct workqueue_attrs *wq_update_unbound_numa_attrs_buf; | |
299 | ||
68e13a67 | 300 | static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */ |
2e109a28 | 301 | static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ |
692b4825 | 302 | static DECLARE_WAIT_QUEUE_HEAD(wq_manager_wait); /* wait for manager to go away */ |
5bcab335 | 303 | |
e2dca7ad | 304 | static LIST_HEAD(workqueues); /* PR: list of all workqueues */ |
68e13a67 | 305 | static bool workqueue_freezing; /* PL: have wqs started freezing? */ |
7d19c5ce | 306 | |
ef557180 MG |
307 | /* PL: allowable cpus for unbound wqs and work items */ |
308 | static cpumask_var_t wq_unbound_cpumask; | |
309 | ||
310 | /* CPU where unbound work was last round robin scheduled from this CPU */ | |
311 | static DEFINE_PER_CPU(int, wq_rr_cpu_last); | |
b05a7928 | 312 | |
f303fccb TH |
313 | /* |
314 | * Local execution of unbound work items is no longer guaranteed. The | |
315 | * following always forces round-robin CPU selection on unbound work items | |
316 | * to uncover usages which depend on it. | |
317 | */ | |
318 | #ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU | |
319 | static bool wq_debug_force_rr_cpu = true; | |
320 | #else | |
321 | static bool wq_debug_force_rr_cpu = false; | |
322 | #endif | |
323 | module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644); | |
324 | ||
7d19c5ce | 325 | /* the per-cpu worker pools */ |
25528213 | 326 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools); |
7d19c5ce | 327 | |
68e13a67 | 328 | static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */ |
7d19c5ce | 329 | |
68e13a67 | 330 | /* PL: hash of all unbound pools keyed by pool->attrs */ |
29c91e99 TH |
331 | static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER); |
332 | ||
c5aa87bb | 333 | /* I: attributes used when instantiating standard unbound pools on demand */ |
29c91e99 TH |
334 | static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS]; |
335 | ||
8a2b7538 TH |
336 | /* I: attributes used when instantiating ordered pools on demand */ |
337 | static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS]; | |
338 | ||
d320c038 | 339 | struct workqueue_struct *system_wq __read_mostly; |
ad7b1f84 | 340 | EXPORT_SYMBOL(system_wq); |
044c782c | 341 | struct workqueue_struct *system_highpri_wq __read_mostly; |
1aabe902 | 342 | EXPORT_SYMBOL_GPL(system_highpri_wq); |
044c782c | 343 | struct workqueue_struct *system_long_wq __read_mostly; |
d320c038 | 344 | EXPORT_SYMBOL_GPL(system_long_wq); |
044c782c | 345 | struct workqueue_struct *system_unbound_wq __read_mostly; |
f3421797 | 346 | EXPORT_SYMBOL_GPL(system_unbound_wq); |
044c782c | 347 | struct workqueue_struct *system_freezable_wq __read_mostly; |
24d51add | 348 | EXPORT_SYMBOL_GPL(system_freezable_wq); |
0668106c VK |
349 | struct workqueue_struct *system_power_efficient_wq __read_mostly; |
350 | EXPORT_SYMBOL_GPL(system_power_efficient_wq); | |
351 | struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly; | |
352 | EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); | |
d320c038 | 353 | |
7d19c5ce | 354 | static int worker_thread(void *__worker); |
6ba94429 | 355 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq); |
7d19c5ce | 356 | |
97bd2347 TH |
357 | #define CREATE_TRACE_POINTS |
358 | #include <trace/events/workqueue.h> | |
359 | ||
68e13a67 | 360 | #define assert_rcu_or_pool_mutex() \ |
f78f5b90 PM |
361 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \ |
362 | !lockdep_is_held(&wq_pool_mutex), \ | |
363 | "sched RCU or wq_pool_mutex should be held") | |
5bcab335 | 364 | |
b09f4fd3 | 365 | #define assert_rcu_or_wq_mutex(wq) \ |
f78f5b90 PM |
366 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \ |
367 | !lockdep_is_held(&wq->mutex), \ | |
368 | "sched RCU or wq->mutex should be held") | |
76af4d93 | 369 | |
5b95e1af | 370 | #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ |
f78f5b90 PM |
371 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held() && \ |
372 | !lockdep_is_held(&wq->mutex) && \ | |
373 | !lockdep_is_held(&wq_pool_mutex), \ | |
374 | "sched RCU, wq->mutex or wq_pool_mutex should be held") | |
5b95e1af | 375 | |
f02ae73a TH |
376 | #define for_each_cpu_worker_pool(pool, cpu) \ |
377 | for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \ | |
378 | (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \ | |
7a62c2c8 | 379 | (pool)++) |
4ce62e9e | 380 | |
17116969 TH |
381 | /** |
382 | * for_each_pool - iterate through all worker_pools in the system | |
383 | * @pool: iteration cursor | |
611c92a0 | 384 | * @pi: integer used for iteration |
fa1b54e6 | 385 | * |
68e13a67 LJ |
386 | * This must be called either with wq_pool_mutex held or sched RCU read |
387 | * locked. If the pool needs to be used beyond the locking in effect, the | |
388 | * caller is responsible for guaranteeing that the pool stays online. | |
fa1b54e6 TH |
389 | * |
390 | * The if/else clause exists only for the lockdep assertion and can be | |
391 | * ignored. | |
17116969 | 392 | */ |
611c92a0 TH |
393 | #define for_each_pool(pool, pi) \ |
394 | idr_for_each_entry(&worker_pool_idr, pool, pi) \ | |
68e13a67 | 395 | if (({ assert_rcu_or_pool_mutex(); false; })) { } \ |
fa1b54e6 | 396 | else |
17116969 | 397 | |
822d8405 TH |
398 | /** |
399 | * for_each_pool_worker - iterate through all workers of a worker_pool | |
400 | * @worker: iteration cursor | |
822d8405 TH |
401 | * @pool: worker_pool to iterate workers of |
402 | * | |
92f9c5c4 | 403 | * This must be called with @pool->attach_mutex. |
822d8405 TH |
404 | * |
405 | * The if/else clause exists only for the lockdep assertion and can be | |
406 | * ignored. | |
407 | */ | |
da028469 LJ |
408 | #define for_each_pool_worker(worker, pool) \ |
409 | list_for_each_entry((worker), &(pool)->workers, node) \ | |
92f9c5c4 | 410 | if (({ lockdep_assert_held(&pool->attach_mutex); false; })) { } \ |
822d8405 TH |
411 | else |
412 | ||
49e3cf44 TH |
413 | /** |
414 | * for_each_pwq - iterate through all pool_workqueues of the specified workqueue | |
415 | * @pwq: iteration cursor | |
416 | * @wq: the target workqueue | |
76af4d93 | 417 | * |
b09f4fd3 | 418 | * This must be called either with wq->mutex held or sched RCU read locked. |
794b18bc TH |
419 | * If the pwq needs to be used beyond the locking in effect, the caller is |
420 | * responsible for guaranteeing that the pwq stays online. | |
76af4d93 TH |
421 | * |
422 | * The if/else clause exists only for the lockdep assertion and can be | |
423 | * ignored. | |
49e3cf44 TH |
424 | */ |
425 | #define for_each_pwq(pwq, wq) \ | |
76af4d93 | 426 | list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \ |
b09f4fd3 | 427 | if (({ assert_rcu_or_wq_mutex(wq); false; })) { } \ |
76af4d93 | 428 | else |
f3421797 | 429 | |
dc186ad7 TG |
430 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
431 | ||
432 | static struct debug_obj_descr work_debug_descr; | |
433 | ||
99777288 SG |
434 | static void *work_debug_hint(void *addr) |
435 | { | |
436 | return ((struct work_struct *) addr)->func; | |
437 | } | |
438 | ||
b9fdac7f DC |
439 | static bool work_is_static_object(void *addr) |
440 | { | |
441 | struct work_struct *work = addr; | |
442 | ||
443 | return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work)); | |
444 | } | |
445 | ||
dc186ad7 TG |
446 | /* |
447 | * fixup_init is called when: | |
448 | * - an active object is initialized | |
449 | */ | |
02a982a6 | 450 | static bool work_fixup_init(void *addr, enum debug_obj_state state) |
dc186ad7 TG |
451 | { |
452 | struct work_struct *work = addr; | |
453 | ||
454 | switch (state) { | |
455 | case ODEBUG_STATE_ACTIVE: | |
456 | cancel_work_sync(work); | |
457 | debug_object_init(work, &work_debug_descr); | |
02a982a6 | 458 | return true; |
dc186ad7 | 459 | default: |
02a982a6 | 460 | return false; |
dc186ad7 TG |
461 | } |
462 | } | |
463 | ||
dc186ad7 TG |
464 | /* |
465 | * fixup_free is called when: | |
466 | * - an active object is freed | |
467 | */ | |
02a982a6 | 468 | static bool work_fixup_free(void *addr, enum debug_obj_state state) |
dc186ad7 TG |
469 | { |
470 | struct work_struct *work = addr; | |
471 | ||
472 | switch (state) { | |
473 | case ODEBUG_STATE_ACTIVE: | |
474 | cancel_work_sync(work); | |
475 | debug_object_free(work, &work_debug_descr); | |
02a982a6 | 476 | return true; |
dc186ad7 | 477 | default: |
02a982a6 | 478 | return false; |
dc186ad7 TG |
479 | } |
480 | } | |
481 | ||
482 | static struct debug_obj_descr work_debug_descr = { | |
483 | .name = "work_struct", | |
99777288 | 484 | .debug_hint = work_debug_hint, |
b9fdac7f | 485 | .is_static_object = work_is_static_object, |
dc186ad7 | 486 | .fixup_init = work_fixup_init, |
dc186ad7 TG |
487 | .fixup_free = work_fixup_free, |
488 | }; | |
489 | ||
490 | static inline void debug_work_activate(struct work_struct *work) | |
491 | { | |
492 | debug_object_activate(work, &work_debug_descr); | |
493 | } | |
494 | ||
495 | static inline void debug_work_deactivate(struct work_struct *work) | |
496 | { | |
497 | debug_object_deactivate(work, &work_debug_descr); | |
498 | } | |
499 | ||
500 | void __init_work(struct work_struct *work, int onstack) | |
501 | { | |
502 | if (onstack) | |
503 | debug_object_init_on_stack(work, &work_debug_descr); | |
504 | else | |
505 | debug_object_init(work, &work_debug_descr); | |
506 | } | |
507 | EXPORT_SYMBOL_GPL(__init_work); | |
508 | ||
509 | void destroy_work_on_stack(struct work_struct *work) | |
510 | { | |
511 | debug_object_free(work, &work_debug_descr); | |
512 | } | |
513 | EXPORT_SYMBOL_GPL(destroy_work_on_stack); | |
514 | ||
ea2e64f2 TG |
515 | void destroy_delayed_work_on_stack(struct delayed_work *work) |
516 | { | |
517 | destroy_timer_on_stack(&work->timer); | |
518 | debug_object_free(&work->work, &work_debug_descr); | |
519 | } | |
520 | EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack); | |
521 | ||
dc186ad7 TG |
522 | #else |
523 | static inline void debug_work_activate(struct work_struct *work) { } | |
524 | static inline void debug_work_deactivate(struct work_struct *work) { } | |
525 | #endif | |
526 | ||
4e8b22bd LB |
527 | /** |
528 | * worker_pool_assign_id - allocate ID and assing it to @pool | |
529 | * @pool: the pool pointer of interest | |
530 | * | |
531 | * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned | |
532 | * successfully, -errno on failure. | |
533 | */ | |
9daf9e67 TH |
534 | static int worker_pool_assign_id(struct worker_pool *pool) |
535 | { | |
536 | int ret; | |
537 | ||
68e13a67 | 538 | lockdep_assert_held(&wq_pool_mutex); |
5bcab335 | 539 | |
4e8b22bd LB |
540 | ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE, |
541 | GFP_KERNEL); | |
229641a6 | 542 | if (ret >= 0) { |
e68035fb | 543 | pool->id = ret; |
229641a6 TH |
544 | return 0; |
545 | } | |
fa1b54e6 | 546 | return ret; |
7c3eed5c TH |
547 | } |
548 | ||
df2d5ae4 TH |
549 | /** |
550 | * unbound_pwq_by_node - return the unbound pool_workqueue for the given node | |
551 | * @wq: the target workqueue | |
552 | * @node: the node ID | |
553 | * | |
5b95e1af LJ |
554 | * This must be called with any of wq_pool_mutex, wq->mutex or sched RCU |
555 | * read locked. | |
df2d5ae4 TH |
556 | * If the pwq needs to be used beyond the locking in effect, the caller is |
557 | * responsible for guaranteeing that the pwq stays online. | |
d185af30 YB |
558 | * |
559 | * Return: The unbound pool_workqueue for @node. | |
df2d5ae4 TH |
560 | */ |
561 | static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq, | |
562 | int node) | |
563 | { | |
5b95e1af | 564 | assert_rcu_or_wq_mutex_or_pool_mutex(wq); |
d6e022f1 TH |
565 | |
566 | /* | |
567 | * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a | |
568 | * delayed item is pending. The plan is to keep CPU -> NODE | |
569 | * mapping valid and stable across CPU on/offlines. Once that | |
570 | * happens, this workaround can be removed. | |
571 | */ | |
572 | if (unlikely(node == NUMA_NO_NODE)) | |
573 | return wq->dfl_pwq; | |
574 | ||
df2d5ae4 TH |
575 | return rcu_dereference_raw(wq->numa_pwq_tbl[node]); |
576 | } | |
577 | ||
73f53c4a TH |
578 | static unsigned int work_color_to_flags(int color) |
579 | { | |
580 | return color << WORK_STRUCT_COLOR_SHIFT; | |
581 | } | |
582 | ||
583 | static int get_work_color(struct work_struct *work) | |
584 | { | |
585 | return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & | |
586 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); | |
587 | } | |
588 | ||
589 | static int work_next_color(int color) | |
590 | { | |
591 | return (color + 1) % WORK_NR_COLORS; | |
592 | } | |
1da177e4 | 593 | |
14441960 | 594 | /* |
112202d9 TH |
595 | * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data |
596 | * contain the pointer to the queued pwq. Once execution starts, the flag | |
7c3eed5c | 597 | * is cleared and the high bits contain OFFQ flags and pool ID. |
7a22ad75 | 598 | * |
112202d9 TH |
599 | * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling() |
600 | * and clear_work_data() can be used to set the pwq, pool or clear | |
bbb68dfa TH |
601 | * work->data. These functions should only be called while the work is |
602 | * owned - ie. while the PENDING bit is set. | |
7a22ad75 | 603 | * |
112202d9 | 604 | * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq |
7c3eed5c | 605 | * corresponding to a work. Pool is available once the work has been |
112202d9 | 606 | * queued anywhere after initialization until it is sync canceled. pwq is |
7c3eed5c | 607 | * available only while the work item is queued. |
7a22ad75 | 608 | * |
bbb68dfa TH |
609 | * %WORK_OFFQ_CANCELING is used to mark a work item which is being |
610 | * canceled. While being canceled, a work item may have its PENDING set | |
611 | * but stay off timer and worklist for arbitrarily long and nobody should | |
612 | * try to steal the PENDING bit. | |
14441960 | 613 | */ |
7a22ad75 TH |
614 | static inline void set_work_data(struct work_struct *work, unsigned long data, |
615 | unsigned long flags) | |
365970a1 | 616 | { |
6183c009 | 617 | WARN_ON_ONCE(!work_pending(work)); |
7a22ad75 TH |
618 | atomic_long_set(&work->data, data | flags | work_static(work)); |
619 | } | |
365970a1 | 620 | |
112202d9 | 621 | static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq, |
7a22ad75 TH |
622 | unsigned long extra_flags) |
623 | { | |
112202d9 TH |
624 | set_work_data(work, (unsigned long)pwq, |
625 | WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags); | |
365970a1 DH |
626 | } |
627 | ||
4468a00f LJ |
628 | static void set_work_pool_and_keep_pending(struct work_struct *work, |
629 | int pool_id) | |
630 | { | |
631 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, | |
632 | WORK_STRUCT_PENDING); | |
633 | } | |
634 | ||
7c3eed5c TH |
635 | static void set_work_pool_and_clear_pending(struct work_struct *work, |
636 | int pool_id) | |
7a22ad75 | 637 | { |
23657bb1 TH |
638 | /* |
639 | * The following wmb is paired with the implied mb in | |
640 | * test_and_set_bit(PENDING) and ensures all updates to @work made | |
641 | * here are visible to and precede any updates by the next PENDING | |
642 | * owner. | |
643 | */ | |
644 | smp_wmb(); | |
7c3eed5c | 645 | set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0); |
346c09f8 RP |
646 | /* |
647 | * The following mb guarantees that previous clear of a PENDING bit | |
648 | * will not be reordered with any speculative LOADS or STORES from | |
649 | * work->current_func, which is executed afterwards. This possible | |
650 | * reordering can lead to a missed execution on attempt to qeueue | |
651 | * the same @work. E.g. consider this case: | |
652 | * | |
653 | * CPU#0 CPU#1 | |
654 | * ---------------------------- -------------------------------- | |
655 | * | |
656 | * 1 STORE event_indicated | |
657 | * 2 queue_work_on() { | |
658 | * 3 test_and_set_bit(PENDING) | |
659 | * 4 } set_..._and_clear_pending() { | |
660 | * 5 set_work_data() # clear bit | |
661 | * 6 smp_mb() | |
662 | * 7 work->current_func() { | |
663 | * 8 LOAD event_indicated | |
664 | * } | |
665 | * | |
666 | * Without an explicit full barrier speculative LOAD on line 8 can | |
667 | * be executed before CPU#0 does STORE on line 1. If that happens, | |
668 | * CPU#0 observes the PENDING bit is still set and new execution of | |
669 | * a @work is not queued in a hope, that CPU#1 will eventually | |
670 | * finish the queued @work. Meanwhile CPU#1 does not see | |
671 | * event_indicated is set, because speculative LOAD was executed | |
672 | * before actual STORE. | |
673 | */ | |
674 | smp_mb(); | |
7a22ad75 | 675 | } |
f756d5e2 | 676 | |
7a22ad75 | 677 | static void clear_work_data(struct work_struct *work) |
1da177e4 | 678 | { |
7c3eed5c TH |
679 | smp_wmb(); /* see set_work_pool_and_clear_pending() */ |
680 | set_work_data(work, WORK_STRUCT_NO_POOL, 0); | |
1da177e4 LT |
681 | } |
682 | ||
112202d9 | 683 | static struct pool_workqueue *get_work_pwq(struct work_struct *work) |
b1f4ec17 | 684 | { |
e120153d | 685 | unsigned long data = atomic_long_read(&work->data); |
7a22ad75 | 686 | |
112202d9 | 687 | if (data & WORK_STRUCT_PWQ) |
e120153d TH |
688 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); |
689 | else | |
690 | return NULL; | |
4d707b9f ON |
691 | } |
692 | ||
7c3eed5c TH |
693 | /** |
694 | * get_work_pool - return the worker_pool a given work was associated with | |
695 | * @work: the work item of interest | |
696 | * | |
68e13a67 LJ |
697 | * Pools are created and destroyed under wq_pool_mutex, and allows read |
698 | * access under sched-RCU read lock. As such, this function should be | |
699 | * called under wq_pool_mutex or with preemption disabled. | |
fa1b54e6 TH |
700 | * |
701 | * All fields of the returned pool are accessible as long as the above | |
702 | * mentioned locking is in effect. If the returned pool needs to be used | |
703 | * beyond the critical section, the caller is responsible for ensuring the | |
704 | * returned pool is and stays online. | |
d185af30 YB |
705 | * |
706 | * Return: The worker_pool @work was last associated with. %NULL if none. | |
7c3eed5c TH |
707 | */ |
708 | static struct worker_pool *get_work_pool(struct work_struct *work) | |
365970a1 | 709 | { |
e120153d | 710 | unsigned long data = atomic_long_read(&work->data); |
7c3eed5c | 711 | int pool_id; |
7a22ad75 | 712 | |
68e13a67 | 713 | assert_rcu_or_pool_mutex(); |
fa1b54e6 | 714 | |
112202d9 TH |
715 | if (data & WORK_STRUCT_PWQ) |
716 | return ((struct pool_workqueue *) | |
7c3eed5c | 717 | (data & WORK_STRUCT_WQ_DATA_MASK))->pool; |
7a22ad75 | 718 | |
7c3eed5c TH |
719 | pool_id = data >> WORK_OFFQ_POOL_SHIFT; |
720 | if (pool_id == WORK_OFFQ_POOL_NONE) | |
7a22ad75 TH |
721 | return NULL; |
722 | ||
fa1b54e6 | 723 | return idr_find(&worker_pool_idr, pool_id); |
7c3eed5c TH |
724 | } |
725 | ||
726 | /** | |
727 | * get_work_pool_id - return the worker pool ID a given work is associated with | |
728 | * @work: the work item of interest | |
729 | * | |
d185af30 | 730 | * Return: The worker_pool ID @work was last associated with. |
7c3eed5c TH |
731 | * %WORK_OFFQ_POOL_NONE if none. |
732 | */ | |
733 | static int get_work_pool_id(struct work_struct *work) | |
734 | { | |
54d5b7d0 LJ |
735 | unsigned long data = atomic_long_read(&work->data); |
736 | ||
112202d9 TH |
737 | if (data & WORK_STRUCT_PWQ) |
738 | return ((struct pool_workqueue *) | |
54d5b7d0 | 739 | (data & WORK_STRUCT_WQ_DATA_MASK))->pool->id; |
7c3eed5c | 740 | |
54d5b7d0 | 741 | return data >> WORK_OFFQ_POOL_SHIFT; |
7c3eed5c TH |
742 | } |
743 | ||
bbb68dfa TH |
744 | static void mark_work_canceling(struct work_struct *work) |
745 | { | |
7c3eed5c | 746 | unsigned long pool_id = get_work_pool_id(work); |
bbb68dfa | 747 | |
7c3eed5c TH |
748 | pool_id <<= WORK_OFFQ_POOL_SHIFT; |
749 | set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING); | |
bbb68dfa TH |
750 | } |
751 | ||
752 | static bool work_is_canceling(struct work_struct *work) | |
753 | { | |
754 | unsigned long data = atomic_long_read(&work->data); | |
755 | ||
112202d9 | 756 | return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING); |
bbb68dfa TH |
757 | } |
758 | ||
e22bee78 | 759 | /* |
3270476a TH |
760 | * Policy functions. These define the policies on how the global worker |
761 | * pools are managed. Unless noted otherwise, these functions assume that | |
d565ed63 | 762 | * they're being called with pool->lock held. |
e22bee78 TH |
763 | */ |
764 | ||
63d95a91 | 765 | static bool __need_more_worker(struct worker_pool *pool) |
a848e3b6 | 766 | { |
e19e397a | 767 | return !atomic_read(&pool->nr_running); |
a848e3b6 ON |
768 | } |
769 | ||
4594bf15 | 770 | /* |
e22bee78 TH |
771 | * Need to wake up a worker? Called from anything but currently |
772 | * running workers. | |
974271c4 TH |
773 | * |
774 | * Note that, because unbound workers never contribute to nr_running, this | |
706026c2 | 775 | * function will always return %true for unbound pools as long as the |
974271c4 | 776 | * worklist isn't empty. |
4594bf15 | 777 | */ |
63d95a91 | 778 | static bool need_more_worker(struct worker_pool *pool) |
365970a1 | 779 | { |
63d95a91 | 780 | return !list_empty(&pool->worklist) && __need_more_worker(pool); |
e22bee78 | 781 | } |
4594bf15 | 782 | |
e22bee78 | 783 | /* Can I start working? Called from busy but !running workers. */ |
63d95a91 | 784 | static bool may_start_working(struct worker_pool *pool) |
e22bee78 | 785 | { |
63d95a91 | 786 | return pool->nr_idle; |
e22bee78 TH |
787 | } |
788 | ||
789 | /* Do I need to keep working? Called from currently running workers. */ | |
63d95a91 | 790 | static bool keep_working(struct worker_pool *pool) |
e22bee78 | 791 | { |
e19e397a TH |
792 | return !list_empty(&pool->worklist) && |
793 | atomic_read(&pool->nr_running) <= 1; | |
e22bee78 TH |
794 | } |
795 | ||
796 | /* Do we need a new worker? Called from manager. */ | |
63d95a91 | 797 | static bool need_to_create_worker(struct worker_pool *pool) |
e22bee78 | 798 | { |
63d95a91 | 799 | return need_more_worker(pool) && !may_start_working(pool); |
e22bee78 | 800 | } |
365970a1 | 801 | |
e22bee78 | 802 | /* Do we have too many workers and should some go away? */ |
63d95a91 | 803 | static bool too_many_workers(struct worker_pool *pool) |
e22bee78 | 804 | { |
692b4825 | 805 | bool managing = pool->flags & POOL_MANAGER_ACTIVE; |
63d95a91 TH |
806 | int nr_idle = pool->nr_idle + managing; /* manager is considered idle */ |
807 | int nr_busy = pool->nr_workers - nr_idle; | |
e22bee78 TH |
808 | |
809 | return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; | |
365970a1 DH |
810 | } |
811 | ||
4d707b9f | 812 | /* |
e22bee78 TH |
813 | * Wake up functions. |
814 | */ | |
815 | ||
1037de36 LJ |
816 | /* Return the first idle worker. Safe with preemption disabled */ |
817 | static struct worker *first_idle_worker(struct worker_pool *pool) | |
7e11629d | 818 | { |
63d95a91 | 819 | if (unlikely(list_empty(&pool->idle_list))) |
7e11629d TH |
820 | return NULL; |
821 | ||
63d95a91 | 822 | return list_first_entry(&pool->idle_list, struct worker, entry); |
7e11629d TH |
823 | } |
824 | ||
825 | /** | |
826 | * wake_up_worker - wake up an idle worker | |
63d95a91 | 827 | * @pool: worker pool to wake worker from |
7e11629d | 828 | * |
63d95a91 | 829 | * Wake up the first idle worker of @pool. |
7e11629d TH |
830 | * |
831 | * CONTEXT: | |
d565ed63 | 832 | * spin_lock_irq(pool->lock). |
7e11629d | 833 | */ |
63d95a91 | 834 | static void wake_up_worker(struct worker_pool *pool) |
7e11629d | 835 | { |
1037de36 | 836 | struct worker *worker = first_idle_worker(pool); |
7e11629d TH |
837 | |
838 | if (likely(worker)) | |
839 | wake_up_process(worker->task); | |
840 | } | |
841 | ||
d302f017 | 842 | /** |
e22bee78 TH |
843 | * wq_worker_waking_up - a worker is waking up |
844 | * @task: task waking up | |
845 | * @cpu: CPU @task is waking up to | |
846 | * | |
847 | * This function is called during try_to_wake_up() when a worker is | |
848 | * being awoken. | |
849 | * | |
850 | * CONTEXT: | |
851 | * spin_lock_irq(rq->lock) | |
852 | */ | |
d84ff051 | 853 | void wq_worker_waking_up(struct task_struct *task, int cpu) |
e22bee78 TH |
854 | { |
855 | struct worker *worker = kthread_data(task); | |
856 | ||
36576000 | 857 | if (!(worker->flags & WORKER_NOT_RUNNING)) { |
ec22ca5e | 858 | WARN_ON_ONCE(worker->pool->cpu != cpu); |
e19e397a | 859 | atomic_inc(&worker->pool->nr_running); |
36576000 | 860 | } |
e22bee78 TH |
861 | } |
862 | ||
863 | /** | |
864 | * wq_worker_sleeping - a worker is going to sleep | |
865 | * @task: task going to sleep | |
e22bee78 TH |
866 | * |
867 | * This function is called during schedule() when a busy worker is | |
868 | * going to sleep. Worker on the same cpu can be woken up by | |
869 | * returning pointer to its task. | |
870 | * | |
871 | * CONTEXT: | |
872 | * spin_lock_irq(rq->lock) | |
873 | * | |
d185af30 | 874 | * Return: |
e22bee78 TH |
875 | * Worker task on @cpu to wake up, %NULL if none. |
876 | */ | |
9b7f6597 | 877 | struct task_struct *wq_worker_sleeping(struct task_struct *task) |
e22bee78 TH |
878 | { |
879 | struct worker *worker = kthread_data(task), *to_wakeup = NULL; | |
111c225a | 880 | struct worker_pool *pool; |
e22bee78 | 881 | |
111c225a TH |
882 | /* |
883 | * Rescuers, which may not have all the fields set up like normal | |
884 | * workers, also reach here, let's not access anything before | |
885 | * checking NOT_RUNNING. | |
886 | */ | |
2d64672e | 887 | if (worker->flags & WORKER_NOT_RUNNING) |
e22bee78 TH |
888 | return NULL; |
889 | ||
111c225a | 890 | pool = worker->pool; |
111c225a | 891 | |
e22bee78 | 892 | /* this can only happen on the local cpu */ |
9b7f6597 | 893 | if (WARN_ON_ONCE(pool->cpu != raw_smp_processor_id())) |
6183c009 | 894 | return NULL; |
e22bee78 TH |
895 | |
896 | /* | |
897 | * The counterpart of the following dec_and_test, implied mb, | |
898 | * worklist not empty test sequence is in insert_work(). | |
899 | * Please read comment there. | |
900 | * | |
628c78e7 TH |
901 | * NOT_RUNNING is clear. This means that we're bound to and |
902 | * running on the local cpu w/ rq lock held and preemption | |
903 | * disabled, which in turn means that none else could be | |
d565ed63 | 904 | * manipulating idle_list, so dereferencing idle_list without pool |
628c78e7 | 905 | * lock is safe. |
e22bee78 | 906 | */ |
e19e397a TH |
907 | if (atomic_dec_and_test(&pool->nr_running) && |
908 | !list_empty(&pool->worklist)) | |
1037de36 | 909 | to_wakeup = first_idle_worker(pool); |
e22bee78 TH |
910 | return to_wakeup ? to_wakeup->task : NULL; |
911 | } | |
912 | ||
913 | /** | |
914 | * worker_set_flags - set worker flags and adjust nr_running accordingly | |
cb444766 | 915 | * @worker: self |
d302f017 | 916 | * @flags: flags to set |
d302f017 | 917 | * |
228f1d00 | 918 | * Set @flags in @worker->flags and adjust nr_running accordingly. |
d302f017 | 919 | * |
cb444766 | 920 | * CONTEXT: |
d565ed63 | 921 | * spin_lock_irq(pool->lock) |
d302f017 | 922 | */ |
228f1d00 | 923 | static inline void worker_set_flags(struct worker *worker, unsigned int flags) |
d302f017 | 924 | { |
bd7bdd43 | 925 | struct worker_pool *pool = worker->pool; |
e22bee78 | 926 | |
cb444766 TH |
927 | WARN_ON_ONCE(worker->task != current); |
928 | ||
228f1d00 | 929 | /* If transitioning into NOT_RUNNING, adjust nr_running. */ |
e22bee78 TH |
930 | if ((flags & WORKER_NOT_RUNNING) && |
931 | !(worker->flags & WORKER_NOT_RUNNING)) { | |
228f1d00 | 932 | atomic_dec(&pool->nr_running); |
e22bee78 TH |
933 | } |
934 | ||
d302f017 TH |
935 | worker->flags |= flags; |
936 | } | |
937 | ||
938 | /** | |
e22bee78 | 939 | * worker_clr_flags - clear worker flags and adjust nr_running accordingly |
cb444766 | 940 | * @worker: self |
d302f017 TH |
941 | * @flags: flags to clear |
942 | * | |
e22bee78 | 943 | * Clear @flags in @worker->flags and adjust nr_running accordingly. |
d302f017 | 944 | * |
cb444766 | 945 | * CONTEXT: |
d565ed63 | 946 | * spin_lock_irq(pool->lock) |
d302f017 TH |
947 | */ |
948 | static inline void worker_clr_flags(struct worker *worker, unsigned int flags) | |
949 | { | |
63d95a91 | 950 | struct worker_pool *pool = worker->pool; |
e22bee78 TH |
951 | unsigned int oflags = worker->flags; |
952 | ||
cb444766 TH |
953 | WARN_ON_ONCE(worker->task != current); |
954 | ||
d302f017 | 955 | worker->flags &= ~flags; |
e22bee78 | 956 | |
42c025f3 TH |
957 | /* |
958 | * If transitioning out of NOT_RUNNING, increment nr_running. Note | |
959 | * that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask | |
960 | * of multiple flags, not a single flag. | |
961 | */ | |
e22bee78 TH |
962 | if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) |
963 | if (!(worker->flags & WORKER_NOT_RUNNING)) | |
e19e397a | 964 | atomic_inc(&pool->nr_running); |
d302f017 TH |
965 | } |
966 | ||
8cca0eea TH |
967 | /** |
968 | * find_worker_executing_work - find worker which is executing a work | |
c9e7cf27 | 969 | * @pool: pool of interest |
8cca0eea TH |
970 | * @work: work to find worker for |
971 | * | |
c9e7cf27 TH |
972 | * Find a worker which is executing @work on @pool by searching |
973 | * @pool->busy_hash which is keyed by the address of @work. For a worker | |
a2c1c57b TH |
974 | * to match, its current execution should match the address of @work and |
975 | * its work function. This is to avoid unwanted dependency between | |
976 | * unrelated work executions through a work item being recycled while still | |
977 | * being executed. | |
978 | * | |
979 | * This is a bit tricky. A work item may be freed once its execution | |
980 | * starts and nothing prevents the freed area from being recycled for | |
981 | * another work item. If the same work item address ends up being reused | |
982 | * before the original execution finishes, workqueue will identify the | |
983 | * recycled work item as currently executing and make it wait until the | |
984 | * current execution finishes, introducing an unwanted dependency. | |
985 | * | |
c5aa87bb TH |
986 | * This function checks the work item address and work function to avoid |
987 | * false positives. Note that this isn't complete as one may construct a | |
988 | * work function which can introduce dependency onto itself through a | |
989 | * recycled work item. Well, if somebody wants to shoot oneself in the | |
990 | * foot that badly, there's only so much we can do, and if such deadlock | |
991 | * actually occurs, it should be easy to locate the culprit work function. | |
8cca0eea TH |
992 | * |
993 | * CONTEXT: | |
d565ed63 | 994 | * spin_lock_irq(pool->lock). |
8cca0eea | 995 | * |
d185af30 YB |
996 | * Return: |
997 | * Pointer to worker which is executing @work if found, %NULL | |
8cca0eea | 998 | * otherwise. |
4d707b9f | 999 | */ |
c9e7cf27 | 1000 | static struct worker *find_worker_executing_work(struct worker_pool *pool, |
8cca0eea | 1001 | struct work_struct *work) |
4d707b9f | 1002 | { |
42f8570f | 1003 | struct worker *worker; |
42f8570f | 1004 | |
b67bfe0d | 1005 | hash_for_each_possible(pool->busy_hash, worker, hentry, |
a2c1c57b TH |
1006 | (unsigned long)work) |
1007 | if (worker->current_work == work && | |
1008 | worker->current_func == work->func) | |
42f8570f SL |
1009 | return worker; |
1010 | ||
1011 | return NULL; | |
4d707b9f ON |
1012 | } |
1013 | ||
bf4ede01 TH |
1014 | /** |
1015 | * move_linked_works - move linked works to a list | |
1016 | * @work: start of series of works to be scheduled | |
1017 | * @head: target list to append @work to | |
402dd89d | 1018 | * @nextp: out parameter for nested worklist walking |
bf4ede01 TH |
1019 | * |
1020 | * Schedule linked works starting from @work to @head. Work series to | |
1021 | * be scheduled starts at @work and includes any consecutive work with | |
1022 | * WORK_STRUCT_LINKED set in its predecessor. | |
1023 | * | |
1024 | * If @nextp is not NULL, it's updated to point to the next work of | |
1025 | * the last scheduled work. This allows move_linked_works() to be | |
1026 | * nested inside outer list_for_each_entry_safe(). | |
1027 | * | |
1028 | * CONTEXT: | |
d565ed63 | 1029 | * spin_lock_irq(pool->lock). |
bf4ede01 TH |
1030 | */ |
1031 | static void move_linked_works(struct work_struct *work, struct list_head *head, | |
1032 | struct work_struct **nextp) | |
1033 | { | |
1034 | struct work_struct *n; | |
1035 | ||
1036 | /* | |
1037 | * Linked worklist will always end before the end of the list, | |
1038 | * use NULL for list head. | |
1039 | */ | |
1040 | list_for_each_entry_safe_from(work, n, NULL, entry) { | |
1041 | list_move_tail(&work->entry, head); | |
1042 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | |
1043 | break; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * If we're already inside safe list traversal and have moved | |
1048 | * multiple works to the scheduled queue, the next position | |
1049 | * needs to be updated. | |
1050 | */ | |
1051 | if (nextp) | |
1052 | *nextp = n; | |
1053 | } | |
1054 | ||
8864b4e5 TH |
1055 | /** |
1056 | * get_pwq - get an extra reference on the specified pool_workqueue | |
1057 | * @pwq: pool_workqueue to get | |
1058 | * | |
1059 | * Obtain an extra reference on @pwq. The caller should guarantee that | |
1060 | * @pwq has positive refcnt and be holding the matching pool->lock. | |
1061 | */ | |
1062 | static void get_pwq(struct pool_workqueue *pwq) | |
1063 | { | |
1064 | lockdep_assert_held(&pwq->pool->lock); | |
1065 | WARN_ON_ONCE(pwq->refcnt <= 0); | |
1066 | pwq->refcnt++; | |
1067 | } | |
1068 | ||
1069 | /** | |
1070 | * put_pwq - put a pool_workqueue reference | |
1071 | * @pwq: pool_workqueue to put | |
1072 | * | |
1073 | * Drop a reference of @pwq. If its refcnt reaches zero, schedule its | |
1074 | * destruction. The caller should be holding the matching pool->lock. | |
1075 | */ | |
1076 | static void put_pwq(struct pool_workqueue *pwq) | |
1077 | { | |
1078 | lockdep_assert_held(&pwq->pool->lock); | |
1079 | if (likely(--pwq->refcnt)) | |
1080 | return; | |
1081 | if (WARN_ON_ONCE(!(pwq->wq->flags & WQ_UNBOUND))) | |
1082 | return; | |
1083 | /* | |
1084 | * @pwq can't be released under pool->lock, bounce to | |
1085 | * pwq_unbound_release_workfn(). This never recurses on the same | |
1086 | * pool->lock as this path is taken only for unbound workqueues and | |
1087 | * the release work item is scheduled on a per-cpu workqueue. To | |
1088 | * avoid lockdep warning, unbound pool->locks are given lockdep | |
1089 | * subclass of 1 in get_unbound_pool(). | |
1090 | */ | |
1091 | schedule_work(&pwq->unbound_release_work); | |
1092 | } | |
1093 | ||
dce90d47 TH |
1094 | /** |
1095 | * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock | |
1096 | * @pwq: pool_workqueue to put (can be %NULL) | |
1097 | * | |
1098 | * put_pwq() with locking. This function also allows %NULL @pwq. | |
1099 | */ | |
1100 | static void put_pwq_unlocked(struct pool_workqueue *pwq) | |
1101 | { | |
1102 | if (pwq) { | |
1103 | /* | |
1104 | * As both pwqs and pools are sched-RCU protected, the | |
1105 | * following lock operations are safe. | |
1106 | */ | |
1107 | spin_lock_irq(&pwq->pool->lock); | |
1108 | put_pwq(pwq); | |
1109 | spin_unlock_irq(&pwq->pool->lock); | |
1110 | } | |
1111 | } | |
1112 | ||
112202d9 | 1113 | static void pwq_activate_delayed_work(struct work_struct *work) |
bf4ede01 | 1114 | { |
112202d9 | 1115 | struct pool_workqueue *pwq = get_work_pwq(work); |
bf4ede01 TH |
1116 | |
1117 | trace_workqueue_activate_work(work); | |
82607adc TH |
1118 | if (list_empty(&pwq->pool->worklist)) |
1119 | pwq->pool->watchdog_ts = jiffies; | |
112202d9 | 1120 | move_linked_works(work, &pwq->pool->worklist, NULL); |
bf4ede01 | 1121 | __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work)); |
112202d9 | 1122 | pwq->nr_active++; |
bf4ede01 TH |
1123 | } |
1124 | ||
112202d9 | 1125 | static void pwq_activate_first_delayed(struct pool_workqueue *pwq) |
3aa62497 | 1126 | { |
112202d9 | 1127 | struct work_struct *work = list_first_entry(&pwq->delayed_works, |
3aa62497 LJ |
1128 | struct work_struct, entry); |
1129 | ||
112202d9 | 1130 | pwq_activate_delayed_work(work); |
3aa62497 LJ |
1131 | } |
1132 | ||
bf4ede01 | 1133 | /** |
112202d9 TH |
1134 | * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight |
1135 | * @pwq: pwq of interest | |
bf4ede01 | 1136 | * @color: color of work which left the queue |
bf4ede01 TH |
1137 | * |
1138 | * A work either has completed or is removed from pending queue, | |
112202d9 | 1139 | * decrement nr_in_flight of its pwq and handle workqueue flushing. |
bf4ede01 TH |
1140 | * |
1141 | * CONTEXT: | |
d565ed63 | 1142 | * spin_lock_irq(pool->lock). |
bf4ede01 | 1143 | */ |
112202d9 | 1144 | static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color) |
bf4ede01 | 1145 | { |
8864b4e5 | 1146 | /* uncolored work items don't participate in flushing or nr_active */ |
bf4ede01 | 1147 | if (color == WORK_NO_COLOR) |
8864b4e5 | 1148 | goto out_put; |
bf4ede01 | 1149 | |
112202d9 | 1150 | pwq->nr_in_flight[color]--; |
bf4ede01 | 1151 | |
112202d9 TH |
1152 | pwq->nr_active--; |
1153 | if (!list_empty(&pwq->delayed_works)) { | |
b3f9f405 | 1154 | /* one down, submit a delayed one */ |
112202d9 TH |
1155 | if (pwq->nr_active < pwq->max_active) |
1156 | pwq_activate_first_delayed(pwq); | |
bf4ede01 TH |
1157 | } |
1158 | ||
1159 | /* is flush in progress and are we at the flushing tip? */ | |
112202d9 | 1160 | if (likely(pwq->flush_color != color)) |
8864b4e5 | 1161 | goto out_put; |
bf4ede01 TH |
1162 | |
1163 | /* are there still in-flight works? */ | |
112202d9 | 1164 | if (pwq->nr_in_flight[color]) |
8864b4e5 | 1165 | goto out_put; |
bf4ede01 | 1166 | |
112202d9 TH |
1167 | /* this pwq is done, clear flush_color */ |
1168 | pwq->flush_color = -1; | |
bf4ede01 TH |
1169 | |
1170 | /* | |
112202d9 | 1171 | * If this was the last pwq, wake up the first flusher. It |
bf4ede01 TH |
1172 | * will handle the rest. |
1173 | */ | |
112202d9 TH |
1174 | if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush)) |
1175 | complete(&pwq->wq->first_flusher->done); | |
8864b4e5 TH |
1176 | out_put: |
1177 | put_pwq(pwq); | |
bf4ede01 TH |
1178 | } |
1179 | ||
36e227d2 | 1180 | /** |
bbb68dfa | 1181 | * try_to_grab_pending - steal work item from worklist and disable irq |
36e227d2 TH |
1182 | * @work: work item to steal |
1183 | * @is_dwork: @work is a delayed_work | |
bbb68dfa | 1184 | * @flags: place to store irq state |
36e227d2 TH |
1185 | * |
1186 | * Try to grab PENDING bit of @work. This function can handle @work in any | |
d185af30 | 1187 | * stable state - idle, on timer or on worklist. |
36e227d2 | 1188 | * |
d185af30 | 1189 | * Return: |
36e227d2 TH |
1190 | * 1 if @work was pending and we successfully stole PENDING |
1191 | * 0 if @work was idle and we claimed PENDING | |
1192 | * -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry | |
bbb68dfa TH |
1193 | * -ENOENT if someone else is canceling @work, this state may persist |
1194 | * for arbitrarily long | |
36e227d2 | 1195 | * |
d185af30 | 1196 | * Note: |
bbb68dfa | 1197 | * On >= 0 return, the caller owns @work's PENDING bit. To avoid getting |
e0aecdd8 TH |
1198 | * interrupted while holding PENDING and @work off queue, irq must be |
1199 | * disabled on entry. This, combined with delayed_work->timer being | |
1200 | * irqsafe, ensures that we return -EAGAIN for finite short period of time. | |
bbb68dfa TH |
1201 | * |
1202 | * On successful return, >= 0, irq is disabled and the caller is | |
1203 | * responsible for releasing it using local_irq_restore(*@flags). | |
1204 | * | |
e0aecdd8 | 1205 | * This function is safe to call from any context including IRQ handler. |
bf4ede01 | 1206 | */ |
bbb68dfa TH |
1207 | static int try_to_grab_pending(struct work_struct *work, bool is_dwork, |
1208 | unsigned long *flags) | |
bf4ede01 | 1209 | { |
d565ed63 | 1210 | struct worker_pool *pool; |
112202d9 | 1211 | struct pool_workqueue *pwq; |
bf4ede01 | 1212 | |
bbb68dfa TH |
1213 | local_irq_save(*flags); |
1214 | ||
36e227d2 TH |
1215 | /* try to steal the timer if it exists */ |
1216 | if (is_dwork) { | |
1217 | struct delayed_work *dwork = to_delayed_work(work); | |
1218 | ||
e0aecdd8 TH |
1219 | /* |
1220 | * dwork->timer is irqsafe. If del_timer() fails, it's | |
1221 | * guaranteed that the timer is not queued anywhere and not | |
1222 | * running on the local CPU. | |
1223 | */ | |
36e227d2 TH |
1224 | if (likely(del_timer(&dwork->timer))) |
1225 | return 1; | |
1226 | } | |
1227 | ||
1228 | /* try to claim PENDING the normal way */ | |
bf4ede01 TH |
1229 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
1230 | return 0; | |
1231 | ||
1232 | /* | |
1233 | * The queueing is in progress, or it is already queued. Try to | |
1234 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | |
1235 | */ | |
d565ed63 TH |
1236 | pool = get_work_pool(work); |
1237 | if (!pool) | |
bbb68dfa | 1238 | goto fail; |
bf4ede01 | 1239 | |
d565ed63 | 1240 | spin_lock(&pool->lock); |
0b3dae68 | 1241 | /* |
112202d9 TH |
1242 | * work->data is guaranteed to point to pwq only while the work |
1243 | * item is queued on pwq->wq, and both updating work->data to point | |
1244 | * to pwq on queueing and to pool on dequeueing are done under | |
1245 | * pwq->pool->lock. This in turn guarantees that, if work->data | |
1246 | * points to pwq which is associated with a locked pool, the work | |
0b3dae68 LJ |
1247 | * item is currently queued on that pool. |
1248 | */ | |
112202d9 TH |
1249 | pwq = get_work_pwq(work); |
1250 | if (pwq && pwq->pool == pool) { | |
16062836 TH |
1251 | debug_work_deactivate(work); |
1252 | ||
1253 | /* | |
1254 | * A delayed work item cannot be grabbed directly because | |
1255 | * it might have linked NO_COLOR work items which, if left | |
112202d9 | 1256 | * on the delayed_list, will confuse pwq->nr_active |
16062836 TH |
1257 | * management later on and cause stall. Make sure the work |
1258 | * item is activated before grabbing. | |
1259 | */ | |
1260 | if (*work_data_bits(work) & WORK_STRUCT_DELAYED) | |
112202d9 | 1261 | pwq_activate_delayed_work(work); |
16062836 TH |
1262 | |
1263 | list_del_init(&work->entry); | |
9c34a704 | 1264 | pwq_dec_nr_in_flight(pwq, get_work_color(work)); |
16062836 | 1265 | |
112202d9 | 1266 | /* work->data points to pwq iff queued, point to pool */ |
16062836 TH |
1267 | set_work_pool_and_keep_pending(work, pool->id); |
1268 | ||
1269 | spin_unlock(&pool->lock); | |
1270 | return 1; | |
bf4ede01 | 1271 | } |
d565ed63 | 1272 | spin_unlock(&pool->lock); |
bbb68dfa TH |
1273 | fail: |
1274 | local_irq_restore(*flags); | |
1275 | if (work_is_canceling(work)) | |
1276 | return -ENOENT; | |
1277 | cpu_relax(); | |
36e227d2 | 1278 | return -EAGAIN; |
bf4ede01 TH |
1279 | } |
1280 | ||
4690c4ab | 1281 | /** |
706026c2 | 1282 | * insert_work - insert a work into a pool |
112202d9 | 1283 | * @pwq: pwq @work belongs to |
4690c4ab TH |
1284 | * @work: work to insert |
1285 | * @head: insertion point | |
1286 | * @extra_flags: extra WORK_STRUCT_* flags to set | |
1287 | * | |
112202d9 | 1288 | * Insert @work which belongs to @pwq after @head. @extra_flags is or'd to |
706026c2 | 1289 | * work_struct flags. |
4690c4ab TH |
1290 | * |
1291 | * CONTEXT: | |
d565ed63 | 1292 | * spin_lock_irq(pool->lock). |
4690c4ab | 1293 | */ |
112202d9 TH |
1294 | static void insert_work(struct pool_workqueue *pwq, struct work_struct *work, |
1295 | struct list_head *head, unsigned int extra_flags) | |
b89deed3 | 1296 | { |
112202d9 | 1297 | struct worker_pool *pool = pwq->pool; |
e22bee78 | 1298 | |
4690c4ab | 1299 | /* we own @work, set data and link */ |
112202d9 | 1300 | set_work_pwq(work, pwq, extra_flags); |
1a4d9b0a | 1301 | list_add_tail(&work->entry, head); |
8864b4e5 | 1302 | get_pwq(pwq); |
e22bee78 TH |
1303 | |
1304 | /* | |
c5aa87bb TH |
1305 | * Ensure either wq_worker_sleeping() sees the above |
1306 | * list_add_tail() or we see zero nr_running to avoid workers lying | |
1307 | * around lazily while there are works to be processed. | |
e22bee78 TH |
1308 | */ |
1309 | smp_mb(); | |
1310 | ||
63d95a91 TH |
1311 | if (__need_more_worker(pool)) |
1312 | wake_up_worker(pool); | |
b89deed3 ON |
1313 | } |
1314 | ||
c8efcc25 TH |
1315 | /* |
1316 | * Test whether @work is being queued from another work executing on the | |
8d03ecfe | 1317 | * same workqueue. |
c8efcc25 TH |
1318 | */ |
1319 | static bool is_chained_work(struct workqueue_struct *wq) | |
1320 | { | |
8d03ecfe TH |
1321 | struct worker *worker; |
1322 | ||
1323 | worker = current_wq_worker(); | |
1324 | /* | |
1325 | * Return %true iff I'm a worker execuing a work item on @wq. If | |
1326 | * I'm @worker, it's safe to dereference it without locking. | |
1327 | */ | |
112202d9 | 1328 | return worker && worker->current_pwq->wq == wq; |
c8efcc25 TH |
1329 | } |
1330 | ||
ef557180 MG |
1331 | /* |
1332 | * When queueing an unbound work item to a wq, prefer local CPU if allowed | |
1333 | * by wq_unbound_cpumask. Otherwise, round robin among the allowed ones to | |
1334 | * avoid perturbing sensitive tasks. | |
1335 | */ | |
1336 | static int wq_select_unbound_cpu(int cpu) | |
1337 | { | |
f303fccb | 1338 | static bool printed_dbg_warning; |
ef557180 MG |
1339 | int new_cpu; |
1340 | ||
f303fccb TH |
1341 | if (likely(!wq_debug_force_rr_cpu)) { |
1342 | if (cpumask_test_cpu(cpu, wq_unbound_cpumask)) | |
1343 | return cpu; | |
1344 | } else if (!printed_dbg_warning) { | |
1345 | pr_warn("workqueue: round-robin CPU selection forced, expect performance impact\n"); | |
1346 | printed_dbg_warning = true; | |
1347 | } | |
1348 | ||
ef557180 MG |
1349 | if (cpumask_empty(wq_unbound_cpumask)) |
1350 | return cpu; | |
1351 | ||
1352 | new_cpu = __this_cpu_read(wq_rr_cpu_last); | |
1353 | new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask); | |
1354 | if (unlikely(new_cpu >= nr_cpu_ids)) { | |
1355 | new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask); | |
1356 | if (unlikely(new_cpu >= nr_cpu_ids)) | |
1357 | return cpu; | |
1358 | } | |
1359 | __this_cpu_write(wq_rr_cpu_last, new_cpu); | |
1360 | ||
1361 | return new_cpu; | |
1362 | } | |
1363 | ||
d84ff051 | 1364 | static void __queue_work(int cpu, struct workqueue_struct *wq, |
1da177e4 LT |
1365 | struct work_struct *work) |
1366 | { | |
112202d9 | 1367 | struct pool_workqueue *pwq; |
c9178087 | 1368 | struct worker_pool *last_pool; |
1e19ffc6 | 1369 | struct list_head *worklist; |
8a2e8e5d | 1370 | unsigned int work_flags; |
b75cac93 | 1371 | unsigned int req_cpu = cpu; |
8930caba TH |
1372 | |
1373 | /* | |
1374 | * While a work item is PENDING && off queue, a task trying to | |
1375 | * steal the PENDING will busy-loop waiting for it to either get | |
1376 | * queued or lose PENDING. Grabbing PENDING and queueing should | |
1377 | * happen with IRQ disabled. | |
1378 | */ | |
1379 | WARN_ON_ONCE(!irqs_disabled()); | |
1da177e4 | 1380 | |
dc186ad7 | 1381 | debug_work_activate(work); |
1e19ffc6 | 1382 | |
9ef28a73 | 1383 | /* if draining, only works from the same workqueue are allowed */ |
618b01eb | 1384 | if (unlikely(wq->flags & __WQ_DRAINING) && |
c8efcc25 | 1385 | WARN_ON_ONCE(!is_chained_work(wq))) |
e41e704b | 1386 | return; |
9e8cd2f5 | 1387 | retry: |
df2d5ae4 | 1388 | if (req_cpu == WORK_CPU_UNBOUND) |
ef557180 | 1389 | cpu = wq_select_unbound_cpu(raw_smp_processor_id()); |
df2d5ae4 | 1390 | |
c9178087 | 1391 | /* pwq which will be used unless @work is executing elsewhere */ |
df2d5ae4 | 1392 | if (!(wq->flags & WQ_UNBOUND)) |
7fb98ea7 | 1393 | pwq = per_cpu_ptr(wq->cpu_pwqs, cpu); |
df2d5ae4 TH |
1394 | else |
1395 | pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu)); | |
dbf2576e | 1396 | |
c9178087 TH |
1397 | /* |
1398 | * If @work was previously on a different pool, it might still be | |
1399 | * running there, in which case the work needs to be queued on that | |
1400 | * pool to guarantee non-reentrancy. | |
1401 | */ | |
1402 | last_pool = get_work_pool(work); | |
1403 | if (last_pool && last_pool != pwq->pool) { | |
1404 | struct worker *worker; | |
18aa9eff | 1405 | |
c9178087 | 1406 | spin_lock(&last_pool->lock); |
18aa9eff | 1407 | |
c9178087 | 1408 | worker = find_worker_executing_work(last_pool, work); |
18aa9eff | 1409 | |
c9178087 TH |
1410 | if (worker && worker->current_pwq->wq == wq) { |
1411 | pwq = worker->current_pwq; | |
8930caba | 1412 | } else { |
c9178087 TH |
1413 | /* meh... not running there, queue here */ |
1414 | spin_unlock(&last_pool->lock); | |
112202d9 | 1415 | spin_lock(&pwq->pool->lock); |
8930caba | 1416 | } |
f3421797 | 1417 | } else { |
112202d9 | 1418 | spin_lock(&pwq->pool->lock); |
502ca9d8 TH |
1419 | } |
1420 | ||
9e8cd2f5 TH |
1421 | /* |
1422 | * pwq is determined and locked. For unbound pools, we could have | |
1423 | * raced with pwq release and it could already be dead. If its | |
1424 | * refcnt is zero, repeat pwq selection. Note that pwqs never die | |
df2d5ae4 TH |
1425 | * without another pwq replacing it in the numa_pwq_tbl or while |
1426 | * work items are executing on it, so the retrying is guaranteed to | |
9e8cd2f5 TH |
1427 | * make forward-progress. |
1428 | */ | |
1429 | if (unlikely(!pwq->refcnt)) { | |
1430 | if (wq->flags & WQ_UNBOUND) { | |
1431 | spin_unlock(&pwq->pool->lock); | |
1432 | cpu_relax(); | |
1433 | goto retry; | |
1434 | } | |
1435 | /* oops */ | |
1436 | WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt", | |
1437 | wq->name, cpu); | |
1438 | } | |
1439 | ||
112202d9 TH |
1440 | /* pwq determined, queue */ |
1441 | trace_workqueue_queue_work(req_cpu, pwq, work); | |
502ca9d8 | 1442 | |
f5b2552b | 1443 | if (WARN_ON(!list_empty(&work->entry))) { |
112202d9 | 1444 | spin_unlock(&pwq->pool->lock); |
f5b2552b DC |
1445 | return; |
1446 | } | |
1e19ffc6 | 1447 | |
112202d9 TH |
1448 | pwq->nr_in_flight[pwq->work_color]++; |
1449 | work_flags = work_color_to_flags(pwq->work_color); | |
1e19ffc6 | 1450 | |
112202d9 | 1451 | if (likely(pwq->nr_active < pwq->max_active)) { |
cdadf009 | 1452 | trace_workqueue_activate_work(work); |
112202d9 TH |
1453 | pwq->nr_active++; |
1454 | worklist = &pwq->pool->worklist; | |
82607adc TH |
1455 | if (list_empty(worklist)) |
1456 | pwq->pool->watchdog_ts = jiffies; | |
8a2e8e5d TH |
1457 | } else { |
1458 | work_flags |= WORK_STRUCT_DELAYED; | |
112202d9 | 1459 | worklist = &pwq->delayed_works; |
8a2e8e5d | 1460 | } |
1e19ffc6 | 1461 | |
112202d9 | 1462 | insert_work(pwq, work, worklist, work_flags); |
1e19ffc6 | 1463 | |
112202d9 | 1464 | spin_unlock(&pwq->pool->lock); |
1da177e4 LT |
1465 | } |
1466 | ||
0fcb78c2 | 1467 | /** |
c1a220e7 ZR |
1468 | * queue_work_on - queue work on specific cpu |
1469 | * @cpu: CPU number to execute work on | |
0fcb78c2 REB |
1470 | * @wq: workqueue to use |
1471 | * @work: work to queue | |
1472 | * | |
c1a220e7 ZR |
1473 | * We queue the work to a specific CPU, the caller must ensure it |
1474 | * can't go away. | |
d185af30 YB |
1475 | * |
1476 | * Return: %false if @work was already on a queue, %true otherwise. | |
1da177e4 | 1477 | */ |
d4283e93 TH |
1478 | bool queue_work_on(int cpu, struct workqueue_struct *wq, |
1479 | struct work_struct *work) | |
1da177e4 | 1480 | { |
d4283e93 | 1481 | bool ret = false; |
8930caba | 1482 | unsigned long flags; |
ef1ca236 | 1483 | |
8930caba | 1484 | local_irq_save(flags); |
c1a220e7 | 1485 | |
22df02bb | 1486 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
4690c4ab | 1487 | __queue_work(cpu, wq, work); |
d4283e93 | 1488 | ret = true; |
c1a220e7 | 1489 | } |
ef1ca236 | 1490 | |
8930caba | 1491 | local_irq_restore(flags); |
1da177e4 LT |
1492 | return ret; |
1493 | } | |
ad7b1f84 | 1494 | EXPORT_SYMBOL(queue_work_on); |
1da177e4 | 1495 | |
d8e794df | 1496 | void delayed_work_timer_fn(unsigned long __data) |
1da177e4 | 1497 | { |
52bad64d | 1498 | struct delayed_work *dwork = (struct delayed_work *)__data; |
1da177e4 | 1499 | |
e0aecdd8 | 1500 | /* should have been called from irqsafe timer with irq already off */ |
60c057bc | 1501 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
1da177e4 | 1502 | } |
1438ade5 | 1503 | EXPORT_SYMBOL(delayed_work_timer_fn); |
1da177e4 | 1504 | |
7beb2edf TH |
1505 | static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, |
1506 | struct delayed_work *dwork, unsigned long delay) | |
1da177e4 | 1507 | { |
7beb2edf TH |
1508 | struct timer_list *timer = &dwork->timer; |
1509 | struct work_struct *work = &dwork->work; | |
7beb2edf | 1510 | |
637fdbae | 1511 | WARN_ON_ONCE(!wq); |
7beb2edf TH |
1512 | WARN_ON_ONCE(timer->function != delayed_work_timer_fn || |
1513 | timer->data != (unsigned long)dwork); | |
fc4b514f TH |
1514 | WARN_ON_ONCE(timer_pending(timer)); |
1515 | WARN_ON_ONCE(!list_empty(&work->entry)); | |
7beb2edf | 1516 | |
8852aac2 TH |
1517 | /* |
1518 | * If @delay is 0, queue @dwork->work immediately. This is for | |
1519 | * both optimization and correctness. The earliest @timer can | |
1520 | * expire is on the closest next tick and delayed_work users depend | |
1521 | * on that there's no such delay when @delay is 0. | |
1522 | */ | |
1523 | if (!delay) { | |
1524 | __queue_work(cpu, wq, &dwork->work); | |
1525 | return; | |
1526 | } | |
1527 | ||
60c057bc | 1528 | dwork->wq = wq; |
1265057f | 1529 | dwork->cpu = cpu; |
7beb2edf TH |
1530 | timer->expires = jiffies + delay; |
1531 | ||
041bd12e TH |
1532 | if (unlikely(cpu != WORK_CPU_UNBOUND)) |
1533 | add_timer_on(timer, cpu); | |
1534 | else | |
1535 | add_timer(timer); | |
1da177e4 LT |
1536 | } |
1537 | ||
0fcb78c2 REB |
1538 | /** |
1539 | * queue_delayed_work_on - queue work on specific CPU after delay | |
1540 | * @cpu: CPU number to execute work on | |
1541 | * @wq: workqueue to use | |
af9997e4 | 1542 | * @dwork: work to queue |
0fcb78c2 REB |
1543 | * @delay: number of jiffies to wait before queueing |
1544 | * | |
d185af30 | 1545 | * Return: %false if @work was already on a queue, %true otherwise. If |
715f1300 TH |
1546 | * @delay is zero and @dwork is idle, it will be scheduled for immediate |
1547 | * execution. | |
0fcb78c2 | 1548 | */ |
d4283e93 TH |
1549 | bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, |
1550 | struct delayed_work *dwork, unsigned long delay) | |
7a6bc1cd | 1551 | { |
52bad64d | 1552 | struct work_struct *work = &dwork->work; |
d4283e93 | 1553 | bool ret = false; |
8930caba | 1554 | unsigned long flags; |
7a6bc1cd | 1555 | |
8930caba TH |
1556 | /* read the comment in __queue_work() */ |
1557 | local_irq_save(flags); | |
7a6bc1cd | 1558 | |
22df02bb | 1559 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
7beb2edf | 1560 | __queue_delayed_work(cpu, wq, dwork, delay); |
d4283e93 | 1561 | ret = true; |
7a6bc1cd | 1562 | } |
8a3e77cc | 1563 | |
8930caba | 1564 | local_irq_restore(flags); |
7a6bc1cd VP |
1565 | return ret; |
1566 | } | |
ad7b1f84 | 1567 | EXPORT_SYMBOL(queue_delayed_work_on); |
c7fc77f7 | 1568 | |
8376fe22 TH |
1569 | /** |
1570 | * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU | |
1571 | * @cpu: CPU number to execute work on | |
1572 | * @wq: workqueue to use | |
1573 | * @dwork: work to queue | |
1574 | * @delay: number of jiffies to wait before queueing | |
1575 | * | |
1576 | * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, | |
1577 | * modify @dwork's timer so that it expires after @delay. If @delay is | |
1578 | * zero, @work is guaranteed to be scheduled immediately regardless of its | |
1579 | * current state. | |
1580 | * | |
d185af30 | 1581 | * Return: %false if @dwork was idle and queued, %true if @dwork was |
8376fe22 TH |
1582 | * pending and its timer was modified. |
1583 | * | |
e0aecdd8 | 1584 | * This function is safe to call from any context including IRQ handler. |
8376fe22 TH |
1585 | * See try_to_grab_pending() for details. |
1586 | */ | |
1587 | bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, | |
1588 | struct delayed_work *dwork, unsigned long delay) | |
1589 | { | |
1590 | unsigned long flags; | |
1591 | int ret; | |
c7fc77f7 | 1592 | |
8376fe22 TH |
1593 | do { |
1594 | ret = try_to_grab_pending(&dwork->work, true, &flags); | |
1595 | } while (unlikely(ret == -EAGAIN)); | |
63bc0362 | 1596 | |
8376fe22 TH |
1597 | if (likely(ret >= 0)) { |
1598 | __queue_delayed_work(cpu, wq, dwork, delay); | |
1599 | local_irq_restore(flags); | |
7a6bc1cd | 1600 | } |
8376fe22 TH |
1601 | |
1602 | /* -ENOENT from try_to_grab_pending() becomes %true */ | |
7a6bc1cd VP |
1603 | return ret; |
1604 | } | |
8376fe22 TH |
1605 | EXPORT_SYMBOL_GPL(mod_delayed_work_on); |
1606 | ||
c8e55f36 TH |
1607 | /** |
1608 | * worker_enter_idle - enter idle state | |
1609 | * @worker: worker which is entering idle state | |
1610 | * | |
1611 | * @worker is entering idle state. Update stats and idle timer if | |
1612 | * necessary. | |
1613 | * | |
1614 | * LOCKING: | |
d565ed63 | 1615 | * spin_lock_irq(pool->lock). |
c8e55f36 TH |
1616 | */ |
1617 | static void worker_enter_idle(struct worker *worker) | |
1da177e4 | 1618 | { |
bd7bdd43 | 1619 | struct worker_pool *pool = worker->pool; |
c8e55f36 | 1620 | |
6183c009 TH |
1621 | if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) || |
1622 | WARN_ON_ONCE(!list_empty(&worker->entry) && | |
1623 | (worker->hentry.next || worker->hentry.pprev))) | |
1624 | return; | |
c8e55f36 | 1625 | |
051e1850 | 1626 | /* can't use worker_set_flags(), also called from create_worker() */ |
cb444766 | 1627 | worker->flags |= WORKER_IDLE; |
bd7bdd43 | 1628 | pool->nr_idle++; |
e22bee78 | 1629 | worker->last_active = jiffies; |
c8e55f36 TH |
1630 | |
1631 | /* idle_list is LIFO */ | |
bd7bdd43 | 1632 | list_add(&worker->entry, &pool->idle_list); |
db7bccf4 | 1633 | |
628c78e7 TH |
1634 | if (too_many_workers(pool) && !timer_pending(&pool->idle_timer)) |
1635 | mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT); | |
cb444766 | 1636 | |
544ecf31 | 1637 | /* |
706026c2 | 1638 | * Sanity check nr_running. Because wq_unbind_fn() releases |
d565ed63 | 1639 | * pool->lock between setting %WORKER_UNBOUND and zapping |
628c78e7 TH |
1640 | * nr_running, the warning may trigger spuriously. Check iff |
1641 | * unbind is not in progress. | |
544ecf31 | 1642 | */ |
24647570 | 1643 | WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && |
bd7bdd43 | 1644 | pool->nr_workers == pool->nr_idle && |
e19e397a | 1645 | atomic_read(&pool->nr_running)); |
c8e55f36 TH |
1646 | } |
1647 | ||
1648 | /** | |
1649 | * worker_leave_idle - leave idle state | |
1650 | * @worker: worker which is leaving idle state | |
1651 | * | |
1652 | * @worker is leaving idle state. Update stats. | |
1653 | * | |
1654 | * LOCKING: | |
d565ed63 | 1655 | * spin_lock_irq(pool->lock). |
c8e55f36 TH |
1656 | */ |
1657 | static void worker_leave_idle(struct worker *worker) | |
1658 | { | |
bd7bdd43 | 1659 | struct worker_pool *pool = worker->pool; |
c8e55f36 | 1660 | |
6183c009 TH |
1661 | if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE))) |
1662 | return; | |
d302f017 | 1663 | worker_clr_flags(worker, WORKER_IDLE); |
bd7bdd43 | 1664 | pool->nr_idle--; |
c8e55f36 TH |
1665 | list_del_init(&worker->entry); |
1666 | } | |
1667 | ||
f7537df5 | 1668 | static struct worker *alloc_worker(int node) |
c34056a3 TH |
1669 | { |
1670 | struct worker *worker; | |
1671 | ||
f7537df5 | 1672 | worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); |
c8e55f36 TH |
1673 | if (worker) { |
1674 | INIT_LIST_HEAD(&worker->entry); | |
affee4b2 | 1675 | INIT_LIST_HEAD(&worker->scheduled); |
da028469 | 1676 | INIT_LIST_HEAD(&worker->node); |
e22bee78 TH |
1677 | /* on creation a worker is in !idle && prep state */ |
1678 | worker->flags = WORKER_PREP; | |
c8e55f36 | 1679 | } |
c34056a3 TH |
1680 | return worker; |
1681 | } | |
1682 | ||
4736cbf7 LJ |
1683 | /** |
1684 | * worker_attach_to_pool() - attach a worker to a pool | |
1685 | * @worker: worker to be attached | |
1686 | * @pool: the target pool | |
1687 | * | |
1688 | * Attach @worker to @pool. Once attached, the %WORKER_UNBOUND flag and | |
1689 | * cpu-binding of @worker are kept coordinated with the pool across | |
1690 | * cpu-[un]hotplugs. | |
1691 | */ | |
1692 | static void worker_attach_to_pool(struct worker *worker, | |
1693 | struct worker_pool *pool) | |
1694 | { | |
1695 | mutex_lock(&pool->attach_mutex); | |
1696 | ||
1697 | /* | |
1698 | * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any | |
1699 | * online CPUs. It'll be re-applied when any of the CPUs come up. | |
1700 | */ | |
1701 | set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask); | |
1702 | ||
1703 | /* | |
1704 | * The pool->attach_mutex ensures %POOL_DISASSOCIATED remains | |
1705 | * stable across this function. See the comments above the | |
1706 | * flag definition for details. | |
1707 | */ | |
1708 | if (pool->flags & POOL_DISASSOCIATED) | |
1709 | worker->flags |= WORKER_UNBOUND; | |
1710 | ||
1711 | list_add_tail(&worker->node, &pool->workers); | |
1712 | ||
1713 | mutex_unlock(&pool->attach_mutex); | |
1714 | } | |
1715 | ||
60f5a4bc LJ |
1716 | /** |
1717 | * worker_detach_from_pool() - detach a worker from its pool | |
1718 | * @worker: worker which is attached to its pool | |
1719 | * @pool: the pool @worker is attached to | |
1720 | * | |
4736cbf7 LJ |
1721 | * Undo the attaching which had been done in worker_attach_to_pool(). The |
1722 | * caller worker shouldn't access to the pool after detached except it has | |
1723 | * other reference to the pool. | |
60f5a4bc LJ |
1724 | */ |
1725 | static void worker_detach_from_pool(struct worker *worker, | |
1726 | struct worker_pool *pool) | |
1727 | { | |
1728 | struct completion *detach_completion = NULL; | |
1729 | ||
92f9c5c4 | 1730 | mutex_lock(&pool->attach_mutex); |
da028469 LJ |
1731 | list_del(&worker->node); |
1732 | if (list_empty(&pool->workers)) | |
60f5a4bc | 1733 | detach_completion = pool->detach_completion; |
92f9c5c4 | 1734 | mutex_unlock(&pool->attach_mutex); |
60f5a4bc | 1735 | |
b62c0751 LJ |
1736 | /* clear leftover flags without pool->lock after it is detached */ |
1737 | worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND); | |
1738 | ||
60f5a4bc LJ |
1739 | if (detach_completion) |
1740 | complete(detach_completion); | |
1741 | } | |
1742 | ||
c34056a3 TH |
1743 | /** |
1744 | * create_worker - create a new workqueue worker | |
63d95a91 | 1745 | * @pool: pool the new worker will belong to |
c34056a3 | 1746 | * |
051e1850 | 1747 | * Create and start a new worker which is attached to @pool. |
c34056a3 TH |
1748 | * |
1749 | * CONTEXT: | |
1750 | * Might sleep. Does GFP_KERNEL allocations. | |
1751 | * | |
d185af30 | 1752 | * Return: |
c34056a3 TH |
1753 | * Pointer to the newly created worker. |
1754 | */ | |
bc2ae0f5 | 1755 | static struct worker *create_worker(struct worker_pool *pool) |
c34056a3 | 1756 | { |
c34056a3 | 1757 | struct worker *worker = NULL; |
f3421797 | 1758 | int id = -1; |
e3c916a4 | 1759 | char id_buf[16]; |
c34056a3 | 1760 | |
7cda9aae LJ |
1761 | /* ID is needed to determine kthread name */ |
1762 | id = ida_simple_get(&pool->worker_ida, 0, 0, GFP_KERNEL); | |
822d8405 TH |
1763 | if (id < 0) |
1764 | goto fail; | |
c34056a3 | 1765 | |
f7537df5 | 1766 | worker = alloc_worker(pool->node); |
c34056a3 TH |
1767 | if (!worker) |
1768 | goto fail; | |
1769 | ||
bd7bdd43 | 1770 | worker->pool = pool; |
c34056a3 TH |
1771 | worker->id = id; |
1772 | ||
29c91e99 | 1773 | if (pool->cpu >= 0) |
e3c916a4 TH |
1774 | snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id, |
1775 | pool->attrs->nice < 0 ? "H" : ""); | |
f3421797 | 1776 | else |
e3c916a4 TH |
1777 | snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id); |
1778 | ||
f3f90ad4 | 1779 | worker->task = kthread_create_on_node(worker_thread, worker, pool->node, |
e3c916a4 | 1780 | "kworker/%s", id_buf); |
c34056a3 TH |
1781 | if (IS_ERR(worker->task)) |
1782 | goto fail; | |
1783 | ||
91151228 | 1784 | set_user_nice(worker->task, pool->attrs->nice); |
25834c73 | 1785 | kthread_bind_mask(worker->task, pool->attrs->cpumask); |
91151228 | 1786 | |
da028469 | 1787 | /* successful, attach the worker to the pool */ |
4736cbf7 | 1788 | worker_attach_to_pool(worker, pool); |
822d8405 | 1789 | |
051e1850 LJ |
1790 | /* start the newly created worker */ |
1791 | spin_lock_irq(&pool->lock); | |
1792 | worker->pool->nr_workers++; | |
1793 | worker_enter_idle(worker); | |
1794 | wake_up_process(worker->task); | |
1795 | spin_unlock_irq(&pool->lock); | |
1796 | ||
c34056a3 | 1797 | return worker; |
822d8405 | 1798 | |
c34056a3 | 1799 | fail: |
9625ab17 | 1800 | if (id >= 0) |
7cda9aae | 1801 | ida_simple_remove(&pool->worker_ida, id); |
c34056a3 TH |
1802 | kfree(worker); |
1803 | return NULL; | |
1804 | } | |
1805 | ||
c34056a3 TH |
1806 | /** |
1807 | * destroy_worker - destroy a workqueue worker | |
1808 | * @worker: worker to be destroyed | |
1809 | * | |
73eb7fe7 LJ |
1810 | * Destroy @worker and adjust @pool stats accordingly. The worker should |
1811 | * be idle. | |
c8e55f36 TH |
1812 | * |
1813 | * CONTEXT: | |
60f5a4bc | 1814 | * spin_lock_irq(pool->lock). |
c34056a3 TH |
1815 | */ |
1816 | static void destroy_worker(struct worker *worker) | |
1817 | { | |
bd7bdd43 | 1818 | struct worker_pool *pool = worker->pool; |
c34056a3 | 1819 | |
cd549687 TH |
1820 | lockdep_assert_held(&pool->lock); |
1821 | ||
c34056a3 | 1822 | /* sanity check frenzy */ |
6183c009 | 1823 | if (WARN_ON(worker->current_work) || |
73eb7fe7 LJ |
1824 | WARN_ON(!list_empty(&worker->scheduled)) || |
1825 | WARN_ON(!(worker->flags & WORKER_IDLE))) | |
6183c009 | 1826 | return; |
c34056a3 | 1827 | |
73eb7fe7 LJ |
1828 | pool->nr_workers--; |
1829 | pool->nr_idle--; | |
5bdfff96 | 1830 | |
c8e55f36 | 1831 | list_del_init(&worker->entry); |
cb444766 | 1832 | worker->flags |= WORKER_DIE; |
60f5a4bc | 1833 | wake_up_process(worker->task); |
c34056a3 TH |
1834 | } |
1835 | ||
63d95a91 | 1836 | static void idle_worker_timeout(unsigned long __pool) |
e22bee78 | 1837 | { |
63d95a91 | 1838 | struct worker_pool *pool = (void *)__pool; |
e22bee78 | 1839 | |
d565ed63 | 1840 | spin_lock_irq(&pool->lock); |
e22bee78 | 1841 | |
3347fc9f | 1842 | while (too_many_workers(pool)) { |
e22bee78 TH |
1843 | struct worker *worker; |
1844 | unsigned long expires; | |
1845 | ||
1846 | /* idle_list is kept in LIFO order, check the last one */ | |
63d95a91 | 1847 | worker = list_entry(pool->idle_list.prev, struct worker, entry); |
e22bee78 TH |
1848 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
1849 | ||
3347fc9f | 1850 | if (time_before(jiffies, expires)) { |
63d95a91 | 1851 | mod_timer(&pool->idle_timer, expires); |
3347fc9f | 1852 | break; |
d5abe669 | 1853 | } |
3347fc9f LJ |
1854 | |
1855 | destroy_worker(worker); | |
e22bee78 TH |
1856 | } |
1857 | ||
d565ed63 | 1858 | spin_unlock_irq(&pool->lock); |
e22bee78 | 1859 | } |
d5abe669 | 1860 | |
493a1724 | 1861 | static void send_mayday(struct work_struct *work) |
e22bee78 | 1862 | { |
112202d9 TH |
1863 | struct pool_workqueue *pwq = get_work_pwq(work); |
1864 | struct workqueue_struct *wq = pwq->wq; | |
493a1724 | 1865 | |
2e109a28 | 1866 | lockdep_assert_held(&wq_mayday_lock); |
e22bee78 | 1867 | |
493008a8 | 1868 | if (!wq->rescuer) |
493a1724 | 1869 | return; |
e22bee78 TH |
1870 | |
1871 | /* mayday mayday mayday */ | |
493a1724 | 1872 | if (list_empty(&pwq->mayday_node)) { |
77668c8b LJ |
1873 | /* |
1874 | * If @pwq is for an unbound wq, its base ref may be put at | |
1875 | * any time due to an attribute change. Pin @pwq until the | |
1876 | * rescuer is done with it. | |
1877 | */ | |
1878 | get_pwq(pwq); | |
493a1724 | 1879 | list_add_tail(&pwq->mayday_node, &wq->maydays); |
e22bee78 | 1880 | wake_up_process(wq->rescuer->task); |
493a1724 | 1881 | } |
e22bee78 TH |
1882 | } |
1883 | ||
706026c2 | 1884 | static void pool_mayday_timeout(unsigned long __pool) |
e22bee78 | 1885 | { |
63d95a91 | 1886 | struct worker_pool *pool = (void *)__pool; |
e22bee78 TH |
1887 | struct work_struct *work; |
1888 | ||
b2d82909 TH |
1889 | spin_lock_irq(&pool->lock); |
1890 | spin_lock(&wq_mayday_lock); /* for wq->maydays */ | |
e22bee78 | 1891 | |
63d95a91 | 1892 | if (need_to_create_worker(pool)) { |
e22bee78 TH |
1893 | /* |
1894 | * We've been trying to create a new worker but | |
1895 | * haven't been successful. We might be hitting an | |
1896 | * allocation deadlock. Send distress signals to | |
1897 | * rescuers. | |
1898 | */ | |
63d95a91 | 1899 | list_for_each_entry(work, &pool->worklist, entry) |
e22bee78 | 1900 | send_mayday(work); |
1da177e4 | 1901 | } |
e22bee78 | 1902 | |
b2d82909 TH |
1903 | spin_unlock(&wq_mayday_lock); |
1904 | spin_unlock_irq(&pool->lock); | |
e22bee78 | 1905 | |
63d95a91 | 1906 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL); |
1da177e4 LT |
1907 | } |
1908 | ||
e22bee78 TH |
1909 | /** |
1910 | * maybe_create_worker - create a new worker if necessary | |
63d95a91 | 1911 | * @pool: pool to create a new worker for |
e22bee78 | 1912 | * |
63d95a91 | 1913 | * Create a new worker for @pool if necessary. @pool is guaranteed to |
e22bee78 TH |
1914 | * have at least one idle worker on return from this function. If |
1915 | * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is | |
63d95a91 | 1916 | * sent to all rescuers with works scheduled on @pool to resolve |
e22bee78 TH |
1917 | * possible allocation deadlock. |
1918 | * | |
c5aa87bb TH |
1919 | * On return, need_to_create_worker() is guaranteed to be %false and |
1920 | * may_start_working() %true. | |
e22bee78 TH |
1921 | * |
1922 | * LOCKING: | |
d565ed63 | 1923 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
1924 | * multiple times. Does GFP_KERNEL allocations. Called only from |
1925 | * manager. | |
e22bee78 | 1926 | */ |
29187a9e | 1927 | static void maybe_create_worker(struct worker_pool *pool) |
d565ed63 TH |
1928 | __releases(&pool->lock) |
1929 | __acquires(&pool->lock) | |
1da177e4 | 1930 | { |
e22bee78 | 1931 | restart: |
d565ed63 | 1932 | spin_unlock_irq(&pool->lock); |
9f9c2364 | 1933 | |
e22bee78 | 1934 | /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ |
63d95a91 | 1935 | mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); |
e22bee78 TH |
1936 | |
1937 | while (true) { | |
051e1850 | 1938 | if (create_worker(pool) || !need_to_create_worker(pool)) |
e22bee78 | 1939 | break; |
1da177e4 | 1940 | |
e212f361 | 1941 | schedule_timeout_interruptible(CREATE_COOLDOWN); |
9f9c2364 | 1942 | |
63d95a91 | 1943 | if (!need_to_create_worker(pool)) |
e22bee78 TH |
1944 | break; |
1945 | } | |
1946 | ||
63d95a91 | 1947 | del_timer_sync(&pool->mayday_timer); |
d565ed63 | 1948 | spin_lock_irq(&pool->lock); |
051e1850 LJ |
1949 | /* |
1950 | * This is necessary even after a new worker was just successfully | |
1951 | * created as @pool->lock was dropped and the new worker might have | |
1952 | * already become busy. | |
1953 | */ | |
63d95a91 | 1954 | if (need_to_create_worker(pool)) |
e22bee78 | 1955 | goto restart; |
e22bee78 TH |
1956 | } |
1957 | ||
73f53c4a | 1958 | /** |
e22bee78 TH |
1959 | * manage_workers - manage worker pool |
1960 | * @worker: self | |
73f53c4a | 1961 | * |
706026c2 | 1962 | * Assume the manager role and manage the worker pool @worker belongs |
e22bee78 | 1963 | * to. At any given time, there can be only zero or one manager per |
706026c2 | 1964 | * pool. The exclusion is handled automatically by this function. |
e22bee78 TH |
1965 | * |
1966 | * The caller can safely start processing works on false return. On | |
1967 | * true return, it's guaranteed that need_to_create_worker() is false | |
1968 | * and may_start_working() is true. | |
73f53c4a TH |
1969 | * |
1970 | * CONTEXT: | |
d565ed63 | 1971 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
e22bee78 TH |
1972 | * multiple times. Does GFP_KERNEL allocations. |
1973 | * | |
d185af30 | 1974 | * Return: |
29187a9e TH |
1975 | * %false if the pool doesn't need management and the caller can safely |
1976 | * start processing works, %true if management function was performed and | |
1977 | * the conditions that the caller verified before calling the function may | |
1978 | * no longer be true. | |
73f53c4a | 1979 | */ |
e22bee78 | 1980 | static bool manage_workers(struct worker *worker) |
73f53c4a | 1981 | { |
63d95a91 | 1982 | struct worker_pool *pool = worker->pool; |
73f53c4a | 1983 | |
692b4825 | 1984 | if (pool->flags & POOL_MANAGER_ACTIVE) |
29187a9e | 1985 | return false; |
692b4825 TH |
1986 | |
1987 | pool->flags |= POOL_MANAGER_ACTIVE; | |
2607d7a6 | 1988 | pool->manager = worker; |
1e19ffc6 | 1989 | |
29187a9e | 1990 | maybe_create_worker(pool); |
e22bee78 | 1991 | |
2607d7a6 | 1992 | pool->manager = NULL; |
692b4825 TH |
1993 | pool->flags &= ~POOL_MANAGER_ACTIVE; |
1994 | wake_up(&wq_manager_wait); | |
29187a9e | 1995 | return true; |
73f53c4a TH |
1996 | } |
1997 | ||
a62428c0 TH |
1998 | /** |
1999 | * process_one_work - process single work | |
c34056a3 | 2000 | * @worker: self |
a62428c0 TH |
2001 | * @work: work to process |
2002 | * | |
2003 | * Process @work. This function contains all the logics necessary to | |
2004 | * process a single work including synchronization against and | |
2005 | * interaction with other workers on the same cpu, queueing and | |
2006 | * flushing. As long as context requirement is met, any worker can | |
2007 | * call this function to process a work. | |
2008 | * | |
2009 | * CONTEXT: | |
d565ed63 | 2010 | * spin_lock_irq(pool->lock) which is released and regrabbed. |
a62428c0 | 2011 | */ |
c34056a3 | 2012 | static void process_one_work(struct worker *worker, struct work_struct *work) |
d565ed63 TH |
2013 | __releases(&pool->lock) |
2014 | __acquires(&pool->lock) | |
a62428c0 | 2015 | { |
112202d9 | 2016 | struct pool_workqueue *pwq = get_work_pwq(work); |
bd7bdd43 | 2017 | struct worker_pool *pool = worker->pool; |
112202d9 | 2018 | bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE; |
73f53c4a | 2019 | int work_color; |
7e11629d | 2020 | struct worker *collision; |
a62428c0 TH |
2021 | #ifdef CONFIG_LOCKDEP |
2022 | /* | |
2023 | * It is permissible to free the struct work_struct from | |
2024 | * inside the function that is called from it, this we need to | |
2025 | * take into account for lockdep too. To avoid bogus "held | |
2026 | * lock freed" warnings as well as problems when looking into | |
2027 | * work->lockdep_map, make a copy and use that here. | |
2028 | */ | |
4d82a1de PZ |
2029 | struct lockdep_map lockdep_map; |
2030 | ||
2031 | lockdep_copy_map(&lockdep_map, &work->lockdep_map); | |
a62428c0 | 2032 | #endif |
807407c0 | 2033 | /* ensure we're on the correct CPU */ |
85327af6 | 2034 | WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) && |
ec22ca5e | 2035 | raw_smp_processor_id() != pool->cpu); |
25511a47 | 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 | */ | |
c9e7cf27 | 2043 | collision = find_worker_executing_work(pool, work); |
7e11629d TH |
2044 | if (unlikely(collision)) { |
2045 | move_linked_works(work, &collision->scheduled, NULL); | |
2046 | return; | |
2047 | } | |
2048 | ||
8930caba | 2049 | /* claim and dequeue */ |
a62428c0 | 2050 | debug_work_deactivate(work); |
c9e7cf27 | 2051 | hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work); |
c34056a3 | 2052 | worker->current_work = work; |
a2c1c57b | 2053 | worker->current_func = work->func; |
112202d9 | 2054 | worker->current_pwq = pwq; |
73f53c4a | 2055 | work_color = get_work_color(work); |
7a22ad75 | 2056 | |
a62428c0 TH |
2057 | list_del_init(&work->entry); |
2058 | ||
fb0e7beb | 2059 | /* |
228f1d00 LJ |
2060 | * CPU intensive works don't participate in concurrency management. |
2061 | * They're the scheduler's responsibility. This takes @worker out | |
2062 | * of concurrency management and the next code block will chain | |
2063 | * execution of the pending work items. | |
fb0e7beb TH |
2064 | */ |
2065 | if (unlikely(cpu_intensive)) | |
228f1d00 | 2066 | worker_set_flags(worker, WORKER_CPU_INTENSIVE); |
fb0e7beb | 2067 | |
974271c4 | 2068 | /* |
a489a03e LJ |
2069 | * Wake up another worker if necessary. The condition is always |
2070 | * false for normal per-cpu workers since nr_running would always | |
2071 | * be >= 1 at this point. This is used to chain execution of the | |
2072 | * pending work items for WORKER_NOT_RUNNING workers such as the | |
228f1d00 | 2073 | * UNBOUND and CPU_INTENSIVE ones. |
974271c4 | 2074 | */ |
a489a03e | 2075 | if (need_more_worker(pool)) |
63d95a91 | 2076 | wake_up_worker(pool); |
974271c4 | 2077 | |
8930caba | 2078 | /* |
7c3eed5c | 2079 | * Record the last pool and clear PENDING which should be the last |
d565ed63 | 2080 | * update to @work. Also, do this inside @pool->lock so that |
23657bb1 TH |
2081 | * PENDING and queued state changes happen together while IRQ is |
2082 | * disabled. | |
8930caba | 2083 | */ |
7c3eed5c | 2084 | set_work_pool_and_clear_pending(work, pool->id); |
a62428c0 | 2085 | |
d565ed63 | 2086 | spin_unlock_irq(&pool->lock); |
a62428c0 | 2087 | |
a1d14934 | 2088 | lock_map_acquire(&pwq->wq->lockdep_map); |
a62428c0 | 2089 | lock_map_acquire(&lockdep_map); |
e6f3faa7 | 2090 | /* |
f52be570 PZ |
2091 | * Strictly speaking we should mark the invariant state without holding |
2092 | * any locks, that is, before these two lock_map_acquire()'s. | |
e6f3faa7 PZ |
2093 | * |
2094 | * However, that would result in: | |
2095 | * | |
2096 | * A(W1) | |
2097 | * WFC(C) | |
2098 | * A(W1) | |
2099 | * C(C) | |
2100 | * | |
2101 | * Which would create W1->C->W1 dependencies, even though there is no | |
2102 | * actual deadlock possible. There are two solutions, using a | |
2103 | * read-recursive acquire on the work(queue) 'locks', but this will then | |
f52be570 | 2104 | * hit the lockdep limitation on recursive locks, or simply discard |
e6f3faa7 PZ |
2105 | * these locks. |
2106 | * | |
2107 | * AFAICT there is no possible deadlock scenario between the | |
2108 | * flush_work() and complete() primitives (except for single-threaded | |
2109 | * workqueues), so hiding them isn't a problem. | |
2110 | */ | |
f52be570 | 2111 | lockdep_invariant_state(true); |
e36c886a | 2112 | trace_workqueue_execute_start(work); |
a2c1c57b | 2113 | worker->current_func(work); |
e36c886a AV |
2114 | /* |
2115 | * While we must be careful to not use "work" after this, the trace | |
2116 | * point will only record its address. | |
2117 | */ | |
2118 | trace_workqueue_execute_end(work); | |
a62428c0 | 2119 | lock_map_release(&lockdep_map); |
112202d9 | 2120 | lock_map_release(&pwq->wq->lockdep_map); |
a62428c0 TH |
2121 | |
2122 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | |
044c782c VI |
2123 | pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n" |
2124 | " last function: %pf\n", | |
a2c1c57b TH |
2125 | current->comm, preempt_count(), task_pid_nr(current), |
2126 | worker->current_func); | |
a62428c0 TH |
2127 | debug_show_held_locks(current); |
2128 | dump_stack(); | |
2129 | } | |
2130 | ||
b22ce278 TH |
2131 | /* |
2132 | * The following prevents a kworker from hogging CPU on !PREEMPT | |
2133 | * kernels, where a requeueing work item waiting for something to | |
2134 | * happen could deadlock with stop_machine as such work item could | |
2135 | * indefinitely requeue itself while all other CPUs are trapped in | |
789cbbec JL |
2136 | * stop_machine. At the same time, report a quiescent RCU state so |
2137 | * the same condition doesn't freeze RCU. | |
b22ce278 | 2138 | */ |
3e28e377 | 2139 | cond_resched_rcu_qs(); |
b22ce278 | 2140 | |
d565ed63 | 2141 | spin_lock_irq(&pool->lock); |
a62428c0 | 2142 | |
fb0e7beb TH |
2143 | /* clear cpu intensive status */ |
2144 | if (unlikely(cpu_intensive)) | |
2145 | worker_clr_flags(worker, WORKER_CPU_INTENSIVE); | |
2146 | ||
a62428c0 | 2147 | /* we're done with it, release */ |
42f8570f | 2148 | hash_del(&worker->hentry); |
c34056a3 | 2149 | worker->current_work = NULL; |
a2c1c57b | 2150 | worker->current_func = NULL; |
112202d9 | 2151 | worker->current_pwq = NULL; |
3d1cb205 | 2152 | worker->desc_valid = false; |
112202d9 | 2153 | pwq_dec_nr_in_flight(pwq, work_color); |
a62428c0 TH |
2154 | } |
2155 | ||
affee4b2 TH |
2156 | /** |
2157 | * process_scheduled_works - process scheduled works | |
2158 | * @worker: self | |
2159 | * | |
2160 | * Process all scheduled works. Please note that the scheduled list | |
2161 | * may change while processing a work, so this function repeatedly | |
2162 | * fetches a work from the top and executes it. | |
2163 | * | |
2164 | * CONTEXT: | |
d565ed63 | 2165 | * spin_lock_irq(pool->lock) which may be released and regrabbed |
affee4b2 TH |
2166 | * multiple times. |
2167 | */ | |
2168 | static void process_scheduled_works(struct worker *worker) | |
1da177e4 | 2169 | { |
affee4b2 TH |
2170 | while (!list_empty(&worker->scheduled)) { |
2171 | struct work_struct *work = list_first_entry(&worker->scheduled, | |
1da177e4 | 2172 | struct work_struct, entry); |
c34056a3 | 2173 | process_one_work(worker, work); |
1da177e4 | 2174 | } |
1da177e4 LT |
2175 | } |
2176 | ||
4690c4ab TH |
2177 | /** |
2178 | * worker_thread - the worker thread function | |
c34056a3 | 2179 | * @__worker: self |
4690c4ab | 2180 | * |
c5aa87bb TH |
2181 | * The worker thread function. All workers belong to a worker_pool - |
2182 | * either a per-cpu one or dynamic unbound one. These workers process all | |
2183 | * work items regardless of their specific target workqueue. The only | |
2184 | * exception is work items which belong to workqueues with a rescuer which | |
2185 | * will be explained in rescuer_thread(). | |
d185af30 YB |
2186 | * |
2187 | * Return: 0 | |
4690c4ab | 2188 | */ |
c34056a3 | 2189 | static int worker_thread(void *__worker) |
1da177e4 | 2190 | { |
c34056a3 | 2191 | struct worker *worker = __worker; |
bd7bdd43 | 2192 | struct worker_pool *pool = worker->pool; |
1da177e4 | 2193 | |
e22bee78 TH |
2194 | /* tell the scheduler that this is a workqueue worker */ |
2195 | worker->task->flags |= PF_WQ_WORKER; | |
c8e55f36 | 2196 | woke_up: |
d565ed63 | 2197 | spin_lock_irq(&pool->lock); |
1da177e4 | 2198 | |
a9ab775b TH |
2199 | /* am I supposed to die? */ |
2200 | if (unlikely(worker->flags & WORKER_DIE)) { | |
d565ed63 | 2201 | spin_unlock_irq(&pool->lock); |
a9ab775b TH |
2202 | WARN_ON_ONCE(!list_empty(&worker->entry)); |
2203 | worker->task->flags &= ~PF_WQ_WORKER; | |
60f5a4bc LJ |
2204 | |
2205 | set_task_comm(worker->task, "kworker/dying"); | |
7cda9aae | 2206 | ida_simple_remove(&pool->worker_ida, worker->id); |
60f5a4bc LJ |
2207 | worker_detach_from_pool(worker, pool); |
2208 | kfree(worker); | |
a9ab775b | 2209 | return 0; |
c8e55f36 | 2210 | } |
affee4b2 | 2211 | |
c8e55f36 | 2212 | worker_leave_idle(worker); |
db7bccf4 | 2213 | recheck: |
e22bee78 | 2214 | /* no more worker necessary? */ |
63d95a91 | 2215 | if (!need_more_worker(pool)) |
e22bee78 TH |
2216 | goto sleep; |
2217 | ||
2218 | /* do we need to manage? */ | |
63d95a91 | 2219 | if (unlikely(!may_start_working(pool)) && manage_workers(worker)) |
e22bee78 TH |
2220 | goto recheck; |
2221 | ||
c8e55f36 TH |
2222 | /* |
2223 | * ->scheduled list can only be filled while a worker is | |
2224 | * preparing to process a work or actually processing it. | |
2225 | * Make sure nobody diddled with it while I was sleeping. | |
2226 | */ | |
6183c009 | 2227 | WARN_ON_ONCE(!list_empty(&worker->scheduled)); |
c8e55f36 | 2228 | |
e22bee78 | 2229 | /* |
a9ab775b TH |
2230 | * Finish PREP stage. We're guaranteed to have at least one idle |
2231 | * worker or that someone else has already assumed the manager | |
2232 | * role. This is where @worker starts participating in concurrency | |
2233 | * management if applicable and concurrency management is restored | |
2234 | * after being rebound. See rebind_workers() for details. | |
e22bee78 | 2235 | */ |
a9ab775b | 2236 | worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND); |
e22bee78 TH |
2237 | |
2238 | do { | |
c8e55f36 | 2239 | struct work_struct *work = |
bd7bdd43 | 2240 | list_first_entry(&pool->worklist, |
c8e55f36 TH |
2241 | struct work_struct, entry); |
2242 | ||
82607adc TH |
2243 | pool->watchdog_ts = jiffies; |
2244 | ||
c8e55f36 TH |
2245 | if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { |
2246 | /* optimization path, not strictly necessary */ | |
2247 | process_one_work(worker, work); | |
2248 | if (unlikely(!list_empty(&worker->scheduled))) | |
affee4b2 | 2249 | process_scheduled_works(worker); |
c8e55f36 TH |
2250 | } else { |
2251 | move_linked_works(work, &worker->scheduled, NULL); | |
2252 | process_scheduled_works(worker); | |
affee4b2 | 2253 | } |
63d95a91 | 2254 | } while (keep_working(pool)); |
e22bee78 | 2255 | |
228f1d00 | 2256 | worker_set_flags(worker, WORKER_PREP); |
d313dd85 | 2257 | sleep: |
c8e55f36 | 2258 | /* |
d565ed63 TH |
2259 | * pool->lock is held and there's no work to process and no need to |
2260 | * manage, sleep. Workers are woken up only while holding | |
2261 | * pool->lock or from local cpu, so setting the current state | |
2262 | * before releasing pool->lock is enough to prevent losing any | |
2263 | * event. | |
c8e55f36 TH |
2264 | */ |
2265 | worker_enter_idle(worker); | |
c5a94a61 | 2266 | __set_current_state(TASK_IDLE); |
d565ed63 | 2267 | spin_unlock_irq(&pool->lock); |
c8e55f36 TH |
2268 | schedule(); |
2269 | goto woke_up; | |
1da177e4 LT |
2270 | } |
2271 | ||
e22bee78 TH |
2272 | /** |
2273 | * rescuer_thread - the rescuer thread function | |
111c225a | 2274 | * @__rescuer: self |
e22bee78 TH |
2275 | * |
2276 | * Workqueue rescuer thread function. There's one rescuer for each | |
493008a8 | 2277 | * workqueue which has WQ_MEM_RECLAIM set. |
e22bee78 | 2278 | * |
706026c2 | 2279 | * Regular work processing on a pool may block trying to create a new |
e22bee78 TH |
2280 | * worker which uses GFP_KERNEL allocation which has slight chance of |
2281 | * developing into deadlock if some works currently on the same queue | |
2282 | * need to be processed to satisfy the GFP_KERNEL allocation. This is | |
2283 | * the problem rescuer solves. | |
2284 | * | |
706026c2 TH |
2285 | * When such condition is possible, the pool summons rescuers of all |
2286 | * workqueues which have works queued on the pool and let them process | |
e22bee78 TH |
2287 | * those works so that forward progress can be guaranteed. |
2288 | * | |
2289 | * This should happen rarely. | |
d185af30 YB |
2290 | * |
2291 | * Return: 0 | |
e22bee78 | 2292 | */ |
111c225a | 2293 | static int rescuer_thread(void *__rescuer) |
e22bee78 | 2294 | { |
111c225a TH |
2295 | struct worker *rescuer = __rescuer; |
2296 | struct workqueue_struct *wq = rescuer->rescue_wq; | |
e22bee78 | 2297 | struct list_head *scheduled = &rescuer->scheduled; |
4d595b86 | 2298 | bool should_stop; |
e22bee78 TH |
2299 | |
2300 | set_user_nice(current, RESCUER_NICE_LEVEL); | |
111c225a TH |
2301 | |
2302 | /* | |
2303 | * Mark rescuer as worker too. As WORKER_PREP is never cleared, it | |
2304 | * doesn't participate in concurrency management. | |
2305 | */ | |
2306 | rescuer->task->flags |= PF_WQ_WORKER; | |
e22bee78 | 2307 | repeat: |
c5a94a61 | 2308 | set_current_state(TASK_IDLE); |
e22bee78 | 2309 | |
4d595b86 LJ |
2310 | /* |
2311 | * By the time the rescuer is requested to stop, the workqueue | |
2312 | * shouldn't have any work pending, but @wq->maydays may still have | |
2313 | * pwq(s) queued. This can happen by non-rescuer workers consuming | |
2314 | * all the work items before the rescuer got to them. Go through | |
2315 | * @wq->maydays processing before acting on should_stop so that the | |
2316 | * list is always empty on exit. | |
2317 | */ | |
2318 | should_stop = kthread_should_stop(); | |
e22bee78 | 2319 | |
493a1724 | 2320 | /* see whether any pwq is asking for help */ |
2e109a28 | 2321 | spin_lock_irq(&wq_mayday_lock); |
493a1724 TH |
2322 | |
2323 | while (!list_empty(&wq->maydays)) { | |
2324 | struct pool_workqueue *pwq = list_first_entry(&wq->maydays, | |
2325 | struct pool_workqueue, mayday_node); | |
112202d9 | 2326 | struct worker_pool *pool = pwq->pool; |
e22bee78 | 2327 | struct work_struct *work, *n; |
82607adc | 2328 | bool first = true; |
e22bee78 TH |
2329 | |
2330 | __set_current_state(TASK_RUNNING); | |
493a1724 TH |
2331 | list_del_init(&pwq->mayday_node); |
2332 | ||
2e109a28 | 2333 | spin_unlock_irq(&wq_mayday_lock); |
e22bee78 | 2334 | |
51697d39 LJ |
2335 | worker_attach_to_pool(rescuer, pool); |
2336 | ||
2337 | spin_lock_irq(&pool->lock); | |
b3104104 | 2338 | rescuer->pool = pool; |
e22bee78 TH |
2339 | |
2340 | /* | |
2341 | * Slurp in all works issued via this workqueue and | |
2342 | * process'em. | |
2343 | */ | |
0479c8c5 | 2344 | WARN_ON_ONCE(!list_empty(scheduled)); |
82607adc TH |
2345 | list_for_each_entry_safe(work, n, &pool->worklist, entry) { |
2346 | if (get_work_pwq(work) == pwq) { | |
2347 | if (first) | |
2348 | pool->watchdog_ts = jiffies; | |
e22bee78 | 2349 | move_linked_works(work, scheduled, &n); |
82607adc TH |
2350 | } |
2351 | first = false; | |
2352 | } | |
e22bee78 | 2353 | |
008847f6 N |
2354 | if (!list_empty(scheduled)) { |
2355 | process_scheduled_works(rescuer); | |
2356 | ||
2357 | /* | |
2358 | * The above execution of rescued work items could | |
2359 | * have created more to rescue through | |
2360 | * pwq_activate_first_delayed() or chained | |
2361 | * queueing. Let's put @pwq back on mayday list so | |
2362 | * that such back-to-back work items, which may be | |
2363 | * being used to relieve memory pressure, don't | |
2364 | * incur MAYDAY_INTERVAL delay inbetween. | |
2365 | */ | |
2366 | if (need_to_create_worker(pool)) { | |
2367 | spin_lock(&wq_mayday_lock); | |
2368 | get_pwq(pwq); | |
2369 | list_move_tail(&pwq->mayday_node, &wq->maydays); | |
2370 | spin_unlock(&wq_mayday_lock); | |
2371 | } | |
2372 | } | |
7576958a | 2373 | |
77668c8b LJ |
2374 | /* |
2375 | * Put the reference grabbed by send_mayday(). @pool won't | |
13b1d625 | 2376 | * go away while we're still attached to it. |
77668c8b LJ |
2377 | */ |
2378 | put_pwq(pwq); | |
2379 | ||
7576958a | 2380 | /* |
d8ca83e6 | 2381 | * Leave this pool. If need_more_worker() is %true, notify a |
7576958a TH |
2382 | * regular worker; otherwise, we end up with 0 concurrency |
2383 | * and stalling the execution. | |
2384 | */ | |
d8ca83e6 | 2385 | if (need_more_worker(pool)) |
63d95a91 | 2386 | wake_up_worker(pool); |
7576958a | 2387 | |
b3104104 | 2388 | rescuer->pool = NULL; |
13b1d625 LJ |
2389 | spin_unlock_irq(&pool->lock); |
2390 | ||
2391 | worker_detach_from_pool(rescuer, pool); | |
2392 | ||
2393 | spin_lock_irq(&wq_mayday_lock); | |
e22bee78 TH |
2394 | } |
2395 | ||
2e109a28 | 2396 | spin_unlock_irq(&wq_mayday_lock); |
493a1724 | 2397 | |
4d595b86 LJ |
2398 | if (should_stop) { |
2399 | __set_current_state(TASK_RUNNING); | |
2400 | rescuer->task->flags &= ~PF_WQ_WORKER; | |
2401 | return 0; | |
2402 | } | |
2403 | ||
111c225a TH |
2404 | /* rescuers should never participate in concurrency management */ |
2405 | WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING)); | |
e22bee78 TH |
2406 | schedule(); |
2407 | goto repeat; | |
1da177e4 LT |
2408 | } |
2409 | ||
fca839c0 TH |
2410 | /** |
2411 | * check_flush_dependency - check for flush dependency sanity | |
2412 | * @target_wq: workqueue being flushed | |
2413 | * @target_work: work item being flushed (NULL for workqueue flushes) | |
2414 | * | |
2415 | * %current is trying to flush the whole @target_wq or @target_work on it. | |
2416 | * If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not | |
2417 | * reclaiming memory or running on a workqueue which doesn't have | |
2418 | * %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to | |
2419 | * a deadlock. | |
2420 | */ | |
2421 | static void check_flush_dependency(struct workqueue_struct *target_wq, | |
2422 | struct work_struct *target_work) | |
2423 | { | |
2424 | work_func_t target_func = target_work ? target_work->func : NULL; | |
2425 | struct worker *worker; | |
2426 | ||
2427 | if (target_wq->flags & WQ_MEM_RECLAIM) | |
2428 | return; | |
2429 | ||
2430 | worker = current_wq_worker(); | |
2431 | ||
2432 | WARN_ONCE(current->flags & PF_MEMALLOC, | |
2433 | "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%pf", | |
2434 | current->pid, current->comm, target_wq->name, target_func); | |
23d11a58 TH |
2435 | WARN_ONCE(worker && ((worker->current_pwq->wq->flags & |
2436 | (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM), | |
fca839c0 TH |
2437 | "workqueue: WQ_MEM_RECLAIM %s:%pf is flushing !WQ_MEM_RECLAIM %s:%pf", |
2438 | worker->current_pwq->wq->name, worker->current_func, | |
2439 | target_wq->name, target_func); | |
2440 | } | |
2441 | ||
fc2e4d70 ON |
2442 | struct wq_barrier { |
2443 | struct work_struct work; | |
2444 | struct completion done; | |
2607d7a6 | 2445 | struct task_struct *task; /* purely informational */ |
fc2e4d70 ON |
2446 | }; |
2447 | ||
2448 | static void wq_barrier_func(struct work_struct *work) | |
2449 | { | |
2450 | struct wq_barrier *barr = container_of(work, struct wq_barrier, work); | |
2451 | complete(&barr->done); | |
2452 | } | |
2453 | ||
4690c4ab TH |
2454 | /** |
2455 | * insert_wq_barrier - insert a barrier work | |
112202d9 | 2456 | * @pwq: pwq to insert barrier into |
4690c4ab | 2457 | * @barr: wq_barrier to insert |
affee4b2 TH |
2458 | * @target: target work to attach @barr to |
2459 | * @worker: worker currently executing @target, NULL if @target is not executing | |
4690c4ab | 2460 | * |
affee4b2 TH |
2461 | * @barr is linked to @target such that @barr is completed only after |
2462 | * @target finishes execution. Please note that the ordering | |
2463 | * guarantee is observed only with respect to @target and on the local | |
2464 | * cpu. | |
2465 | * | |
2466 | * Currently, a queued barrier can't be canceled. This is because | |
2467 | * try_to_grab_pending() can't determine whether the work to be | |
2468 | * grabbed is at the head of the queue and thus can't clear LINKED | |
2469 | * flag of the previous work while there must be a valid next work | |
2470 | * after a work with LINKED flag set. | |
2471 | * | |
2472 | * Note that when @worker is non-NULL, @target may be modified | |
112202d9 | 2473 | * underneath us, so we can't reliably determine pwq from @target. |
4690c4ab TH |
2474 | * |
2475 | * CONTEXT: | |
d565ed63 | 2476 | * spin_lock_irq(pool->lock). |
4690c4ab | 2477 | */ |
112202d9 | 2478 | static void insert_wq_barrier(struct pool_workqueue *pwq, |
affee4b2 TH |
2479 | struct wq_barrier *barr, |
2480 | struct work_struct *target, struct worker *worker) | |
fc2e4d70 | 2481 | { |
affee4b2 TH |
2482 | struct list_head *head; |
2483 | unsigned int linked = 0; | |
2484 | ||
dc186ad7 | 2485 | /* |
d565ed63 | 2486 | * debugobject calls are safe here even with pool->lock locked |
dc186ad7 TG |
2487 | * as we know for sure that this will not trigger any of the |
2488 | * checks and call back into the fixup functions where we | |
2489 | * might deadlock. | |
2490 | */ | |
ca1cab37 | 2491 | INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); |
22df02bb | 2492 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
52fa5bc5 BF |
2493 | |
2494 | /* | |
2495 | * Explicitly init the crosslock for wq_barrier::done, make its lock | |
2496 | * key a subkey of the corresponding work. As a result we won't | |
2497 | * build a dependency between wq_barrier::done and unrelated work. | |
2498 | */ | |
2499 | lockdep_init_map_crosslock((struct lockdep_map *)&barr->done.map, | |
2500 | "(complete)wq_barr::done", | |
2501 | target->lockdep_map.key, 1); | |
2502 | __init_completion(&barr->done); | |
2607d7a6 | 2503 | barr->task = current; |
83c22520 | 2504 | |
affee4b2 TH |
2505 | /* |
2506 | * If @target is currently being executed, schedule the | |
2507 | * barrier to the worker; otherwise, put it after @target. | |
2508 | */ | |
2509 | if (worker) | |
2510 | head = worker->scheduled.next; | |
2511 | else { | |
2512 | unsigned long *bits = work_data_bits(target); | |
2513 | ||
2514 | head = target->entry.next; | |
2515 | /* there can already be other linked works, inherit and set */ | |
2516 | linked = *bits & WORK_STRUCT_LINKED; | |
2517 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); | |
2518 | } | |
2519 | ||
dc186ad7 | 2520 | debug_work_activate(&barr->work); |
112202d9 | 2521 | insert_work(pwq, &barr->work, head, |
affee4b2 | 2522 | work_color_to_flags(WORK_NO_COLOR) | linked); |
fc2e4d70 ON |
2523 | } |
2524 | ||
73f53c4a | 2525 | /** |
112202d9 | 2526 | * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing |
73f53c4a TH |
2527 | * @wq: workqueue being flushed |
2528 | * @flush_color: new flush color, < 0 for no-op | |
2529 | * @work_color: new work color, < 0 for no-op | |
2530 | * | |
112202d9 | 2531 | * Prepare pwqs for workqueue flushing. |
73f53c4a | 2532 | * |
112202d9 TH |
2533 | * If @flush_color is non-negative, flush_color on all pwqs should be |
2534 | * -1. If no pwq has in-flight commands at the specified color, all | |
2535 | * pwq->flush_color's stay at -1 and %false is returned. If any pwq | |
2536 | * has in flight commands, its pwq->flush_color is set to | |
2537 | * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq | |
73f53c4a TH |
2538 | * wakeup logic is armed and %true is returned. |
2539 | * | |
2540 | * The caller should have initialized @wq->first_flusher prior to | |
2541 | * calling this function with non-negative @flush_color. If | |
2542 | * @flush_color is negative, no flush color update is done and %false | |
2543 | * is returned. | |
2544 | * | |
112202d9 | 2545 | * If @work_color is non-negative, all pwqs should have the same |
73f53c4a TH |
2546 | * work_color which is previous to @work_color and all will be |
2547 | * advanced to @work_color. | |
2548 | * | |
2549 | * CONTEXT: | |
3c25a55d | 2550 | * mutex_lock(wq->mutex). |
73f53c4a | 2551 | * |
d185af30 | 2552 | * Return: |
73f53c4a TH |
2553 | * %true if @flush_color >= 0 and there's something to flush. %false |
2554 | * otherwise. | |
2555 | */ | |
112202d9 | 2556 | static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq, |
73f53c4a | 2557 | int flush_color, int work_color) |
1da177e4 | 2558 | { |
73f53c4a | 2559 | bool wait = false; |
49e3cf44 | 2560 | struct pool_workqueue *pwq; |
1da177e4 | 2561 | |
73f53c4a | 2562 | if (flush_color >= 0) { |
6183c009 | 2563 | WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush)); |
112202d9 | 2564 | atomic_set(&wq->nr_pwqs_to_flush, 1); |
1da177e4 | 2565 | } |
2355b70f | 2566 | |
49e3cf44 | 2567 | for_each_pwq(pwq, wq) { |
112202d9 | 2568 | struct worker_pool *pool = pwq->pool; |
fc2e4d70 | 2569 | |
b09f4fd3 | 2570 | spin_lock_irq(&pool->lock); |
83c22520 | 2571 | |
73f53c4a | 2572 | if (flush_color >= 0) { |
6183c009 | 2573 | WARN_ON_ONCE(pwq->flush_color != -1); |
fc2e4d70 | 2574 | |
112202d9 TH |
2575 | if (pwq->nr_in_flight[flush_color]) { |
2576 | pwq->flush_color = flush_color; | |
2577 | atomic_inc(&wq->nr_pwqs_to_flush); | |
73f53c4a TH |
2578 | wait = true; |
2579 | } | |
2580 | } | |
1da177e4 | 2581 | |
73f53c4a | 2582 | if (work_color >= 0) { |
6183c009 | 2583 | WARN_ON_ONCE(work_color != work_next_color(pwq->work_color)); |
112202d9 | 2584 | pwq->work_color = work_color; |
73f53c4a | 2585 | } |
1da177e4 | 2586 | |
b09f4fd3 | 2587 | spin_unlock_irq(&pool->lock); |
1da177e4 | 2588 | } |
2355b70f | 2589 | |
112202d9 | 2590 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush)) |
73f53c4a | 2591 | complete(&wq->first_flusher->done); |
14441960 | 2592 | |
73f53c4a | 2593 | return wait; |
1da177e4 LT |
2594 | } |
2595 | ||
0fcb78c2 | 2596 | /** |
1da177e4 | 2597 | * flush_workqueue - ensure that any scheduled work has run to completion. |
0fcb78c2 | 2598 | * @wq: workqueue to flush |
1da177e4 | 2599 | * |
c5aa87bb TH |
2600 | * This function sleeps until all work items which were queued on entry |
2601 | * have finished execution, but it is not livelocked by new incoming ones. | |
1da177e4 | 2602 | */ |
7ad5b3a5 | 2603 | void flush_workqueue(struct workqueue_struct *wq) |
1da177e4 | 2604 | { |
73f53c4a TH |
2605 | struct wq_flusher this_flusher = { |
2606 | .list = LIST_HEAD_INIT(this_flusher.list), | |
2607 | .flush_color = -1, | |
2608 | .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), | |
2609 | }; | |
2610 | int next_color; | |
1da177e4 | 2611 | |
3347fa09 TH |
2612 | if (WARN_ON(!wq_online)) |
2613 | return; | |
2614 | ||
3295f0ef IM |
2615 | lock_map_acquire(&wq->lockdep_map); |
2616 | lock_map_release(&wq->lockdep_map); | |
73f53c4a | 2617 | |
3c25a55d | 2618 | mutex_lock(&wq->mutex); |
73f53c4a TH |
2619 | |
2620 | /* | |
2621 | * Start-to-wait phase | |
2622 | */ | |
2623 | next_color = work_next_color(wq->work_color); | |
2624 | ||
2625 | if (next_color != wq->flush_color) { | |
2626 | /* | |
2627 | * Color space is not full. The current work_color | |
2628 | * becomes our flush_color and work_color is advanced | |
2629 | * by one. | |
2630 | */ | |
6183c009 | 2631 | WARN_ON_ONCE(!list_empty(&wq->flusher_overflow)); |
73f53c4a TH |
2632 | this_flusher.flush_color = wq->work_color; |
2633 | wq->work_color = next_color; | |
2634 | ||
2635 | if (!wq->first_flusher) { | |
2636 | /* no flush in progress, become the first flusher */ | |
6183c009 | 2637 | WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); |
73f53c4a TH |
2638 | |
2639 | wq->first_flusher = &this_flusher; | |
2640 | ||
112202d9 | 2641 | if (!flush_workqueue_prep_pwqs(wq, wq->flush_color, |
73f53c4a TH |
2642 | wq->work_color)) { |
2643 | /* nothing to flush, done */ | |
2644 | wq->flush_color = next_color; | |
2645 | wq->first_flusher = NULL; | |
2646 | goto out_unlock; | |
2647 | } | |
2648 | } else { | |
2649 | /* wait in queue */ | |
6183c009 | 2650 | WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color); |
73f53c4a | 2651 | list_add_tail(&this_flusher.list, &wq->flusher_queue); |
112202d9 | 2652 | flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
73f53c4a TH |
2653 | } |
2654 | } else { | |
2655 | /* | |
2656 | * Oops, color space is full, wait on overflow queue. | |
2657 | * The next flush completion will assign us | |
2658 | * flush_color and transfer to flusher_queue. | |
2659 | */ | |
2660 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | |
2661 | } | |
2662 | ||
fca839c0 TH |
2663 | check_flush_dependency(wq, NULL); |
2664 | ||
3c25a55d | 2665 | mutex_unlock(&wq->mutex); |
73f53c4a TH |
2666 | |
2667 | wait_for_completion(&this_flusher.done); | |
2668 | ||
2669 | /* | |
2670 | * Wake-up-and-cascade phase | |
2671 | * | |
2672 | * First flushers are responsible for cascading flushes and | |
2673 | * handling overflow. Non-first flushers can simply return. | |
2674 | */ | |
2675 | if (wq->first_flusher != &this_flusher) | |
2676 | return; | |
2677 | ||
3c25a55d | 2678 | mutex_lock(&wq->mutex); |
73f53c4a | 2679 | |
4ce48b37 TH |
2680 | /* we might have raced, check again with mutex held */ |
2681 | if (wq->first_flusher != &this_flusher) | |
2682 | goto out_unlock; | |
2683 | ||
73f53c4a TH |
2684 | wq->first_flusher = NULL; |
2685 | ||
6183c009 TH |
2686 | WARN_ON_ONCE(!list_empty(&this_flusher.list)); |
2687 | WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color); | |
73f53c4a TH |
2688 | |
2689 | while (true) { | |
2690 | struct wq_flusher *next, *tmp; | |
2691 | ||
2692 | /* complete all the flushers sharing the current flush color */ | |
2693 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | |
2694 | if (next->flush_color != wq->flush_color) | |
2695 | break; | |
2696 | list_del_init(&next->list); | |
2697 | complete(&next->done); | |
2698 | } | |
2699 | ||
6183c009 TH |
2700 | WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) && |
2701 | wq->flush_color != work_next_color(wq->work_color)); | |
73f53c4a TH |
2702 | |
2703 | /* this flush_color is finished, advance by one */ | |
2704 | wq->flush_color = work_next_color(wq->flush_color); | |
2705 | ||
2706 | /* one color has been freed, handle overflow queue */ | |
2707 | if (!list_empty(&wq->flusher_overflow)) { | |
2708 | /* | |
2709 | * Assign the same color to all overflowed | |
2710 | * flushers, advance work_color and append to | |
2711 | * flusher_queue. This is the start-to-wait | |
2712 | * phase for these overflowed flushers. | |
2713 | */ | |
2714 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | |
2715 | tmp->flush_color = wq->work_color; | |
2716 | ||
2717 | wq->work_color = work_next_color(wq->work_color); | |
2718 | ||
2719 | list_splice_tail_init(&wq->flusher_overflow, | |
2720 | &wq->flusher_queue); | |
112202d9 | 2721 | flush_workqueue_prep_pwqs(wq, -1, wq->work_color); |
73f53c4a TH |
2722 | } |
2723 | ||
2724 | if (list_empty(&wq->flusher_queue)) { | |
6183c009 | 2725 | WARN_ON_ONCE(wq->flush_color != wq->work_color); |
73f53c4a TH |
2726 | break; |
2727 | } | |
2728 | ||
2729 | /* | |
2730 | * Need to flush more colors. Make the next flusher | |
112202d9 | 2731 | * the new first flusher and arm pwqs. |
73f53c4a | 2732 | */ |
6183c009 TH |
2733 | WARN_ON_ONCE(wq->flush_color == wq->work_color); |
2734 | WARN_ON_ONCE(wq->flush_color != next->flush_color); | |
73f53c4a TH |
2735 | |
2736 | list_del_init(&next->list); | |
2737 | wq->first_flusher = next; | |
2738 | ||
112202d9 | 2739 | if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1)) |
73f53c4a TH |
2740 | break; |
2741 | ||
2742 | /* | |
2743 | * Meh... this color is already done, clear first | |
2744 | * flusher and repeat cascading. | |
2745 | */ | |
2746 | wq->first_flusher = NULL; | |
2747 | } | |
2748 | ||
2749 | out_unlock: | |
3c25a55d | 2750 | mutex_unlock(&wq->mutex); |
1da177e4 | 2751 | } |
1dadafa8 | 2752 | EXPORT_SYMBOL(flush_workqueue); |
1da177e4 | 2753 | |
9c5a2ba7 TH |
2754 | /** |
2755 | * drain_workqueue - drain a workqueue | |
2756 | * @wq: workqueue to drain | |
2757 | * | |
2758 | * Wait until the workqueue becomes empty. While draining is in progress, | |
2759 | * only chain queueing is allowed. IOW, only currently pending or running | |
2760 | * work items on @wq can queue further work items on it. @wq is flushed | |
b749b1b6 | 2761 | * repeatedly until it becomes empty. The number of flushing is determined |
9c5a2ba7 TH |
2762 | * by the depth of chaining and should be relatively short. Whine if it |
2763 | * takes too long. | |
2764 | */ | |
2765 | void drain_workqueue(struct workqueue_struct *wq) | |
2766 | { | |
2767 | unsigned int flush_cnt = 0; | |
49e3cf44 | 2768 | struct pool_workqueue *pwq; |
9c5a2ba7 TH |
2769 | |
2770 | /* | |
2771 | * __queue_work() needs to test whether there are drainers, is much | |
2772 | * hotter than drain_workqueue() and already looks at @wq->flags. | |
618b01eb | 2773 | * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers. |
9c5a2ba7 | 2774 | */ |
87fc741e | 2775 | mutex_lock(&wq->mutex); |
9c5a2ba7 | 2776 | if (!wq->nr_drainers++) |
618b01eb | 2777 | wq->flags |= __WQ_DRAINING; |
87fc741e | 2778 | mutex_unlock(&wq->mutex); |
9c5a2ba7 TH |
2779 | reflush: |
2780 | flush_workqueue(wq); | |
2781 | ||
b09f4fd3 | 2782 | mutex_lock(&wq->mutex); |
76af4d93 | 2783 | |
49e3cf44 | 2784 | for_each_pwq(pwq, wq) { |
fa2563e4 | 2785 | bool drained; |
9c5a2ba7 | 2786 | |
b09f4fd3 | 2787 | spin_lock_irq(&pwq->pool->lock); |
112202d9 | 2788 | drained = !pwq->nr_active && list_empty(&pwq->delayed_works); |
b09f4fd3 | 2789 | spin_unlock_irq(&pwq->pool->lock); |
fa2563e4 TT |
2790 | |
2791 | if (drained) | |
9c5a2ba7 TH |
2792 | continue; |
2793 | ||
2794 | if (++flush_cnt == 10 || | |
2795 | (flush_cnt % 100 == 0 && flush_cnt <= 1000)) | |
c5aa87bb | 2796 | pr_warn("workqueue %s: drain_workqueue() isn't complete after %u tries\n", |
044c782c | 2797 | wq->name, flush_cnt); |
76af4d93 | 2798 | |
b09f4fd3 | 2799 | mutex_unlock(&wq->mutex); |
9c5a2ba7 TH |
2800 | goto reflush; |
2801 | } | |
2802 | ||
9c5a2ba7 | 2803 | if (!--wq->nr_drainers) |
618b01eb | 2804 | wq->flags &= ~__WQ_DRAINING; |
87fc741e | 2805 | mutex_unlock(&wq->mutex); |
9c5a2ba7 TH |
2806 | } |
2807 | EXPORT_SYMBOL_GPL(drain_workqueue); | |
2808 | ||
606a5020 | 2809 | static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) |
db700897 | 2810 | { |
affee4b2 | 2811 | struct worker *worker = NULL; |
c9e7cf27 | 2812 | struct worker_pool *pool; |
112202d9 | 2813 | struct pool_workqueue *pwq; |
db700897 ON |
2814 | |
2815 | might_sleep(); | |
fa1b54e6 TH |
2816 | |
2817 | local_irq_disable(); | |
c9e7cf27 | 2818 | pool = get_work_pool(work); |
fa1b54e6 TH |
2819 | if (!pool) { |
2820 | local_irq_enable(); | |
baf59022 | 2821 | return false; |
fa1b54e6 | 2822 | } |
db700897 | 2823 | |
fa1b54e6 | 2824 | spin_lock(&pool->lock); |
0b3dae68 | 2825 | /* see the comment in try_to_grab_pending() with the same code */ |
112202d9 TH |
2826 | pwq = get_work_pwq(work); |
2827 | if (pwq) { | |
2828 | if (unlikely(pwq->pool != pool)) | |
4690c4ab | 2829 | goto already_gone; |
606a5020 | 2830 | } else { |
c9e7cf27 | 2831 | worker = find_worker_executing_work(pool, work); |
affee4b2 | 2832 | if (!worker) |
4690c4ab | 2833 | goto already_gone; |
112202d9 | 2834 | pwq = worker->current_pwq; |
606a5020 | 2835 | } |
db700897 | 2836 | |
fca839c0 TH |
2837 | check_flush_dependency(pwq->wq, work); |
2838 | ||
112202d9 | 2839 | insert_wq_barrier(pwq, barr, work, worker); |
d565ed63 | 2840 | spin_unlock_irq(&pool->lock); |
7a22ad75 | 2841 | |
e159489b | 2842 | /* |
a1d14934 PZ |
2843 | * Force a lock recursion deadlock when using flush_work() inside a |
2844 | * single-threaded or rescuer equipped workqueue. | |
2845 | * | |
2846 | * For single threaded workqueues the deadlock happens when the work | |
2847 | * is after the work issuing the flush_work(). For rescuer equipped | |
2848 | * workqueues the deadlock happens when the rescuer stalls, blocking | |
2849 | * forward progress. | |
e159489b | 2850 | */ |
a1d14934 | 2851 | if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) { |
112202d9 | 2852 | lock_map_acquire(&pwq->wq->lockdep_map); |
a1d14934 PZ |
2853 | lock_map_release(&pwq->wq->lockdep_map); |
2854 | } | |
e159489b | 2855 | |
401a8d04 | 2856 | return true; |
4690c4ab | 2857 | already_gone: |
d565ed63 | 2858 | spin_unlock_irq(&pool->lock); |
401a8d04 | 2859 | return false; |
db700897 | 2860 | } |
baf59022 TH |
2861 | |
2862 | /** | |
2863 | * flush_work - wait for a work to finish executing the last queueing instance | |
2864 | * @work: the work to flush | |
2865 | * | |
606a5020 TH |
2866 | * Wait until @work has finished execution. @work is guaranteed to be idle |
2867 | * on return if it hasn't been requeued since flush started. | |
baf59022 | 2868 | * |
d185af30 | 2869 | * Return: |
baf59022 TH |
2870 | * %true if flush_work() waited for the work to finish execution, |
2871 | * %false if it was already idle. | |
2872 | */ | |
2873 | bool flush_work(struct work_struct *work) | |
2874 | { | |
12997d1a BH |
2875 | struct wq_barrier barr; |
2876 | ||
3347fa09 TH |
2877 | if (WARN_ON(!wq_online)) |
2878 | return false; | |
2879 | ||
0976dfc1 SB |
2880 | lock_map_acquire(&work->lockdep_map); |
2881 | lock_map_release(&work->lockdep_map); | |
2882 | ||
12997d1a BH |
2883 | if (start_flush_work(work, &barr)) { |
2884 | wait_for_completion(&barr.done); | |
2885 | destroy_work_on_stack(&barr.work); | |
2886 | return true; | |
2887 | } else { | |
2888 | return false; | |
2889 | } | |
6e84d644 | 2890 | } |
606a5020 | 2891 | EXPORT_SYMBOL_GPL(flush_work); |
6e84d644 | 2892 | |
8603e1b3 | 2893 | struct cwt_wait { |
ac6424b9 | 2894 | wait_queue_entry_t wait; |
8603e1b3 TH |
2895 | struct work_struct *work; |
2896 | }; | |
2897 | ||
ac6424b9 | 2898 | static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
8603e1b3 TH |
2899 | { |
2900 | struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait); | |
2901 | ||
2902 | if (cwait->work != key) | |
2903 | return 0; | |
2904 | return autoremove_wake_function(wait, mode, sync, key); | |
2905 | } | |
2906 | ||
36e227d2 | 2907 | static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) |
1f1f642e | 2908 | { |
8603e1b3 | 2909 | static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq); |
bbb68dfa | 2910 | unsigned long flags; |
1f1f642e ON |
2911 | int ret; |
2912 | ||
2913 | do { | |
bbb68dfa TH |
2914 | ret = try_to_grab_pending(work, is_dwork, &flags); |
2915 | /* | |
8603e1b3 TH |
2916 | * If someone else is already canceling, wait for it to |
2917 | * finish. flush_work() doesn't work for PREEMPT_NONE | |
2918 | * because we may get scheduled between @work's completion | |
2919 | * and the other canceling task resuming and clearing | |
2920 | * CANCELING - flush_work() will return false immediately | |
2921 | * as @work is no longer busy, try_to_grab_pending() will | |
2922 | * return -ENOENT as @work is still being canceled and the | |
2923 | * other canceling task won't be able to clear CANCELING as | |
2924 | * we're hogging the CPU. | |
2925 | * | |
2926 | * Let's wait for completion using a waitqueue. As this | |
2927 | * may lead to the thundering herd problem, use a custom | |
2928 | * wake function which matches @work along with exclusive | |
2929 | * wait and wakeup. | |
bbb68dfa | 2930 | */ |
8603e1b3 TH |
2931 | if (unlikely(ret == -ENOENT)) { |
2932 | struct cwt_wait cwait; | |
2933 | ||
2934 | init_wait(&cwait.wait); | |
2935 | cwait.wait.func = cwt_wakefn; | |
2936 | cwait.work = work; | |
2937 | ||
2938 | prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait, | |
2939 | TASK_UNINTERRUPTIBLE); | |
2940 | if (work_is_canceling(work)) | |
2941 | schedule(); | |
2942 | finish_wait(&cancel_waitq, &cwait.wait); | |
2943 | } | |
1f1f642e ON |
2944 | } while (unlikely(ret < 0)); |
2945 | ||
bbb68dfa TH |
2946 | /* tell other tasks trying to grab @work to back off */ |
2947 | mark_work_canceling(work); | |
2948 | local_irq_restore(flags); | |
2949 | ||
3347fa09 TH |
2950 | /* |
2951 | * This allows canceling during early boot. We know that @work | |
2952 | * isn't executing. | |
2953 | */ | |
2954 | if (wq_online) | |
2955 | flush_work(work); | |
2956 | ||
7a22ad75 | 2957 | clear_work_data(work); |
8603e1b3 TH |
2958 | |
2959 | /* | |
2960 | * Paired with prepare_to_wait() above so that either | |
2961 | * waitqueue_active() is visible here or !work_is_canceling() is | |
2962 | * visible there. | |
2963 | */ | |
2964 | smp_mb(); | |
2965 | if (waitqueue_active(&cancel_waitq)) | |
2966 | __wake_up(&cancel_waitq, TASK_NORMAL, 1, work); | |
2967 | ||
1f1f642e ON |
2968 | return ret; |
2969 | } | |
2970 | ||
6e84d644 | 2971 | /** |
401a8d04 TH |
2972 | * cancel_work_sync - cancel a work and wait for it to finish |
2973 | * @work: the work to cancel | |
6e84d644 | 2974 | * |
401a8d04 TH |
2975 | * Cancel @work and wait for its execution to finish. This function |
2976 | * can be used even if the work re-queues itself or migrates to | |
2977 | * another workqueue. On return from this function, @work is | |
2978 | * guaranteed to be not pending or executing on any CPU. | |
1f1f642e | 2979 | * |
401a8d04 TH |
2980 | * cancel_work_sync(&delayed_work->work) must not be used for |
2981 | * delayed_work's. Use cancel_delayed_work_sync() instead. | |
6e84d644 | 2982 | * |
401a8d04 | 2983 | * The caller must ensure that the workqueue on which @work was last |
6e84d644 | 2984 | * queued can't be destroyed before this function returns. |
401a8d04 | 2985 | * |
d185af30 | 2986 | * Return: |
401a8d04 | 2987 | * %true if @work was pending, %false otherwise. |
6e84d644 | 2988 | */ |
401a8d04 | 2989 | bool cancel_work_sync(struct work_struct *work) |
6e84d644 | 2990 | { |
36e227d2 | 2991 | return __cancel_work_timer(work, false); |
b89deed3 | 2992 | } |
28e53bdd | 2993 | EXPORT_SYMBOL_GPL(cancel_work_sync); |
b89deed3 | 2994 | |
6e84d644 | 2995 | /** |
401a8d04 TH |
2996 | * flush_delayed_work - wait for a dwork to finish executing the last queueing |
2997 | * @dwork: the delayed work to flush | |
6e84d644 | 2998 | * |
401a8d04 TH |
2999 | * Delayed timer is cancelled and the pending work is queued for |
3000 | * immediate execution. Like flush_work(), this function only | |
3001 | * considers the last queueing instance of @dwork. | |
1f1f642e | 3002 | * |
d185af30 | 3003 | * Return: |
401a8d04 TH |
3004 | * %true if flush_work() waited for the work to finish execution, |
3005 | * %false if it was already idle. | |
6e84d644 | 3006 | */ |
401a8d04 TH |
3007 | bool flush_delayed_work(struct delayed_work *dwork) |
3008 | { | |
8930caba | 3009 | local_irq_disable(); |
401a8d04 | 3010 | if (del_timer_sync(&dwork->timer)) |
60c057bc | 3011 | __queue_work(dwork->cpu, dwork->wq, &dwork->work); |
8930caba | 3012 | local_irq_enable(); |
401a8d04 TH |
3013 | return flush_work(&dwork->work); |
3014 | } | |
3015 | EXPORT_SYMBOL(flush_delayed_work); | |
3016 | ||
f72b8792 JA |
3017 | static bool __cancel_work(struct work_struct *work, bool is_dwork) |
3018 | { | |
3019 | unsigned long flags; | |
3020 | int ret; | |
3021 | ||
3022 | do { | |
3023 | ret = try_to_grab_pending(work, is_dwork, &flags); | |
3024 | } while (unlikely(ret == -EAGAIN)); | |
3025 | ||
3026 | if (unlikely(ret < 0)) | |
3027 | return false; | |
3028 | ||
3029 | set_work_pool_and_clear_pending(work, get_work_pool_id(work)); | |
3030 | local_irq_restore(flags); | |
3031 | return ret; | |
3032 | } | |
3033 | ||
3034 | /* | |
3035 | * See cancel_delayed_work() | |
3036 | */ | |
3037 | bool cancel_work(struct work_struct *work) | |
3038 | { | |
3039 | return __cancel_work(work, false); | |
3040 | } | |
3041 | ||
09383498 | 3042 | /** |
57b30ae7 TH |
3043 | * cancel_delayed_work - cancel a delayed work |
3044 | * @dwork: delayed_work to cancel | |
09383498 | 3045 | * |
d185af30 YB |
3046 | * Kill off a pending delayed_work. |
3047 | * | |
3048 | * Return: %true if @dwork was pending and canceled; %false if it wasn't | |
3049 | * pending. | |
3050 | * | |
3051 | * Note: | |
3052 | * The work callback function may still be running on return, unless | |
3053 | * it returns %true and the work doesn't re-arm itself. Explicitly flush or | |
3054 | * use cancel_delayed_work_sync() to wait on it. | |
09383498 | 3055 | * |
57b30ae7 | 3056 | * This function is safe to call from any context including IRQ handler. |
09383498 | 3057 | */ |
57b30ae7 | 3058 | bool cancel_delayed_work(struct delayed_work *dwork) |
09383498 | 3059 | { |
f72b8792 | 3060 | return __cancel_work(&dwork->work, true); |
09383498 | 3061 | } |
57b30ae7 | 3062 | EXPORT_SYMBOL(cancel_delayed_work); |
09383498 | 3063 | |
401a8d04 TH |
3064 | /** |
3065 | * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish | |
3066 | * @dwork: the delayed work cancel | |
3067 | * | |
3068 | * This is cancel_work_sync() for delayed works. | |
3069 | * | |
d185af30 | 3070 | * Return: |
401a8d04 TH |
3071 | * %true if @dwork was pending, %false otherwise. |
3072 | */ | |
3073 | bool cancel_delayed_work_sync(struct delayed_work *dwork) | |
6e84d644 | 3074 | { |
36e227d2 | 3075 | return __cancel_work_timer(&dwork->work, true); |
6e84d644 | 3076 | } |
f5a421a4 | 3077 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
1da177e4 | 3078 | |
b6136773 | 3079 | /** |
31ddd871 | 3080 | * schedule_on_each_cpu - execute a function synchronously on each online CPU |
b6136773 | 3081 | * @func: the function to call |
b6136773 | 3082 | * |
31ddd871 TH |
3083 | * schedule_on_each_cpu() executes @func on each online CPU using the |
3084 | * system workqueue and blocks until all CPUs have completed. | |
b6136773 | 3085 | * schedule_on_each_cpu() is very slow. |
31ddd871 | 3086 | * |
d185af30 | 3087 | * Return: |
31ddd871 | 3088 | * 0 on success, -errno on failure. |
b6136773 | 3089 | */ |
65f27f38 | 3090 | int schedule_on_each_cpu(work_func_t func) |
15316ba8 CL |
3091 | { |
3092 | int cpu; | |
38f51568 | 3093 | struct work_struct __percpu *works; |
15316ba8 | 3094 | |
b6136773 AM |
3095 | works = alloc_percpu(struct work_struct); |
3096 | if (!works) | |
15316ba8 | 3097 | return -ENOMEM; |
b6136773 | 3098 | |
93981800 TH |
3099 | get_online_cpus(); |
3100 | ||
15316ba8 | 3101 | for_each_online_cpu(cpu) { |
9bfb1839 IM |
3102 | struct work_struct *work = per_cpu_ptr(works, cpu); |
3103 | ||
3104 | INIT_WORK(work, func); | |
b71ab8c2 | 3105 | schedule_work_on(cpu, work); |
65a64464 | 3106 | } |
93981800 TH |
3107 | |
3108 | for_each_online_cpu(cpu) | |
3109 | flush_work(per_cpu_ptr(works, cpu)); | |
3110 | ||
95402b38 | 3111 | put_online_cpus(); |
b6136773 | 3112 | free_percpu(works); |
15316ba8 CL |
3113 | return 0; |
3114 | } | |
3115 | ||
1fa44eca JB |
3116 | /** |
3117 | * execute_in_process_context - reliably execute the routine with user context | |
3118 | * @fn: the function to execute | |
1fa44eca JB |
3119 | * @ew: guaranteed storage for the execute work structure (must |
3120 | * be available when the work executes) | |
3121 | * | |
3122 | * Executes the function immediately if process context is available, | |
3123 | * otherwise schedules the function for delayed execution. | |
3124 | * | |
d185af30 | 3125 | * Return: 0 - function was executed |
1fa44eca JB |
3126 | * 1 - function was scheduled for execution |
3127 | */ | |
65f27f38 | 3128 | int execute_in_process_context(work_func_t fn, struct execute_work *ew) |
1fa44eca JB |
3129 | { |
3130 | if (!in_interrupt()) { | |
65f27f38 | 3131 | fn(&ew->work); |
1fa44eca JB |
3132 | return 0; |
3133 | } | |
3134 | ||
65f27f38 | 3135 | INIT_WORK(&ew->work, fn); |
1fa44eca JB |
3136 | schedule_work(&ew->work); |
3137 | ||
3138 | return 1; | |
3139 | } | |
3140 | EXPORT_SYMBOL_GPL(execute_in_process_context); | |
3141 | ||
6ba94429 FW |
3142 | /** |
3143 | * free_workqueue_attrs - free a workqueue_attrs | |
3144 | * @attrs: workqueue_attrs to free | |
226223ab | 3145 | * |
6ba94429 | 3146 | * Undo alloc_workqueue_attrs(). |
226223ab | 3147 | */ |
6ba94429 | 3148 | void free_workqueue_attrs(struct workqueue_attrs *attrs) |
226223ab | 3149 | { |
6ba94429 FW |
3150 | if (attrs) { |
3151 | free_cpumask_var(attrs->cpumask); | |
3152 | kfree(attrs); | |
3153 | } | |
226223ab TH |
3154 | } |
3155 | ||
6ba94429 FW |
3156 | /** |
3157 | * alloc_workqueue_attrs - allocate a workqueue_attrs | |
3158 | * @gfp_mask: allocation mask to use | |
3159 | * | |
3160 | * Allocate a new workqueue_attrs, initialize with default settings and | |
3161 | * return it. | |
3162 | * | |
3163 | * Return: The allocated new workqueue_attr on success. %NULL on failure. | |
3164 | */ | |
3165 | struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask) | |
226223ab | 3166 | { |
6ba94429 | 3167 | struct workqueue_attrs *attrs; |
226223ab | 3168 | |
6ba94429 FW |
3169 | attrs = kzalloc(sizeof(*attrs), gfp_mask); |
3170 | if (!attrs) | |
3171 | goto fail; | |
3172 | if (!alloc_cpumask_var(&attrs->cpumask, gfp_mask)) | |
3173 | goto fail; | |
3174 | ||
3175 | cpumask_copy(attrs->cpumask, cpu_possible_mask); | |
3176 | return attrs; | |
3177 | fail: | |
3178 | free_workqueue_attrs(attrs); | |
3179 | return NULL; | |
226223ab TH |
3180 | } |
3181 | ||
6ba94429 FW |
3182 | static void copy_workqueue_attrs(struct workqueue_attrs *to, |
3183 | const struct workqueue_attrs *from) | |
226223ab | 3184 | { |
6ba94429 FW |
3185 | to->nice = from->nice; |
3186 | cpumask_copy(to->cpumask, from->cpumask); | |
3187 | /* | |
3188 | * Unlike hash and equality test, this function doesn't ignore | |
3189 | * ->no_numa as it is used for both pool and wq attrs. Instead, | |
3190 | * get_unbound_pool() explicitly clears ->no_numa after copying. | |
3191 | */ | |
3192 | to->no_numa = from->no_numa; | |
226223ab TH |
3193 | } |
3194 | ||
6ba94429 FW |
3195 | /* hash value of the content of @attr */ |
3196 | static u32 wqattrs_hash(const struct workqueue_attrs *attrs) | |
226223ab | 3197 | { |
6ba94429 | 3198 | u32 hash = 0; |
226223ab | 3199 | |
6ba94429 FW |
3200 | hash = jhash_1word(attrs->nice, hash); |
3201 | hash = jhash(cpumask_bits(attrs->cpumask), | |
3202 | BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash); | |
3203 | return hash; | |
226223ab | 3204 | } |
226223ab | 3205 | |
6ba94429 FW |
3206 | /* content equality test */ |
3207 | static bool wqattrs_equal(const struct workqueue_attrs *a, | |
3208 | const struct workqueue_attrs *b) | |
226223ab | 3209 | { |
6ba94429 FW |
3210 | if (a->nice != b->nice) |
3211 | return false; | |
3212 | if (!cpumask_equal(a->cpumask, b->cpumask)) | |
3213 | return false; | |
3214 | return true; | |
226223ab TH |
3215 | } |
3216 | ||
6ba94429 FW |
3217 | /** |
3218 | * init_worker_pool - initialize a newly zalloc'd worker_pool | |
3219 | * @pool: worker_pool to initialize | |
3220 | * | |
402dd89d | 3221 | * Initialize a newly zalloc'd @pool. It also allocates @pool->attrs. |
6ba94429 FW |
3222 | * |
3223 | * Return: 0 on success, -errno on failure. Even on failure, all fields | |
3224 | * inside @pool proper are initialized and put_unbound_pool() can be called | |
3225 | * on @pool safely to release it. | |
3226 | */ | |
3227 | static int init_worker_pool(struct worker_pool *pool) | |
226223ab | 3228 | { |
6ba94429 FW |
3229 | spin_lock_init(&pool->lock); |
3230 | pool->id = -1; | |
3231 | pool->cpu = -1; | |
3232 | pool->node = NUMA_NO_NODE; | |
3233 | pool->flags |= POOL_DISASSOCIATED; | |
82607adc | 3234 | pool->watchdog_ts = jiffies; |
6ba94429 FW |
3235 | INIT_LIST_HEAD(&pool->worklist); |
3236 | INIT_LIST_HEAD(&pool->idle_list); | |
3237 | hash_init(pool->busy_hash); | |
226223ab | 3238 | |
c30fb26b GT |
3239 | setup_deferrable_timer(&pool->idle_timer, idle_worker_timeout, |
3240 | (unsigned long)pool); | |
226223ab | 3241 | |
6ba94429 FW |
3242 | setup_timer(&pool->mayday_timer, pool_mayday_timeout, |
3243 | (unsigned long)pool); | |
226223ab | 3244 | |
6ba94429 FW |
3245 | mutex_init(&pool->attach_mutex); |
3246 | INIT_LIST_HEAD(&pool->workers); | |
226223ab | 3247 | |
6ba94429 FW |
3248 | ida_init(&pool->worker_ida); |
3249 | INIT_HLIST_NODE(&pool->hash_node); | |
3250 | pool->refcnt = 1; | |
226223ab | 3251 | |
6ba94429 FW |
3252 | /* shouldn't fail above this point */ |
3253 | pool->attrs = alloc_workqueue_attrs(GFP_KERNEL); | |
3254 | if (!pool->attrs) | |
3255 | return -ENOMEM; | |
3256 | return 0; | |
226223ab TH |
3257 | } |
3258 | ||
6ba94429 | 3259 | static void rcu_free_wq(struct rcu_head *rcu) |
226223ab | 3260 | { |
6ba94429 FW |
3261 | struct workqueue_struct *wq = |
3262 | container_of(rcu, struct workqueue_struct, rcu); | |
226223ab | 3263 | |
6ba94429 FW |
3264 | if (!(wq->flags & WQ_UNBOUND)) |
3265 | free_percpu(wq->cpu_pwqs); | |
226223ab | 3266 | else |
6ba94429 | 3267 | free_workqueue_attrs(wq->unbound_attrs); |
226223ab | 3268 | |
6ba94429 FW |
3269 | kfree(wq->rescuer); |
3270 | kfree(wq); | |
226223ab TH |
3271 | } |
3272 | ||
6ba94429 | 3273 | static void rcu_free_pool(struct rcu_head *rcu) |
226223ab | 3274 | { |
6ba94429 | 3275 | struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu); |
226223ab | 3276 | |
6ba94429 FW |
3277 | ida_destroy(&pool->worker_ida); |
3278 | free_workqueue_attrs(pool->attrs); | |
3279 | kfree(pool); | |
226223ab TH |
3280 | } |
3281 | ||
6ba94429 FW |
3282 | /** |
3283 | * put_unbound_pool - put a worker_pool | |
3284 | * @pool: worker_pool to put | |
3285 | * | |
3286 | * Put @pool. If its refcnt reaches zero, it gets destroyed in sched-RCU | |
3287 | * safe manner. get_unbound_pool() calls this function on its failure path | |
3288 | * and this function should be able to release pools which went through, | |
3289 | * successfully or not, init_worker_pool(). | |
3290 | * | |
3291 | * Should be called with wq_pool_mutex held. | |
3292 | */ | |
3293 | static void put_unbound_pool(struct worker_pool *pool) | |
226223ab | 3294 | { |
6ba94429 FW |
3295 | DECLARE_COMPLETION_ONSTACK(detach_completion); |
3296 | struct worker *worker; | |
226223ab | 3297 | |
6ba94429 | 3298 | lockdep_assert_held(&wq_pool_mutex); |
226223ab | 3299 | |
6ba94429 FW |
3300 | if (--pool->refcnt) |
3301 | return; | |
226223ab | 3302 | |
6ba94429 FW |
3303 | /* sanity checks */ |
3304 | if (WARN_ON(!(pool->cpu < 0)) || | |
3305 | WARN_ON(!list_empty(&pool->worklist))) | |
3306 | return; | |
226223ab | 3307 | |
6ba94429 FW |
3308 | /* release id and unhash */ |
3309 | if (pool->id >= 0) | |
3310 | idr_remove(&worker_pool_idr, pool->id); | |
3311 | hash_del(&pool->hash_node); | |
d55262c4 | 3312 | |
6ba94429 | 3313 | /* |
692b4825 TH |
3314 | * Become the manager and destroy all workers. This prevents |
3315 | * @pool's workers from blocking on attach_mutex. We're the last | |
3316 | * manager and @pool gets freed with the flag set. | |
6ba94429 | 3317 | */ |
6ba94429 | 3318 | spin_lock_irq(&pool->lock); |
692b4825 TH |
3319 | wait_event_lock_irq(wq_manager_wait, |
3320 | !(pool->flags & POOL_MANAGER_ACTIVE), pool->lock); | |
3321 | pool->flags |= POOL_MANAGER_ACTIVE; | |
3322 | ||
6ba94429 FW |
3323 | while ((worker = first_idle_worker(pool))) |
3324 | destroy_worker(worker); | |
3325 | WARN_ON(pool->nr_workers || pool->nr_idle); | |
3326 | spin_unlock_irq(&pool->lock); | |
d55262c4 | 3327 | |
6ba94429 FW |
3328 | mutex_lock(&pool->attach_mutex); |
3329 | if (!list_empty(&pool->workers)) | |
3330 | pool->detach_completion = &detach_completion; | |
3331 | mutex_unlock(&pool->attach_mutex); | |
226223ab | 3332 | |
6ba94429 FW |
3333 | if (pool->detach_completion) |
3334 | wait_for_completion(pool->detach_completion); | |
226223ab | 3335 | |
6ba94429 FW |
3336 | /* shut down the timers */ |
3337 | del_timer_sync(&pool->idle_timer); | |
3338 | del_timer_sync(&pool->mayday_timer); | |
226223ab | 3339 | |
6ba94429 FW |
3340 | /* sched-RCU protected to allow dereferences from get_work_pool() */ |
3341 | call_rcu_sched(&pool->rcu, rcu_free_pool); | |
226223ab TH |
3342 | } |
3343 | ||
3344 | /** | |
6ba94429 FW |
3345 | * get_unbound_pool - get a worker_pool with the specified attributes |
3346 | * @attrs: the attributes of the worker_pool to get | |
226223ab | 3347 | * |
6ba94429 FW |
3348 | * Obtain a worker_pool which has the same attributes as @attrs, bump the |
3349 | * reference count and return it. If there already is a matching | |
3350 | * worker_pool, it will be used; otherwise, this function attempts to | |
3351 | * create a new one. | |
226223ab | 3352 | * |
6ba94429 | 3353 | * Should be called with wq_pool_mutex held. |
226223ab | 3354 | * |
6ba94429 FW |
3355 | * Return: On success, a worker_pool with the same attributes as @attrs. |
3356 | * On failure, %NULL. | |
226223ab | 3357 | */ |
6ba94429 | 3358 | static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) |
226223ab | 3359 | { |
6ba94429 FW |
3360 | u32 hash = wqattrs_hash(attrs); |
3361 | struct worker_pool *pool; | |
3362 | int node; | |
e2273584 | 3363 | int target_node = NUMA_NO_NODE; |
226223ab | 3364 | |
6ba94429 | 3365 | lockdep_assert_held(&wq_pool_mutex); |
226223ab | 3366 | |
6ba94429 FW |
3367 | /* do we already have a matching pool? */ |
3368 | hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) { | |
3369 | if (wqattrs_equal(pool->attrs, attrs)) { | |
3370 | pool->refcnt++; | |
3371 | return pool; | |
3372 | } | |
3373 | } | |
226223ab | 3374 | |
e2273584 XP |
3375 | /* if cpumask is contained inside a NUMA node, we belong to that node */ |
3376 | if (wq_numa_enabled) { | |
3377 | for_each_node(node) { | |
3378 | if (cpumask_subset(attrs->cpumask, | |
3379 | wq_numa_possible_cpumask[node])) { | |
3380 | target_node = node; | |
3381 | break; | |
3382 | } | |
3383 | } | |
3384 | } | |
3385 | ||
6ba94429 | 3386 | /* nope, create a new one */ |
e2273584 | 3387 | pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, target_node); |
6ba94429 FW |
3388 | if (!pool || init_worker_pool(pool) < 0) |
3389 | goto fail; | |
3390 | ||
3391 | lockdep_set_subclass(&pool->lock, 1); /* see put_pwq() */ | |
3392 | copy_workqueue_attrs(pool->attrs, attrs); | |
e2273584 | 3393 | pool->node = target_node; |
226223ab TH |
3394 | |
3395 | /* | |
6ba94429 FW |
3396 | * no_numa isn't a worker_pool attribute, always clear it. See |
3397 | * 'struct workqueue_attrs' comments for detail. | |
226223ab | 3398 | */ |
6ba94429 | 3399 | pool->attrs->no_numa = false; |
226223ab | 3400 | |
6ba94429 FW |
3401 | if (worker_pool_assign_id(pool) < 0) |
3402 | goto fail; | |
226223ab | 3403 | |
6ba94429 | 3404 | /* create and start the initial worker */ |
3347fa09 | 3405 | if (wq_online && !create_worker(pool)) |
6ba94429 | 3406 | goto fail; |
226223ab | 3407 | |
6ba94429 FW |
3408 | /* install */ |
3409 | hash_add(unbound_pool_hash, &pool->hash_node, hash); | |
226223ab | 3410 | |
6ba94429 FW |
3411 | return pool; |
3412 | fail: | |
3413 | if (pool) | |
3414 | put_unbound_pool(pool); | |
3415 | return NULL; | |
226223ab | 3416 | } |
226223ab | 3417 | |
6ba94429 | 3418 | static void rcu_free_pwq(struct rcu_head *rcu) |
7a4e344c | 3419 | { |
6ba94429 FW |
3420 | kmem_cache_free(pwq_cache, |
3421 | container_of(rcu, struct pool_workqueue, rcu)); | |
7a4e344c TH |
3422 | } |
3423 | ||
6ba94429 FW |
3424 | /* |
3425 | * Scheduled on system_wq by put_pwq() when an unbound pwq hits zero refcnt | |
3426 | * and needs to be destroyed. | |
7a4e344c | 3427 | */ |
6ba94429 | 3428 | static void pwq_unbound_release_workfn(struct work_struct *work) |
7a4e344c | 3429 | { |
6ba94429 FW |
3430 | struct pool_workqueue *pwq = container_of(work, struct pool_workqueue, |
3431 | unbound_release_work); | |
3432 | struct workqueue_struct *wq = pwq->wq; | |
3433 | struct worker_pool *pool = pwq->pool; | |
3434 | bool is_last; | |
7a4e344c | 3435 | |
6ba94429 FW |
3436 | if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND))) |
3437 | return; | |
7a4e344c | 3438 | |
6ba94429 FW |
3439 | mutex_lock(&wq->mutex); |
3440 | list_del_rcu(&pwq->pwqs_node); | |
3441 | is_last = list_empty(&wq->pwqs); | |
3442 | mutex_unlock(&wq->mutex); | |
3443 | ||
3444 | mutex_lock(&wq_pool_mutex); | |
3445 | put_unbound_pool(pool); | |
3446 | mutex_unlock(&wq_pool_mutex); | |
3447 | ||
3448 | call_rcu_sched(&pwq->rcu, rcu_free_pwq); | |
7a4e344c | 3449 | |
2865a8fb | 3450 | /* |
6ba94429 FW |
3451 | * If we're the last pwq going away, @wq is already dead and no one |
3452 | * is gonna access it anymore. Schedule RCU free. | |
2865a8fb | 3453 | */ |
6ba94429 FW |
3454 | if (is_last) |
3455 | call_rcu_sched(&wq->rcu, rcu_free_wq); | |
29c91e99 TH |
3456 | } |
3457 | ||
7a4e344c | 3458 | /** |
6ba94429 FW |
3459 | * pwq_adjust_max_active - update a pwq's max_active to the current setting |
3460 | * @pwq: target pool_workqueue | |
d185af30 | 3461 | * |
6ba94429 FW |
3462 | * If @pwq isn't freezing, set @pwq->max_active to the associated |
3463 | * workqueue's saved_max_active and activate delayed work items | |
3464 | * accordingly. If @pwq is freezing, clear @pwq->max_active to zero. | |
7a4e344c | 3465 | */ |
6ba94429 | 3466 | static void pwq_adjust_max_active(struct pool_workqueue *pwq) |
4e1a1f9a | 3467 | { |
6ba94429 FW |
3468 | struct workqueue_struct *wq = pwq->wq; |
3469 | bool freezable = wq->flags & WQ_FREEZABLE; | |
3347fa09 | 3470 | unsigned long flags; |
4e1a1f9a | 3471 | |
6ba94429 FW |
3472 | /* for @wq->saved_max_active */ |
3473 | lockdep_assert_held(&wq->mutex); | |
4e1a1f9a | 3474 | |
6ba94429 FW |
3475 | /* fast exit for non-freezable wqs */ |
3476 | if (!freezable && pwq->max_active == wq->saved_max_active) | |
3477 | return; | |
7a4e344c | 3478 | |
3347fa09 TH |
3479 | /* this function can be called during early boot w/ irq disabled */ |
3480 | spin_lock_irqsave(&pwq->pool->lock, flags); | |
29c91e99 | 3481 | |
6ba94429 FW |
3482 | /* |
3483 | * During [un]freezing, the caller is responsible for ensuring that | |
3484 | * this function is called at least once after @workqueue_freezing | |
3485 | * is updated and visible. | |
3486 | */ | |
3487 | if (!freezable || !workqueue_freezing) { | |
3488 | pwq->max_active = wq->saved_max_active; | |
4e1a1f9a | 3489 | |
6ba94429 FW |
3490 | while (!list_empty(&pwq->delayed_works) && |
3491 | pwq->nr_active < pwq->max_active) | |
3492 | pwq_activate_first_delayed(pwq); | |
e2dca7ad | 3493 | |
6ba94429 FW |
3494 | /* |
3495 | * Need to kick a worker after thawed or an unbound wq's | |
3496 | * max_active is bumped. It's a slow path. Do it always. | |
3497 | */ | |
3498 | wake_up_worker(pwq->pool); | |
3499 | } else { | |
3500 | pwq->max_active = 0; | |
3501 | } | |
e2dca7ad | 3502 | |
3347fa09 | 3503 | spin_unlock_irqrestore(&pwq->pool->lock, flags); |
e2dca7ad TH |
3504 | } |
3505 | ||
6ba94429 FW |
3506 | /* initialize newly alloced @pwq which is associated with @wq and @pool */ |
3507 | static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq, | |
3508 | struct worker_pool *pool) | |
29c91e99 | 3509 | { |
6ba94429 | 3510 | BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK); |
29c91e99 | 3511 | |
6ba94429 FW |
3512 | memset(pwq, 0, sizeof(*pwq)); |
3513 | ||
3514 | pwq->pool = pool; | |
3515 | pwq->wq = wq; | |
3516 | pwq->flush_color = -1; | |
3517 | pwq->refcnt = 1; | |
3518 | INIT_LIST_HEAD(&pwq->delayed_works); | |
3519 | INIT_LIST_HEAD(&pwq->pwqs_node); | |
3520 | INIT_LIST_HEAD(&pwq->mayday_node); | |
3521 | INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn); | |
29c91e99 TH |
3522 | } |
3523 | ||
6ba94429 FW |
3524 | /* sync @pwq with the current state of its associated wq and link it */ |
3525 | static void link_pwq(struct pool_workqueue *pwq) | |
29c91e99 | 3526 | { |
6ba94429 | 3527 | struct workqueue_struct *wq = pwq->wq; |
29c91e99 | 3528 | |
6ba94429 | 3529 | lockdep_assert_held(&wq->mutex); |
a892cacc | 3530 | |
6ba94429 FW |
3531 | /* may be called multiple times, ignore if already linked */ |
3532 | if (!list_empty(&pwq->pwqs_node)) | |
29c91e99 | 3533 | return; |
29c91e99 | 3534 | |
6ba94429 FW |
3535 | /* set the matching work_color */ |
3536 | pwq->work_color = wq->work_color; | |
29c91e99 | 3537 | |
6ba94429 FW |
3538 | /* sync max_active to the current setting */ |
3539 | pwq_adjust_max_active(pwq); | |
29c91e99 | 3540 | |
6ba94429 FW |
3541 | /* link in @pwq */ |
3542 | list_add_rcu(&pwq->pwqs_node, &wq->pwqs); | |
3543 | } | |
29c91e99 | 3544 | |
6ba94429 FW |
3545 | /* obtain a pool matching @attr and create a pwq associating the pool and @wq */ |
3546 | static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq, | |
3547 | const struct workqueue_attrs *attrs) | |
3548 | { | |
3549 | struct worker_pool *pool; | |
3550 | struct pool_workqueue *pwq; | |
60f5a4bc | 3551 | |
6ba94429 | 3552 | lockdep_assert_held(&wq_pool_mutex); |
60f5a4bc | 3553 | |
6ba94429 FW |
3554 | pool = get_unbound_pool(attrs); |
3555 | if (!pool) | |
3556 | return NULL; | |
60f5a4bc | 3557 | |
6ba94429 FW |
3558 | pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node); |
3559 | if (!pwq) { | |
3560 | put_unbound_pool(pool); | |
3561 | return NULL; | |
3562 | } | |
29c91e99 | 3563 | |
6ba94429 FW |
3564 | init_pwq(pwq, wq, pool); |
3565 | return pwq; | |
3566 | } | |
29c91e99 | 3567 | |
29c91e99 | 3568 | /** |
30186c6f | 3569 | * wq_calc_node_cpumask - calculate a wq_attrs' cpumask for the specified node |
042f7df1 | 3570 | * @attrs: the wq_attrs of the default pwq of the target workqueue |
6ba94429 FW |
3571 | * @node: the target NUMA node |
3572 | * @cpu_going_down: if >= 0, the CPU to consider as offline | |
3573 | * @cpumask: outarg, the resulting cpumask | |
29c91e99 | 3574 | * |
6ba94429 FW |
3575 | * Calculate the cpumask a workqueue with @attrs should use on @node. If |
3576 | * @cpu_going_down is >= 0, that cpu is considered offline during | |
3577 | * calculation. The result is stored in @cpumask. | |
a892cacc | 3578 | * |
6ba94429 FW |
3579 | * If NUMA affinity is not enabled, @attrs->cpumask is always used. If |
3580 | * enabled and @node has online CPUs requested by @attrs, the returned | |
3581 | * cpumask is the intersection of the possible CPUs of @node and | |
3582 | * @attrs->cpumask. | |
d185af30 | 3583 | * |
6ba94429 FW |
3584 | * The caller is responsible for ensuring that the cpumask of @node stays |
3585 | * stable. | |
3586 | * | |
3587 | * Return: %true if the resulting @cpumask is different from @attrs->cpumask, | |
3588 | * %false if equal. | |
29c91e99 | 3589 | */ |
6ba94429 FW |
3590 | static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node, |
3591 | int cpu_going_down, cpumask_t *cpumask) | |
29c91e99 | 3592 | { |
6ba94429 FW |
3593 | if (!wq_numa_enabled || attrs->no_numa) |
3594 | goto use_dfl; | |
29c91e99 | 3595 | |
6ba94429 FW |
3596 | /* does @node have any online CPUs @attrs wants? */ |
3597 | cpumask_and(cpumask, cpumask_of_node(node), attrs->cpumask); | |
3598 | if (cpu_going_down >= 0) | |
3599 | cpumask_clear_cpu(cpu_going_down, cpumask); | |
29c91e99 | 3600 | |
6ba94429 FW |
3601 | if (cpumask_empty(cpumask)) |
3602 | goto use_dfl; | |
4c16bd32 TH |
3603 | |
3604 | /* yeap, return possible CPUs in @node that @attrs wants */ | |
3605 | cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]); | |
1ad0f0a7 MB |
3606 | |
3607 | if (cpumask_empty(cpumask)) { | |
3608 | pr_warn_once("WARNING: workqueue cpumask: online intersect > " | |
3609 | "possible intersect\n"); | |
3610 | return false; | |
3611 | } | |
3612 | ||
4c16bd32 TH |
3613 | return !cpumask_equal(cpumask, attrs->cpumask); |
3614 | ||
3615 | use_dfl: | |
3616 | cpumask_copy(cpumask, attrs->cpumask); | |
3617 | return false; | |
3618 | } | |
3619 | ||
1befcf30 TH |
3620 | /* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */ |
3621 | static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq, | |
3622 | int node, | |
3623 | struct pool_workqueue *pwq) | |
3624 | { | |
3625 | struct pool_workqueue *old_pwq; | |
3626 | ||
5b95e1af | 3627 | lockdep_assert_held(&wq_pool_mutex); |
1befcf30 TH |
3628 | lockdep_assert_held(&wq->mutex); |
3629 | ||
3630 | /* link_pwq() can handle duplicate calls */ | |
3631 | link_pwq(pwq); | |
3632 | ||
3633 | old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]); | |
3634 | rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq); | |
3635 | return old_pwq; | |
3636 | } | |
3637 | ||
2d5f0764 LJ |
3638 | /* context to store the prepared attrs & pwqs before applying */ |
3639 | struct apply_wqattrs_ctx { | |
3640 | struct workqueue_struct *wq; /* target workqueue */ | |
3641 | struct workqueue_attrs *attrs; /* attrs to apply */ | |
042f7df1 | 3642 | struct list_head list; /* queued for batching commit */ |
2d5f0764 LJ |
3643 | struct pool_workqueue *dfl_pwq; |
3644 | struct pool_workqueue *pwq_tbl[]; | |
3645 | }; | |
3646 | ||
3647 | /* free the resources after success or abort */ | |
3648 | static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx) | |
3649 | { | |
3650 | if (ctx) { | |
3651 | int node; | |
3652 | ||
3653 | for_each_node(node) | |
3654 | put_pwq_unlocked(ctx->pwq_tbl[node]); | |
3655 | put_pwq_unlocked(ctx->dfl_pwq); | |
3656 | ||
3657 | free_workqueue_attrs(ctx->attrs); | |
3658 | ||
3659 | kfree(ctx); | |
3660 | } | |
3661 | } | |
3662 | ||
3663 | /* allocate the attrs and pwqs for later installation */ | |
3664 | static struct apply_wqattrs_ctx * | |
3665 | apply_wqattrs_prepare(struct workqueue_struct *wq, | |
3666 | const struct workqueue_attrs *attrs) | |
9e8cd2f5 | 3667 | { |
2d5f0764 | 3668 | struct apply_wqattrs_ctx *ctx; |
4c16bd32 | 3669 | struct workqueue_attrs *new_attrs, *tmp_attrs; |
2d5f0764 | 3670 | int node; |
9e8cd2f5 | 3671 | |
2d5f0764 | 3672 | lockdep_assert_held(&wq_pool_mutex); |
9e8cd2f5 | 3673 | |
2d5f0764 LJ |
3674 | ctx = kzalloc(sizeof(*ctx) + nr_node_ids * sizeof(ctx->pwq_tbl[0]), |
3675 | GFP_KERNEL); | |
8719dcea | 3676 | |
13e2e556 | 3677 | new_attrs = alloc_workqueue_attrs(GFP_KERNEL); |
4c16bd32 | 3678 | tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL); |
2d5f0764 LJ |
3679 | if (!ctx || !new_attrs || !tmp_attrs) |
3680 | goto out_free; | |
13e2e556 | 3681 | |
042f7df1 LJ |
3682 | /* |
3683 | * Calculate the attrs of the default pwq. | |
3684 | * If the user configured cpumask doesn't overlap with the | |
3685 | * wq_unbound_cpumask, we fallback to the wq_unbound_cpumask. | |
3686 | */ | |
13e2e556 | 3687 | copy_workqueue_attrs(new_attrs, attrs); |
b05a7928 | 3688 | cpumask_and(new_attrs->cpumask, new_attrs->cpumask, wq_unbound_cpumask); |
042f7df1 LJ |
3689 | if (unlikely(cpumask_empty(new_attrs->cpumask))) |
3690 | cpumask_copy(new_attrs->cpumask, wq_unbound_cpumask); | |
13e2e556 | 3691 | |
4c16bd32 TH |
3692 | /* |
3693 | * We may create multiple pwqs with differing cpumasks. Make a | |
3694 | * copy of @new_attrs which will be modified and used to obtain | |
3695 | * pools. | |
3696 | */ | |
3697 | copy_workqueue_attrs(tmp_attrs, new_attrs); | |
3698 | ||
4c16bd32 TH |
3699 | /* |
3700 | * If something goes wrong during CPU up/down, we'll fall back to | |
3701 | * the default pwq covering whole @attrs->cpumask. Always create | |
3702 | * it even if we don't use it immediately. | |
3703 | */ | |
2d5f0764 LJ |
3704 | ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs); |
3705 | if (!ctx->dfl_pwq) | |
3706 | goto out_free; | |
4c16bd32 TH |
3707 | |
3708 | for_each_node(node) { | |
042f7df1 | 3709 | if (wq_calc_node_cpumask(new_attrs, node, -1, tmp_attrs->cpumask)) { |
2d5f0764 LJ |
3710 | ctx->pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs); |
3711 | if (!ctx->pwq_tbl[node]) | |
3712 | goto out_free; | |
4c16bd32 | 3713 | } else { |
2d5f0764 LJ |
3714 | ctx->dfl_pwq->refcnt++; |
3715 | ctx->pwq_tbl[node] = ctx->dfl_pwq; | |
4c16bd32 TH |
3716 | } |
3717 | } | |
3718 | ||
042f7df1 LJ |
3719 | /* save the user configured attrs and sanitize it. */ |
3720 | copy_workqueue_attrs(new_attrs, attrs); | |
3721 | cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask); | |
2d5f0764 | 3722 | ctx->attrs = new_attrs; |
042f7df1 | 3723 | |
2d5f0764 LJ |
3724 | ctx->wq = wq; |
3725 | free_workqueue_attrs(tmp_attrs); | |
3726 | return ctx; | |
3727 | ||
3728 | out_free: | |
3729 | free_workqueue_attrs(tmp_attrs); | |
3730 | free_workqueue_attrs(new_attrs); | |
3731 | apply_wqattrs_cleanup(ctx); | |
3732 | return NULL; | |
3733 | } | |
3734 | ||
3735 | /* set attrs and install prepared pwqs, @ctx points to old pwqs on return */ | |
3736 | static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx) | |
3737 | { | |
3738 | int node; | |
9e8cd2f5 | 3739 | |
4c16bd32 | 3740 | /* all pwqs have been created successfully, let's install'em */ |
2d5f0764 | 3741 | mutex_lock(&ctx->wq->mutex); |
a892cacc | 3742 | |
2d5f0764 | 3743 | copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs); |
4c16bd32 TH |
3744 | |
3745 | /* save the previous pwq and install the new one */ | |
f147f29e | 3746 | for_each_node(node) |
2d5f0764 LJ |
3747 | ctx->pwq_tbl[node] = numa_pwq_tbl_install(ctx->wq, node, |
3748 | ctx->pwq_tbl[node]); | |
4c16bd32 TH |
3749 | |
3750 | /* @dfl_pwq might not have been used, ensure it's linked */ | |
2d5f0764 LJ |
3751 | link_pwq(ctx->dfl_pwq); |
3752 | swap(ctx->wq->dfl_pwq, ctx->dfl_pwq); | |
f147f29e | 3753 | |
2d5f0764 LJ |
3754 | mutex_unlock(&ctx->wq->mutex); |
3755 | } | |
9e8cd2f5 | 3756 | |
a0111cf6 LJ |
3757 | static void apply_wqattrs_lock(void) |
3758 | { | |
3759 | /* CPUs should stay stable across pwq creations and installations */ | |
3760 | get_online_cpus(); | |
3761 | mutex_lock(&wq_pool_mutex); | |
3762 | } | |
3763 | ||
3764 | static void apply_wqattrs_unlock(void) | |
3765 | { | |
3766 | mutex_unlock(&wq_pool_mutex); | |
3767 | put_online_cpus(); | |
3768 | } | |
3769 | ||
3770 | static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, | |
3771 | const struct workqueue_attrs *attrs) | |
2d5f0764 LJ |
3772 | { |
3773 | struct apply_wqattrs_ctx *ctx; | |
4c16bd32 | 3774 | |
2d5f0764 LJ |
3775 | /* only unbound workqueues can change attributes */ |
3776 | if (WARN_ON(!(wq->flags & WQ_UNBOUND))) | |
3777 | return -EINVAL; | |
13e2e556 | 3778 | |
2d5f0764 | 3779 | /* creating multiple pwqs breaks ordering guarantee */ |
0a94efb5 TH |
3780 | if (!list_empty(&wq->pwqs)) { |
3781 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) | |
3782 | return -EINVAL; | |
3783 | ||
3784 | wq->flags &= ~__WQ_ORDERED; | |
3785 | } | |
2d5f0764 | 3786 | |
2d5f0764 | 3787 | ctx = apply_wqattrs_prepare(wq, attrs); |
6201171e | 3788 | if (!ctx) |
3789 | return -ENOMEM; | |
2d5f0764 LJ |
3790 | |
3791 | /* the ctx has been prepared successfully, let's commit it */ | |
6201171e | 3792 | apply_wqattrs_commit(ctx); |
2d5f0764 LJ |
3793 | apply_wqattrs_cleanup(ctx); |
3794 | ||
6201171e | 3795 | return 0; |
9e8cd2f5 TH |
3796 | } |
3797 | ||
a0111cf6 LJ |
3798 | /** |
3799 | * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue | |
3800 | * @wq: the target workqueue | |
3801 | * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs() | |
3802 | * | |
3803 | * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA | |
3804 | * machines, this function maps a separate pwq to each NUMA node with | |
3805 | * possibles CPUs in @attrs->cpumask so that work items are affine to the | |
3806 | * NUMA node it was issued on. Older pwqs are released as in-flight work | |
3807 | * items finish. Note that a work item which repeatedly requeues itself | |
3808 | * back-to-back will stay on its current pwq. | |
3809 | * | |
3810 | * Performs GFP_KERNEL allocations. | |
3811 | * | |
3812 | * Return: 0 on success and -errno on failure. | |
3813 | */ | |
3814 | int apply_workqueue_attrs(struct workqueue_struct *wq, | |
3815 | const struct workqueue_attrs *attrs) | |
3816 | { | |
3817 | int ret; | |
3818 | ||
3819 | apply_wqattrs_lock(); | |
3820 | ret = apply_workqueue_attrs_locked(wq, attrs); | |
3821 | apply_wqattrs_unlock(); | |
3822 | ||
3823 | return ret; | |
3824 | } | |
3825 | ||
4c16bd32 TH |
3826 | /** |
3827 | * wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug | |
3828 | * @wq: the target workqueue | |
3829 | * @cpu: the CPU coming up or going down | |
3830 | * @online: whether @cpu is coming up or going down | |
3831 | * | |
3832 | * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and | |
3833 | * %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update NUMA affinity of | |
3834 | * @wq accordingly. | |
3835 | * | |
3836 | * If NUMA affinity can't be adjusted due to memory allocation failure, it | |
3837 | * falls back to @wq->dfl_pwq which may not be optimal but is always | |
3838 | * correct. | |
3839 | * | |
3840 | * Note that when the last allowed CPU of a NUMA node goes offline for a | |
3841 | * workqueue with a cpumask spanning multiple nodes, the workers which were | |
3842 | * already executing the work items for the workqueue will lose their CPU | |
3843 | * affinity and may execute on any CPU. This is similar to how per-cpu | |
3844 | * workqueues behave on CPU_DOWN. If a workqueue user wants strict | |
3845 | * affinity, it's the user's responsibility to flush the work item from | |
3846 | * CPU_DOWN_PREPARE. | |
3847 | */ | |
3848 | static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu, | |
3849 | bool online) | |
3850 | { | |
3851 | int node = cpu_to_node(cpu); | |
3852 | int cpu_off = online ? -1 : cpu; | |
3853 | struct pool_workqueue *old_pwq = NULL, *pwq; | |
3854 | struct workqueue_attrs *target_attrs; | |
3855 | cpumask_t *cpumask; | |
3856 | ||
3857 | lockdep_assert_held(&wq_pool_mutex); | |
3858 | ||
f7142ed4 LJ |
3859 | if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND) || |
3860 | wq->unbound_attrs->no_numa) | |
4c16bd32 TH |
3861 | return; |
3862 | ||
3863 | /* | |
3864 | * We don't wanna alloc/free wq_attrs for each wq for each CPU. | |
3865 | * Let's use a preallocated one. The following buf is protected by | |
3866 | * CPU hotplug exclusion. | |
3867 | */ | |
3868 | target_attrs = wq_update_unbound_numa_attrs_buf; | |
3869 | cpumask = target_attrs->cpumask; | |
3870 | ||
4c16bd32 TH |
3871 | copy_workqueue_attrs(target_attrs, wq->unbound_attrs); |
3872 | pwq = unbound_pwq_by_node(wq, node); | |
3873 | ||
3874 | /* | |
3875 | * Let's determine what needs to be done. If the target cpumask is | |
042f7df1 LJ |
3876 | * different from the default pwq's, we need to compare it to @pwq's |
3877 | * and create a new one if they don't match. If the target cpumask | |
3878 | * equals the default pwq's, the default pwq should be used. | |
4c16bd32 | 3879 | */ |
042f7df1 | 3880 | if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, cpu_off, cpumask)) { |
4c16bd32 | 3881 | if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask)) |
f7142ed4 | 3882 | return; |
4c16bd32 | 3883 | } else { |
534a3fbb | 3884 | goto use_dfl_pwq; |
4c16bd32 TH |
3885 | } |
3886 | ||
4c16bd32 TH |
3887 | /* create a new pwq */ |
3888 | pwq = alloc_unbound_pwq(wq, target_attrs); | |
3889 | if (!pwq) { | |
2d916033 FF |
3890 | pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n", |
3891 | wq->name); | |
77f300b1 | 3892 | goto use_dfl_pwq; |
4c16bd32 TH |
3893 | } |
3894 | ||
f7142ed4 | 3895 | /* Install the new pwq. */ |
4c16bd32 TH |
3896 | mutex_lock(&wq->mutex); |
3897 | old_pwq = numa_pwq_tbl_install(wq, node, pwq); | |
3898 | goto out_unlock; | |
3899 | ||
3900 | use_dfl_pwq: | |
f7142ed4 | 3901 | mutex_lock(&wq->mutex); |
4c16bd32 TH |
3902 | spin_lock_irq(&wq->dfl_pwq->pool->lock); |
3903 | get_pwq(wq->dfl_pwq); | |
3904 | spin_unlock_irq(&wq->dfl_pwq->pool->lock); | |
3905 | old_pwq = numa_pwq_tbl_install(wq, node, wq->dfl_pwq); | |
3906 | out_unlock: | |
3907 | mutex_unlock(&wq->mutex); | |
3908 | put_pwq_unlocked(old_pwq); | |
3909 | } | |
3910 | ||
30cdf249 | 3911 | static int alloc_and_link_pwqs(struct workqueue_struct *wq) |
0f900049 | 3912 | { |
49e3cf44 | 3913 | bool highpri = wq->flags & WQ_HIGHPRI; |
8a2b7538 | 3914 | int cpu, ret; |
30cdf249 TH |
3915 | |
3916 | if (!(wq->flags & WQ_UNBOUND)) { | |
420c0ddb TH |
3917 | wq->cpu_pwqs = alloc_percpu(struct pool_workqueue); |
3918 | if (!wq->cpu_pwqs) | |
30cdf249 TH |
3919 | return -ENOMEM; |
3920 | ||
3921 | for_each_possible_cpu(cpu) { | |
7fb98ea7 TH |
3922 | struct pool_workqueue *pwq = |
3923 | per_cpu_ptr(wq->cpu_pwqs, cpu); | |
7a62c2c8 | 3924 | struct worker_pool *cpu_pools = |
f02ae73a | 3925 | per_cpu(cpu_worker_pools, cpu); |
f3421797 | 3926 | |
f147f29e TH |
3927 | init_pwq(pwq, wq, &cpu_pools[highpri]); |
3928 | ||
3929 | mutex_lock(&wq->mutex); | |
1befcf30 | 3930 | link_pwq(pwq); |
f147f29e | 3931 | mutex_unlock(&wq->mutex); |
30cdf249 | 3932 | } |
9e8cd2f5 | 3933 | return 0; |
8a2b7538 TH |
3934 | } else if (wq->flags & __WQ_ORDERED) { |
3935 | ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]); | |
3936 | /* there should only be single pwq for ordering guarantee */ | |
3937 | WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node || | |
3938 | wq->pwqs.prev != &wq->dfl_pwq->pwqs_node), | |
3939 | "ordering guarantee broken for workqueue %s\n", wq->name); | |
3940 | return ret; | |
30cdf249 | 3941 | } else { |
9e8cd2f5 | 3942 | return apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); |
30cdf249 | 3943 | } |
0f900049 TH |
3944 | } |
3945 | ||
f3421797 TH |
3946 | static int wq_clamp_max_active(int max_active, unsigned int flags, |
3947 | const char *name) | |
b71ab8c2 | 3948 | { |
f3421797 TH |
3949 | int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; |
3950 | ||
3951 | if (max_active < 1 || max_active > lim) | |
044c782c VI |
3952 | pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n", |
3953 | max_active, name, 1, lim); | |
b71ab8c2 | 3954 | |
f3421797 | 3955 | return clamp_val(max_active, 1, lim); |
b71ab8c2 TH |
3956 | } |
3957 | ||
b196be89 | 3958 | struct workqueue_struct *__alloc_workqueue_key(const char *fmt, |
d320c038 TH |
3959 | unsigned int flags, |
3960 | int max_active, | |
3961 | struct lock_class_key *key, | |
b196be89 | 3962 | const char *lock_name, ...) |
1da177e4 | 3963 | { |
df2d5ae4 | 3964 | size_t tbl_size = 0; |
ecf6881f | 3965 | va_list args; |
1da177e4 | 3966 | struct workqueue_struct *wq; |
49e3cf44 | 3967 | struct pool_workqueue *pwq; |
b196be89 | 3968 | |
5c0338c6 TH |
3969 | /* |
3970 | * Unbound && max_active == 1 used to imply ordered, which is no | |
3971 | * longer the case on NUMA machines due to per-node pools. While | |
3972 | * alloc_ordered_workqueue() is the right way to create an ordered | |
3973 | * workqueue, keep the previous behavior to avoid subtle breakages | |
3974 | * on NUMA. | |
3975 | */ | |
3976 | if ((flags & WQ_UNBOUND) && max_active == 1) | |
3977 | flags |= __WQ_ORDERED; | |
3978 | ||
cee22a15 VK |
3979 | /* see the comment above the definition of WQ_POWER_EFFICIENT */ |
3980 | if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient) | |
3981 | flags |= WQ_UNBOUND; | |
3982 | ||
ecf6881f | 3983 | /* allocate wq and format name */ |
df2d5ae4 | 3984 | if (flags & WQ_UNBOUND) |
ddcb57e2 | 3985 | tbl_size = nr_node_ids * sizeof(wq->numa_pwq_tbl[0]); |
df2d5ae4 TH |
3986 | |
3987 | wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL); | |
b196be89 | 3988 | if (!wq) |
d2c1d404 | 3989 | return NULL; |
b196be89 | 3990 | |
6029a918 TH |
3991 | if (flags & WQ_UNBOUND) { |
3992 | wq->unbound_attrs = alloc_workqueue_attrs(GFP_KERNEL); | |
3993 | if (!wq->unbound_attrs) | |
3994 | goto err_free_wq; | |
3995 | } | |
3996 | ||
ecf6881f TH |
3997 | va_start(args, lock_name); |
3998 | vsnprintf(wq->name, sizeof(wq->name), fmt, args); | |
b196be89 | 3999 | va_end(args); |
1da177e4 | 4000 | |
d320c038 | 4001 | max_active = max_active ?: WQ_DFL_ACTIVE; |
b196be89 | 4002 | max_active = wq_clamp_max_active(max_active, flags, wq->name); |
3af24433 | 4003 | |
b196be89 | 4004 | /* init wq */ |
97e37d7b | 4005 | wq->flags = flags; |
a0a1a5fd | 4006 | wq->saved_max_active = max_active; |
3c25a55d | 4007 | mutex_init(&wq->mutex); |
112202d9 | 4008 | atomic_set(&wq->nr_pwqs_to_flush, 0); |
30cdf249 | 4009 | INIT_LIST_HEAD(&wq->pwqs); |
73f53c4a TH |
4010 | INIT_LIST_HEAD(&wq->flusher_queue); |
4011 | INIT_LIST_HEAD(&wq->flusher_overflow); | |
493a1724 | 4012 | INIT_LIST_HEAD(&wq->maydays); |
502ca9d8 | 4013 | |
eb13ba87 | 4014 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
cce1a165 | 4015 | INIT_LIST_HEAD(&wq->list); |
3af24433 | 4016 | |
30cdf249 | 4017 | if (alloc_and_link_pwqs(wq) < 0) |
d2c1d404 | 4018 | goto err_free_wq; |
1537663f | 4019 | |
493008a8 TH |
4020 | /* |
4021 | * Workqueues which may be used during memory reclaim should | |
4022 | * have a rescuer to guarantee forward progress. | |
4023 | */ | |
4024 | if (flags & WQ_MEM_RECLAIM) { | |
e22bee78 TH |
4025 | struct worker *rescuer; |
4026 | ||
f7537df5 | 4027 | rescuer = alloc_worker(NUMA_NO_NODE); |
e22bee78 | 4028 | if (!rescuer) |
d2c1d404 | 4029 | goto err_destroy; |
e22bee78 | 4030 | |
111c225a TH |
4031 | rescuer->rescue_wq = wq; |
4032 | rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", | |
b196be89 | 4033 | wq->name); |
d2c1d404 TH |
4034 | if (IS_ERR(rescuer->task)) { |
4035 | kfree(rescuer); | |
4036 | goto err_destroy; | |
4037 | } | |
e22bee78 | 4038 | |
d2c1d404 | 4039 | wq->rescuer = rescuer; |
25834c73 | 4040 | kthread_bind_mask(rescuer->task, cpu_possible_mask); |
e22bee78 | 4041 | wake_up_process(rescuer->task); |
3af24433 ON |
4042 | } |
4043 | ||
226223ab TH |
4044 | if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq)) |
4045 | goto err_destroy; | |
4046 | ||
a0a1a5fd | 4047 | /* |
68e13a67 LJ |
4048 | * wq_pool_mutex protects global freeze state and workqueues list. |
4049 | * Grab it, adjust max_active and add the new @wq to workqueues | |
4050 | * list. | |
a0a1a5fd | 4051 | */ |
68e13a67 | 4052 | mutex_lock(&wq_pool_mutex); |
a0a1a5fd | 4053 | |
a357fc03 | 4054 | mutex_lock(&wq->mutex); |
699ce097 TH |
4055 | for_each_pwq(pwq, wq) |
4056 | pwq_adjust_max_active(pwq); | |
a357fc03 | 4057 | mutex_unlock(&wq->mutex); |
a0a1a5fd | 4058 | |
e2dca7ad | 4059 | list_add_tail_rcu(&wq->list, &workqueues); |
a0a1a5fd | 4060 | |
68e13a67 | 4061 | mutex_unlock(&wq_pool_mutex); |
1537663f | 4062 | |
3af24433 | 4063 | return wq; |
d2c1d404 TH |
4064 | |
4065 | err_free_wq: | |
6029a918 | 4066 | free_workqueue_attrs(wq->unbound_attrs); |
d2c1d404 TH |
4067 | kfree(wq); |
4068 | return NULL; | |
4069 | err_destroy: | |
4070 | destroy_workqueue(wq); | |
4690c4ab | 4071 | return NULL; |
3af24433 | 4072 | } |
d320c038 | 4073 | EXPORT_SYMBOL_GPL(__alloc_workqueue_key); |
1da177e4 | 4074 | |
3af24433 ON |
4075 | /** |
4076 | * destroy_workqueue - safely terminate a workqueue | |
4077 | * @wq: target workqueue | |
4078 | * | |
4079 | * Safely destroy a workqueue. All work currently pending will be done first. | |
4080 | */ | |
4081 | void destroy_workqueue(struct workqueue_struct *wq) | |
4082 | { | |
49e3cf44 | 4083 | struct pool_workqueue *pwq; |
4c16bd32 | 4084 | int node; |
3af24433 | 4085 | |
9c5a2ba7 TH |
4086 | /* drain it before proceeding with destruction */ |
4087 | drain_workqueue(wq); | |
c8efcc25 | 4088 | |
6183c009 | 4089 | /* sanity checks */ |
b09f4fd3 | 4090 | mutex_lock(&wq->mutex); |
49e3cf44 | 4091 | for_each_pwq(pwq, wq) { |
6183c009 TH |
4092 | int i; |
4093 | ||
76af4d93 TH |
4094 | for (i = 0; i < WORK_NR_COLORS; i++) { |
4095 | if (WARN_ON(pwq->nr_in_flight[i])) { | |
b09f4fd3 | 4096 | mutex_unlock(&wq->mutex); |
fa07fb6a | 4097 | show_workqueue_state(); |
6183c009 | 4098 | return; |
76af4d93 TH |
4099 | } |
4100 | } | |
4101 | ||
5c529597 | 4102 | if (WARN_ON((pwq != wq->dfl_pwq) && (pwq->refcnt > 1)) || |
8864b4e5 | 4103 | WARN_ON(pwq->nr_active) || |
76af4d93 | 4104 | WARN_ON(!list_empty(&pwq->delayed_works))) { |
b09f4fd3 | 4105 | mutex_unlock(&wq->mutex); |
fa07fb6a | 4106 | show_workqueue_state(); |
6183c009 | 4107 | return; |
76af4d93 | 4108 | } |
6183c009 | 4109 | } |
b09f4fd3 | 4110 | mutex_unlock(&wq->mutex); |
6183c009 | 4111 | |
a0a1a5fd TH |
4112 | /* |
4113 | * wq list is used to freeze wq, remove from list after | |
4114 | * flushing is complete in case freeze races us. | |
4115 | */ | |
68e13a67 | 4116 | mutex_lock(&wq_pool_mutex); |
e2dca7ad | 4117 | list_del_rcu(&wq->list); |
68e13a67 | 4118 | mutex_unlock(&wq_pool_mutex); |
3af24433 | 4119 | |
226223ab TH |
4120 | workqueue_sysfs_unregister(wq); |
4121 | ||
e2dca7ad | 4122 | if (wq->rescuer) |
e22bee78 | 4123 | kthread_stop(wq->rescuer->task); |
e22bee78 | 4124 | |
8864b4e5 TH |
4125 | if (!(wq->flags & WQ_UNBOUND)) { |
4126 | /* | |
4127 | * The base ref is never dropped on per-cpu pwqs. Directly | |
e2dca7ad | 4128 | * schedule RCU free. |
8864b4e5 | 4129 | */ |
e2dca7ad | 4130 | call_rcu_sched(&wq->rcu, rcu_free_wq); |
8864b4e5 TH |
4131 | } else { |
4132 | /* | |
4133 | * We're the sole accessor of @wq at this point. Directly | |
4c16bd32 TH |
4134 | * access numa_pwq_tbl[] and dfl_pwq to put the base refs. |
4135 | * @wq will be freed when the last pwq is released. | |
8864b4e5 | 4136 | */ |
4c16bd32 TH |
4137 | for_each_node(node) { |
4138 | pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]); | |
4139 | RCU_INIT_POINTER(wq->numa_pwq_tbl[node], NULL); | |
4140 | put_pwq_unlocked(pwq); | |
4141 | } | |
4142 | ||
4143 | /* | |
4144 | * Put dfl_pwq. @wq may be freed any time after dfl_pwq is | |
4145 | * put. Don't access it afterwards. | |
4146 | */ | |
4147 | pwq = wq->dfl_pwq; | |
4148 | wq->dfl_pwq = NULL; | |
dce90d47 | 4149 | put_pwq_unlocked(pwq); |
29c91e99 | 4150 | } |
3af24433 ON |
4151 | } |
4152 | EXPORT_SYMBOL_GPL(destroy_workqueue); | |
4153 | ||
dcd989cb TH |
4154 | /** |
4155 | * workqueue_set_max_active - adjust max_active of a workqueue | |
4156 | * @wq: target workqueue | |
4157 | * @max_active: new max_active value. | |
4158 | * | |
4159 | * Set max_active of @wq to @max_active. | |
4160 | * | |
4161 | * CONTEXT: | |
4162 | * Don't call from IRQ context. | |
4163 | */ | |
4164 | void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) | |
4165 | { | |
49e3cf44 | 4166 | struct pool_workqueue *pwq; |
dcd989cb | 4167 | |
8719dcea | 4168 | /* disallow meddling with max_active for ordered workqueues */ |
0a94efb5 | 4169 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
8719dcea TH |
4170 | return; |
4171 | ||
f3421797 | 4172 | max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); |
dcd989cb | 4173 | |
a357fc03 | 4174 | mutex_lock(&wq->mutex); |
dcd989cb | 4175 | |
0a94efb5 | 4176 | wq->flags &= ~__WQ_ORDERED; |
dcd989cb TH |
4177 | wq->saved_max_active = max_active; |
4178 | ||
699ce097 TH |
4179 | for_each_pwq(pwq, wq) |
4180 | pwq_adjust_max_active(pwq); | |
93981800 | 4181 | |
a357fc03 | 4182 | mutex_unlock(&wq->mutex); |
15316ba8 | 4183 | } |
dcd989cb | 4184 | EXPORT_SYMBOL_GPL(workqueue_set_max_active); |
15316ba8 | 4185 | |
e6267616 TH |
4186 | /** |
4187 | * current_is_workqueue_rescuer - is %current workqueue rescuer? | |
4188 | * | |
4189 | * Determine whether %current is a workqueue rescuer. Can be used from | |
4190 | * work functions to determine whether it's being run off the rescuer task. | |
d185af30 YB |
4191 | * |
4192 | * Return: %true if %current is a workqueue rescuer. %false otherwise. | |
e6267616 TH |
4193 | */ |
4194 | bool current_is_workqueue_rescuer(void) | |
4195 | { | |
4196 | struct worker *worker = current_wq_worker(); | |
4197 | ||
6a092dfd | 4198 | return worker && worker->rescue_wq; |
e6267616 TH |
4199 | } |
4200 | ||
eef6a7d5 | 4201 | /** |
dcd989cb TH |
4202 | * workqueue_congested - test whether a workqueue is congested |
4203 | * @cpu: CPU in question | |
4204 | * @wq: target workqueue | |
eef6a7d5 | 4205 | * |
dcd989cb TH |
4206 | * Test whether @wq's cpu workqueue for @cpu is congested. There is |
4207 | * no synchronization around this function and the test result is | |
4208 | * unreliable and only useful as advisory hints or for debugging. | |
eef6a7d5 | 4209 | * |
d3251859 TH |
4210 | * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU. |
4211 | * Note that both per-cpu and unbound workqueues may be associated with | |
4212 | * multiple pool_workqueues which have separate congested states. A | |
4213 | * workqueue being congested on one CPU doesn't mean the workqueue is also | |
4214 | * contested on other CPUs / NUMA nodes. | |
4215 | * | |
d185af30 | 4216 | * Return: |
dcd989cb | 4217 | * %true if congested, %false otherwise. |
eef6a7d5 | 4218 | */ |
d84ff051 | 4219 | bool workqueue_congested(int cpu, struct workqueue_struct *wq) |
1da177e4 | 4220 | { |
7fb98ea7 | 4221 | struct pool_workqueue *pwq; |
76af4d93 TH |
4222 | bool ret; |
4223 | ||
88109453 | 4224 | rcu_read_lock_sched(); |
7fb98ea7 | 4225 | |
d3251859 TH |
4226 | if (cpu == WORK_CPU_UNBOUND) |
4227 | cpu = smp_processor_id(); | |
4228 | ||
7fb98ea7 TH |
4229 | if (!(wq->flags & WQ_UNBOUND)) |
4230 | pwq = per_cpu_ptr(wq->cpu_pwqs, cpu); | |
4231 | else | |
df2d5ae4 | 4232 | pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu)); |
dcd989cb | 4233 | |
76af4d93 | 4234 | ret = !list_empty(&pwq->delayed_works); |
88109453 | 4235 | rcu_read_unlock_sched(); |
76af4d93 TH |
4236 | |
4237 | return ret; | |
1da177e4 | 4238 | } |
dcd989cb | 4239 | EXPORT_SYMBOL_GPL(workqueue_congested); |
1da177e4 | 4240 | |
dcd989cb TH |
4241 | /** |
4242 | * work_busy - test whether a work is currently pending or running | |
4243 | * @work: the work to be tested | |
4244 | * | |
4245 | * Test whether @work is currently pending or running. There is no | |
4246 | * synchronization around this function and the test result is | |
4247 | * unreliable and only useful as advisory hints or for debugging. | |
dcd989cb | 4248 | * |
d185af30 | 4249 | * Return: |
dcd989cb TH |
4250 | * OR'd bitmask of WORK_BUSY_* bits. |
4251 | */ | |
4252 | unsigned int work_busy(struct work_struct *work) | |
1da177e4 | 4253 | { |
fa1b54e6 | 4254 | struct worker_pool *pool; |
dcd989cb TH |
4255 | unsigned long flags; |
4256 | unsigned int ret = 0; | |
1da177e4 | 4257 | |
dcd989cb TH |
4258 | if (work_pending(work)) |
4259 | ret |= WORK_BUSY_PENDING; | |
1da177e4 | 4260 | |
fa1b54e6 TH |
4261 | local_irq_save(flags); |
4262 | pool = get_work_pool(work); | |
038366c5 | 4263 | if (pool) { |
fa1b54e6 | 4264 | spin_lock(&pool->lock); |
038366c5 LJ |
4265 | if (find_worker_executing_work(pool, work)) |
4266 | ret |= WORK_BUSY_RUNNING; | |
fa1b54e6 | 4267 | spin_unlock(&pool->lock); |
038366c5 | 4268 | } |
fa1b54e6 | 4269 | local_irq_restore(flags); |
1da177e4 | 4270 | |
dcd989cb | 4271 | return ret; |
1da177e4 | 4272 | } |
dcd989cb | 4273 | EXPORT_SYMBOL_GPL(work_busy); |
1da177e4 | 4274 | |
3d1cb205 TH |
4275 | /** |
4276 | * set_worker_desc - set description for the current work item | |
4277 | * @fmt: printf-style format string | |
4278 | * @...: arguments for the format string | |
4279 | * | |
4280 | * This function can be called by a running work function to describe what | |
4281 | * the work item is about. If the worker task gets dumped, this | |
4282 | * information will be printed out together to help debugging. The | |
4283 | * description can be at most WORKER_DESC_LEN including the trailing '\0'. | |
4284 | */ | |
4285 | void set_worker_desc(const char *fmt, ...) | |
4286 | { | |
4287 | struct worker *worker = current_wq_worker(); | |
4288 | va_list args; | |
4289 | ||
4290 | if (worker) { | |
4291 | va_start(args, fmt); | |
4292 | vsnprintf(worker->desc, sizeof(worker->desc), fmt, args); | |
4293 | va_end(args); | |
4294 | worker->desc_valid = true; | |
4295 | } | |
4296 | } | |
4297 | ||
4298 | /** | |
4299 | * print_worker_info - print out worker information and description | |
4300 | * @log_lvl: the log level to use when printing | |
4301 | * @task: target task | |
4302 | * | |
4303 | * If @task is a worker and currently executing a work item, print out the | |
4304 | * name of the workqueue being serviced and worker description set with | |
4305 | * set_worker_desc() by the currently executing work item. | |
4306 | * | |
4307 | * This function can be safely called on any task as long as the | |
4308 | * task_struct itself is accessible. While safe, this function isn't | |
4309 | * synchronized and may print out mixups or garbages of limited length. | |
4310 | */ | |
4311 | void print_worker_info(const char *log_lvl, struct task_struct *task) | |
4312 | { | |
4313 | work_func_t *fn = NULL; | |
4314 | char name[WQ_NAME_LEN] = { }; | |
4315 | char desc[WORKER_DESC_LEN] = { }; | |
4316 | struct pool_workqueue *pwq = NULL; | |
4317 | struct workqueue_struct *wq = NULL; | |
4318 | bool desc_valid = false; | |
4319 | struct worker *worker; | |
4320 | ||
4321 | if (!(task->flags & PF_WQ_WORKER)) | |
4322 | return; | |
4323 | ||
4324 | /* | |
4325 | * This function is called without any synchronization and @task | |
4326 | * could be in any state. Be careful with dereferences. | |
4327 | */ | |
e700591a | 4328 | worker = kthread_probe_data(task); |
3d1cb205 TH |
4329 | |
4330 | /* | |
4331 | * Carefully copy the associated workqueue's workfn and name. Keep | |
4332 | * the original last '\0' in case the original contains garbage. | |
4333 | */ | |
4334 | probe_kernel_read(&fn, &worker->current_func, sizeof(fn)); | |
4335 | probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq)); | |
4336 | probe_kernel_read(&wq, &pwq->wq, sizeof(wq)); | |
4337 | probe_kernel_read(name, wq->name, sizeof(name) - 1); | |
4338 | ||
4339 | /* copy worker description */ | |
4340 | probe_kernel_read(&desc_valid, &worker->desc_valid, sizeof(desc_valid)); | |
4341 | if (desc_valid) | |
4342 | probe_kernel_read(desc, worker->desc, sizeof(desc) - 1); | |
4343 | ||
4344 | if (fn || name[0] || desc[0]) { | |
4345 | printk("%sWorkqueue: %s %pf", log_lvl, name, fn); | |
4346 | if (desc[0]) | |
4347 | pr_cont(" (%s)", desc); | |
4348 | pr_cont("\n"); | |
4349 | } | |
4350 | } | |
4351 | ||
3494fc30 TH |
4352 | static void pr_cont_pool_info(struct worker_pool *pool) |
4353 | { | |
4354 | pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask); | |
4355 | if (pool->node != NUMA_NO_NODE) | |
4356 | pr_cont(" node=%d", pool->node); | |
4357 | pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice); | |
4358 | } | |
4359 | ||
4360 | static void pr_cont_work(bool comma, struct work_struct *work) | |
4361 | { | |
4362 | if (work->func == wq_barrier_func) { | |
4363 | struct wq_barrier *barr; | |
4364 | ||
4365 | barr = container_of(work, struct wq_barrier, work); | |
4366 | ||
4367 | pr_cont("%s BAR(%d)", comma ? "," : "", | |
4368 | task_pid_nr(barr->task)); | |
4369 | } else { | |
4370 | pr_cont("%s %pf", comma ? "," : "", work->func); | |
4371 | } | |
4372 | } | |
4373 | ||
4374 | static void show_pwq(struct pool_workqueue *pwq) | |
4375 | { | |
4376 | struct worker_pool *pool = pwq->pool; | |
4377 | struct work_struct *work; | |
4378 | struct worker *worker; | |
4379 | bool has_in_flight = false, has_pending = false; | |
4380 | int bkt; | |
4381 | ||
4382 | pr_info(" pwq %d:", pool->id); | |
4383 | pr_cont_pool_info(pool); | |
4384 | ||
4385 | pr_cont(" active=%d/%d%s\n", pwq->nr_active, pwq->max_active, | |
4386 | !list_empty(&pwq->mayday_node) ? " MAYDAY" : ""); | |
4387 | ||
4388 | hash_for_each(pool->busy_hash, bkt, worker, hentry) { | |
4389 | if (worker->current_pwq == pwq) { | |
4390 | has_in_flight = true; | |
4391 | break; | |
4392 | } | |
4393 | } | |
4394 | if (has_in_flight) { | |
4395 | bool comma = false; | |
4396 | ||
4397 | pr_info(" in-flight:"); | |
4398 | hash_for_each(pool->busy_hash, bkt, worker, hentry) { | |
4399 | if (worker->current_pwq != pwq) | |
4400 | continue; | |
4401 | ||
4402 | pr_cont("%s %d%s:%pf", comma ? "," : "", | |
4403 | task_pid_nr(worker->task), | |
4404 | worker == pwq->wq->rescuer ? "(RESCUER)" : "", | |
4405 | worker->current_func); | |
4406 | list_for_each_entry(work, &worker->scheduled, entry) | |
4407 | pr_cont_work(false, work); | |
4408 | comma = true; | |
4409 | } | |
4410 | pr_cont("\n"); | |
4411 | } | |
4412 | ||
4413 | list_for_each_entry(work, &pool->worklist, entry) { | |
4414 | if (get_work_pwq(work) == pwq) { | |
4415 | has_pending = true; | |
4416 | break; | |
4417 | } | |
4418 | } | |
4419 | if (has_pending) { | |
4420 | bool comma = false; | |
4421 | ||
4422 | pr_info(" pending:"); | |
4423 | list_for_each_entry(work, &pool->worklist, entry) { | |
4424 | if (get_work_pwq(work) != pwq) | |
4425 | continue; | |
4426 | ||
4427 | pr_cont_work(comma, work); | |
4428 | comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); | |
4429 | } | |
4430 | pr_cont("\n"); | |
4431 | } | |
4432 | ||
4433 | if (!list_empty(&pwq->delayed_works)) { | |
4434 | bool comma = false; | |
4435 | ||
4436 | pr_info(" delayed:"); | |
4437 | list_for_each_entry(work, &pwq->delayed_works, entry) { | |
4438 | pr_cont_work(comma, work); | |
4439 | comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); | |
4440 | } | |
4441 | pr_cont("\n"); | |
4442 | } | |
4443 | } | |
4444 | ||
4445 | /** | |
4446 | * show_workqueue_state - dump workqueue state | |
4447 | * | |
7b776af6 RL |
4448 | * Called from a sysrq handler or try_to_freeze_tasks() and prints out |
4449 | * all busy workqueues and pools. | |
3494fc30 TH |
4450 | */ |
4451 | void show_workqueue_state(void) | |
4452 | { | |
4453 | struct workqueue_struct *wq; | |
4454 | struct worker_pool *pool; | |
4455 | unsigned long flags; | |
4456 | int pi; | |
4457 | ||
4458 | rcu_read_lock_sched(); | |
4459 | ||
4460 | pr_info("Showing busy workqueues and worker pools:\n"); | |
4461 | ||
4462 | list_for_each_entry_rcu(wq, &workqueues, list) { | |
4463 | struct pool_workqueue *pwq; | |
4464 | bool idle = true; | |
4465 | ||
4466 | for_each_pwq(pwq, wq) { | |
4467 | if (pwq->nr_active || !list_empty(&pwq->delayed_works)) { | |
4468 | idle = false; | |
4469 | break; | |
4470 | } | |
4471 | } | |
4472 | if (idle) | |
4473 | continue; | |
4474 | ||
4475 | pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags); | |
4476 | ||
4477 | for_each_pwq(pwq, wq) { | |
4478 | spin_lock_irqsave(&pwq->pool->lock, flags); | |
4479 | if (pwq->nr_active || !list_empty(&pwq->delayed_works)) | |
4480 | show_pwq(pwq); | |
4481 | spin_unlock_irqrestore(&pwq->pool->lock, flags); | |
4482 | } | |
4483 | } | |
4484 | ||
4485 | for_each_pool(pool, pi) { | |
4486 | struct worker *worker; | |
4487 | bool first = true; | |
4488 | ||
4489 | spin_lock_irqsave(&pool->lock, flags); | |
4490 | if (pool->nr_workers == pool->nr_idle) | |
4491 | goto next_pool; | |
4492 | ||
4493 | pr_info("pool %d:", pool->id); | |
4494 | pr_cont_pool_info(pool); | |
82607adc TH |
4495 | pr_cont(" hung=%us workers=%d", |
4496 | jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000, | |
4497 | pool->nr_workers); | |
3494fc30 TH |
4498 | if (pool->manager) |
4499 | pr_cont(" manager: %d", | |
4500 | task_pid_nr(pool->manager->task)); | |
4501 | list_for_each_entry(worker, &pool->idle_list, entry) { | |
4502 | pr_cont(" %s%d", first ? "idle: " : "", | |
4503 | task_pid_nr(worker->task)); | |
4504 | first = false; | |
4505 | } | |
4506 | pr_cont("\n"); | |
4507 | next_pool: | |
4508 | spin_unlock_irqrestore(&pool->lock, flags); | |
4509 | } | |
4510 | ||
4511 | rcu_read_unlock_sched(); | |
4512 | } | |
4513 | ||
db7bccf4 TH |
4514 | /* |
4515 | * CPU hotplug. | |
4516 | * | |
e22bee78 | 4517 | * There are two challenges in supporting CPU hotplug. Firstly, there |
112202d9 | 4518 | * are a lot of assumptions on strong associations among work, pwq and |
706026c2 | 4519 | * pool which make migrating pending and scheduled works very |
e22bee78 | 4520 | * difficult to implement without impacting hot paths. Secondly, |
94cf58bb | 4521 | * worker pools serve mix of short, long and very long running works making |
e22bee78 TH |
4522 | * blocked draining impractical. |
4523 | * | |
24647570 | 4524 | * This is solved by allowing the pools to be disassociated from the CPU |
628c78e7 TH |
4525 | * running as an unbound one and allowing it to be reattached later if the |
4526 | * cpu comes back online. | |
db7bccf4 | 4527 | */ |
1da177e4 | 4528 | |
706026c2 | 4529 | static void wq_unbind_fn(struct work_struct *work) |
3af24433 | 4530 | { |
38db41d9 | 4531 | int cpu = smp_processor_id(); |
4ce62e9e | 4532 | struct worker_pool *pool; |
db7bccf4 | 4533 | struct worker *worker; |
3af24433 | 4534 | |
f02ae73a | 4535 | for_each_cpu_worker_pool(pool, cpu) { |
92f9c5c4 | 4536 | mutex_lock(&pool->attach_mutex); |
94cf58bb | 4537 | spin_lock_irq(&pool->lock); |
3af24433 | 4538 | |
94cf58bb | 4539 | /* |
92f9c5c4 | 4540 | * We've blocked all attach/detach operations. Make all workers |
94cf58bb TH |
4541 | * unbound and set DISASSOCIATED. Before this, all workers |
4542 | * except for the ones which are still executing works from | |
4543 | * before the last CPU down must be on the cpu. After | |
4544 | * this, they may become diasporas. | |
4545 | */ | |
da028469 | 4546 | for_each_pool_worker(worker, pool) |
c9e7cf27 | 4547 | worker->flags |= WORKER_UNBOUND; |
06ba38a9 | 4548 | |
24647570 | 4549 | pool->flags |= POOL_DISASSOCIATED; |
f2d5a0ee | 4550 | |
94cf58bb | 4551 | spin_unlock_irq(&pool->lock); |
92f9c5c4 | 4552 | mutex_unlock(&pool->attach_mutex); |
628c78e7 | 4553 | |
eb283428 LJ |
4554 | /* |
4555 | * Call schedule() so that we cross rq->lock and thus can | |
4556 | * guarantee sched callbacks see the %WORKER_UNBOUND flag. | |
4557 | * This is necessary as scheduler callbacks may be invoked | |
4558 | * from other cpus. | |
4559 | */ | |
4560 | schedule(); | |
06ba38a9 | 4561 | |
eb283428 LJ |
4562 | /* |
4563 | * Sched callbacks are disabled now. Zap nr_running. | |
4564 | * After this, nr_running stays zero and need_more_worker() | |
4565 | * and keep_working() are always true as long as the | |
4566 | * worklist is not empty. This pool now behaves as an | |
4567 | * unbound (in terms of concurrency management) pool which | |
4568 | * are served by workers tied to the pool. | |
4569 | */ | |
e19e397a | 4570 | atomic_set(&pool->nr_running, 0); |
eb283428 LJ |
4571 | |
4572 | /* | |
4573 | * With concurrency management just turned off, a busy | |
4574 | * worker blocking could lead to lengthy stalls. Kick off | |
4575 | * unbound chain execution of currently pending work items. | |
4576 | */ | |
4577 | spin_lock_irq(&pool->lock); | |
4578 | wake_up_worker(pool); | |
4579 | spin_unlock_irq(&pool->lock); | |
4580 | } | |
3af24433 | 4581 | } |
3af24433 | 4582 | |
bd7c089e TH |
4583 | /** |
4584 | * rebind_workers - rebind all workers of a pool to the associated CPU | |
4585 | * @pool: pool of interest | |
4586 | * | |
a9ab775b | 4587 | * @pool->cpu is coming online. Rebind all workers to the CPU. |
bd7c089e TH |
4588 | */ |
4589 | static void rebind_workers(struct worker_pool *pool) | |
4590 | { | |
a9ab775b | 4591 | struct worker *worker; |
bd7c089e | 4592 | |
92f9c5c4 | 4593 | lockdep_assert_held(&pool->attach_mutex); |
bd7c089e | 4594 | |
a9ab775b TH |
4595 | /* |
4596 | * Restore CPU affinity of all workers. As all idle workers should | |
4597 | * be on the run-queue of the associated CPU before any local | |
402dd89d | 4598 | * wake-ups for concurrency management happen, restore CPU affinity |
a9ab775b TH |
4599 | * of all workers first and then clear UNBOUND. As we're called |
4600 | * from CPU_ONLINE, the following shouldn't fail. | |
4601 | */ | |
da028469 | 4602 | for_each_pool_worker(worker, pool) |
a9ab775b TH |
4603 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, |
4604 | pool->attrs->cpumask) < 0); | |
bd7c089e | 4605 | |
a9ab775b | 4606 | spin_lock_irq(&pool->lock); |
f7c17d26 WL |
4607 | |
4608 | /* | |
4609 | * XXX: CPU hotplug notifiers are weird and can call DOWN_FAILED | |
4610 | * w/o preceding DOWN_PREPARE. Work around it. CPU hotplug is | |
4611 | * being reworked and this can go away in time. | |
4612 | */ | |
4613 | if (!(pool->flags & POOL_DISASSOCIATED)) { | |
4614 | spin_unlock_irq(&pool->lock); | |
4615 | return; | |
4616 | } | |
4617 | ||
3de5e884 | 4618 | pool->flags &= ~POOL_DISASSOCIATED; |
bd7c089e | 4619 | |
da028469 | 4620 | for_each_pool_worker(worker, pool) { |
a9ab775b | 4621 | unsigned int worker_flags = worker->flags; |
bd7c089e TH |
4622 | |
4623 | /* | |
a9ab775b TH |
4624 | * A bound idle worker should actually be on the runqueue |
4625 | * of the associated CPU for local wake-ups targeting it to | |
4626 | * work. Kick all idle workers so that they migrate to the | |
4627 | * associated CPU. Doing this in the same loop as | |
4628 | * replacing UNBOUND with REBOUND is safe as no worker will | |
4629 | * be bound before @pool->lock is released. | |
bd7c089e | 4630 | */ |
a9ab775b TH |
4631 | if (worker_flags & WORKER_IDLE) |
4632 | wake_up_process(worker->task); | |
bd7c089e | 4633 | |
a9ab775b TH |
4634 | /* |
4635 | * We want to clear UNBOUND but can't directly call | |
4636 | * worker_clr_flags() or adjust nr_running. Atomically | |
4637 | * replace UNBOUND with another NOT_RUNNING flag REBOUND. | |
4638 | * @worker will clear REBOUND using worker_clr_flags() when | |
4639 | * it initiates the next execution cycle thus restoring | |
4640 | * concurrency management. Note that when or whether | |
4641 | * @worker clears REBOUND doesn't affect correctness. | |
4642 | * | |
4643 | * ACCESS_ONCE() is necessary because @worker->flags may be | |
4644 | * tested without holding any lock in | |
4645 | * wq_worker_waking_up(). Without it, NOT_RUNNING test may | |
4646 | * fail incorrectly leading to premature concurrency | |
4647 | * management operations. | |
4648 | */ | |
4649 | WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND)); | |
4650 | worker_flags |= WORKER_REBOUND; | |
4651 | worker_flags &= ~WORKER_UNBOUND; | |
4652 | ACCESS_ONCE(worker->flags) = worker_flags; | |
bd7c089e | 4653 | } |
a9ab775b TH |
4654 | |
4655 | spin_unlock_irq(&pool->lock); | |
bd7c089e TH |
4656 | } |
4657 | ||
7dbc725e TH |
4658 | /** |
4659 | * restore_unbound_workers_cpumask - restore cpumask of unbound workers | |
4660 | * @pool: unbound pool of interest | |
4661 | * @cpu: the CPU which is coming up | |
4662 | * | |
4663 | * An unbound pool may end up with a cpumask which doesn't have any online | |
4664 | * CPUs. When a worker of such pool get scheduled, the scheduler resets | |
4665 | * its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any | |
4666 | * online CPU before, cpus_allowed of all its workers should be restored. | |
4667 | */ | |
4668 | static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) | |
4669 | { | |
4670 | static cpumask_t cpumask; | |
4671 | struct worker *worker; | |
7dbc725e | 4672 | |
92f9c5c4 | 4673 | lockdep_assert_held(&pool->attach_mutex); |
7dbc725e TH |
4674 | |
4675 | /* is @cpu allowed for @pool? */ | |
4676 | if (!cpumask_test_cpu(cpu, pool->attrs->cpumask)) | |
4677 | return; | |
4678 | ||
7dbc725e | 4679 | cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask); |
7dbc725e TH |
4680 | |
4681 | /* as we're called from CPU_ONLINE, the following shouldn't fail */ | |
da028469 | 4682 | for_each_pool_worker(worker, pool) |
d945b5e9 | 4683 | WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0); |
7dbc725e TH |
4684 | } |
4685 | ||
7ee681b2 TG |
4686 | int workqueue_prepare_cpu(unsigned int cpu) |
4687 | { | |
4688 | struct worker_pool *pool; | |
4689 | ||
4690 | for_each_cpu_worker_pool(pool, cpu) { | |
4691 | if (pool->nr_workers) | |
4692 | continue; | |
4693 | if (!create_worker(pool)) | |
4694 | return -ENOMEM; | |
4695 | } | |
4696 | return 0; | |
4697 | } | |
4698 | ||
4699 | int workqueue_online_cpu(unsigned int cpu) | |
3af24433 | 4700 | { |
4ce62e9e | 4701 | struct worker_pool *pool; |
4c16bd32 | 4702 | struct workqueue_struct *wq; |
7dbc725e | 4703 | int pi; |
3ce63377 | 4704 | |
7ee681b2 | 4705 | mutex_lock(&wq_pool_mutex); |
7dbc725e | 4706 | |
7ee681b2 TG |
4707 | for_each_pool(pool, pi) { |
4708 | mutex_lock(&pool->attach_mutex); | |
94cf58bb | 4709 | |
7ee681b2 TG |
4710 | if (pool->cpu == cpu) |
4711 | rebind_workers(pool); | |
4712 | else if (pool->cpu < 0) | |
4713 | restore_unbound_workers_cpumask(pool, cpu); | |
94cf58bb | 4714 | |
7ee681b2 TG |
4715 | mutex_unlock(&pool->attach_mutex); |
4716 | } | |
6ba94429 | 4717 | |
7ee681b2 TG |
4718 | /* update NUMA affinity of unbound workqueues */ |
4719 | list_for_each_entry(wq, &workqueues, list) | |
4720 | wq_update_unbound_numa(wq, cpu, true); | |
6ba94429 | 4721 | |
7ee681b2 TG |
4722 | mutex_unlock(&wq_pool_mutex); |
4723 | return 0; | |
6ba94429 FW |
4724 | } |
4725 | ||
7ee681b2 | 4726 | int workqueue_offline_cpu(unsigned int cpu) |
6ba94429 | 4727 | { |
6ba94429 FW |
4728 | struct work_struct unbind_work; |
4729 | struct workqueue_struct *wq; | |
4730 | ||
7ee681b2 TG |
4731 | /* unbinding per-cpu workers should happen on the local CPU */ |
4732 | INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn); | |
4733 | queue_work_on(cpu, system_highpri_wq, &unbind_work); | |
4734 | ||
4735 | /* update NUMA affinity of unbound workqueues */ | |
4736 | mutex_lock(&wq_pool_mutex); | |
4737 | list_for_each_entry(wq, &workqueues, list) | |
4738 | wq_update_unbound_numa(wq, cpu, false); | |
4739 | mutex_unlock(&wq_pool_mutex); | |
4740 | ||
4741 | /* wait for per-cpu unbinding to finish */ | |
4742 | flush_work(&unbind_work); | |
4743 | destroy_work_on_stack(&unbind_work); | |
4744 | return 0; | |
6ba94429 FW |
4745 | } |
4746 | ||
4747 | #ifdef CONFIG_SMP | |
4748 | ||
4749 | struct work_for_cpu { | |
4750 | struct work_struct work; | |
4751 | long (*fn)(void *); | |
4752 | void *arg; | |
4753 | long ret; | |
4754 | }; | |
4755 | ||
4756 | static void work_for_cpu_fn(struct work_struct *work) | |
4757 | { | |
4758 | struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work); | |
4759 | ||
4760 | wfc->ret = wfc->fn(wfc->arg); | |
4761 | } | |
4762 | ||
4763 | /** | |
22aceb31 | 4764 | * work_on_cpu - run a function in thread context on a particular cpu |
6ba94429 FW |
4765 | * @cpu: the cpu to run on |
4766 | * @fn: the function to run | |
4767 | * @arg: the function arg | |
4768 | * | |
4769 | * It is up to the caller to ensure that the cpu doesn't go offline. | |
4770 | * The caller must not hold any locks which would prevent @fn from completing. | |
4771 | * | |
4772 | * Return: The value @fn returns. | |
4773 | */ | |
4774 | long work_on_cpu(int cpu, long (*fn)(void *), void *arg) | |
4775 | { | |
4776 | struct work_for_cpu wfc = { .fn = fn, .arg = arg }; | |
4777 | ||
4778 | INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); | |
4779 | schedule_work_on(cpu, &wfc.work); | |
4780 | flush_work(&wfc.work); | |
4781 | destroy_work_on_stack(&wfc.work); | |
4782 | return wfc.ret; | |
4783 | } | |
4784 | EXPORT_SYMBOL_GPL(work_on_cpu); | |
0e8d6a93 TG |
4785 | |
4786 | /** | |
4787 | * work_on_cpu_safe - run a function in thread context on a particular cpu | |
4788 | * @cpu: the cpu to run on | |
4789 | * @fn: the function to run | |
4790 | * @arg: the function argument | |
4791 | * | |
4792 | * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold | |
4793 | * any locks which would prevent @fn from completing. | |
4794 | * | |
4795 | * Return: The value @fn returns. | |
4796 | */ | |
4797 | long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) | |
4798 | { | |
4799 | long ret = -ENODEV; | |
4800 | ||
4801 | get_online_cpus(); | |
4802 | if (cpu_online(cpu)) | |
4803 | ret = work_on_cpu(cpu, fn, arg); | |
4804 | put_online_cpus(); | |
4805 | return ret; | |
4806 | } | |
4807 | EXPORT_SYMBOL_GPL(work_on_cpu_safe); | |
6ba94429 FW |
4808 | #endif /* CONFIG_SMP */ |
4809 | ||
4810 | #ifdef CONFIG_FREEZER | |
4811 | ||
4812 | /** | |
4813 | * freeze_workqueues_begin - begin freezing workqueues | |
4814 | * | |
4815 | * Start freezing workqueues. After this function returns, all freezable | |
4816 | * workqueues will queue new works to their delayed_works list instead of | |
4817 | * pool->worklist. | |
4818 | * | |
4819 | * CONTEXT: | |
4820 | * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. | |
4821 | */ | |
4822 | void freeze_workqueues_begin(void) | |
4823 | { | |
4824 | struct workqueue_struct *wq; | |
4825 | struct pool_workqueue *pwq; | |
4826 | ||
4827 | mutex_lock(&wq_pool_mutex); | |
4828 | ||
4829 | WARN_ON_ONCE(workqueue_freezing); | |
4830 | workqueue_freezing = true; | |
4831 | ||
4832 | list_for_each_entry(wq, &workqueues, list) { | |
4833 | mutex_lock(&wq->mutex); | |
4834 | for_each_pwq(pwq, wq) | |
4835 | pwq_adjust_max_active(pwq); | |
4836 | mutex_unlock(&wq->mutex); | |
4837 | } | |
4838 | ||
4839 | mutex_unlock(&wq_pool_mutex); | |
4840 | } | |
4841 | ||
4842 | /** | |
4843 | * freeze_workqueues_busy - are freezable workqueues still busy? | |
4844 | * | |
4845 | * Check whether freezing is complete. This function must be called | |
4846 | * between freeze_workqueues_begin() and thaw_workqueues(). | |
4847 | * | |
4848 | * CONTEXT: | |
4849 | * Grabs and releases wq_pool_mutex. | |
4850 | * | |
4851 | * Return: | |
4852 | * %true if some freezable workqueues are still busy. %false if freezing | |
4853 | * is complete. | |
4854 | */ | |
4855 | bool freeze_workqueues_busy(void) | |
4856 | { | |
4857 | bool busy = false; | |
4858 | struct workqueue_struct *wq; | |
4859 | struct pool_workqueue *pwq; | |
4860 | ||
4861 | mutex_lock(&wq_pool_mutex); | |
4862 | ||
4863 | WARN_ON_ONCE(!workqueue_freezing); | |
4864 | ||
4865 | list_for_each_entry(wq, &workqueues, list) { | |
4866 | if (!(wq->flags & WQ_FREEZABLE)) | |
4867 | continue; | |
4868 | /* | |
4869 | * nr_active is monotonically decreasing. It's safe | |
4870 | * to peek without lock. | |
4871 | */ | |
4872 | rcu_read_lock_sched(); | |
4873 | for_each_pwq(pwq, wq) { | |
4874 | WARN_ON_ONCE(pwq->nr_active < 0); | |
4875 | if (pwq->nr_active) { | |
4876 | busy = true; | |
4877 | rcu_read_unlock_sched(); | |
4878 | goto out_unlock; | |
4879 | } | |
4880 | } | |
4881 | rcu_read_unlock_sched(); | |
4882 | } | |
4883 | out_unlock: | |
4884 | mutex_unlock(&wq_pool_mutex); | |
4885 | return busy; | |
4886 | } | |
4887 | ||
4888 | /** | |
4889 | * thaw_workqueues - thaw workqueues | |
4890 | * | |
4891 | * Thaw workqueues. Normal queueing is restored and all collected | |
4892 | * frozen works are transferred to their respective pool worklists. | |
4893 | * | |
4894 | * CONTEXT: | |
4895 | * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's. | |
4896 | */ | |
4897 | void thaw_workqueues(void) | |
4898 | { | |
4899 | struct workqueue_struct *wq; | |
4900 | struct pool_workqueue *pwq; | |
4901 | ||
4902 | mutex_lock(&wq_pool_mutex); | |
4903 | ||
4904 | if (!workqueue_freezing) | |
4905 | goto out_unlock; | |
4906 | ||
4907 | workqueue_freezing = false; | |
4908 | ||
4909 | /* restore max_active and repopulate worklist */ | |
4910 | list_for_each_entry(wq, &workqueues, list) { | |
4911 | mutex_lock(&wq->mutex); | |
4912 | for_each_pwq(pwq, wq) | |
4913 | pwq_adjust_max_active(pwq); | |
4914 | mutex_unlock(&wq->mutex); | |
4915 | } | |
4916 | ||
4917 | out_unlock: | |
4918 | mutex_unlock(&wq_pool_mutex); | |
4919 | } | |
4920 | #endif /* CONFIG_FREEZER */ | |
4921 | ||
042f7df1 LJ |
4922 | static int workqueue_apply_unbound_cpumask(void) |
4923 | { | |
4924 | LIST_HEAD(ctxs); | |
4925 | int ret = 0; | |
4926 | struct workqueue_struct *wq; | |
4927 | struct apply_wqattrs_ctx *ctx, *n; | |
4928 | ||
4929 | lockdep_assert_held(&wq_pool_mutex); | |
4930 | ||
4931 | list_for_each_entry(wq, &workqueues, list) { | |
4932 | if (!(wq->flags & WQ_UNBOUND)) | |
4933 | continue; | |
4934 | /* creating multiple pwqs breaks ordering guarantee */ | |
4935 | if (wq->flags & __WQ_ORDERED) | |
4936 | continue; | |
4937 | ||
4938 | ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs); | |
4939 | if (!ctx) { | |
4940 | ret = -ENOMEM; | |
4941 | break; | |
4942 | } | |
4943 | ||
4944 | list_add_tail(&ctx->list, &ctxs); | |
4945 | } | |
4946 | ||
4947 | list_for_each_entry_safe(ctx, n, &ctxs, list) { | |
4948 | if (!ret) | |
4949 | apply_wqattrs_commit(ctx); | |
4950 | apply_wqattrs_cleanup(ctx); | |
4951 | } | |
4952 | ||
4953 | return ret; | |
4954 | } | |
4955 | ||
4956 | /** | |
4957 | * workqueue_set_unbound_cpumask - Set the low-level unbound cpumask | |
4958 | * @cpumask: the cpumask to set | |
4959 | * | |
4960 | * The low-level workqueues cpumask is a global cpumask that limits | |
4961 | * the affinity of all unbound workqueues. This function check the @cpumask | |
4962 | * and apply it to all unbound workqueues and updates all pwqs of them. | |
4963 | * | |
4964 | * Retun: 0 - Success | |
4965 | * -EINVAL - Invalid @cpumask | |
4966 | * -ENOMEM - Failed to allocate memory for attrs or pwqs. | |
4967 | */ | |
4968 | int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) | |
4969 | { | |
4970 | int ret = -EINVAL; | |
4971 | cpumask_var_t saved_cpumask; | |
4972 | ||
4973 | if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) | |
4974 | return -ENOMEM; | |
4975 | ||
042f7df1 LJ |
4976 | cpumask_and(cpumask, cpumask, cpu_possible_mask); |
4977 | if (!cpumask_empty(cpumask)) { | |
a0111cf6 | 4978 | apply_wqattrs_lock(); |
042f7df1 LJ |
4979 | |
4980 | /* save the old wq_unbound_cpumask. */ | |
4981 | cpumask_copy(saved_cpumask, wq_unbound_cpumask); | |
4982 | ||
4983 | /* update wq_unbound_cpumask at first and apply it to wqs. */ | |
4984 | cpumask_copy(wq_unbound_cpumask, cpumask); | |
4985 | ret = workqueue_apply_unbound_cpumask(); | |
4986 | ||
4987 | /* restore the wq_unbound_cpumask when failed. */ | |
4988 | if (ret < 0) | |
4989 | cpumask_copy(wq_unbound_cpumask, saved_cpumask); | |
4990 | ||
a0111cf6 | 4991 | apply_wqattrs_unlock(); |
042f7df1 | 4992 | } |
042f7df1 LJ |
4993 | |
4994 | free_cpumask_var(saved_cpumask); | |
4995 | return ret; | |
4996 | } | |
4997 | ||
6ba94429 FW |
4998 | #ifdef CONFIG_SYSFS |
4999 | /* | |
5000 | * Workqueues with WQ_SYSFS flag set is visible to userland via | |
5001 | * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the | |
5002 | * following attributes. | |
5003 | * | |
5004 | * per_cpu RO bool : whether the workqueue is per-cpu or unbound | |
5005 | * max_active RW int : maximum number of in-flight work items | |
5006 | * | |
5007 | * Unbound workqueues have the following extra attributes. | |
5008 | * | |
5009 | * id RO int : the associated pool ID | |
5010 | * nice RW int : nice value of the workers | |
5011 | * cpumask RW mask : bitmask of allowed CPUs for the workers | |
5012 | */ | |
5013 | struct wq_device { | |
5014 | struct workqueue_struct *wq; | |
5015 | struct device dev; | |
5016 | }; | |
5017 | ||
5018 | static struct workqueue_struct *dev_to_wq(struct device *dev) | |
5019 | { | |
5020 | struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); | |
5021 | ||
5022 | return wq_dev->wq; | |
5023 | } | |
5024 | ||
5025 | static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr, | |
5026 | char *buf) | |
5027 | { | |
5028 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5029 | ||
5030 | return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND)); | |
5031 | } | |
5032 | static DEVICE_ATTR_RO(per_cpu); | |
5033 | ||
5034 | static ssize_t max_active_show(struct device *dev, | |
5035 | struct device_attribute *attr, char *buf) | |
5036 | { | |
5037 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5038 | ||
5039 | return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active); | |
5040 | } | |
5041 | ||
5042 | static ssize_t max_active_store(struct device *dev, | |
5043 | struct device_attribute *attr, const char *buf, | |
5044 | size_t count) | |
5045 | { | |
5046 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5047 | int val; | |
5048 | ||
5049 | if (sscanf(buf, "%d", &val) != 1 || val <= 0) | |
5050 | return -EINVAL; | |
5051 | ||
5052 | workqueue_set_max_active(wq, val); | |
5053 | return count; | |
5054 | } | |
5055 | static DEVICE_ATTR_RW(max_active); | |
5056 | ||
5057 | static struct attribute *wq_sysfs_attrs[] = { | |
5058 | &dev_attr_per_cpu.attr, | |
5059 | &dev_attr_max_active.attr, | |
5060 | NULL, | |
5061 | }; | |
5062 | ATTRIBUTE_GROUPS(wq_sysfs); | |
5063 | ||
5064 | static ssize_t wq_pool_ids_show(struct device *dev, | |
5065 | struct device_attribute *attr, char *buf) | |
5066 | { | |
5067 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5068 | const char *delim = ""; | |
5069 | int node, written = 0; | |
5070 | ||
5071 | rcu_read_lock_sched(); | |
5072 | for_each_node(node) { | |
5073 | written += scnprintf(buf + written, PAGE_SIZE - written, | |
5074 | "%s%d:%d", delim, node, | |
5075 | unbound_pwq_by_node(wq, node)->pool->id); | |
5076 | delim = " "; | |
5077 | } | |
5078 | written += scnprintf(buf + written, PAGE_SIZE - written, "\n"); | |
5079 | rcu_read_unlock_sched(); | |
5080 | ||
5081 | return written; | |
5082 | } | |
5083 | ||
5084 | static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, | |
5085 | char *buf) | |
5086 | { | |
5087 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5088 | int written; | |
5089 | ||
5090 | mutex_lock(&wq->mutex); | |
5091 | written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); | |
5092 | mutex_unlock(&wq->mutex); | |
5093 | ||
5094 | return written; | |
5095 | } | |
5096 | ||
5097 | /* prepare workqueue_attrs for sysfs store operations */ | |
5098 | static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) | |
5099 | { | |
5100 | struct workqueue_attrs *attrs; | |
5101 | ||
899a94fe LJ |
5102 | lockdep_assert_held(&wq_pool_mutex); |
5103 | ||
6ba94429 FW |
5104 | attrs = alloc_workqueue_attrs(GFP_KERNEL); |
5105 | if (!attrs) | |
5106 | return NULL; | |
5107 | ||
6ba94429 | 5108 | copy_workqueue_attrs(attrs, wq->unbound_attrs); |
6ba94429 FW |
5109 | return attrs; |
5110 | } | |
5111 | ||
5112 | static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, | |
5113 | const char *buf, size_t count) | |
5114 | { | |
5115 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5116 | struct workqueue_attrs *attrs; | |
d4d3e257 LJ |
5117 | int ret = -ENOMEM; |
5118 | ||
5119 | apply_wqattrs_lock(); | |
6ba94429 FW |
5120 | |
5121 | attrs = wq_sysfs_prep_attrs(wq); | |
5122 | if (!attrs) | |
d4d3e257 | 5123 | goto out_unlock; |
6ba94429 FW |
5124 | |
5125 | if (sscanf(buf, "%d", &attrs->nice) == 1 && | |
5126 | attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) | |
d4d3e257 | 5127 | ret = apply_workqueue_attrs_locked(wq, attrs); |
6ba94429 FW |
5128 | else |
5129 | ret = -EINVAL; | |
5130 | ||
d4d3e257 LJ |
5131 | out_unlock: |
5132 | apply_wqattrs_unlock(); | |
6ba94429 FW |
5133 | free_workqueue_attrs(attrs); |
5134 | return ret ?: count; | |
5135 | } | |
5136 | ||
5137 | static ssize_t wq_cpumask_show(struct device *dev, | |
5138 | struct device_attribute *attr, char *buf) | |
5139 | { | |
5140 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5141 | int written; | |
5142 | ||
5143 | mutex_lock(&wq->mutex); | |
5144 | written = scnprintf(buf, PAGE_SIZE, "%*pb\n", | |
5145 | cpumask_pr_args(wq->unbound_attrs->cpumask)); | |
5146 | mutex_unlock(&wq->mutex); | |
5147 | return written; | |
5148 | } | |
5149 | ||
5150 | static ssize_t wq_cpumask_store(struct device *dev, | |
5151 | struct device_attribute *attr, | |
5152 | const char *buf, size_t count) | |
5153 | { | |
5154 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5155 | struct workqueue_attrs *attrs; | |
d4d3e257 LJ |
5156 | int ret = -ENOMEM; |
5157 | ||
5158 | apply_wqattrs_lock(); | |
6ba94429 FW |
5159 | |
5160 | attrs = wq_sysfs_prep_attrs(wq); | |
5161 | if (!attrs) | |
d4d3e257 | 5162 | goto out_unlock; |
6ba94429 FW |
5163 | |
5164 | ret = cpumask_parse(buf, attrs->cpumask); | |
5165 | if (!ret) | |
d4d3e257 | 5166 | ret = apply_workqueue_attrs_locked(wq, attrs); |
6ba94429 | 5167 | |
d4d3e257 LJ |
5168 | out_unlock: |
5169 | apply_wqattrs_unlock(); | |
6ba94429 FW |
5170 | free_workqueue_attrs(attrs); |
5171 | return ret ?: count; | |
5172 | } | |
5173 | ||
5174 | static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr, | |
5175 | char *buf) | |
5176 | { | |
5177 | struct workqueue_struct *wq = dev_to_wq(dev); | |
5178 | int written; | |
7dbc725e | 5179 | |
6ba94429 FW |
5180 | mutex_lock(&wq->mutex); |
5181 | written = scnprintf(buf, PAGE_SIZE, "%d\n", | |
5182 | !wq->unbound_attrs->no_numa); | |
5183 | mutex_unlock(&wq->mutex); | |
4c16bd32 | 5184 | |
6ba94429 | 5185 | return written; |
65758202 TH |
5186 | } |
5187 | ||
6ba94429 FW |
5188 | static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr, |
5189 | const char *buf, size_t count) | |
65758202 | 5190 | { |
6ba94429 FW |
5191 | struct workqueue_struct *wq = dev_to_wq(dev); |
5192 | struct workqueue_attrs *attrs; | |
d4d3e257 LJ |
5193 | int v, ret = -ENOMEM; |
5194 | ||
5195 | apply_wqattrs_lock(); | |
4c16bd32 | 5196 | |
6ba94429 FW |
5197 | attrs = wq_sysfs_prep_attrs(wq); |
5198 | if (!attrs) | |
d4d3e257 | 5199 | goto out_unlock; |
4c16bd32 | 5200 | |
6ba94429 FW |
5201 | ret = -EINVAL; |
5202 | if (sscanf(buf, "%d", &v) == 1) { | |
5203 | attrs->no_numa = !v; | |
d4d3e257 | 5204 | ret = apply_workqueue_attrs_locked(wq, attrs); |
65758202 | 5205 | } |
6ba94429 | 5206 | |
d4d3e257 LJ |
5207 | out_unlock: |
5208 | apply_wqattrs_unlock(); | |
6ba94429 FW |
5209 | free_workqueue_attrs(attrs); |
5210 | return ret ?: count; | |
65758202 TH |
5211 | } |
5212 | ||
6ba94429 FW |
5213 | static struct device_attribute wq_sysfs_unbound_attrs[] = { |
5214 | __ATTR(pool_ids, 0444, wq_pool_ids_show, NULL), | |
5215 | __ATTR(nice, 0644, wq_nice_show, wq_nice_store), | |
5216 | __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store), | |
5217 | __ATTR(numa, 0644, wq_numa_show, wq_numa_store), | |
5218 | __ATTR_NULL, | |
5219 | }; | |
8ccad40d | 5220 | |
6ba94429 FW |
5221 | static struct bus_type wq_subsys = { |
5222 | .name = "workqueue", | |
5223 | .dev_groups = wq_sysfs_groups, | |
2d3854a3 RR |
5224 | }; |
5225 | ||
b05a7928 FW |
5226 | static ssize_t wq_unbound_cpumask_show(struct device *dev, |
5227 | struct device_attribute *attr, char *buf) | |
5228 | { | |
5229 | int written; | |
5230 | ||
042f7df1 | 5231 | mutex_lock(&wq_pool_mutex); |
b05a7928 FW |
5232 | written = scnprintf(buf, PAGE_SIZE, "%*pb\n", |
5233 | cpumask_pr_args(wq_unbound_cpumask)); | |
042f7df1 | 5234 | mutex_unlock(&wq_pool_mutex); |
b05a7928 FW |
5235 | |
5236 | return written; | |
5237 | } | |
5238 | ||
042f7df1 LJ |
5239 | static ssize_t wq_unbound_cpumask_store(struct device *dev, |
5240 | struct device_attribute *attr, const char *buf, size_t count) | |
5241 | { | |
5242 | cpumask_var_t cpumask; | |
5243 | int ret; | |
5244 | ||
5245 | if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) | |
5246 | return -ENOMEM; | |
5247 | ||
5248 | ret = cpumask_parse(buf, cpumask); | |
5249 | if (!ret) | |
5250 | ret = workqueue_set_unbound_cpumask(cpumask); | |
5251 | ||
5252 | free_cpumask_var(cpumask); | |
5253 | return ret ? ret : count; | |
5254 | } | |
5255 | ||
b05a7928 | 5256 | static struct device_attribute wq_sysfs_cpumask_attr = |
042f7df1 LJ |
5257 | __ATTR(cpumask, 0644, wq_unbound_cpumask_show, |
5258 | wq_unbound_cpumask_store); | |
b05a7928 | 5259 | |
6ba94429 | 5260 | static int __init wq_sysfs_init(void) |
2d3854a3 | 5261 | { |
b05a7928 FW |
5262 | int err; |
5263 | ||
5264 | err = subsys_virtual_register(&wq_subsys, NULL); | |
5265 | if (err) | |
5266 | return err; | |
5267 | ||
5268 | return device_create_file(wq_subsys.dev_root, &wq_sysfs_cpumask_attr); | |
2d3854a3 | 5269 | } |
6ba94429 | 5270 | core_initcall(wq_sysfs_init); |
2d3854a3 | 5271 | |
6ba94429 | 5272 | static void wq_device_release(struct device *dev) |
2d3854a3 | 5273 | { |
6ba94429 | 5274 | struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); |
6b44003e | 5275 | |
6ba94429 | 5276 | kfree(wq_dev); |
2d3854a3 | 5277 | } |
a0a1a5fd TH |
5278 | |
5279 | /** | |
6ba94429 FW |
5280 | * workqueue_sysfs_register - make a workqueue visible in sysfs |
5281 | * @wq: the workqueue to register | |
a0a1a5fd | 5282 | * |
6ba94429 FW |
5283 | * Expose @wq in sysfs under /sys/bus/workqueue/devices. |
5284 | * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set | |
5285 | * which is the preferred method. | |
a0a1a5fd | 5286 | * |
6ba94429 FW |
5287 | * Workqueue user should use this function directly iff it wants to apply |
5288 | * workqueue_attrs before making the workqueue visible in sysfs; otherwise, | |
5289 | * apply_workqueue_attrs() may race against userland updating the | |
5290 | * attributes. | |
5291 | * | |
5292 | * Return: 0 on success, -errno on failure. | |
a0a1a5fd | 5293 | */ |
6ba94429 | 5294 | int workqueue_sysfs_register(struct workqueue_struct *wq) |
a0a1a5fd | 5295 | { |
6ba94429 FW |
5296 | struct wq_device *wq_dev; |
5297 | int ret; | |
a0a1a5fd | 5298 | |
6ba94429 | 5299 | /* |
402dd89d | 5300 | * Adjusting max_active or creating new pwqs by applying |
6ba94429 FW |
5301 | * attributes breaks ordering guarantee. Disallow exposing ordered |
5302 | * workqueues. | |
5303 | */ | |
0a94efb5 | 5304 | if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) |
6ba94429 | 5305 | return -EINVAL; |
a0a1a5fd | 5306 | |
6ba94429 FW |
5307 | wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); |
5308 | if (!wq_dev) | |
5309 | return -ENOMEM; | |
5bcab335 | 5310 | |
6ba94429 FW |
5311 | wq_dev->wq = wq; |
5312 | wq_dev->dev.bus = &wq_subsys; | |
6ba94429 | 5313 | wq_dev->dev.release = wq_device_release; |
23217b44 | 5314 | dev_set_name(&wq_dev->dev, "%s", wq->name); |
a0a1a5fd | 5315 | |
6ba94429 FW |
5316 | /* |
5317 | * unbound_attrs are created separately. Suppress uevent until | |
5318 | * everything is ready. | |
5319 | */ | |
5320 | dev_set_uevent_suppress(&wq_dev->dev, true); | |
a0a1a5fd | 5321 | |
6ba94429 FW |
5322 | ret = device_register(&wq_dev->dev); |
5323 | if (ret) { | |
5324 | kfree(wq_dev); | |
5325 | wq->wq_dev = NULL; | |
5326 | return ret; | |
5327 | } | |
a0a1a5fd | 5328 | |
6ba94429 FW |
5329 | if (wq->flags & WQ_UNBOUND) { |
5330 | struct device_attribute *attr; | |
a0a1a5fd | 5331 | |
6ba94429 FW |
5332 | for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) { |
5333 | ret = device_create_file(&wq_dev->dev, attr); | |
5334 | if (ret) { | |
5335 | device_unregister(&wq_dev->dev); | |
5336 | wq->wq_dev = NULL; | |
5337 | return ret; | |
a0a1a5fd TH |
5338 | } |
5339 | } | |
5340 | } | |
6ba94429 FW |
5341 | |
5342 | dev_set_uevent_suppress(&wq_dev->dev, false); | |
5343 | kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD); | |
5344 | return 0; | |
a0a1a5fd TH |
5345 | } |
5346 | ||
5347 | /** | |
6ba94429 FW |
5348 | * workqueue_sysfs_unregister - undo workqueue_sysfs_register() |
5349 | * @wq: the workqueue to unregister | |
a0a1a5fd | 5350 | * |
6ba94429 | 5351 | * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister. |
a0a1a5fd | 5352 | */ |
6ba94429 | 5353 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq) |
a0a1a5fd | 5354 | { |
6ba94429 | 5355 | struct wq_device *wq_dev = wq->wq_dev; |
8b03ae3c | 5356 | |
6ba94429 FW |
5357 | if (!wq->wq_dev) |
5358 | return; | |
a0a1a5fd | 5359 | |
6ba94429 FW |
5360 | wq->wq_dev = NULL; |
5361 | device_unregister(&wq_dev->dev); | |
a0a1a5fd | 5362 | } |
6ba94429 FW |
5363 | #else /* CONFIG_SYSFS */ |
5364 | static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { } | |
5365 | #endif /* CONFIG_SYSFS */ | |
a0a1a5fd | 5366 | |
82607adc TH |
5367 | /* |
5368 | * Workqueue watchdog. | |
5369 | * | |
5370 | * Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal | |
5371 | * flush dependency, a concurrency managed work item which stays RUNNING | |
5372 | * indefinitely. Workqueue stalls can be very difficult to debug as the | |
5373 | * usual warning mechanisms don't trigger and internal workqueue state is | |
5374 | * largely opaque. | |
5375 | * | |
5376 | * Workqueue watchdog monitors all worker pools periodically and dumps | |
5377 | * state if some pools failed to make forward progress for a while where | |
5378 | * forward progress is defined as the first item on ->worklist changing. | |
5379 | * | |
5380 | * This mechanism is controlled through the kernel parameter | |
5381 | * "workqueue.watchdog_thresh" which can be updated at runtime through the | |
5382 | * corresponding sysfs parameter file. | |
5383 | */ | |
5384 | #ifdef CONFIG_WQ_WATCHDOG | |
5385 | ||
5386 | static void wq_watchdog_timer_fn(unsigned long data); | |
5387 | ||
5388 | static unsigned long wq_watchdog_thresh = 30; | |
5389 | static struct timer_list wq_watchdog_timer = | |
5390 | TIMER_DEFERRED_INITIALIZER(wq_watchdog_timer_fn, 0, 0); | |
5391 | ||
5392 | static unsigned long wq_watchdog_touched = INITIAL_JIFFIES; | |
5393 | static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES; | |
5394 | ||
5395 | static void wq_watchdog_reset_touched(void) | |
5396 | { | |
5397 | int cpu; | |
5398 | ||
5399 | wq_watchdog_touched = jiffies; | |
5400 | for_each_possible_cpu(cpu) | |
5401 | per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; | |
5402 | } | |
5403 | ||
5404 | static void wq_watchdog_timer_fn(unsigned long data) | |
5405 | { | |
5406 | unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ; | |
5407 | bool lockup_detected = false; | |
5408 | struct worker_pool *pool; | |
5409 | int pi; | |
5410 | ||
5411 | if (!thresh) | |
5412 | return; | |
5413 | ||
5414 | rcu_read_lock(); | |
5415 | ||
5416 | for_each_pool(pool, pi) { | |
5417 | unsigned long pool_ts, touched, ts; | |
5418 | ||
5419 | if (list_empty(&pool->worklist)) | |
5420 | continue; | |
5421 | ||
5422 | /* get the latest of pool and touched timestamps */ | |
5423 | pool_ts = READ_ONCE(pool->watchdog_ts); | |
5424 | touched = READ_ONCE(wq_watchdog_touched); | |
5425 | ||
5426 | if (time_after(pool_ts, touched)) | |
5427 | ts = pool_ts; | |
5428 | else | |
5429 | ts = touched; | |
5430 | ||
5431 | if (pool->cpu >= 0) { | |
5432 | unsigned long cpu_touched = | |
5433 | READ_ONCE(per_cpu(wq_watchdog_touched_cpu, | |
5434 | pool->cpu)); | |
5435 | if (time_after(cpu_touched, ts)) | |
5436 | ts = cpu_touched; | |
5437 | } | |
5438 | ||
5439 | /* did we stall? */ | |
5440 | if (time_after(jiffies, ts + thresh)) { | |
5441 | lockup_detected = true; | |
5442 | pr_emerg("BUG: workqueue lockup - pool"); | |
5443 | pr_cont_pool_info(pool); | |
5444 | pr_cont(" stuck for %us!\n", | |
5445 | jiffies_to_msecs(jiffies - pool_ts) / 1000); | |
5446 | } | |
5447 | } | |
5448 | ||
5449 | rcu_read_unlock(); | |
5450 | ||
5451 | if (lockup_detected) | |
5452 | show_workqueue_state(); | |
5453 | ||
5454 | wq_watchdog_reset_touched(); | |
5455 | mod_timer(&wq_watchdog_timer, jiffies + thresh); | |
5456 | } | |
5457 | ||
5458 | void wq_watchdog_touch(int cpu) | |
5459 | { | |
5460 | if (cpu >= 0) | |
5461 | per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; | |
5462 | else | |
5463 | wq_watchdog_touched = jiffies; | |
5464 | } | |
5465 | ||
5466 | static void wq_watchdog_set_thresh(unsigned long thresh) | |
5467 | { | |
5468 | wq_watchdog_thresh = 0; | |
5469 | del_timer_sync(&wq_watchdog_timer); | |
5470 | ||
5471 | if (thresh) { | |
5472 | wq_watchdog_thresh = thresh; | |
5473 | wq_watchdog_reset_touched(); | |
5474 | mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ); | |
5475 | } | |
5476 | } | |
5477 | ||
5478 | static int wq_watchdog_param_set_thresh(const char *val, | |
5479 | const struct kernel_param *kp) | |
5480 | { | |
5481 | unsigned long thresh; | |
5482 | int ret; | |
5483 | ||
5484 | ret = kstrtoul(val, 0, &thresh); | |
5485 | if (ret) | |
5486 | return ret; | |
5487 | ||
5488 | if (system_wq) | |
5489 | wq_watchdog_set_thresh(thresh); | |
5490 | else | |
5491 | wq_watchdog_thresh = thresh; | |
5492 | ||
5493 | return 0; | |
5494 | } | |
5495 | ||
5496 | static const struct kernel_param_ops wq_watchdog_thresh_ops = { | |
5497 | .set = wq_watchdog_param_set_thresh, | |
5498 | .get = param_get_ulong, | |
5499 | }; | |
5500 | ||
5501 | module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh, | |
5502 | 0644); | |
5503 | ||
5504 | static void wq_watchdog_init(void) | |
5505 | { | |
5506 | wq_watchdog_set_thresh(wq_watchdog_thresh); | |
5507 | } | |
5508 | ||
5509 | #else /* CONFIG_WQ_WATCHDOG */ | |
5510 | ||
5511 | static inline void wq_watchdog_init(void) { } | |
5512 | ||
5513 | #endif /* CONFIG_WQ_WATCHDOG */ | |
5514 | ||
bce90380 TH |
5515 | static void __init wq_numa_init(void) |
5516 | { | |
5517 | cpumask_var_t *tbl; | |
5518 | int node, cpu; | |
5519 | ||
bce90380 TH |
5520 | if (num_possible_nodes() <= 1) |
5521 | return; | |
5522 | ||
d55262c4 TH |
5523 | if (wq_disable_numa) { |
5524 | pr_info("workqueue: NUMA affinity support disabled\n"); | |
5525 | return; | |
5526 | } | |
5527 | ||
4c16bd32 TH |
5528 | wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs(GFP_KERNEL); |
5529 | BUG_ON(!wq_update_unbound_numa_attrs_buf); | |
5530 | ||
bce90380 TH |
5531 | /* |
5532 | * We want masks of possible CPUs of each node which isn't readily | |
5533 | * available. Build one from cpu_to_node() which should have been | |
5534 | * fully initialized by now. | |
5535 | */ | |
ddcb57e2 | 5536 | tbl = kzalloc(nr_node_ids * sizeof(tbl[0]), GFP_KERNEL); |
bce90380 TH |
5537 | BUG_ON(!tbl); |
5538 | ||
5539 | for_each_node(node) | |
5a6024f1 | 5540 | BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL, |
1be0c25d | 5541 | node_online(node) ? node : NUMA_NO_NODE)); |
bce90380 TH |
5542 | |
5543 | for_each_possible_cpu(cpu) { | |
5544 | node = cpu_to_node(cpu); | |
5545 | if (WARN_ON(node == NUMA_NO_NODE)) { | |
5546 | pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu); | |
5547 | /* happens iff arch is bonkers, let's just proceed */ | |
5548 | return; | |
5549 | } | |
5550 | cpumask_set_cpu(cpu, tbl[node]); | |
5551 | } | |
5552 | ||
5553 | wq_numa_possible_cpumask = tbl; | |
5554 | wq_numa_enabled = true; | |
5555 | } | |
5556 | ||
3347fa09 TH |
5557 | /** |
5558 | * workqueue_init_early - early init for workqueue subsystem | |
5559 | * | |
5560 | * This is the first half of two-staged workqueue subsystem initialization | |
5561 | * and invoked as soon as the bare basics - memory allocation, cpumasks and | |
5562 | * idr are up. It sets up all the data structures and system workqueues | |
5563 | * and allows early boot code to create workqueues and queue/cancel work | |
5564 | * items. Actual work item execution starts only after kthreads can be | |
5565 | * created and scheduled right before early initcalls. | |
5566 | */ | |
5567 | int __init workqueue_init_early(void) | |
1da177e4 | 5568 | { |
7a4e344c TH |
5569 | int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL }; |
5570 | int i, cpu; | |
c34056a3 | 5571 | |
e904e6c2 TH |
5572 | WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long)); |
5573 | ||
b05a7928 FW |
5574 | BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL)); |
5575 | cpumask_copy(wq_unbound_cpumask, cpu_possible_mask); | |
5576 | ||
e904e6c2 TH |
5577 | pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC); |
5578 | ||
706026c2 | 5579 | /* initialize CPU pools */ |
29c91e99 | 5580 | for_each_possible_cpu(cpu) { |
4ce62e9e | 5581 | struct worker_pool *pool; |
8b03ae3c | 5582 | |
7a4e344c | 5583 | i = 0; |
f02ae73a | 5584 | for_each_cpu_worker_pool(pool, cpu) { |
7a4e344c | 5585 | BUG_ON(init_worker_pool(pool)); |
ec22ca5e | 5586 | pool->cpu = cpu; |
29c91e99 | 5587 | cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu)); |
7a4e344c | 5588 | pool->attrs->nice = std_nice[i++]; |
f3f90ad4 | 5589 | pool->node = cpu_to_node(cpu); |
7a4e344c | 5590 | |
9daf9e67 | 5591 | /* alloc pool ID */ |
68e13a67 | 5592 | mutex_lock(&wq_pool_mutex); |
9daf9e67 | 5593 | BUG_ON(worker_pool_assign_id(pool)); |
68e13a67 | 5594 | mutex_unlock(&wq_pool_mutex); |
4ce62e9e | 5595 | } |
8b03ae3c TH |
5596 | } |
5597 | ||
8a2b7538 | 5598 | /* create default unbound and ordered wq attrs */ |
29c91e99 TH |
5599 | for (i = 0; i < NR_STD_WORKER_POOLS; i++) { |
5600 | struct workqueue_attrs *attrs; | |
5601 | ||
5602 | BUG_ON(!(attrs = alloc_workqueue_attrs(GFP_KERNEL))); | |
29c91e99 | 5603 | attrs->nice = std_nice[i]; |
29c91e99 | 5604 | unbound_std_wq_attrs[i] = attrs; |
8a2b7538 TH |
5605 | |
5606 | /* | |
5607 | * An ordered wq should have only one pwq as ordering is | |
5608 | * guaranteed by max_active which is enforced by pwqs. | |
5609 | * Turn off NUMA so that dfl_pwq is used for all nodes. | |
5610 | */ | |
5611 | BUG_ON(!(attrs = alloc_workqueue_attrs(GFP_KERNEL))); | |
5612 | attrs->nice = std_nice[i]; | |
5613 | attrs->no_numa = true; | |
5614 | ordered_wq_attrs[i] = attrs; | |
29c91e99 TH |
5615 | } |
5616 | ||
d320c038 | 5617 | system_wq = alloc_workqueue("events", 0, 0); |
1aabe902 | 5618 | system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0); |
d320c038 | 5619 | system_long_wq = alloc_workqueue("events_long", 0, 0); |
f3421797 TH |
5620 | system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, |
5621 | WQ_UNBOUND_MAX_ACTIVE); | |
24d51add TH |
5622 | system_freezable_wq = alloc_workqueue("events_freezable", |
5623 | WQ_FREEZABLE, 0); | |
0668106c VK |
5624 | system_power_efficient_wq = alloc_workqueue("events_power_efficient", |
5625 | WQ_POWER_EFFICIENT, 0); | |
5626 | system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient", | |
5627 | WQ_FREEZABLE | WQ_POWER_EFFICIENT, | |
5628 | 0); | |
1aabe902 | 5629 | BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || |
0668106c VK |
5630 | !system_unbound_wq || !system_freezable_wq || |
5631 | !system_power_efficient_wq || | |
5632 | !system_freezable_power_efficient_wq); | |
82607adc | 5633 | |
3347fa09 TH |
5634 | return 0; |
5635 | } | |
5636 | ||
5637 | /** | |
5638 | * workqueue_init - bring workqueue subsystem fully online | |
5639 | * | |
5640 | * This is the latter half of two-staged workqueue subsystem initialization | |
5641 | * and invoked as soon as kthreads can be created and scheduled. | |
5642 | * Workqueues have been created and work items queued on them, but there | |
5643 | * are no kworkers executing the work items yet. Populate the worker pools | |
5644 | * with the initial workers and enable future kworker creations. | |
5645 | */ | |
5646 | int __init workqueue_init(void) | |
5647 | { | |
2186d9f9 | 5648 | struct workqueue_struct *wq; |
3347fa09 TH |
5649 | struct worker_pool *pool; |
5650 | int cpu, bkt; | |
5651 | ||
2186d9f9 TH |
5652 | /* |
5653 | * It'd be simpler to initialize NUMA in workqueue_init_early() but | |
5654 | * CPU to node mapping may not be available that early on some | |
5655 | * archs such as power and arm64. As per-cpu pools created | |
5656 | * previously could be missing node hint and unbound pools NUMA | |
5657 | * affinity, fix them up. | |
5658 | */ | |
5659 | wq_numa_init(); | |
5660 | ||
5661 | mutex_lock(&wq_pool_mutex); | |
5662 | ||
5663 | for_each_possible_cpu(cpu) { | |
5664 | for_each_cpu_worker_pool(pool, cpu) { | |
5665 | pool->node = cpu_to_node(cpu); | |
5666 | } | |
5667 | } | |
5668 | ||
5669 | list_for_each_entry(wq, &workqueues, list) | |
5670 | wq_update_unbound_numa(wq, smp_processor_id(), true); | |
5671 | ||
5672 | mutex_unlock(&wq_pool_mutex); | |
5673 | ||
3347fa09 TH |
5674 | /* create the initial workers */ |
5675 | for_each_online_cpu(cpu) { | |
5676 | for_each_cpu_worker_pool(pool, cpu) { | |
5677 | pool->flags &= ~POOL_DISASSOCIATED; | |
5678 | BUG_ON(!create_worker(pool)); | |
5679 | } | |
5680 | } | |
5681 | ||
5682 | hash_for_each(unbound_pool_hash, bkt, pool, hash_node) | |
5683 | BUG_ON(!create_worker(pool)); | |
5684 | ||
5685 | wq_online = true; | |
82607adc TH |
5686 | wq_watchdog_init(); |
5687 | ||
6ee0578b | 5688 | return 0; |
1da177e4 | 5689 | } |