include/linux/workqueue.h

   1 /*
   2  * workqueue.h --- work queue handling for Linux.
   3  */
   4
   5 #ifndef _LINUX_WORKQUEUE_H
   6 #define _LINUX_WORKQUEUE_H
   7
   8 #include <linux/timer.h>
   9 #include <linux/linkage.h>
  10 #include <linux/bitops.h>
  11 #include <linux/lockdep.h>
  12 #include <linux/threads.h>
  13 #include <linux/atomic.h>
  14
  15 struct workqueue_struct;
  16
  17 struct work_struct;
  18 typedef void (*work_func_t)(struct work_struct *work);
  19 void delayed_work_timer_fn(unsigned long __data);
  20
  21 /*
  22  * The first word is the work queue pointer and the flags rolled into
  23  * one
  24  */
  25 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  26
  27 enum {
  28         WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
  29         WORK_STRUCT_DELAYED_BIT = 1,    /* work item is delayed */
  30         WORK_STRUCT_CWQ_BIT     = 2,    /* data points to cwq */
  31         WORK_STRUCT_LINKED_BIT  = 3,    /* next work is linked to this one */
  32 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  33         WORK_STRUCT_STATIC_BIT  = 4,    /* static initializer (debugobjects) */
  34         WORK_STRUCT_COLOR_SHIFT = 5,    /* color for workqueue flushing */
  35 #else
  36         WORK_STRUCT_COLOR_SHIFT = 4,    /* color for workqueue flushing */
  37 #endif
  38
  39         WORK_STRUCT_COLOR_BITS  = 4,
  40
  41         WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
  42         WORK_STRUCT_DELAYED     = 1 << WORK_STRUCT_DELAYED_BIT,
  43         WORK_STRUCT_CWQ         = 1 << WORK_STRUCT_CWQ_BIT,
  44         WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
  45 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  46         WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
  47 #else
  48         WORK_STRUCT_STATIC      = 0,
  49 #endif
  50
  51         /*
  52          * The last color is no color used for works which don't
  53          * participate in workqueue flushing.
  54          */
  55         WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS) - 1,
  56         WORK_NO_COLOR           = WORK_NR_COLORS,
  57
  58         /* special cpu IDs */
  59         WORK_CPU_UNBOUND        = NR_CPUS,
  60         WORK_CPU_NONE           = NR_CPUS + 1,
  61         WORK_CPU_LAST           = WORK_CPU_NONE,
  62
  63         /*
  64          * Reserve 7 bits off of cwq pointer w/ debugobjects turned
  65          * off.  This makes cwqs aligned to 256 bytes and allows 15
  66          * workqueue flush colors.
  67          */
  68         WORK_STRUCT_FLAG_BITS   = WORK_STRUCT_COLOR_SHIFT +
  69                                   WORK_STRUCT_COLOR_BITS,
  70
  71         /* data contains off-queue information when !WORK_STRUCT_CWQ */
  72         WORK_OFFQ_FLAG_BASE     = WORK_STRUCT_FLAG_BITS,
  73         WORK_OFFQ_FLAG_BITS     = 0,
  74         WORK_OFFQ_CPU_SHIFT     = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  75
  76         /* convenience constants */
  77         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  78         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  79         WORK_STRUCT_NO_CPU      = (unsigned long)WORK_CPU_NONE << WORK_OFFQ_CPU_SHIFT,
  80
  81         /* bit mask for work_busy() return values */
  82         WORK_BUSY_PENDING       = 1 << 0,
  83         WORK_BUSY_RUNNING       = 1 << 1,
  84 };
  85
  86 struct work_struct {
  87         atomic_long_t data;
  88         struct list_head entry;
  89         work_func_t func;
  90 #ifdef CONFIG_LOCKDEP
  91         struct lockdep_map lockdep_map;
  92 #endif
  93 };
  94
  95 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
  96 #define WORK_DATA_STATIC_INIT() \
  97         ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)
  98
  99 struct delayed_work {
 100         struct work_struct work;
 101         struct timer_list timer;
 102 };
 103
 104 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 105 {
 106         return container_of(work, struct delayed_work, work);
 107 }
 108
 109 struct execute_work {
 110         struct work_struct work;
 111 };
 112
 113 #ifdef CONFIG_LOCKDEP
 114 /*
 115  * NB: because we have to copy the lockdep_map, setting _key
 116  * here is required, otherwise it could get initialised to the
 117  * copy of the lockdep_map!
 118  */
 119 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 120         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 121 #else
 122 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 123 #endif
 124
 125 #define __WORK_INITIALIZER(n, f) {                              \
 126         .data = WORK_DATA_STATIC_INIT(),                        \
 127         .entry  = { &(n).entry, &(n).entry },                   \
 128         .func = (f),                                            \
 129         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                       \
 130         }
 131
 132 #define __DELAYED_WORK_INITIALIZER(n, f) {                      \
 133         .work = __WORK_INITIALIZER((n).work, (f)),              \
 134         .timer = TIMER_INITIALIZER(delayed_work_timer_fn,       \
 135                                 0, (unsigned long)&(n)),        \
 136         }
 137
 138 #define __DEFERRED_WORK_INITIALIZER(n, f) {                     \
 139         .work = __WORK_INITIALIZER((n).work, (f)),              \
 140         .timer = TIMER_DEFERRED_INITIALIZER(delayed_work_timer_fn, \
 141                                 0, (unsigned long)&(n)),        \
 142         }
 143
 144 #define DECLARE_WORK(n, f)                                      \
 145         struct work_struct n = __WORK_INITIALIZER(n, f)
 146
 147 #define DECLARE_DELAYED_WORK(n, f)                              \
 148         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
 149
 150 #define DECLARE_DEFERRED_WORK(n, f)                             \
 151         struct delayed_work n = __DEFERRED_WORK_INITIALIZER(n, f)
 152
 153 /*
 154  * initialize a work item's function pointer
 155  */
 156 #define PREPARE_WORK(_work, _func)                              \
 157         do {                                                    \
 158                 (_work)->func = (_func);                        \
 159         } while (0)
 160
 161 #define PREPARE_DELAYED_WORK(_work, _func)                      \
 162         PREPARE_WORK(&(_work)->work, (_func))
 163
 164 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 165 extern void __init_work(struct work_struct *work, int onstack);
 166 extern void destroy_work_on_stack(struct work_struct *work);
 167 static inline unsigned int work_static(struct work_struct *work)
 168 {
 169         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 170 }
 171 #else
 172 static inline void __init_work(struct work_struct *work, int onstack) { }
 173 static inline void destroy_work_on_stack(struct work_struct *work) { }
 174 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 175 #endif
 176
 177 /*
 178  * initialize all of a work item in one go
 179  *
 180  * NOTE! No point in using "atomic_long_set()": using a direct
 181  * assignment of the work data initializer allows the compiler
 182  * to generate better code.
 183  */
 184 #ifdef CONFIG_LOCKDEP
 185 #define __INIT_WORK(_work, _func, _onstack)                             \
 186         do {                                                            \
 187                 static struct lock_class_key __key;                     \
 188                                                                         \
 189                 __init_work((_work), _onstack);                         \
 190                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 191                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\
 192                 INIT_LIST_HEAD(&(_work)->entry);                        \
 193                 PREPARE_WORK((_work), (_func));                         \
 194         } while (0)
 195 #else
 196 #define __INIT_WORK(_work, _func, _onstack)                             \
 197         do {                                                            \
 198                 __init_work((_work), _onstack);                         \
 199                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 200                 INIT_LIST_HEAD(&(_work)->entry);                        \
 201                 PREPARE_WORK((_work), (_func));                         \
 202         } while (0)
 203 #endif
 204
 205 #define INIT_WORK(_work, _func)                                 \
 206         do {                                                    \
 207                 __INIT_WORK((_work), (_func), 0);               \
 208         } while (0)
 209
 210 #define INIT_WORK_ONSTACK(_work, _func)                         \
 211         do {                                                    \
 212                 __INIT_WORK((_work), (_func), 1);               \
 213         } while (0)
 214
 215 #define INIT_DELAYED_WORK(_work, _func)                         \
 216         do {                                                    \
 217                 INIT_WORK(&(_work)->work, (_func));             \
 218                 init_timer(&(_work)->timer);                    \
 219                 (_work)->timer.function = delayed_work_timer_fn;\
 220                 (_work)->timer.data = (unsigned long)(_work);   \
 221         } while (0)
 222
 223 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                 \
 224         do {                                                    \
 225                 INIT_WORK_ONSTACK(&(_work)->work, (_func));     \
 226                 init_timer_on_stack(&(_work)->timer);           \
 227                 (_work)->timer.function = delayed_work_timer_fn;\
 228                 (_work)->timer.data = (unsigned long)(_work);   \
 229         } while (0)
 230
 231 #define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)              \
 232         do {                                                    \
 233                 INIT_WORK(&(_work)->work, (_func));             \
 234                 init_timer_deferrable(&(_work)->timer);         \
 235                 (_work)->timer.function = delayed_work_timer_fn;\
 236                 (_work)->timer.data = (unsigned long)(_work);   \
 237         } while (0)
 238
 239 /**
 240  * work_pending - Find out whether a work item is currently pending
 241  * @work: The work item in question
 242  */
 243 #define work_pending(work) \
 244         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 245
 246 /**
 247  * delayed_work_pending - Find out whether a delayable work item is currently
 248  * pending
 249  * @work: The work item in question
 250  */
 251 #define delayed_work_pending(w) \
 252         work_pending(&(w)->work)
 253
 254 /**
 255  * work_clear_pending - for internal use only, mark a work item as not pending
 256  * @work: The work item in question
 257  */
 258 #define work_clear_pending(work) \
 259         clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 260
 261 /*
 262  * Workqueue flags and constants.  For details, please refer to
 263  * Documentation/workqueue.txt.
 264  */
 265 enum {
 266         WQ_NON_REENTRANT        = 1 << 0, /* guarantee non-reentrance */
 267         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 268         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 269         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 270         WQ_HIGHPRI              = 1 << 4, /* high priority */
 271         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu instensive workqueue */
 272
 273         WQ_DRAINING             = 1 << 6, /* internal: workqueue is draining */
 274         WQ_RESCUER              = 1 << 7, /* internal: workqueue has rescuer */
 275
 276         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 277         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 278         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 279 };
 280
 281 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 282 #define WQ_UNBOUND_MAX_ACTIVE   \
 283         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 284
 285 /*
 286  * System-wide workqueues which are always present.
 287  *
 288  * system_wq is the one used by schedule[_delayed]_work[_on]().
 289  * Multi-CPU multi-threaded.  There are users which expect relatively
 290  * short queue flush time.  Don't queue works which can run for too
 291  * long.
 292  *
 293  * system_long_wq is similar to system_wq but may host long running
 294  * works.  Queue flushing might take relatively long.
 295  *
 296  * system_nrt_wq is non-reentrant and guarantees that any given work
 297  * item is never executed in parallel by multiple CPUs.  Queue
 298  * flushing might take relatively long.
 299  *
 300  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 301  * any specific CPU, not concurrency managed, and all queued works are
 302  * executed immediately as long as max_active limit is not reached and
 303  * resources are available.
 304  *
 305  * system_freezable_wq is equivalent to system_wq except that it's
 306  * freezable.
 307  *
 308  * system_nrt_freezable_wq is equivalent to system_nrt_wq except that
 309  * it's freezable.
 310  */
 311 extern struct workqueue_struct *system_wq;
 312 extern struct workqueue_struct *system_long_wq;
 313 extern struct workqueue_struct *system_nrt_wq;
 314 extern struct workqueue_struct *system_unbound_wq;
 315 extern struct workqueue_struct *system_freezable_wq;
 316 extern struct workqueue_struct *system_nrt_freezable_wq;
 317
 318 extern struct workqueue_struct *
 319 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 320         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 321
 322 /**
 323  * alloc_workqueue - allocate a workqueue
 324  * @fmt: printf format for the name of the workqueue
 325  * @flags: WQ_* flags
 326  * @max_active: max in-flight work items, 0 for default
 327  * @args: args for @fmt
 328  *
 329  * Allocate a workqueue with the specified parameters.  For detailed
 330  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
 331  *
 332  * The __lock_name macro dance is to guarantee that single lock_class_key
 333  * doesn't end up with different namesm, which isn't allowed by lockdep.
 334  *
 335  * RETURNS:
 336  * Pointer to the allocated workqueue on success, %NULL on failure.
 337  */
 338 #ifdef CONFIG_LOCKDEP
 339 #define alloc_workqueue(fmt, flags, max_active, args...)        \
 340 ({                                                              \
 341         static struct lock_class_key __key;                     \
 342         const char *__lock_name;                                \
 343                                                                 \
 344         if (__builtin_constant_p(fmt))                          \
 345                 __lock_name = (fmt);                            \
 346         else                                                    \
 347                 __lock_name = #fmt;                             \
 348                                                                 \
 349         __alloc_workqueue_key((fmt), (flags), (max_active),     \
 350                               &__key, __lock_name, ##args);     \
 351 })
 352 #else
 353 #define alloc_workqueue(fmt, flags, max_active, args...)        \
 354         __alloc_workqueue_key((fmt), (flags), (max_active),     \
 355                               NULL, NULL, ##args)
 356 #endif
 357
 358 /**
 359  * alloc_ordered_workqueue - allocate an ordered workqueue
 360  * @fmt: printf format for the name of the workqueue
 361  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 362  * @args: args for @fmt
 363  *
 364  * Allocate an ordered workqueue.  An ordered workqueue executes at
 365  * most one work item at any given time in the queued order.  They are
 366  * implemented as unbound workqueues with @max_active of one.
 367  *
 368  * RETURNS:
 369  * Pointer to the allocated workqueue on success, %NULL on failure.
 370  */
 371 #define alloc_ordered_workqueue(fmt, flags, args...)            \
 372         alloc_workqueue(fmt, WQ_UNBOUND | (flags), 1, ##args)
 373
 374 #define create_workqueue(name)                                  \
 375         alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
 376 #define create_freezable_workqueue(name)                        \
 377         alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 378 #define create_singlethread_workqueue(name)                     \
 379         alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 380
 381 extern void destroy_workqueue(struct workqueue_struct *wq);
 382
 383 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 384                         struct work_struct *work);
 385 extern bool queue_work(struct workqueue_struct *wq, struct work_struct *work);
 386 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 387                         struct delayed_work *work, unsigned long delay);
 388 extern bool queue_delayed_work(struct workqueue_struct *wq,
 389                         struct delayed_work *work, unsigned long delay);
 390
 391 extern void flush_workqueue(struct workqueue_struct *wq);
 392 extern void drain_workqueue(struct workqueue_struct *wq);
 393 extern void flush_scheduled_work(void);
 394
 395 extern bool schedule_work_on(int cpu, struct work_struct *work);
 396 extern bool schedule_work(struct work_struct *work);
 397 extern bool schedule_delayed_work_on(int cpu, struct delayed_work *work,
 398                                      unsigned long delay);
 399 extern bool schedule_delayed_work(struct delayed_work *work,
 400                                   unsigned long delay);
 401 extern int schedule_on_each_cpu(work_func_t func);
 402 extern int keventd_up(void);
 403
 404 int execute_in_process_context(work_func_t fn, struct execute_work *);
 405
 406 extern bool flush_work(struct work_struct *work);
 407 extern bool flush_work_sync(struct work_struct *work);
 408 extern bool cancel_work_sync(struct work_struct *work);
 409
 410 extern bool flush_delayed_work(struct delayed_work *dwork);
 411 extern bool flush_delayed_work_sync(struct delayed_work *work);
 412 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 413
 414 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 415                                      int max_active);
 416 extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
 417 extern unsigned int work_cpu(struct work_struct *work);
 418 extern unsigned int work_busy(struct work_struct *work);
 419
 420 /*
 421  * Kill off a pending schedule_delayed_work().  Note that the work callback
 422  * function may still be running on return from cancel_delayed_work(), unless
 423  * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
 424  * cancel_work_sync() to wait on it.
 425  */
 426 static inline bool cancel_delayed_work(struct delayed_work *work)
 427 {
 428         bool ret;
 429
 430         ret = del_timer_sync(&work->timer);
 431         if (ret)
 432                 work_clear_pending(&work->work);
 433         return ret;
 434 }
 435
 436 /*
 437  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
 438  * if it returns 0 the timer function may be running and the queueing is in
 439  * progress.
 440  */
 441 static inline bool __cancel_delayed_work(struct delayed_work *work)
 442 {
 443         bool ret;
 444
 445         ret = del_timer(&work->timer);
 446         if (ret)
 447                 work_clear_pending(&work->work);
 448         return ret;
 449 }
 450
 451 #ifndef CONFIG_SMP
 452 static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 453 {
 454         return fn(arg);
 455 }
 456 #else
 457 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
 458 #endif /* CONFIG_SMP */
 459
 460 #ifdef CONFIG_FREEZER
 461 extern void freeze_workqueues_begin(void);
 462 extern bool freeze_workqueues_busy(void);
 463 extern void thaw_workqueues(void);
 464 #endif /* CONFIG_FREEZER */
 465
 466 #endif