2 * Copyright (c) 2000 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/systm.h>
33 #include <sys/interrupt.h>
34 #include <sys/kernel.h>
35 #include <sys/kthread.h>
36 #include <sys/limits.h>
38 #include <sys/malloc.h>
39 #include <sys/mutex.h>
41 #include <sys/sched.h>
42 #include <sys/taskqueue.h>
43 #include <sys/unistd.h>
44 #include <machine/stdarg.h>
46 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
47 static void *taskqueue_giant_ih;
48 static void *taskqueue_ih;
49 static void taskqueue_fast_enqueue(void *);
50 static void taskqueue_swi_enqueue(void *);
51 static void taskqueue_swi_giant_enqueue(void *);
53 struct taskqueue_busy {
54 struct task *tb_running;
55 TAILQ_ENTRY(taskqueue_busy) tb_link;
59 STAILQ_HEAD(, task) tq_queue;
60 taskqueue_enqueue_fn tq_enqueue;
62 TAILQ_HEAD(, taskqueue_busy) tq_active;
64 struct thread **tq_threads;
69 taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
70 void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
73 #define TQ_FLAGS_ACTIVE (1 << 0)
74 #define TQ_FLAGS_BLOCKED (1 << 1)
75 #define TQ_FLAGS_UNLOCKED_ENQUEUE (1 << 2)
77 #define DT_CALLOUT_ARMED (1 << 0)
78 #define DT_DRAIN_IN_PROGRESS (1 << 1)
83 mtx_lock_spin(&(tq)->tq_mutex); \
85 mtx_lock(&(tq)->tq_mutex); \
87 #define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED)
89 #define TQ_UNLOCK(tq) \
92 mtx_unlock_spin(&(tq)->tq_mutex); \
94 mtx_unlock(&(tq)->tq_mutex); \
96 #define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
99 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
100 int priority, task_fn_t func, void *context)
103 TASK_INIT(&timeout_task->t, priority, func, context);
104 callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
105 CALLOUT_RETURNUNLOCKED);
106 timeout_task->q = queue;
111 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
115 return (msleep_spin(p, m, wm, t));
116 return (msleep(p, m, pri, wm, t));
119 static struct taskqueue *
120 _taskqueue_create(const char *name __unused, int mflags,
121 taskqueue_enqueue_fn enqueue, void *context,
122 int mtxflags, const char *mtxname)
124 struct taskqueue *queue;
126 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
130 STAILQ_INIT(&queue->tq_queue);
131 TAILQ_INIT(&queue->tq_active);
132 queue->tq_enqueue = enqueue;
133 queue->tq_context = context;
134 queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
135 queue->tq_flags |= TQ_FLAGS_ACTIVE;
136 if (enqueue == taskqueue_fast_enqueue ||
137 enqueue == taskqueue_swi_enqueue ||
138 enqueue == taskqueue_swi_giant_enqueue ||
139 enqueue == taskqueue_thread_enqueue)
140 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
141 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
147 taskqueue_create(const char *name, int mflags,
148 taskqueue_enqueue_fn enqueue, void *context)
150 return _taskqueue_create(name, mflags, enqueue, context,
151 MTX_DEF, "taskqueue");
155 taskqueue_set_callback(struct taskqueue *queue,
156 enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
160 KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
161 (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
162 ("Callback type %d not valid, must be %d-%d", cb_type,
163 TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
164 KASSERT((queue->tq_callbacks[cb_type] == NULL),
165 ("Re-initialization of taskqueue callback?"));
167 queue->tq_callbacks[cb_type] = callback;
168 queue->tq_cb_contexts[cb_type] = context;
172 * Signal a taskqueue thread to terminate.
175 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
178 while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
180 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
185 taskqueue_free(struct taskqueue *queue)
189 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
190 taskqueue_terminate(queue->tq_threads, queue);
191 KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
192 KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
193 mtx_destroy(&queue->tq_mutex);
194 free(queue->tq_threads, M_TASKQUEUE);
195 free(queue, M_TASKQUEUE);
199 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
205 * Count multiple enqueues.
207 if (task->ta_pending) {
208 if (task->ta_pending < USHRT_MAX)
215 * Optimise the case when all tasks have the same priority.
217 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
218 if (!prev || prev->ta_priority >= task->ta_priority) {
219 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
222 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
223 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
224 if (ins->ta_priority < task->ta_priority)
228 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
230 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
233 task->ta_pending = 1;
234 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
236 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
237 queue->tq_enqueue(queue->tq_context);
238 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
241 /* Return with lock released. */
245 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
250 res = taskqueue_enqueue_locked(queue, task);
251 /* The lock is released inside. */
257 taskqueue_timeout_func(void *arg)
259 struct taskqueue *queue;
260 struct timeout_task *timeout_task;
263 queue = timeout_task->q;
264 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
265 timeout_task->f &= ~DT_CALLOUT_ARMED;
266 queue->tq_callouts--;
267 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
268 /* The lock is released inside. */
272 taskqueue_enqueue_timeout(struct taskqueue *queue,
273 struct timeout_task *timeout_task, int ticks)
278 KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
280 KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
281 timeout_task->q = queue;
282 res = timeout_task->t.ta_pending;
283 if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
287 } else if (ticks == 0) {
288 taskqueue_enqueue_locked(queue, &timeout_task->t);
289 /* The lock is released inside. */
291 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
294 queue->tq_callouts++;
295 timeout_task->f |= DT_CALLOUT_ARMED;
297 ticks = -ticks; /* Ignore overflow. */
300 callout_reset(&timeout_task->c, ticks,
301 taskqueue_timeout_func, timeout_task);
309 taskqueue_drain_running(struct taskqueue *queue)
312 while (!TAILQ_EMPTY(&queue->tq_active))
313 TQ_SLEEP(queue, &queue->tq_active, &queue->tq_mutex,
318 taskqueue_block(struct taskqueue *queue)
322 queue->tq_flags |= TQ_FLAGS_BLOCKED;
327 taskqueue_unblock(struct taskqueue *queue)
331 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
332 if (!STAILQ_EMPTY(&queue->tq_queue))
333 queue->tq_enqueue(queue->tq_context);
338 taskqueue_run_locked(struct taskqueue *queue)
340 struct taskqueue_busy tb;
344 TQ_ASSERT_LOCKED(queue);
345 tb.tb_running = NULL;
346 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
348 while (STAILQ_FIRST(&queue->tq_queue)) {
350 * Carefully remove the first task from the queue and
351 * zero its pending count.
353 task = STAILQ_FIRST(&queue->tq_queue);
354 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
355 pending = task->ta_pending;
356 task->ta_pending = 0;
357 tb.tb_running = task;
360 task->ta_func(task->ta_context, pending);
363 tb.tb_running = NULL;
366 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
367 if (TAILQ_EMPTY(&queue->tq_active))
368 wakeup(&queue->tq_active);
372 taskqueue_run(struct taskqueue *queue)
376 taskqueue_run_locked(queue);
381 task_is_running(struct taskqueue *queue, struct task *task)
383 struct taskqueue_busy *tb;
385 TQ_ASSERT_LOCKED(queue);
386 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
387 if (tb->tb_running == task)
394 * Only use this function in single threaded contexts. It returns
395 * non-zero if the given task is either pending or running. Else the
396 * task is idle and can be queued again or freed.
399 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
404 retval = task->ta_pending > 0 || task_is_running(queue, task);
411 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
415 if (task->ta_pending > 0)
416 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
418 *pendp = task->ta_pending;
419 task->ta_pending = 0;
420 return (task_is_running(queue, task) ? EBUSY : 0);
424 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
429 error = taskqueue_cancel_locked(queue, task, pendp);
436 taskqueue_cancel_timeout(struct taskqueue *queue,
437 struct timeout_task *timeout_task, u_int *pendp)
439 u_int pending, pending1;
443 pending = !!callout_stop(&timeout_task->c);
444 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
445 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
446 timeout_task->f &= ~DT_CALLOUT_ARMED;
447 queue->tq_callouts--;
452 *pendp = pending + pending1;
457 taskqueue_drain(struct taskqueue *queue, struct task *task)
461 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
464 while (task->ta_pending != 0 || task_is_running(queue, task))
465 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
470 taskqueue_drain_all(struct taskqueue *queue)
475 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
478 task = STAILQ_LAST(&queue->tq_queue, task, ta_link);
479 while (task != NULL && task->ta_pending != 0) {
480 struct task *oldtask;
481 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
483 * While we were asleeep the last entry may have been freed.
484 * We need to check if it's still even in the queue.
485 * Not perfect, but it's better than referencing bad memory.
486 * first guess is the current 'end of queue' but if a new
487 * item has been added we need to take the expensive path
492 (task = STAILQ_LAST(&queue->tq_queue, task, ta_link))) {
493 STAILQ_FOREACH(task, &queue->tq_queue, ta_link) {
499 taskqueue_drain_running(queue);
500 KASSERT(STAILQ_EMPTY(&queue->tq_queue),
501 ("taskqueue queue is not empty after draining"));
506 taskqueue_drain_timeout(struct taskqueue *queue,
507 struct timeout_task *timeout_task)
511 * Set flag to prevent timer from re-starting during drain:
514 KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
515 ("Drain already in progress"));
516 timeout_task->f |= DT_DRAIN_IN_PROGRESS;
519 callout_drain(&timeout_task->c);
520 taskqueue_drain(queue, &timeout_task->t);
523 * Clear flag to allow timer to re-start:
526 timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
531 taskqueue_swi_enqueue(void *context)
533 swi_sched(taskqueue_ih, 0);
537 taskqueue_swi_run(void *dummy)
539 taskqueue_run(taskqueue_swi);
543 taskqueue_swi_giant_enqueue(void *context)
545 swi_sched(taskqueue_giant_ih, 0);
549 taskqueue_swi_giant_run(void *dummy)
551 taskqueue_run(taskqueue_swi_giant);
555 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
556 const char *name, ...)
560 struct taskqueue *tq;
562 char ktname[MAXCOMLEN + 1];
570 vsnprintf(ktname, sizeof(ktname), name, ap);
573 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
575 if (tq->tq_threads == NULL) {
576 printf("%s: no memory for %s threads\n", __func__, ktname);
580 for (i = 0; i < count; i++) {
582 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
583 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
585 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
586 &tq->tq_threads[i], RFSTOPPED, 0,
589 /* should be ok to continue, taskqueue_free will dtrt */
590 printf("%s: kthread_add(%s): error %d", __func__,
592 tq->tq_threads[i] = NULL; /* paranoid */
596 for (i = 0; i < count; i++) {
597 if (tq->tq_threads[i] == NULL)
599 td = tq->tq_threads[i];
602 sched_add(td, SRQ_BORING);
610 taskqueue_run_callback(struct taskqueue *tq,
611 enum taskqueue_callback_type cb_type)
613 taskqueue_callback_fn tq_callback;
615 TQ_ASSERT_UNLOCKED(tq);
616 tq_callback = tq->tq_callbacks[cb_type];
617 if (tq_callback != NULL)
618 tq_callback(tq->tq_cb_contexts[cb_type]);
622 taskqueue_thread_loop(void *arg)
624 struct taskqueue **tqp, *tq;
628 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
630 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
631 taskqueue_run_locked(tq);
633 * Because taskqueue_run() can drop tq_mutex, we need to
634 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
635 * meantime, which means we missed a wakeup.
637 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
639 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
641 taskqueue_run_locked(tq);
644 * This thread is on its way out, so just drop the lock temporarily
645 * in order to call the shutdown callback. This allows the callback
646 * to look at the taskqueue, even just before it dies.
649 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
652 /* rendezvous with thread that asked us to terminate */
654 wakeup_one(tq->tq_threads);
660 taskqueue_thread_enqueue(void *context)
662 struct taskqueue **tqp, *tq;
670 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
671 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
672 INTR_MPSAFE, &taskqueue_ih));
674 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
675 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
676 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
678 TASKQUEUE_DEFINE_THREAD(thread);
681 taskqueue_create_fast(const char *name, int mflags,
682 taskqueue_enqueue_fn enqueue, void *context)
684 return _taskqueue_create(name, mflags, enqueue, context,
685 MTX_SPIN, "fast_taskqueue");
688 /* NB: for backwards compatibility */
690 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
692 return taskqueue_enqueue(queue, task);
695 static void *taskqueue_fast_ih;
698 taskqueue_fast_enqueue(void *context)
700 swi_sched(taskqueue_fast_ih, 0);
704 taskqueue_fast_run(void *dummy)
706 taskqueue_run(taskqueue_fast);
709 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
710 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
711 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
714 taskqueue_member(struct taskqueue *queue, struct thread *td)
718 for (i = 0, j = 0; ; i++) {
719 if (queue->tq_threads[i] == NULL)
721 if (queue->tq_threads[i] == td) {
725 if (++j >= queue->tq_tcount)