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/cpuset.h>
34 #include <sys/interrupt.h>
35 #include <sys/kernel.h>
36 #include <sys/kthread.h>
37 #include <sys/libkern.h>
38 #include <sys/limits.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
43 #include <sys/sched.h>
45 #include <sys/taskqueue.h>
46 #include <sys/unistd.h>
47 #include <machine/stdarg.h>
49 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
50 static void *taskqueue_giant_ih;
51 static void *taskqueue_ih;
52 static void taskqueue_fast_enqueue(void *);
53 static void taskqueue_swi_enqueue(void *);
54 static void taskqueue_swi_giant_enqueue(void *);
56 struct taskqueue_busy {
57 struct task *tb_running;
58 TAILQ_ENTRY(taskqueue_busy) tb_link;
61 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
64 STAILQ_HEAD(, task) tq_queue;
65 taskqueue_enqueue_fn tq_enqueue;
68 TAILQ_HEAD(, taskqueue_busy) tq_active;
70 struct thread **tq_threads;
75 taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
76 void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
79 #define TQ_FLAGS_ACTIVE (1 << 0)
80 #define TQ_FLAGS_BLOCKED (1 << 1)
81 #define TQ_FLAGS_UNLOCKED_ENQUEUE (1 << 2)
83 #define DT_CALLOUT_ARMED (1 << 0)
84 #define DT_DRAIN_IN_PROGRESS (1 << 1)
89 mtx_lock_spin(&(tq)->tq_mutex); \
91 mtx_lock(&(tq)->tq_mutex); \
93 #define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED)
95 #define TQ_UNLOCK(tq) \
98 mtx_unlock_spin(&(tq)->tq_mutex); \
100 mtx_unlock(&(tq)->tq_mutex); \
102 #define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
105 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
106 int priority, task_fn_t func, void *context)
109 TASK_INIT(&timeout_task->t, priority, func, context);
110 callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
111 CALLOUT_RETURNUNLOCKED);
112 timeout_task->q = queue;
117 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
121 return (msleep_spin(p, m, wm, t));
122 return (msleep(p, m, pri, wm, t));
125 static struct taskqueue *
126 _taskqueue_create(const char *name, int mflags,
127 taskqueue_enqueue_fn enqueue, void *context,
128 int mtxflags, const char *mtxname __unused)
130 struct taskqueue *queue;
133 tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
137 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
139 free(tq_name, M_TASKQUEUE);
143 snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
145 STAILQ_INIT(&queue->tq_queue);
146 TAILQ_INIT(&queue->tq_active);
147 queue->tq_enqueue = enqueue;
148 queue->tq_context = context;
149 queue->tq_name = tq_name;
150 queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
151 queue->tq_flags |= TQ_FLAGS_ACTIVE;
152 if (enqueue == taskqueue_fast_enqueue ||
153 enqueue == taskqueue_swi_enqueue ||
154 enqueue == taskqueue_swi_giant_enqueue ||
155 enqueue == taskqueue_thread_enqueue)
156 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
157 mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
163 taskqueue_create(const char *name, int mflags,
164 taskqueue_enqueue_fn enqueue, void *context)
167 return _taskqueue_create(name, mflags, enqueue, context,
172 taskqueue_set_callback(struct taskqueue *queue,
173 enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
177 KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
178 (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
179 ("Callback type %d not valid, must be %d-%d", cb_type,
180 TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
181 KASSERT((queue->tq_callbacks[cb_type] == NULL),
182 ("Re-initialization of taskqueue callback?"));
184 queue->tq_callbacks[cb_type] = callback;
185 queue->tq_cb_contexts[cb_type] = context;
189 * Signal a taskqueue thread to terminate.
192 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
195 while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
197 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
202 taskqueue_free(struct taskqueue *queue)
206 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
207 taskqueue_terminate(queue->tq_threads, queue);
208 KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
209 KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
210 mtx_destroy(&queue->tq_mutex);
211 free(queue->tq_threads, M_TASKQUEUE);
212 free(queue->tq_name, M_TASKQUEUE);
213 free(queue, M_TASKQUEUE);
217 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
222 KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
224 * Count multiple enqueues.
226 if (task->ta_pending) {
227 if (task->ta_pending < USHRT_MAX)
234 * Optimise the case when all tasks have the same priority.
236 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
237 if (!prev || prev->ta_priority >= task->ta_priority) {
238 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
241 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
242 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
243 if (ins->ta_priority < task->ta_priority)
247 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
249 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
252 task->ta_pending = 1;
253 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
255 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
256 queue->tq_enqueue(queue->tq_context);
257 if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
260 /* Return with lock released. */
265 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
270 res = taskqueue_enqueue_locked(queue, task);
271 /* The lock is released inside. */
277 taskqueue_timeout_func(void *arg)
279 struct taskqueue *queue;
280 struct timeout_task *timeout_task;
283 queue = timeout_task->q;
284 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
285 timeout_task->f &= ~DT_CALLOUT_ARMED;
286 queue->tq_callouts--;
287 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
288 /* The lock is released inside. */
292 taskqueue_enqueue_timeout(struct taskqueue *queue,
293 struct timeout_task *timeout_task, int ticks)
298 KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
300 KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
301 timeout_task->q = queue;
302 res = timeout_task->t.ta_pending;
303 if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
307 } else if (ticks == 0) {
308 taskqueue_enqueue_locked(queue, &timeout_task->t);
309 /* The lock is released inside. */
311 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
314 queue->tq_callouts++;
315 timeout_task->f |= DT_CALLOUT_ARMED;
317 ticks = -ticks; /* Ignore overflow. */
320 callout_reset(&timeout_task->c, ticks,
321 taskqueue_timeout_func, timeout_task);
329 taskqueue_task_nop_fn(void *context, int pending)
334 * Block until all currently queued tasks in this taskqueue
335 * have begun execution. Tasks queued during execution of
336 * this function are ignored.
339 taskqueue_drain_tq_queue(struct taskqueue *queue)
341 struct task t_barrier;
343 if (STAILQ_EMPTY(&queue->tq_queue))
347 * Enqueue our barrier after all current tasks, but with
348 * the highest priority so that newly queued tasks cannot
349 * pass it. Because of the high priority, we can not use
350 * taskqueue_enqueue_locked directly (which drops the lock
351 * anyway) so just insert it at tail while we have the
354 TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
355 STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
356 t_barrier.ta_pending = 1;
359 * Once the barrier has executed, all previously queued tasks
360 * have completed or are currently executing.
362 while (t_barrier.ta_pending != 0)
363 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
367 * Block until all currently executing tasks for this taskqueue
368 * complete. Tasks that begin execution during the execution
369 * of this function are ignored.
372 taskqueue_drain_tq_active(struct taskqueue *queue)
374 struct taskqueue_busy tb_marker, *tb_first;
376 if (TAILQ_EMPTY(&queue->tq_active))
379 /* Block taskq_terminate().*/
380 queue->tq_callouts++;
383 * Wait for all currently executing taskqueue threads
386 tb_marker.tb_running = TB_DRAIN_WAITER;
387 TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
388 while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
389 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
390 TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
393 * Wakeup any other drain waiter that happened to queue up
394 * without any intervening active thread.
396 tb_first = TAILQ_FIRST(&queue->tq_active);
397 if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
400 /* Release taskqueue_terminate(). */
401 queue->tq_callouts--;
402 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
403 wakeup_one(queue->tq_threads);
407 taskqueue_block(struct taskqueue *queue)
411 queue->tq_flags |= TQ_FLAGS_BLOCKED;
416 taskqueue_unblock(struct taskqueue *queue)
420 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
421 if (!STAILQ_EMPTY(&queue->tq_queue))
422 queue->tq_enqueue(queue->tq_context);
427 taskqueue_run_locked(struct taskqueue *queue)
429 struct taskqueue_busy tb;
430 struct taskqueue_busy *tb_first;
434 KASSERT(queue != NULL, ("tq is NULL"));
435 TQ_ASSERT_LOCKED(queue);
436 tb.tb_running = NULL;
438 while (STAILQ_FIRST(&queue->tq_queue)) {
439 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
442 * Carefully remove the first task from the queue and
443 * zero its pending count.
445 task = STAILQ_FIRST(&queue->tq_queue);
446 KASSERT(task != NULL, ("task is NULL"));
447 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
448 pending = task->ta_pending;
449 task->ta_pending = 0;
450 tb.tb_running = task;
453 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
454 task->ta_func(task->ta_context, pending);
457 tb.tb_running = NULL;
460 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
461 tb_first = TAILQ_FIRST(&queue->tq_active);
462 if (tb_first != NULL &&
463 tb_first->tb_running == TB_DRAIN_WAITER)
469 taskqueue_run(struct taskqueue *queue)
473 taskqueue_run_locked(queue);
478 task_is_running(struct taskqueue *queue, struct task *task)
480 struct taskqueue_busy *tb;
482 TQ_ASSERT_LOCKED(queue);
483 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
484 if (tb->tb_running == task)
491 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
495 if (task->ta_pending > 0)
496 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
498 *pendp = task->ta_pending;
499 task->ta_pending = 0;
500 return (task_is_running(queue, task) ? EBUSY : 0);
504 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
509 error = taskqueue_cancel_locked(queue, task, pendp);
516 taskqueue_cancel_timeout(struct taskqueue *queue,
517 struct timeout_task *timeout_task, u_int *pendp)
519 u_int pending, pending1;
523 pending = !!(callout_stop(&timeout_task->c) > 0);
524 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
525 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
526 timeout_task->f &= ~DT_CALLOUT_ARMED;
527 queue->tq_callouts--;
532 *pendp = pending + pending1;
537 taskqueue_drain(struct taskqueue *queue, struct task *task)
541 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
544 while (task->ta_pending != 0 || task_is_running(queue, task))
545 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
550 taskqueue_drain_all(struct taskqueue *queue)
554 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
557 taskqueue_drain_tq_queue(queue);
558 taskqueue_drain_tq_active(queue);
563 taskqueue_drain_timeout(struct taskqueue *queue,
564 struct timeout_task *timeout_task)
568 * Set flag to prevent timer from re-starting during drain:
571 KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
572 ("Drain already in progress"));
573 timeout_task->f |= DT_DRAIN_IN_PROGRESS;
576 callout_drain(&timeout_task->c);
577 taskqueue_drain(queue, &timeout_task->t);
580 * Clear flag to allow timer to re-start:
583 timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
588 taskqueue_swi_enqueue(void *context)
590 swi_sched(taskqueue_ih, 0);
594 taskqueue_swi_run(void *dummy)
596 taskqueue_run(taskqueue_swi);
600 taskqueue_swi_giant_enqueue(void *context)
602 swi_sched(taskqueue_giant_ih, 0);
606 taskqueue_swi_giant_run(void *dummy)
608 taskqueue_run(taskqueue_swi_giant);
612 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
613 cpuset_t *mask, const char *name, va_list ap)
615 char ktname[MAXCOMLEN + 1];
617 struct taskqueue *tq;
623 vsnprintf(ktname, sizeof(ktname), name, ap);
626 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
628 if (tq->tq_threads == NULL) {
629 printf("%s: no memory for %s threads\n", __func__, ktname);
633 for (i = 0; i < count; i++) {
635 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
636 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
638 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
639 &tq->tq_threads[i], RFSTOPPED, 0,
642 /* should be ok to continue, taskqueue_free will dtrt */
643 printf("%s: kthread_add(%s): error %d", __func__,
645 tq->tq_threads[i] = NULL; /* paranoid */
649 if (tq->tq_tcount == 0) {
650 free(tq->tq_threads, M_TASKQUEUE);
651 tq->tq_threads = NULL;
654 for (i = 0; i < count; i++) {
655 if (tq->tq_threads[i] == NULL)
657 td = tq->tq_threads[i];
659 error = cpuset_setthread(td->td_tid, mask);
661 * Failing to pin is rarely an actual fatal error;
662 * it'll just affect performance.
665 printf("%s: curthread=%llu: can't pin; "
668 (unsigned long long) td->td_tid,
673 sched_add(td, SRQ_BORING);
681 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
682 const char *name, ...)
688 error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
694 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
695 cpuset_t *mask, const char *name, ...)
701 error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
707 taskqueue_run_callback(struct taskqueue *tq,
708 enum taskqueue_callback_type cb_type)
710 taskqueue_callback_fn tq_callback;
712 TQ_ASSERT_UNLOCKED(tq);
713 tq_callback = tq->tq_callbacks[cb_type];
714 if (tq_callback != NULL)
715 tq_callback(tq->tq_cb_contexts[cb_type]);
719 taskqueue_thread_loop(void *arg)
721 struct taskqueue **tqp, *tq;
725 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
727 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
729 taskqueue_run_locked(tq);
731 * Because taskqueue_run() can drop tq_mutex, we need to
732 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
733 * meantime, which means we missed a wakeup.
735 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
737 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
739 taskqueue_run_locked(tq);
741 * This thread is on its way out, so just drop the lock temporarily
742 * in order to call the shutdown callback. This allows the callback
743 * to look at the taskqueue, even just before it dies.
746 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
749 /* rendezvous with thread that asked us to terminate */
751 wakeup_one(tq->tq_threads);
757 taskqueue_thread_enqueue(void *context)
759 struct taskqueue **tqp, *tq;
766 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
767 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
768 INTR_MPSAFE, &taskqueue_ih));
770 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
771 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
772 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
774 TASKQUEUE_DEFINE_THREAD(thread);
777 taskqueue_create_fast(const char *name, int mflags,
778 taskqueue_enqueue_fn enqueue, void *context)
780 return _taskqueue_create(name, mflags, enqueue, context,
781 MTX_SPIN, "fast_taskqueue");
784 static void *taskqueue_fast_ih;
787 taskqueue_fast_enqueue(void *context)
789 swi_sched(taskqueue_fast_ih, 0);
793 taskqueue_fast_run(void *dummy)
795 taskqueue_run(taskqueue_fast);
798 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
799 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
800 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
803 taskqueue_member(struct taskqueue *queue, struct thread *td)
807 for (i = 0, j = 0; ; i++) {
808 if (queue->tq_threads[i] == NULL)
810 if (queue->tq_threads[i] == td) {
814 if (++j >= queue->tq_tcount)