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_sbt(struct taskqueue *queue,
293 struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
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 (sbt == 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 sbt = -sbt; /* Ignore overflow. */
320 callout_reset_sbt(&timeout_task->c, sbt, pr,
321 taskqueue_timeout_func, timeout_task, flags);
329 taskqueue_enqueue_timeout(struct taskqueue *queue,
330 struct timeout_task *ttask, int ticks)
333 return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
338 taskqueue_task_nop_fn(void *context, int pending)
343 * Block until all currently queued tasks in this taskqueue
344 * have begun execution. Tasks queued during execution of
345 * this function are ignored.
348 taskqueue_drain_tq_queue(struct taskqueue *queue)
350 struct task t_barrier;
352 if (STAILQ_EMPTY(&queue->tq_queue))
356 * Enqueue our barrier after all current tasks, but with
357 * the highest priority so that newly queued tasks cannot
358 * pass it. Because of the high priority, we can not use
359 * taskqueue_enqueue_locked directly (which drops the lock
360 * anyway) so just insert it at tail while we have the
363 TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
364 STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
365 t_barrier.ta_pending = 1;
368 * Once the barrier has executed, all previously queued tasks
369 * have completed or are currently executing.
371 while (t_barrier.ta_pending != 0)
372 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
376 * Block until all currently executing tasks for this taskqueue
377 * complete. Tasks that begin execution during the execution
378 * of this function are ignored.
381 taskqueue_drain_tq_active(struct taskqueue *queue)
383 struct taskqueue_busy tb_marker, *tb_first;
385 if (TAILQ_EMPTY(&queue->tq_active))
388 /* Block taskq_terminate().*/
389 queue->tq_callouts++;
392 * Wait for all currently executing taskqueue threads
395 tb_marker.tb_running = TB_DRAIN_WAITER;
396 TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
397 while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
398 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
399 TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
402 * Wakeup any other drain waiter that happened to queue up
403 * without any intervening active thread.
405 tb_first = TAILQ_FIRST(&queue->tq_active);
406 if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
409 /* Release taskqueue_terminate(). */
410 queue->tq_callouts--;
411 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
412 wakeup_one(queue->tq_threads);
416 taskqueue_block(struct taskqueue *queue)
420 queue->tq_flags |= TQ_FLAGS_BLOCKED;
425 taskqueue_unblock(struct taskqueue *queue)
429 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
430 if (!STAILQ_EMPTY(&queue->tq_queue))
431 queue->tq_enqueue(queue->tq_context);
436 taskqueue_run_locked(struct taskqueue *queue)
438 struct taskqueue_busy tb;
439 struct taskqueue_busy *tb_first;
443 KASSERT(queue != NULL, ("tq is NULL"));
444 TQ_ASSERT_LOCKED(queue);
445 tb.tb_running = NULL;
447 while (STAILQ_FIRST(&queue->tq_queue)) {
448 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
451 * Carefully remove the first task from the queue and
452 * zero its pending count.
454 task = STAILQ_FIRST(&queue->tq_queue);
455 KASSERT(task != NULL, ("task is NULL"));
456 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
457 pending = task->ta_pending;
458 task->ta_pending = 0;
459 tb.tb_running = task;
462 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
463 task->ta_func(task->ta_context, pending);
466 tb.tb_running = NULL;
469 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
470 tb_first = TAILQ_FIRST(&queue->tq_active);
471 if (tb_first != NULL &&
472 tb_first->tb_running == TB_DRAIN_WAITER)
478 taskqueue_run(struct taskqueue *queue)
482 taskqueue_run_locked(queue);
487 task_is_running(struct taskqueue *queue, struct task *task)
489 struct taskqueue_busy *tb;
491 TQ_ASSERT_LOCKED(queue);
492 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
493 if (tb->tb_running == task)
500 * Only use this function in single threaded contexts. It returns
501 * non-zero if the given task is either pending or running. Else the
502 * task is idle and can be queued again or freed.
505 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
510 retval = task->ta_pending > 0 || task_is_running(queue, task);
517 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
521 if (task->ta_pending > 0)
522 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
524 *pendp = task->ta_pending;
525 task->ta_pending = 0;
526 return (task_is_running(queue, task) ? EBUSY : 0);
530 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
535 error = taskqueue_cancel_locked(queue, task, pendp);
542 taskqueue_cancel_timeout(struct taskqueue *queue,
543 struct timeout_task *timeout_task, u_int *pendp)
545 u_int pending, pending1;
549 pending = !!(callout_stop(&timeout_task->c) > 0);
550 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
551 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
552 timeout_task->f &= ~DT_CALLOUT_ARMED;
553 queue->tq_callouts--;
558 *pendp = pending + pending1;
563 taskqueue_drain(struct taskqueue *queue, struct task *task)
567 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
570 while (task->ta_pending != 0 || task_is_running(queue, task))
571 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
576 taskqueue_drain_all(struct taskqueue *queue)
580 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
583 taskqueue_drain_tq_queue(queue);
584 taskqueue_drain_tq_active(queue);
589 taskqueue_drain_timeout(struct taskqueue *queue,
590 struct timeout_task *timeout_task)
594 * Set flag to prevent timer from re-starting during drain:
597 KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
598 ("Drain already in progress"));
599 timeout_task->f |= DT_DRAIN_IN_PROGRESS;
602 callout_drain(&timeout_task->c);
603 taskqueue_drain(queue, &timeout_task->t);
606 * Clear flag to allow timer to re-start:
609 timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
614 taskqueue_swi_enqueue(void *context)
616 swi_sched(taskqueue_ih, 0);
620 taskqueue_swi_run(void *dummy)
622 taskqueue_run(taskqueue_swi);
626 taskqueue_swi_giant_enqueue(void *context)
628 swi_sched(taskqueue_giant_ih, 0);
632 taskqueue_swi_giant_run(void *dummy)
634 taskqueue_run(taskqueue_swi_giant);
638 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
639 cpuset_t *mask, const char *name, va_list ap)
641 char ktname[MAXCOMLEN + 1];
643 struct taskqueue *tq;
649 vsnprintf(ktname, sizeof(ktname), name, ap);
652 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
654 if (tq->tq_threads == NULL) {
655 printf("%s: no memory for %s threads\n", __func__, ktname);
659 for (i = 0; i < count; i++) {
661 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
662 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
664 error = kthread_add(taskqueue_thread_loop, tqp, NULL,
665 &tq->tq_threads[i], RFSTOPPED, 0,
668 /* should be ok to continue, taskqueue_free will dtrt */
669 printf("%s: kthread_add(%s): error %d", __func__,
671 tq->tq_threads[i] = NULL; /* paranoid */
675 if (tq->tq_tcount == 0) {
676 free(tq->tq_threads, M_TASKQUEUE);
677 tq->tq_threads = NULL;
680 for (i = 0; i < count; i++) {
681 if (tq->tq_threads[i] == NULL)
683 td = tq->tq_threads[i];
685 error = cpuset_setthread(td->td_tid, mask);
687 * Failing to pin is rarely an actual fatal error;
688 * it'll just affect performance.
691 printf("%s: curthread=%llu: can't pin; "
694 (unsigned long long) td->td_tid,
699 sched_add(td, SRQ_BORING);
707 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
708 const char *name, ...)
714 error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
720 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
721 cpuset_t *mask, const char *name, ...)
727 error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
733 taskqueue_run_callback(struct taskqueue *tq,
734 enum taskqueue_callback_type cb_type)
736 taskqueue_callback_fn tq_callback;
738 TQ_ASSERT_UNLOCKED(tq);
739 tq_callback = tq->tq_callbacks[cb_type];
740 if (tq_callback != NULL)
741 tq_callback(tq->tq_cb_contexts[cb_type]);
745 taskqueue_thread_loop(void *arg)
747 struct taskqueue **tqp, *tq;
751 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
753 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
755 taskqueue_run_locked(tq);
757 * Because taskqueue_run() can drop tq_mutex, we need to
758 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
759 * meantime, which means we missed a wakeup.
761 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
763 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
765 taskqueue_run_locked(tq);
767 * This thread is on its way out, so just drop the lock temporarily
768 * in order to call the shutdown callback. This allows the callback
769 * to look at the taskqueue, even just before it dies.
772 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
775 /* rendezvous with thread that asked us to terminate */
777 wakeup_one(tq->tq_threads);
783 taskqueue_thread_enqueue(void *context)
785 struct taskqueue **tqp, *tq;
792 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
793 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
794 INTR_MPSAFE, &taskqueue_ih));
796 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
797 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
798 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
800 TASKQUEUE_DEFINE_THREAD(thread);
803 taskqueue_create_fast(const char *name, int mflags,
804 taskqueue_enqueue_fn enqueue, void *context)
806 return _taskqueue_create(name, mflags, enqueue, context,
807 MTX_SPIN, "fast_taskqueue");
810 static void *taskqueue_fast_ih;
813 taskqueue_fast_enqueue(void *context)
815 swi_sched(taskqueue_fast_ih, 0);
819 taskqueue_fast_run(void *dummy)
821 taskqueue_run(taskqueue_fast);
824 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
825 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
826 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
829 taskqueue_member(struct taskqueue *queue, struct thread *td)
833 for (i = 0, j = 0; ; i++) {
834 if (queue->tq_threads[i] == NULL)
836 if (queue->tq_threads[i] == td) {
840 if (++j >= queue->tq_tcount)