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
26 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.69 2012/08/28 13:35:37 jhb Exp $"
29 #include <sys/param.h>
30 #include <sys/queue.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/taskqueue.h>
34 #include <sys/interrupt.h>
36 #include <sys/malloc.h>
37 #include <sys/kthread.h>
38 #include <sys/spinlock.h>
39 #include <sys/spinlock2.h>
40 #include <sys/serialize.h>
43 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
45 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
46 static struct lock taskqueue_queues_lock;
47 struct spinlock taskqueue_queues_spin;
50 STAILQ_ENTRY(taskqueue) tq_link;
51 STAILQ_HEAD(, task) tq_queue;
53 /* NOTE: tq must be locked before calling tq_enqueue */
54 taskqueue_enqueue_fn tq_enqueue;
57 struct task *tq_running;
58 struct spinlock tq_lock;
59 struct thread **tq_threads;
65 #define TQ_FLAGS_ACTIVE (1 << 0)
66 #define TQ_FLAGS_BLOCKED (1 << 1)
67 #define TQ_FLAGS_PENDING (1 << 2)
69 #define DT_CALLOUT_ARMED (1 << 0)
72 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
73 int priority, task_fn_t func, void *context)
76 TASK_INIT(&timeout_task->t, priority, func, context);
77 callout_init(&timeout_task->c); /* XXX use callout_init_mp() */
78 timeout_task->t.ta_queue = queue;
82 static void taskqueue_run(struct taskqueue *queue, int lock_held);
85 TQ_LOCK_INIT(struct taskqueue *tq)
87 spin_init(&tq->tq_lock, "tqlock");
91 TQ_LOCK_UNINIT(struct taskqueue *tq)
93 spin_uninit(&tq->tq_lock);
97 TQ_LOCK(struct taskqueue *tq)
99 spin_lock(&tq->tq_lock);
103 TQ_UNLOCK(struct taskqueue *tq)
105 spin_unlock(&tq->tq_lock);
109 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg)
111 ssleep(ident, &tq->tq_lock, 0, wmesg, 0);
115 taskqueue_create(const char *name, int mflags,
116 taskqueue_enqueue_fn enqueue, void *context)
118 struct taskqueue *queue;
120 queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO);
123 STAILQ_INIT(&queue->tq_queue);
124 queue->tq_name = name;
125 queue->tq_enqueue = enqueue;
126 queue->tq_context = context;
127 queue->tq_flags |= TQ_FLAGS_ACTIVE;
130 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
131 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
132 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
137 /* NOTE: tq must be locked */
139 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
141 while(tq->tq_tcount > 0) {
142 /* Unlock spinlock before wakeup() */
146 TQ_SLEEP(tq, pp, "taskqueue_terminate");
151 taskqueue_free(struct taskqueue *queue)
154 queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
155 taskqueue_run(queue, 1);
156 taskqueue_terminate(queue->tq_threads, queue);
159 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
160 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
161 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
163 TQ_LOCK_UNINIT(queue);
165 kfree(queue, M_TASKQUEUE);
169 taskqueue_find(const char *name)
171 struct taskqueue *queue;
173 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE);
174 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
175 if (!strcmp(queue->tq_name, name)) {
176 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
180 lockmgr(&taskqueue_queues_lock, LK_RELEASE);
185 * NOTE! If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'',
186 * be sure NOT TO SHARE the ``task'' between CPUs. TASKS ARE NOT LOCKED.
187 * So either use a throwaway task which will only be enqueued once, or
188 * use one task per CPU!
191 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
197 * Don't allow new tasks on a queue which is being freed.
199 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
203 * Count multiple enqueues.
205 if (task->ta_pending) {
206 KKASSERT(queue == task->ta_queue);
210 task->ta_queue = queue;
213 * Optimise the case when all tasks have the same priority.
215 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
216 if (!prev || prev->ta_priority >= task->ta_priority) {
217 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
220 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
221 prev = ins, ins = STAILQ_NEXT(ins, ta_link))
222 if (ins->ta_priority < task->ta_priority)
226 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
228 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
231 task->ta_pending = 1;
232 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) {
233 if (queue->tq_enqueue)
234 queue->tq_enqueue(queue->tq_context);
236 queue->tq_flags |= TQ_FLAGS_PENDING;
243 * This version requires that the task not be moved between queues
244 * in an uncontrolled fashion.
247 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
252 res = taskqueue_enqueue_locked(queue, task);
259 * This version allows a task to be moved between queues in an uncontrolled
260 * fashion. (*qpp) is set to the queue the task is (possibly already)
261 * enqueued on, or the specified queue if it is possible to move the task.
264 taskqueue_enqueue_optq(struct taskqueue *queue, struct taskqueue **qpp,
267 struct taskqueue *qtmp;
271 * Interlock for task structure check, handle the case where we
272 * are unable to safely shift the task to the specified queue.
275 qtmp = task->ta_queue;
279 spin_lock(&taskqueue_queues_spin);
280 if (task->ta_queue == NULL)
281 task->ta_queue = queue;
282 spin_unlock(&taskqueue_queues_spin);
285 if (task->ta_queue == qtmp) {
290 * If qtmp is pending on a different queue
291 * it must stay on that queue.
293 * WARNING: Once ta_queue is reassigned
294 * our qtmp lock is no longer
295 * sufficient and we lose control
298 if (task->ta_pending) {
305 task->ta_queue = queue;
314 * The task is assigned to (queue), enqueue it there.
317 res = taskqueue_enqueue_locked(queue, task);
324 taskqueue_timeout_func(void *arg)
326 struct taskqueue *queue;
327 struct timeout_task *timeout_task;
330 queue = timeout_task->t.ta_queue;
333 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
334 timeout_task->f &= ~DT_CALLOUT_ARMED;
335 queue->tq_callouts--;
336 taskqueue_enqueue_locked(queue, &timeout_task->t);
341 taskqueue_enqueue_timeout(struct taskqueue *queue,
342 struct timeout_task *timeout_task, int ticks)
347 KASSERT(timeout_task->t.ta_queue == NULL ||
348 timeout_task->t.ta_queue == queue,
350 timeout_task->t.ta_queue = queue;
351 res = timeout_task->t.ta_pending;
353 taskqueue_enqueue_locked(queue, &timeout_task->t);
356 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
359 queue->tq_callouts++;
360 timeout_task->f |= DT_CALLOUT_ARMED;
363 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func,
370 taskqueue_block(struct taskqueue *queue)
373 queue->tq_flags |= TQ_FLAGS_BLOCKED;
378 taskqueue_unblock(struct taskqueue *queue)
381 queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
382 if (queue->tq_flags & TQ_FLAGS_PENDING) {
383 queue->tq_flags &= ~TQ_FLAGS_PENDING;
384 if (queue->tq_enqueue)
385 queue->tq_enqueue(queue->tq_context);
391 taskqueue_run(struct taskqueue *queue, int lock_held)
398 while (STAILQ_FIRST(&queue->tq_queue)) {
400 * Carefully remove the first task from the queue and
401 * zero its pending count.
403 task = STAILQ_FIRST(&queue->tq_queue);
404 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
405 pending = task->ta_pending;
406 task->ta_pending = 0;
407 queue->tq_running = task;
410 task->ta_func(task->ta_context, pending);
411 queue->tq_running = NULL;
420 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
424 if (task->ta_pending > 0)
425 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
427 *pendp = task->ta_pending;
428 task->ta_pending = 0;
429 return (task == queue->tq_running ? EBUSY : 0);
433 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
438 error = taskqueue_cancel_locked(queue, task, pendp);
445 taskqueue_cancel_simple(struct task *task)
447 struct taskqueue *queue;
451 queue = task->ta_queue;
458 if (queue == task->ta_queue) {
459 error = taskqueue_cancel_locked(queue, task, NULL);
469 taskqueue_cancel_timeout(struct taskqueue *queue,
470 struct timeout_task *timeout_task, u_int *pendp)
472 u_int pending, pending1;
475 pending = !!callout_stop(&timeout_task->c);
477 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
478 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
479 timeout_task->f &= ~DT_CALLOUT_ARMED;
480 queue->tq_callouts--;
485 *pendp = pending + pending1;
490 taskqueue_drain(struct taskqueue *queue, struct task *task)
493 while (task->ta_pending != 0 || task == queue->tq_running)
494 TQ_SLEEP(queue, task, "-");
499 * Wait for the task to drain and return
502 taskqueue_drain_simple(struct task *task)
504 struct taskqueue *queue;
507 queue = task->ta_queue;
512 if (task->ta_pending == 0 && task != queue->tq_running) {
516 TQ_SLEEP(queue, task, "-");
522 taskqueue_drain_timeout(struct taskqueue *queue,
523 struct timeout_task *timeout_task)
525 callout_cancel(&timeout_task->c);
526 taskqueue_drain(queue, &timeout_task->t);
530 taskqueue_swi_enqueue(void *context)
536 taskqueue_swi_run(void *arg, void *frame)
538 taskqueue_run(taskqueue_swi, 0);
542 taskqueue_swi_mp_run(void *arg, void *frame)
544 taskqueue_run(taskqueue_swi_mp, 0);
548 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu,
549 const char *fmt, ...)
553 struct taskqueue *tq;
555 char ktname[MAXCOMLEN];
559 /* catch call argument mistakes */
560 KKASSERT(pri > 0 && pri < TDPRI_MAX);
566 kvsnprintf(ktname, MAXCOMLEN, fmt, ap);
569 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE,
572 for (i = 0; i < count; i++) {
574 * If no specific cpu was specified and more than one thread
575 * is to be created, we distribute the threads amongst all
578 if ((ncpu <= -1) && (count > 1))
582 error = lwkt_create(taskqueue_thread_loop, tqp,
583 &tq->tq_threads[i], NULL,
587 error = lwkt_create(taskqueue_thread_loop, tqp,
588 &tq->tq_threads[i], NULL,
593 kprintf("%s: lwkt_create(%s): error %d", __func__,
595 tq->tq_threads[i] = NULL;
597 td = tq->tq_threads[i];
598 lwkt_setpri_initial(td, pri);
608 taskqueue_thread_loop(void *arg)
610 struct taskqueue **tqp, *tq;
615 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
616 taskqueue_run(tq, 1);
617 TQ_SLEEP(tq, tq, "tqthr");
620 /* rendezvous with thread that asked us to terminate */
623 wakeup_one(tq->tq_threads);
627 /* NOTE: tq must be locked */
629 taskqueue_thread_enqueue(void *context)
631 struct taskqueue **tqp, *tq;
636 /* Unlock spinlock before wakeup_one() */
642 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
643 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1));
645 * XXX: possibly use a different SWI_TQ_MP or so.
646 * related: sys/interrupt.h
647 * related: platform/XXX/isa/ipl_funcs.c
649 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0,
650 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL,
653 struct taskqueue *taskqueue_thread[MAXCPU];
660 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0);
661 spin_init(&taskqueue_queues_spin, "tqspin");
662 STAILQ_INIT(&taskqueue_queues);
664 for (cpu = 0; cpu < ncpus; cpu++) {
665 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT,
666 taskqueue_thread_enqueue, &taskqueue_thread[cpu]);
667 taskqueue_start_threads(&taskqueue_thread[cpu], 1,
668 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu);
672 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_FIRST, taskqueue_init, NULL);