ebcbe046b9
stopped before adjusting their priority and setting them on the run q so they cannot race for resources (pointed out by njl). While here add a console printf on thread create fails; otherwise noone may notice (e.g. return value is always 0 and caller has no way to verify). Reviewed by: jhb, scottl MFC after: 2 weeks
439 lines
10 KiB
C
439 lines
10 KiB
C
/*-
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* Copyright (c) 2000 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/interrupt.h>
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#include <sys/kernel.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sched.h>
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#include <sys/taskqueue.h>
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#include <sys/unistd.h>
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#include <machine/stdarg.h>
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static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
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static void *taskqueue_giant_ih;
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static void *taskqueue_ih;
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static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
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static struct mtx taskqueue_queues_mutex;
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struct taskqueue {
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STAILQ_ENTRY(taskqueue) tq_link;
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STAILQ_HEAD(, task) tq_queue;
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const char *tq_name;
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taskqueue_enqueue_fn tq_enqueue;
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void *tq_context;
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struct task *tq_running;
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struct mtx tq_mutex;
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struct proc **tq_pproc;
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int tq_pcount;
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int tq_spin;
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int tq_flags;
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};
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#define TQ_FLAGS_ACTIVE (1 << 0)
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static __inline void
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TQ_LOCK(struct taskqueue *tq)
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{
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if (tq->tq_spin)
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mtx_lock_spin(&tq->tq_mutex);
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else
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mtx_lock(&tq->tq_mutex);
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}
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static __inline void
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TQ_UNLOCK(struct taskqueue *tq)
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{
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if (tq->tq_spin)
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mtx_unlock_spin(&tq->tq_mutex);
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else
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mtx_unlock(&tq->tq_mutex);
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}
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static void init_taskqueue_list(void *data);
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static __inline int
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TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
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int t)
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{
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if (tq->tq_spin)
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return (msleep_spin(p, m, wm, t));
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return (msleep(p, m, pri, wm, t));
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}
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static void
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init_taskqueue_list(void *data __unused)
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{
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mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
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STAILQ_INIT(&taskqueue_queues);
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}
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SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
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NULL);
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static struct taskqueue *
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_taskqueue_create(const char *name, int mflags,
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taskqueue_enqueue_fn enqueue, void *context,
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int mtxflags, const char *mtxname)
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{
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struct taskqueue *queue;
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queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
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if (!queue)
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return 0;
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STAILQ_INIT(&queue->tq_queue);
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queue->tq_name = name;
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queue->tq_enqueue = enqueue;
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queue->tq_context = context;
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queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
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queue->tq_flags |= TQ_FLAGS_ACTIVE;
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mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
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mtx_lock(&taskqueue_queues_mutex);
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STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link);
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mtx_unlock(&taskqueue_queues_mutex);
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return queue;
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}
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struct taskqueue *
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taskqueue_create(const char *name, int mflags,
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taskqueue_enqueue_fn enqueue, void *context)
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{
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return _taskqueue_create(name, mflags, enqueue, context,
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MTX_DEF, "taskqueue");
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}
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/*
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* Signal a taskqueue thread to terminate.
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*/
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static void
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taskqueue_terminate(struct proc **pp, struct taskqueue *tq)
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{
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while (tq->tq_pcount > 0) {
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wakeup(tq);
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TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
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}
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}
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void
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taskqueue_free(struct taskqueue *queue)
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{
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mtx_lock(&taskqueue_queues_mutex);
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STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link);
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mtx_unlock(&taskqueue_queues_mutex);
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TQ_LOCK(queue);
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queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
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taskqueue_run(queue);
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taskqueue_terminate(queue->tq_pproc, queue);
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mtx_destroy(&queue->tq_mutex);
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free(queue->tq_pproc, M_TASKQUEUE);
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free(queue, M_TASKQUEUE);
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}
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/*
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* Returns with the taskqueue locked.
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*/
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struct taskqueue *
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taskqueue_find(const char *name)
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{
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struct taskqueue *queue;
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mtx_lock(&taskqueue_queues_mutex);
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STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) {
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if (strcmp(queue->tq_name, name) == 0) {
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TQ_LOCK(queue);
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mtx_unlock(&taskqueue_queues_mutex);
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return queue;
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}
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}
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mtx_unlock(&taskqueue_queues_mutex);
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return NULL;
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}
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int
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taskqueue_enqueue(struct taskqueue *queue, struct task *task)
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{
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struct task *ins;
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struct task *prev;
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TQ_LOCK(queue);
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/*
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* Count multiple enqueues.
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*/
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if (task->ta_pending) {
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task->ta_pending++;
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TQ_UNLOCK(queue);
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return 0;
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}
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/*
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* Optimise the case when all tasks have the same priority.
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*/
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prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
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if (!prev || prev->ta_priority >= task->ta_priority) {
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STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
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} else {
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prev = 0;
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for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
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prev = ins, ins = STAILQ_NEXT(ins, ta_link))
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if (ins->ta_priority < task->ta_priority)
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break;
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if (prev)
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STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
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else
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STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
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}
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task->ta_pending = 1;
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queue->tq_enqueue(queue->tq_context);
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TQ_UNLOCK(queue);
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return 0;
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}
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void
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taskqueue_run(struct taskqueue *queue)
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{
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struct task *task;
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int owned, pending;
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owned = mtx_owned(&queue->tq_mutex);
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if (!owned)
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TQ_LOCK(queue);
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while (STAILQ_FIRST(&queue->tq_queue)) {
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/*
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* Carefully remove the first task from the queue and
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* zero its pending count.
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*/
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task = STAILQ_FIRST(&queue->tq_queue);
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STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
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pending = task->ta_pending;
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task->ta_pending = 0;
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queue->tq_running = task;
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TQ_UNLOCK(queue);
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task->ta_func(task->ta_context, pending);
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TQ_LOCK(queue);
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queue->tq_running = NULL;
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wakeup(task);
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}
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/*
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* For compatibility, unlock on return if the queue was not locked
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* on entry, although this opens a race window.
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*/
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if (!owned)
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TQ_UNLOCK(queue);
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}
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void
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taskqueue_drain(struct taskqueue *queue, struct task *task)
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{
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if (queue->tq_spin) { /* XXX */
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mtx_lock_spin(&queue->tq_mutex);
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while (task->ta_pending != 0 || task == queue->tq_running)
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msleep_spin(task, &queue->tq_mutex, "-", 0);
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mtx_unlock_spin(&queue->tq_mutex);
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} else {
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WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
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mtx_lock(&queue->tq_mutex);
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while (task->ta_pending != 0 || task == queue->tq_running)
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msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
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mtx_unlock(&queue->tq_mutex);
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}
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}
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static void
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taskqueue_swi_enqueue(void *context)
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{
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swi_sched(taskqueue_ih, 0);
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}
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static void
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taskqueue_swi_run(void *dummy)
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{
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taskqueue_run(taskqueue_swi);
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}
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static void
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taskqueue_swi_giant_enqueue(void *context)
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{
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swi_sched(taskqueue_giant_ih, 0);
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}
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static void
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taskqueue_swi_giant_run(void *dummy)
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{
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taskqueue_run(taskqueue_swi_giant);
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}
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int
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taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
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const char *name, ...)
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{
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va_list ap;
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struct taskqueue *tq;
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struct thread *td;
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char ktname[MAXCOMLEN];
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int i, error;
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if (count <= 0)
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return (EINVAL);
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tq = *tqp;
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va_start(ap, name);
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vsnprintf(ktname, MAXCOMLEN, name, ap);
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va_end(ap);
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tq->tq_pproc = malloc(sizeof(struct proc *) * count, M_TASKQUEUE,
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M_NOWAIT | M_ZERO);
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if (tq->tq_pproc == NULL) {
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printf("%s: no memory for %s threads\n", __func__, ktname);
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return (ENOMEM);
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}
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for (i = 0; i < count; i++) {
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if (count == 1)
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error = kthread_create(taskqueue_thread_loop, tqp,
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&tq->tq_pproc[i], RFSTOPPED, 0, ktname);
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else
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error = kthread_create(taskqueue_thread_loop, tqp,
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&tq->tq_pproc[i], RFSTOPPED, 0, "%s_%d", ktname, i);
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if (error) {
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/* should be ok to continue, taskqueue_free will dtrt */
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printf("%s: kthread_create(%s): error %d",
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__func__, ktname, error);
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tq->tq_pproc[i] = NULL; /* paranoid */
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} else
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tq->tq_pcount++;
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}
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mtx_lock_spin(&sched_lock);
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for (i = 0; i < count; i++) {
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if (tq->tq_pproc[i] == NULL)
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continue;
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td = FIRST_THREAD_IN_PROC(tq->tq_pproc[i]);
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sched_prio(td, pri);
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setrunqueue(td, SRQ_BORING);
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}
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mtx_unlock_spin(&sched_lock);
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return (0);
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}
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void
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taskqueue_thread_loop(void *arg)
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{
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struct taskqueue **tqp, *tq;
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tqp = arg;
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tq = *tqp;
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TQ_LOCK(tq);
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do {
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taskqueue_run(tq);
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TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
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} while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0);
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/* rendezvous with thread that asked us to terminate */
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tq->tq_pcount--;
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wakeup_one(tq->tq_pproc);
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TQ_UNLOCK(tq);
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kthread_exit(0);
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}
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void
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taskqueue_thread_enqueue(void *context)
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{
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struct taskqueue **tqp, *tq;
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tqp = context;
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tq = *tqp;
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mtx_assert(&tq->tq_mutex, MA_OWNED);
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wakeup_one(tq);
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}
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TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
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swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
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INTR_MPSAFE, &taskqueue_ih));
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TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
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swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
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NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
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TASKQUEUE_DEFINE_THREAD(thread);
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struct taskqueue *
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taskqueue_create_fast(const char *name, int mflags,
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taskqueue_enqueue_fn enqueue, void *context)
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{
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return _taskqueue_create(name, mflags, enqueue, context,
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MTX_SPIN, "fast_taskqueue");
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}
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/* NB: for backwards compatibility */
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int
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taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
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{
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return taskqueue_enqueue(queue, task);
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}
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static void *taskqueue_fast_ih;
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static void
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taskqueue_fast_enqueue(void *context)
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{
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swi_sched(taskqueue_fast_ih, 0);
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}
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static void
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taskqueue_fast_run(void *dummy)
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{
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taskqueue_run(taskqueue_fast);
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}
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TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0,
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swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL,
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SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
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