subr_taskqueue.c revision 116182
1121936Sharti/*- 2121936Sharti * Copyright (c) 2000 Doug Rabson 3121936Sharti * All rights reserved. 4121936Sharti * 5121936Sharti * Redistribution and use in source and binary forms, with or without 6121936Sharti * modification, are permitted provided that the following conditions 7121936Sharti * are met: 8121936Sharti * 1. Redistributions of source code must retain the above copyright 9121936Sharti * notice, this list of conditions and the following disclaimer. 10121936Sharti * 2. Redistributions in binary form must reproduce the above copyright 11121936Sharti * notice, this list of conditions and the following disclaimer in the 12121936Sharti * documentation and/or other materials provided with the distribution. 13121936Sharti * 14121936Sharti * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15121936Sharti * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16121936Sharti * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17121936Sharti * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18121936Sharti * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19121936Sharti * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20121936Sharti * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21121936Sharti * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22121936Sharti * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23121936Sharti * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24121936Sharti * SUCH DAMAGE. 25121936Sharti */ 26121936Sharti 27121936Sharti#include <sys/cdefs.h> 28121936Sharti__FBSDID("$FreeBSD: head/sys/kern/subr_taskqueue.c 116182 2003-06-11 00:56:59Z obrien $"); 29121936Sharti 30121936Sharti#include <sys/param.h> 31121936Sharti#include <sys/systm.h> 32121936Sharti#include <sys/bus.h> 33121936Sharti#include <sys/interrupt.h> 34121936Sharti#include <sys/kernel.h> 35121936Sharti#include <sys/lock.h> 36121936Sharti#include <sys/malloc.h> 37121936Sharti#include <sys/mutex.h> 38121936Sharti#include <sys/taskqueue.h> 39121936Sharti 40121936Shartistatic MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 41121936Sharti 42121936Shartistatic STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 43121936Sharti 44121936Shartistatic void *taskqueue_ih; 45121936Shartistatic void *taskqueue_giant_ih; 46121936Shartistatic struct mtx taskqueue_queues_mutex; 47121936Sharti 48121936Shartistruct taskqueue { 49121936Sharti STAILQ_ENTRY(taskqueue) tq_link; 50121936Sharti STAILQ_HEAD(, task) tq_queue; 51121936Sharti const char *tq_name; 52121936Sharti taskqueue_enqueue_fn tq_enqueue; 53121936Sharti void *tq_context; 54121936Sharti int tq_draining; 55121936Sharti struct mtx tq_mutex; 56121936Sharti}; 57121936Sharti 58121936Shartistatic void init_taskqueue_list(void *data); 59121936Sharti 60121936Shartistatic void 61121936Shartiinit_taskqueue_list(void *data __unused) 62121936Sharti{ 63121936Sharti 64121936Sharti mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 65121936Sharti STAILQ_INIT(&taskqueue_queues); 66121936Sharti} 67121936ShartiSYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 68121936Sharti NULL); 69121936Sharti 70121936Shartistruct taskqueue * 71121936Shartitaskqueue_create(const char *name, int mflags, 72121936Sharti taskqueue_enqueue_fn enqueue, void *context) 73121936Sharti{ 74121936Sharti struct taskqueue *queue; 75121936Sharti 76121936Sharti queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 77121936Sharti if (!queue) 78121936Sharti return 0; 79121936Sharti 80121936Sharti STAILQ_INIT(&queue->tq_queue); 81121936Sharti queue->tq_name = name; 82121936Sharti queue->tq_enqueue = enqueue; 83121936Sharti queue->tq_context = context; 84121936Sharti queue->tq_draining = 0; 85121936Sharti mtx_init(&queue->tq_mutex, "taskqueue", NULL, MTX_DEF); 86121936Sharti 87121936Sharti mtx_lock(&taskqueue_queues_mutex); 88121936Sharti STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 89121936Sharti mtx_unlock(&taskqueue_queues_mutex); 90121936Sharti 91121936Sharti return queue; 92121936Sharti} 93121936Sharti 94121936Shartivoid 95121936Shartitaskqueue_free(struct taskqueue *queue) 96121936Sharti{ 97121936Sharti 98121936Sharti mtx_lock(&queue->tq_mutex); 99121936Sharti KASSERT(queue->tq_draining == 0, ("free'ing a draining taskqueue")); 100121936Sharti queue->tq_draining = 1; 101121936Sharti mtx_unlock(&queue->tq_mutex); 102121936Sharti 103121936Sharti taskqueue_run(queue); 104121936Sharti 105121936Sharti mtx_lock(&taskqueue_queues_mutex); 106121936Sharti STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 107121936Sharti mtx_unlock(&taskqueue_queues_mutex); 108121936Sharti 109121936Sharti mtx_destroy(&queue->tq_mutex); 110121936Sharti free(queue, M_TASKQUEUE); 111121936Sharti} 112121936Sharti 113121936Sharti/* 114121936Sharti * Returns with the taskqueue locked. 115121936Sharti */ 116121936Shartistruct taskqueue * 117121936Shartitaskqueue_find(const char *name) 118121936Sharti{ 119121936Sharti struct taskqueue *queue; 120121936Sharti 121121936Sharti mtx_lock(&taskqueue_queues_mutex); 122121936Sharti STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 123121936Sharti mtx_lock(&queue->tq_mutex); 124121936Sharti if (!strcmp(queue->tq_name, name)) { 125121936Sharti mtx_unlock(&taskqueue_queues_mutex); 126121936Sharti return queue; 127121936Sharti } 128121936Sharti mtx_unlock(&queue->tq_mutex); 129121936Sharti } 130121936Sharti mtx_unlock(&taskqueue_queues_mutex); 131121936Sharti return 0; 132121936Sharti} 133121936Sharti 134121936Shartiint 135121936Shartitaskqueue_enqueue(struct taskqueue *queue, struct task *task) 136121936Sharti{ 137121936Sharti struct task *ins; 138121936Sharti struct task *prev; 139121936Sharti 140121936Sharti mtx_lock(&queue->tq_mutex); 141121936Sharti 142121936Sharti /* 143121936Sharti * Don't allow new tasks on a queue which is being freed. 144121936Sharti */ 145121936Sharti if (queue->tq_draining) { 146121936Sharti mtx_unlock(&queue->tq_mutex); 147121936Sharti return EPIPE; 148121936Sharti } 149121936Sharti 150121936Sharti /* 151121936Sharti * Count multiple enqueues. 152121936Sharti */ 153121936Sharti if (task->ta_pending) { 154121936Sharti task->ta_pending++; 155121936Sharti mtx_unlock(&queue->tq_mutex); 156121936Sharti return 0; 157121936Sharti } 158121936Sharti 159121936Sharti /* 160121936Sharti * Optimise the case when all tasks have the same priority. 161121936Sharti */ 162121936Sharti prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 163121936Sharti if (!prev || prev->ta_priority >= task->ta_priority) { 164121936Sharti STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 165121936Sharti } else { 166121936Sharti prev = 0; 167121936Sharti for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 168121936Sharti prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 169121936Sharti if (ins->ta_priority < task->ta_priority) 170121936Sharti break; 171121936Sharti 172121936Sharti if (prev) 173121936Sharti STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 174121936Sharti else 175121936Sharti STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 176121936Sharti } 177121936Sharti 178121936Sharti task->ta_pending = 1; 179121936Sharti if (queue->tq_enqueue) 180121936Sharti queue->tq_enqueue(queue->tq_context); 181121936Sharti 182121936Sharti mtx_unlock(&queue->tq_mutex); 183121936Sharti 184121936Sharti return 0; 185121936Sharti} 186121936Sharti 187121936Shartivoid 188121936Shartitaskqueue_run(struct taskqueue *queue) 189121936Sharti{ 190121936Sharti struct task *task; 191121936Sharti int pending; 192121936Sharti 193121936Sharti mtx_lock(&queue->tq_mutex); 194121936Sharti while (STAILQ_FIRST(&queue->tq_queue)) { 195121936Sharti /* 196121936Sharti * Carefully remove the first task from the queue and 197121936Sharti * zero its pending count. 198121936Sharti */ 199121936Sharti task = STAILQ_FIRST(&queue->tq_queue); 200121936Sharti STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 201121936Sharti pending = task->ta_pending; 202121936Sharti task->ta_pending = 0; 203121936Sharti mtx_unlock(&queue->tq_mutex); 204121936Sharti 205121936Sharti task->ta_func(task->ta_context, pending); 206121936Sharti 207121936Sharti mtx_lock(&queue->tq_mutex); 208121936Sharti } 209121936Sharti mtx_unlock(&queue->tq_mutex); 210121936Sharti} 211121936Sharti 212121936Shartistatic void 213121936Shartitaskqueue_swi_enqueue(void *context) 214121936Sharti{ 215121936Sharti swi_sched(taskqueue_ih, 0); 216121936Sharti} 217121936Sharti 218121936Shartistatic void 219121936Shartitaskqueue_swi_run(void *dummy) 220121936Sharti{ 221121936Sharti taskqueue_run(taskqueue_swi); 222121936Sharti} 223121936Sharti 224121936Shartistatic void 225121936Shartitaskqueue_swi_giant_enqueue(void *context) 226121936Sharti{ 227121936Sharti swi_sched(taskqueue_giant_ih, 0); 228121936Sharti} 229121936Sharti 230121936Shartistatic void 231121936Shartitaskqueue_swi_giant_run(void *dummy) 232121936Sharti{ 233121936Sharti taskqueue_run(taskqueue_swi_giant); 234121936Sharti} 235121936Sharti 236121936ShartiTASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 237121936Sharti swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 238121936Sharti INTR_MPSAFE, &taskqueue_ih)); 239121936Sharti 240121936ShartiTASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 241121936Sharti swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run, 242121936Sharti NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 243121936Sharti