1 /*- 2 * Copyright (c) 2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 13 * 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 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.1.2.3 2003/09/10 00:40:39 ken Exp $ 27 * $DragonFly: src/sys/kern/subr_taskqueue.c,v 1.11 2006/11/07 18:50:06 dillon Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/queue.h> 32 #include <sys/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/taskqueue.h> 35 #include <sys/interrupt.h> 36 #include <sys/lock.h> 37 #include <sys/malloc.h> 38 #include <sys/kthread.h> 39 #include <sys/thread2.h> 40 41 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 42 43 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 44 45 struct taskqueue { 46 STAILQ_ENTRY(taskqueue) tq_link; 47 STAILQ_HEAD(, task) tq_queue; 48 const char *tq_name; 49 taskqueue_enqueue_fn tq_enqueue; 50 void *tq_context; 51 int tq_draining; 52 }; 53 54 struct taskqueue * 55 taskqueue_create(const char *name, int mflags, 56 taskqueue_enqueue_fn enqueue, void *context) 57 { 58 struct taskqueue *queue; 59 static int once = 1; 60 61 queue = kmalloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags); 62 if (!queue) 63 return 0; 64 STAILQ_INIT(&queue->tq_queue); 65 queue->tq_name = name; 66 queue->tq_enqueue = enqueue; 67 queue->tq_context = context; 68 queue->tq_draining = 0; 69 70 crit_enter(); 71 if (once) { 72 STAILQ_INIT(&taskqueue_queues); 73 once = 0; 74 } 75 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 76 crit_exit(); 77 78 return queue; 79 } 80 81 void 82 taskqueue_free(struct taskqueue *queue) 83 { 84 crit_enter(); 85 queue->tq_draining = 1; 86 crit_exit(); 87 88 taskqueue_run(queue); 89 90 crit_enter(); 91 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 92 crit_exit(); 93 94 kfree(queue, M_TASKQUEUE); 95 } 96 97 struct taskqueue * 98 taskqueue_find(const char *name) 99 { 100 struct taskqueue *queue; 101 102 crit_enter(); 103 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 104 if (!strcmp(queue->tq_name, name)) { 105 crit_exit(); 106 return queue; 107 } 108 } 109 crit_exit(); 110 return 0; 111 } 112 113 int 114 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 115 { 116 struct task *ins; 117 struct task *prev; 118 119 crit_enter(); 120 121 /* 122 * Don't allow new tasks on a queue which is being freed. 123 */ 124 if (queue->tq_draining) { 125 crit_exit(); 126 return EPIPE; 127 } 128 129 /* 130 * Count multiple enqueues. 131 */ 132 if (task->ta_pending) { 133 task->ta_pending++; 134 crit_exit(); 135 return 0; 136 } 137 138 /* 139 * Optimise the case when all tasks have the same priority. 140 */ 141 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 142 if (!prev || prev->ta_priority >= task->ta_priority) { 143 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 144 } else { 145 prev = 0; 146 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 147 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 148 if (ins->ta_priority < task->ta_priority) 149 break; 150 151 if (prev) 152 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 153 else 154 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 155 } 156 157 task->ta_pending = 1; 158 if (queue->tq_enqueue) 159 queue->tq_enqueue(queue->tq_context); 160 161 crit_exit(); 162 163 return 0; 164 } 165 166 void 167 taskqueue_run(struct taskqueue *queue) 168 { 169 struct task *task; 170 int pending; 171 172 crit_enter(); 173 while (STAILQ_FIRST(&queue->tq_queue)) { 174 /* 175 * Carefully remove the first task from the queue and 176 * zero its pending count. 177 */ 178 task = STAILQ_FIRST(&queue->tq_queue); 179 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 180 pending = task->ta_pending; 181 task->ta_pending = 0; 182 crit_exit(); 183 184 task->ta_func(task->ta_context, pending); 185 186 crit_enter(); 187 } 188 crit_exit(); 189 } 190 191 static void 192 taskqueue_swi_enqueue(void *context) 193 { 194 setsofttq(); 195 } 196 197 static void 198 taskqueue_swi_run(void *arg, void *frame) 199 { 200 taskqueue_run(taskqueue_swi); 201 } 202 203 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 204 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL)); 205 206 static void 207 taskqueue_kthread(void *arg) 208 { 209 for (;;) { 210 taskqueue_run(taskqueue_thread[mycpuid]); 211 crit_enter(); 212 if (STAILQ_EMPTY(&taskqueue_thread[mycpuid]->tq_queue)) 213 tsleep(taskqueue_thread[mycpuid], 0, "tqthr", 0); 214 crit_exit(); 215 } 216 } 217 218 static void 219 taskqueue_thread_enqueue(void *context) 220 { 221 wakeup(taskqueue_thread[mycpuid]); 222 } 223 224 struct taskqueue *taskqueue_thread[MAXCPU]; 225 static struct thread *taskqueue_thread_td[MAXCPU]; 226 227 static void 228 taskqueue_init(void) 229 { 230 int cpu; 231 232 for (cpu = 0; cpu < ncpus; cpu++) { 233 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 234 taskqueue_thread_enqueue, NULL); 235 kthread_create(taskqueue_kthread, NULL, 236 &taskqueue_thread_td[cpu], "taskqueue"); 237 } 238 } 239 240 SYSINIT(taskqueueinit, SI_SUB_CONFIGURE, SI_ORDER_SECOND, taskqueue_init, NULL); 241