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 1.9 2005/10/13 00:02:22 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 #include <machine/ipl.h> 42 43 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 44 45 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 46 47 struct taskqueue { 48 STAILQ_ENTRY(taskqueue) tq_link; 49 STAILQ_HEAD(, task) tq_queue; 50 const char *tq_name; 51 taskqueue_enqueue_fn tq_enqueue; 52 void *tq_context; 53 int tq_draining; 54 }; 55 56 struct taskqueue * 57 taskqueue_create(const char *name, int mflags, 58 taskqueue_enqueue_fn enqueue, void *context) 59 { 60 struct taskqueue *queue; 61 static int once = 1; 62 63 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags); 64 if (!queue) 65 return 0; 66 STAILQ_INIT(&queue->tq_queue); 67 queue->tq_name = name; 68 queue->tq_enqueue = enqueue; 69 queue->tq_context = context; 70 queue->tq_draining = 0; 71 72 crit_enter(); 73 if (once) { 74 STAILQ_INIT(&taskqueue_queues); 75 once = 0; 76 } 77 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 78 crit_exit(); 79 80 return queue; 81 } 82 83 void 84 taskqueue_free(struct taskqueue *queue) 85 { 86 crit_enter(); 87 queue->tq_draining = 1; 88 crit_exit(); 89 90 taskqueue_run(queue); 91 92 crit_enter(); 93 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 94 crit_exit(); 95 96 free(queue, M_TASKQUEUE); 97 } 98 99 struct taskqueue * 100 taskqueue_find(const char *name) 101 { 102 struct taskqueue *queue; 103 104 crit_enter(); 105 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 106 if (!strcmp(queue->tq_name, name)) { 107 crit_exit(); 108 return queue; 109 } 110 } 111 crit_exit(); 112 return 0; 113 } 114 115 int 116 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 117 { 118 struct task *ins; 119 struct task *prev; 120 121 crit_enter(); 122 123 /* 124 * Don't allow new tasks on a queue which is being freed. 125 */ 126 if (queue->tq_draining) { 127 crit_exit(); 128 return EPIPE; 129 } 130 131 /* 132 * Count multiple enqueues. 133 */ 134 if (task->ta_pending) { 135 task->ta_pending++; 136 crit_exit(); 137 return 0; 138 } 139 140 /* 141 * Optimise the case when all tasks have the same priority. 142 */ 143 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 144 if (!prev || prev->ta_priority >= task->ta_priority) { 145 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 146 } else { 147 prev = 0; 148 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 149 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 150 if (ins->ta_priority < task->ta_priority) 151 break; 152 153 if (prev) 154 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 155 else 156 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 157 } 158 159 task->ta_pending = 1; 160 if (queue->tq_enqueue) 161 queue->tq_enqueue(queue->tq_context); 162 163 crit_exit(); 164 165 return 0; 166 } 167 168 void 169 taskqueue_run(struct taskqueue *queue) 170 { 171 struct task *task; 172 int pending; 173 174 crit_enter(); 175 while (STAILQ_FIRST(&queue->tq_queue)) { 176 /* 177 * Carefully remove the first task from the queue and 178 * zero its pending count. 179 */ 180 task = STAILQ_FIRST(&queue->tq_queue); 181 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 182 pending = task->ta_pending; 183 task->ta_pending = 0; 184 crit_exit(); 185 186 task->ta_func(task->ta_context, pending); 187 188 crit_enter(); 189 } 190 crit_exit(); 191 } 192 193 static void 194 taskqueue_swi_enqueue(void *context) 195 { 196 setsofttq(); 197 } 198 199 static void 200 taskqueue_swi_run(void *arg, void *frame) 201 { 202 taskqueue_run(taskqueue_swi); 203 } 204 205 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 206 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL)); 207 208 static void 209 taskqueue_kthread(void *arg) 210 { 211 for (;;) { 212 taskqueue_run(taskqueue_thread[mycpuid]); 213 crit_enter(); 214 if (STAILQ_EMPTY(&taskqueue_thread[mycpuid]->tq_queue)) 215 tsleep(taskqueue_thread[mycpuid], 0, "tqthr", 0); 216 crit_exit(); 217 } 218 } 219 220 static void 221 taskqueue_thread_enqueue(void *context) 222 { 223 wakeup(taskqueue_thread[mycpuid]); 224 } 225 226 struct taskqueue *taskqueue_thread[MAXCPU]; 227 static struct thread *taskqueue_thread_td[MAXCPU]; 228 229 static void 230 taskqueue_init(void) 231 { 232 int cpu; 233 234 for (cpu = 0; cpu < ncpus; cpu++) { 235 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 236 taskqueue_thread_enqueue, NULL); 237 kthread_create(taskqueue_kthread, NULL, 238 &taskqueue_thread_td[cpu], "taskqueue"); 239 } 240 } 241 242 SYSINIT(taskqueueinit, SI_SUB_CONFIGURE, SI_ORDER_SECOND, taskqueue_init, NULL); 243