subr_taskqueue.c revision 145473
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 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/kern/subr_taskqueue.c 145473 2005-04-24 16:52:45Z sam $"); 29 30#include <sys/param.h> 31#include <sys/systm.h> 32#include <sys/bus.h> 33#include <sys/interrupt.h> 34#include <sys/kernel.h> 35#include <sys/kthread.h> 36#include <sys/lock.h> 37#include <sys/malloc.h> 38#include <sys/mutex.h> 39#include <sys/taskqueue.h> 40#include <sys/unistd.h> 41 42static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 43static void *taskqueue_giant_ih; 44static void *taskqueue_ih; 45static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 46static struct mtx taskqueue_queues_mutex; 47 48struct taskqueue { 49 STAILQ_ENTRY(taskqueue) tq_link; 50 STAILQ_HEAD(, task) tq_queue; 51 const char *tq_name; 52 taskqueue_enqueue_fn tq_enqueue; 53 void *tq_context; 54 struct task *tq_running; 55 struct mtx tq_mutex; 56}; 57 58static void init_taskqueue_list(void *data); 59 60static void 61init_taskqueue_list(void *data __unused) 62{ 63 64 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 65 STAILQ_INIT(&taskqueue_queues); 66} 67SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 68 NULL); 69 70struct taskqueue * 71taskqueue_create(const char *name, int mflags, 72 taskqueue_enqueue_fn enqueue, void *context) 73{ 74 struct taskqueue *queue; 75 76 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 77 if (!queue) 78 return 0; 79 80 STAILQ_INIT(&queue->tq_queue); 81 queue->tq_name = name; 82 queue->tq_enqueue = enqueue; 83 queue->tq_context = context; 84 mtx_init(&queue->tq_mutex, "taskqueue", NULL, MTX_DEF); 85 86 mtx_lock(&taskqueue_queues_mutex); 87 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 88 mtx_unlock(&taskqueue_queues_mutex); 89 90 return queue; 91} 92 93void 94taskqueue_free(struct taskqueue *queue) 95{ 96 97 mtx_lock(&taskqueue_queues_mutex); 98 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 99 mtx_unlock(&taskqueue_queues_mutex); 100 101 mtx_lock(&queue->tq_mutex); 102 taskqueue_run(queue); 103 mtx_destroy(&queue->tq_mutex); 104 free(queue, M_TASKQUEUE); 105} 106 107/* 108 * Returns with the taskqueue locked. 109 */ 110struct taskqueue * 111taskqueue_find(const char *name) 112{ 113 struct taskqueue *queue; 114 115 mtx_lock(&taskqueue_queues_mutex); 116 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 117 if (strcmp(queue->tq_name, name) == 0) { 118 mtx_lock(&queue->tq_mutex); 119 mtx_unlock(&taskqueue_queues_mutex); 120 return queue; 121 } 122 } 123 mtx_unlock(&taskqueue_queues_mutex); 124 return NULL; 125} 126 127int 128taskqueue_enqueue(struct taskqueue *queue, struct task *task) 129{ 130 struct task *ins; 131 struct task *prev; 132 133 mtx_lock(&queue->tq_mutex); 134 135 /* 136 * Count multiple enqueues. 137 */ 138 if (task->ta_pending) { 139 task->ta_pending++; 140 mtx_unlock(&queue->tq_mutex); 141 return 0; 142 } 143 144 /* 145 * Optimise the case when all tasks have the same priority. 146 */ 147 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 148 if (!prev || prev->ta_priority >= task->ta_priority) { 149 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 150 } else { 151 prev = 0; 152 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 153 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 154 if (ins->ta_priority < task->ta_priority) 155 break; 156 157 if (prev) 158 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 159 else 160 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 161 } 162 163 task->ta_pending = 1; 164 if (queue->tq_enqueue) 165 queue->tq_enqueue(queue->tq_context); 166 167 mtx_unlock(&queue->tq_mutex); 168 169 return 0; 170} 171 172void 173taskqueue_run(struct taskqueue *queue) 174{ 175 struct task *task; 176 int owned, pending; 177 178 owned = mtx_owned(&queue->tq_mutex); 179 if (!owned) 180 mtx_lock(&queue->tq_mutex); 181 while (STAILQ_FIRST(&queue->tq_queue)) { 182 /* 183 * Carefully remove the first task from the queue and 184 * zero its pending count. 185 */ 186 task = STAILQ_FIRST(&queue->tq_queue); 187 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 188 pending = task->ta_pending; 189 task->ta_pending = 0; 190 queue->tq_running = task; 191 mtx_unlock(&queue->tq_mutex); 192 193 task->ta_func(task->ta_context, pending); 194 195 mtx_lock(&queue->tq_mutex); 196 queue->tq_running = NULL; 197 wakeup(task); 198 } 199 200 /* 201 * For compatibility, unlock on return if the queue was not locked 202 * on entry, although this opens a race window. 203 */ 204 if (!owned) 205 mtx_unlock(&queue->tq_mutex); 206} 207 208void 209taskqueue_drain(struct taskqueue *queue, struct task *task) 210{ 211 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "taskqueue_drain"); 212 mtx_lock(&queue->tq_mutex); 213 while (task->ta_pending != 0 || task == queue->tq_running) { 214 msleep(task, &queue->tq_mutex, PWAIT, "-", 0); 215 } 216 mtx_unlock(&queue->tq_mutex); 217} 218 219static void 220taskqueue_swi_enqueue(void *context) 221{ 222 swi_sched(taskqueue_ih, 0); 223} 224 225static void 226taskqueue_swi_run(void *dummy) 227{ 228 taskqueue_run(taskqueue_swi); 229} 230 231static void 232taskqueue_swi_giant_enqueue(void *context) 233{ 234 swi_sched(taskqueue_giant_ih, 0); 235} 236 237static void 238taskqueue_swi_giant_run(void *dummy) 239{ 240 taskqueue_run(taskqueue_swi_giant); 241} 242 243void 244taskqueue_thread_loop(void *arg) 245{ 246 struct taskqueue **tqp, *tq; 247 248 tqp = arg; 249 tq = *tqp; 250 mtx_lock(&tq->tq_mutex); 251 for (;;) { 252 taskqueue_run(tq); 253 msleep(tq, &tq->tq_mutex, PWAIT, "-", 0); 254 } 255} 256 257void 258taskqueue_thread_enqueue(void *context) 259{ 260 struct taskqueue **tqp, *tq; 261 262 tqp = context; 263 tq = *tqp; 264 265 mtx_assert(&tq->tq_mutex, MA_OWNED); 266 wakeup(tq); 267} 268 269TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 270 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 271 INTR_MPSAFE, &taskqueue_ih)); 272 273TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 274 swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run, 275 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 276 277TASKQUEUE_DEFINE_THREAD(thread); 278 279int 280taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 281{ 282 struct task *ins; 283 struct task *prev; 284 285 mtx_lock_spin(&queue->tq_mutex); 286 287 /* 288 * Count multiple enqueues. 289 */ 290 if (task->ta_pending) { 291 task->ta_pending++; 292 mtx_unlock_spin(&queue->tq_mutex); 293 return 0; 294 } 295 296 /* 297 * Optimise the case when all tasks have the same priority. 298 */ 299 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 300 if (!prev || prev->ta_priority >= task->ta_priority) { 301 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 302 } else { 303 prev = 0; 304 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 305 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 306 if (ins->ta_priority < task->ta_priority) 307 break; 308 309 if (prev) 310 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 311 else 312 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 313 } 314 315 task->ta_pending = 1; 316 if (queue->tq_enqueue) 317 queue->tq_enqueue(queue->tq_context); 318 319 mtx_unlock_spin(&queue->tq_mutex); 320 321 return 0; 322} 323 324static void 325taskqueue_run_fast(struct taskqueue *queue) 326{ 327 struct task *task; 328 int pending; 329 330 mtx_lock_spin(&queue->tq_mutex); 331 while (STAILQ_FIRST(&queue->tq_queue)) { 332 /* 333 * Carefully remove the first task from the queue and 334 * zero its pending count. 335 */ 336 task = STAILQ_FIRST(&queue->tq_queue); 337 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 338 pending = task->ta_pending; 339 task->ta_pending = 0; 340 mtx_unlock_spin(&queue->tq_mutex); 341 342 task->ta_func(task->ta_context, pending); 343 344 mtx_lock_spin(&queue->tq_mutex); 345 } 346 mtx_unlock_spin(&queue->tq_mutex); 347} 348 349struct taskqueue *taskqueue_fast; 350static void *taskqueue_fast_ih; 351 352static void 353taskqueue_fast_schedule(void *context) 354{ 355 swi_sched(taskqueue_fast_ih, 0); 356} 357 358static void 359taskqueue_fast_run(void *dummy) 360{ 361 taskqueue_run_fast(taskqueue_fast); 362} 363 364static void 365taskqueue_define_fast(void *arg) 366{ 367 368 taskqueue_fast = malloc(sizeof(struct taskqueue), M_TASKQUEUE, 369 M_NOWAIT | M_ZERO); 370 if (!taskqueue_fast) { 371 printf("%s: Unable to allocate fast task queue!\n", __func__); 372 return; 373 } 374 375 STAILQ_INIT(&taskqueue_fast->tq_queue); 376 taskqueue_fast->tq_name = "fast"; 377 taskqueue_fast->tq_enqueue = taskqueue_fast_schedule; 378 mtx_init(&taskqueue_fast->tq_mutex, "taskqueue_fast", NULL, MTX_SPIN); 379 380 mtx_lock(&taskqueue_queues_mutex); 381 STAILQ_INSERT_TAIL(&taskqueue_queues, taskqueue_fast, tq_link); 382 mtx_unlock(&taskqueue_queues_mutex); 383 384 swi_add(NULL, "Fast task queue", taskqueue_fast_run, 385 NULL, SWI_TQ_FAST, 0, &taskqueue_fast_ih); 386} 387SYSINIT(taskqueue_fast, SI_SUB_CONFIGURE, SI_ORDER_SECOND, 388 taskqueue_define_fast, NULL); 389