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("$FreeBSD$"); 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/proc.h> 40 #include <sys/taskqueue.h> 41 #include <sys/unistd.h> 42 43 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 44 static void *taskqueue_giant_ih; 45 static void *taskqueue_ih; 46 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 47 static struct mtx taskqueue_queues_mutex; 48 49 struct taskqueue { 50 STAILQ_ENTRY(taskqueue) tq_link; 51 STAILQ_HEAD(, task) tq_queue; 52 const char *tq_name; 53 taskqueue_enqueue_fn tq_enqueue; 54 void *tq_context; 55 struct task *tq_running; 56 struct mtx tq_mutex; 57 struct proc **tq_pproc; 58 }; 59 60 static void init_taskqueue_list(void *data); 61 62 static void 63 init_taskqueue_list(void *data __unused) 64 { 65 66 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 67 STAILQ_INIT(&taskqueue_queues); 68 } 69 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 70 NULL); 71 72 struct taskqueue * 73 taskqueue_create(const char *name, int mflags, 74 taskqueue_enqueue_fn enqueue, void *context, 75 struct proc **pp) 76 { 77 struct taskqueue *queue; 78 79 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 80 if (!queue) 81 return 0; 82 83 STAILQ_INIT(&queue->tq_queue); 84 queue->tq_name = name; 85 queue->tq_enqueue = enqueue; 86 queue->tq_context = context; 87 queue->tq_pproc = pp; 88 mtx_init(&queue->tq_mutex, "taskqueue", NULL, MTX_DEF); 89 90 mtx_lock(&taskqueue_queues_mutex); 91 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 92 mtx_unlock(&taskqueue_queues_mutex); 93 94 return queue; 95 } 96 97 /* 98 * Signal a taskqueue thread to terminate. 99 */ 100 static void 101 taskqueue_terminate(struct proc **pp, struct taskqueue *tq) 102 { 103 struct proc *p; 104 105 p = *pp; 106 *pp = NULL; 107 if (p) { 108 wakeup_one(tq); 109 PROC_LOCK(p); /* NB: insure we don't miss wakeup */ 110 mtx_unlock(&tq->tq_mutex); /* let taskqueue thread run */ 111 msleep(p, &p->p_mtx, PWAIT, "taskqueue_destroy", 0); 112 PROC_UNLOCK(p); 113 mtx_lock(&tq->tq_mutex); 114 } 115 } 116 117 void 118 taskqueue_free(struct taskqueue *queue) 119 { 120 121 mtx_lock(&taskqueue_queues_mutex); 122 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 123 mtx_unlock(&taskqueue_queues_mutex); 124 125 mtx_lock(&queue->tq_mutex); 126 taskqueue_run(queue); 127 taskqueue_terminate(queue->tq_pproc, queue); 128 mtx_destroy(&queue->tq_mutex); 129 free(queue, M_TASKQUEUE); 130 } 131 132 /* 133 * Returns with the taskqueue locked. 134 */ 135 struct taskqueue * 136 taskqueue_find(const char *name) 137 { 138 struct taskqueue *queue; 139 140 mtx_lock(&taskqueue_queues_mutex); 141 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 142 if (strcmp(queue->tq_name, name) == 0) { 143 mtx_lock(&queue->tq_mutex); 144 mtx_unlock(&taskqueue_queues_mutex); 145 return queue; 146 } 147 } 148 mtx_unlock(&taskqueue_queues_mutex); 149 return NULL; 150 } 151 152 int 153 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 154 { 155 struct task *ins; 156 struct task *prev; 157 158 mtx_lock(&queue->tq_mutex); 159 160 /* 161 * Count multiple enqueues. 162 */ 163 if (task->ta_pending) { 164 task->ta_pending++; 165 mtx_unlock(&queue->tq_mutex); 166 return 0; 167 } 168 169 /* 170 * Optimise the case when all tasks have the same priority. 171 */ 172 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 173 if (!prev || prev->ta_priority >= task->ta_priority) { 174 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 175 } else { 176 prev = 0; 177 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 178 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 179 if (ins->ta_priority < task->ta_priority) 180 break; 181 182 if (prev) 183 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 184 else 185 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 186 } 187 188 task->ta_pending = 1; 189 queue->tq_enqueue(queue->tq_context); 190 191 mtx_unlock(&queue->tq_mutex); 192 193 return 0; 194 } 195 196 void 197 taskqueue_run(struct taskqueue *queue) 198 { 199 struct task *task; 200 int owned, pending; 201 202 owned = mtx_owned(&queue->tq_mutex); 203 if (!owned) 204 mtx_lock(&queue->tq_mutex); 205 while (STAILQ_FIRST(&queue->tq_queue)) { 206 /* 207 * Carefully remove the first task from the queue and 208 * zero its pending count. 209 */ 210 task = STAILQ_FIRST(&queue->tq_queue); 211 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 212 pending = task->ta_pending; 213 task->ta_pending = 0; 214 queue->tq_running = task; 215 mtx_unlock(&queue->tq_mutex); 216 217 task->ta_func(task->ta_context, pending); 218 219 mtx_lock(&queue->tq_mutex); 220 queue->tq_running = NULL; 221 wakeup(task); 222 } 223 224 /* 225 * For compatibility, unlock on return if the queue was not locked 226 * on entry, although this opens a race window. 227 */ 228 if (!owned) 229 mtx_unlock(&queue->tq_mutex); 230 } 231 232 void 233 taskqueue_drain(struct taskqueue *queue, struct task *task) 234 { 235 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "taskqueue_drain"); 236 237 mtx_lock(&queue->tq_mutex); 238 while (task->ta_pending != 0 || task == queue->tq_running) 239 msleep(task, &queue->tq_mutex, PWAIT, "-", 0); 240 mtx_unlock(&queue->tq_mutex); 241 } 242 243 static void 244 taskqueue_swi_enqueue(void *context) 245 { 246 swi_sched(taskqueue_ih, 0); 247 } 248 249 static void 250 taskqueue_swi_run(void *dummy) 251 { 252 taskqueue_run(taskqueue_swi); 253 } 254 255 static void 256 taskqueue_swi_giant_enqueue(void *context) 257 { 258 swi_sched(taskqueue_giant_ih, 0); 259 } 260 261 static void 262 taskqueue_swi_giant_run(void *dummy) 263 { 264 taskqueue_run(taskqueue_swi_giant); 265 } 266 267 void 268 taskqueue_thread_loop(void *arg) 269 { 270 struct taskqueue **tqp, *tq; 271 272 tqp = arg; 273 tq = *tqp; 274 mtx_lock(&tq->tq_mutex); 275 do { 276 taskqueue_run(tq); 277 msleep(tq, &tq->tq_mutex, PWAIT, "-", 0); 278 } while (*tq->tq_pproc != NULL); 279 280 /* rendezvous with thread that asked us to terminate */ 281 wakeup_one(tq); 282 mtx_unlock(&tq->tq_mutex); 283 kthread_exit(0); 284 } 285 286 void 287 taskqueue_thread_enqueue(void *context) 288 { 289 struct taskqueue **tqp, *tq; 290 291 tqp = context; 292 tq = *tqp; 293 294 mtx_assert(&tq->tq_mutex, MA_OWNED); 295 wakeup_one(tq); 296 } 297 298 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 299 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 300 INTR_MPSAFE, &taskqueue_ih)); 301 302 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 303 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 304 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 305 306 TASKQUEUE_DEFINE_THREAD(thread); 307 308 int 309 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 310 { 311 struct task *ins; 312 struct task *prev; 313 314 mtx_lock_spin(&queue->tq_mutex); 315 316 /* 317 * Count multiple enqueues. 318 */ 319 if (task->ta_pending) { 320 task->ta_pending++; 321 mtx_unlock_spin(&queue->tq_mutex); 322 return 0; 323 } 324 325 /* 326 * Optimise the case when all tasks have the same priority. 327 */ 328 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 329 if (!prev || prev->ta_priority >= task->ta_priority) { 330 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 331 } else { 332 prev = 0; 333 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 334 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 335 if (ins->ta_priority < task->ta_priority) 336 break; 337 338 if (prev) 339 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 340 else 341 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 342 } 343 344 task->ta_pending = 1; 345 queue->tq_enqueue(queue->tq_context); 346 347 mtx_unlock_spin(&queue->tq_mutex); 348 349 return 0; 350 } 351 352 static void 353 taskqueue_run_fast(struct taskqueue *queue) 354 { 355 struct task *task; 356 int pending; 357 358 mtx_lock_spin(&queue->tq_mutex); 359 while (STAILQ_FIRST(&queue->tq_queue)) { 360 /* 361 * Carefully remove the first task from the queue and 362 * zero its pending count. 363 */ 364 task = STAILQ_FIRST(&queue->tq_queue); 365 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 366 pending = task->ta_pending; 367 task->ta_pending = 0; 368 mtx_unlock_spin(&queue->tq_mutex); 369 370 task->ta_func(task->ta_context, pending); 371 372 mtx_lock_spin(&queue->tq_mutex); 373 } 374 mtx_unlock_spin(&queue->tq_mutex); 375 } 376 377 struct taskqueue *taskqueue_fast; 378 static void *taskqueue_fast_ih; 379 380 static void 381 taskqueue_fast_schedule(void *context) 382 { 383 swi_sched(taskqueue_fast_ih, 0); 384 } 385 386 static void 387 taskqueue_fast_run(void *dummy) 388 { 389 taskqueue_run_fast(taskqueue_fast); 390 } 391 392 static void 393 taskqueue_define_fast(void *arg) 394 { 395 396 taskqueue_fast = malloc(sizeof(struct taskqueue), M_TASKQUEUE, 397 M_NOWAIT | M_ZERO); 398 if (!taskqueue_fast) { 399 printf("%s: Unable to allocate fast task queue!\n", __func__); 400 return; 401 } 402 403 STAILQ_INIT(&taskqueue_fast->tq_queue); 404 taskqueue_fast->tq_name = "fast"; 405 taskqueue_fast->tq_enqueue = taskqueue_fast_schedule; 406 mtx_init(&taskqueue_fast->tq_mutex, "taskqueue_fast", NULL, MTX_SPIN); 407 408 mtx_lock(&taskqueue_queues_mutex); 409 STAILQ_INSERT_TAIL(&taskqueue_queues, taskqueue_fast, tq_link); 410 mtx_unlock(&taskqueue_queues_mutex); 411 412 swi_add(NULL, "Fast taskq", taskqueue_fast_run, 413 NULL, SWI_TQ_FAST, 0, &taskqueue_fast_ih); 414 } 415 SYSINIT(taskqueue_fast, SI_SUB_CONFIGURE, SI_ORDER_SECOND, 416 taskqueue_define_fast, NULL); 417