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/sched.h> 41 #include <sys/taskqueue.h> 42 #include <sys/unistd.h> 43 #include <machine/stdarg.h> 44 45 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 46 static void *taskqueue_giant_ih; 47 static void *taskqueue_ih; 48 49 struct taskqueue { 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 struct thread **tq_threads; 57 int tq_tcount; 58 int tq_spin; 59 int tq_flags; 60 }; 61 62 #define TQ_FLAGS_ACTIVE (1 << 0) 63 #define TQ_FLAGS_BLOCKED (1 << 1) 64 #define TQ_FLAGS_PENDING (1 << 2) 65 66 static void taskqueue_run(struct taskqueue *, struct task **); 67 68 static __inline void 69 TQ_LOCK(struct taskqueue *tq) 70 { 71 if (tq->tq_spin) 72 mtx_lock_spin(&tq->tq_mutex); 73 else 74 mtx_lock(&tq->tq_mutex); 75 } 76 77 static __inline void 78 TQ_UNLOCK(struct taskqueue *tq) 79 { 80 if (tq->tq_spin) 81 mtx_unlock_spin(&tq->tq_mutex); 82 else 83 mtx_unlock(&tq->tq_mutex); 84 } 85 86 static __inline int 87 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm, 88 int t) 89 { 90 if (tq->tq_spin) 91 return (msleep_spin(p, m, wm, t)); 92 return (msleep(p, m, pri, wm, t)); 93 } 94 95 static struct taskqueue * 96 _taskqueue_create(const char *name, int mflags, 97 taskqueue_enqueue_fn enqueue, void *context, 98 int mtxflags, const char *mtxname) 99 { 100 struct taskqueue *queue; 101 102 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 103 if (!queue) 104 return NULL; 105 106 STAILQ_INIT(&queue->tq_queue); 107 queue->tq_name = name; 108 queue->tq_enqueue = enqueue; 109 queue->tq_context = context; 110 queue->tq_spin = (mtxflags & MTX_SPIN) != 0; 111 queue->tq_flags |= TQ_FLAGS_ACTIVE; 112 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags); 113 114 return queue; 115 } 116 117 struct taskqueue * 118 taskqueue_create(const char *name, int mflags, 119 taskqueue_enqueue_fn enqueue, void *context) 120 { 121 return _taskqueue_create(name, mflags, enqueue, context, 122 MTX_DEF, "taskqueue"); 123 } 124 125 /* 126 * Signal a taskqueue thread to terminate. 127 */ 128 static void 129 taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 130 { 131 132 while (tq->tq_tcount > 0) { 133 wakeup(tq); 134 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0); 135 } 136 } 137 138 void 139 taskqueue_free(struct taskqueue *queue) 140 { 141 142 TQ_LOCK(queue); 143 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 144 taskqueue_run(queue, &queue->tq_running); 145 taskqueue_terminate(queue->tq_threads, queue); 146 mtx_destroy(&queue->tq_mutex); 147 free(queue->tq_threads, M_TASKQUEUE); 148 free(queue, M_TASKQUEUE); 149 } 150 151 int 152 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 153 { 154 struct task *ins; 155 struct task *prev; 156 157 TQ_LOCK(queue); 158 159 /* 160 * Count multiple enqueues. 161 */ 162 if (task->ta_pending) { 163 task->ta_pending++; 164 TQ_UNLOCK(queue); 165 return 0; 166 } 167 168 /* 169 * Optimise the case when all tasks have the same priority. 170 */ 171 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 172 if (!prev || prev->ta_priority >= task->ta_priority) { 173 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 174 } else { 175 prev = NULL; 176 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 177 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 178 if (ins->ta_priority < task->ta_priority) 179 break; 180 181 if (prev) 182 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 183 else 184 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 185 } 186 187 task->ta_pending = 1; 188 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) 189 queue->tq_enqueue(queue->tq_context); 190 else 191 queue->tq_flags |= TQ_FLAGS_PENDING; 192 193 TQ_UNLOCK(queue); 194 195 return 0; 196 } 197 198 void 199 taskqueue_block(struct taskqueue *queue) 200 { 201 202 TQ_LOCK(queue); 203 queue->tq_flags |= TQ_FLAGS_BLOCKED; 204 TQ_UNLOCK(queue); 205 } 206 207 void 208 taskqueue_unblock(struct taskqueue *queue) 209 { 210 211 TQ_LOCK(queue); 212 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 213 if (queue->tq_flags & TQ_FLAGS_PENDING) { 214 queue->tq_flags &= ~TQ_FLAGS_PENDING; 215 queue->tq_enqueue(queue->tq_context); 216 } 217 TQ_UNLOCK(queue); 218 } 219 220 static void 221 taskqueue_run(struct taskqueue *queue, struct task **tpp) 222 { 223 struct task *task; 224 int pending; 225 226 mtx_assert(&queue->tq_mutex, MA_OWNED); 227 while (STAILQ_FIRST(&queue->tq_queue)) { 228 /* 229 * Carefully remove the first task from the queue and 230 * zero its pending count. 231 */ 232 task = STAILQ_FIRST(&queue->tq_queue); 233 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 234 pending = task->ta_pending; 235 task->ta_pending = 0; 236 task->ta_running = tpp; 237 *tpp = task; 238 TQ_UNLOCK(queue); 239 240 task->ta_func(task->ta_context, pending); 241 242 TQ_LOCK(queue); 243 *tpp = NULL; 244 wakeup(task); 245 } 246 } 247 248 void 249 taskqueue_drain(struct taskqueue *queue, struct task *task) 250 { 251 252 if (!queue->tq_spin) 253 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 254 255 TQ_LOCK(queue); 256 while (task->ta_pending != 0 || 257 (task->ta_running != NULL && task == *task->ta_running)) { 258 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0); 259 } 260 TQ_UNLOCK(queue); 261 } 262 263 static void 264 taskqueue_swi_enqueue(void *context) 265 { 266 swi_sched(taskqueue_ih, 0); 267 } 268 269 static void 270 taskqueue_swi_run(void *dummy) 271 { 272 TQ_LOCK(taskqueue_swi); 273 taskqueue_run(taskqueue_swi, &taskqueue_swi->tq_running); 274 TQ_UNLOCK(taskqueue_swi); 275 } 276 277 static void 278 taskqueue_swi_giant_enqueue(void *context) 279 { 280 swi_sched(taskqueue_giant_ih, 0); 281 } 282 283 static void 284 taskqueue_swi_giant_run(void *dummy) 285 { 286 TQ_LOCK(taskqueue_swi_giant); 287 taskqueue_run(taskqueue_swi_giant, &taskqueue_swi_giant->tq_running); 288 TQ_UNLOCK(taskqueue_swi_giant); 289 } 290 291 int 292 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 293 const char *name, ...) 294 { 295 va_list ap; 296 struct thread *td; 297 struct taskqueue *tq; 298 int i, error; 299 char ktname[MAXCOMLEN + 1]; 300 301 if (count <= 0) 302 return (EINVAL); 303 304 tq = *tqp; 305 306 va_start(ap, name); 307 vsnprintf(ktname, sizeof(ktname), name, ap); 308 va_end(ap); 309 310 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE, 311 M_NOWAIT | M_ZERO); 312 if (tq->tq_threads == NULL) { 313 printf("%s: no memory for %s threads\n", __func__, ktname); 314 return (ENOMEM); 315 } 316 317 for (i = 0; i < count; i++) { 318 if (count == 1) 319 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 320 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname); 321 else 322 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 323 &tq->tq_threads[i], RFSTOPPED, 0, 324 "%s_%d", ktname, i); 325 if (error) { 326 /* should be ok to continue, taskqueue_free will dtrt */ 327 printf("%s: kthread_add(%s): error %d", __func__, 328 ktname, error); 329 tq->tq_threads[i] = NULL; /* paranoid */ 330 } else 331 tq->tq_tcount++; 332 } 333 for (i = 0; i < count; i++) { 334 if (tq->tq_threads[i] == NULL) 335 continue; 336 td = tq->tq_threads[i]; 337 thread_lock(td); 338 sched_prio(td, pri); 339 sched_add(td, SRQ_BORING); 340 thread_unlock(td); 341 } 342 343 return (0); 344 } 345 346 void 347 taskqueue_thread_loop(void *arg) 348 { 349 struct taskqueue **tqp, *tq; 350 struct task *running; 351 352 /* 353 * The kernel stack space is globaly addressable, and it would 354 * be an error to ask whether a task is running after the 355 * taskqueue has been released. So it is safe to have the 356 * task point back to an address in the taskqueue's stack to 357 * determine if the task is running. 358 */ 359 running = NULL; 360 361 tqp = arg; 362 tq = *tqp; 363 TQ_LOCK(tq); 364 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 365 taskqueue_run(tq, &running); 366 /* 367 * Because taskqueue_run() can drop tq_mutex, we need to 368 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the 369 * meantime, which means we missed a wakeup. 370 */ 371 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0) 372 break; 373 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 374 } 375 376 /* rendezvous with thread that asked us to terminate */ 377 tq->tq_tcount--; 378 wakeup_one(tq->tq_threads); 379 TQ_UNLOCK(tq); 380 kthread_exit(); 381 } 382 383 void 384 taskqueue_thread_enqueue(void *context) 385 { 386 struct taskqueue **tqp, *tq; 387 388 tqp = context; 389 tq = *tqp; 390 391 mtx_assert(&tq->tq_mutex, MA_OWNED); 392 wakeup_one(tq); 393 } 394 395 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL, 396 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 397 INTR_MPSAFE, &taskqueue_ih)); 398 399 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL, 400 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 401 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 402 403 TASKQUEUE_DEFINE_THREAD(thread); 404 405 struct taskqueue * 406 taskqueue_create_fast(const char *name, int mflags, 407 taskqueue_enqueue_fn enqueue, void *context) 408 { 409 return _taskqueue_create(name, mflags, enqueue, context, 410 MTX_SPIN, "fast_taskqueue"); 411 } 412 413 /* NB: for backwards compatibility */ 414 int 415 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 416 { 417 return taskqueue_enqueue(queue, task); 418 } 419 420 static void *taskqueue_fast_ih; 421 422 static void 423 taskqueue_fast_enqueue(void *context) 424 { 425 swi_sched(taskqueue_fast_ih, 0); 426 } 427 428 static void 429 taskqueue_fast_run(void *dummy) 430 { 431 TQ_LOCK(taskqueue_fast); 432 taskqueue_run(taskqueue_fast, &taskqueue_fast->tq_running); 433 TQ_UNLOCK(taskqueue_fast); 434 } 435 436 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL, 437 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL, 438 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 439 440 int 441 taskqueue_member(struct taskqueue *queue, struct thread *td) 442 { 443 int i, j, ret = 0; 444 445 TQ_LOCK(queue); 446 for (i = 0, j = 0; ; i++) { 447 if (queue->tq_threads[i] == NULL) 448 continue; 449 if (queue->tq_threads[i] == td) { 450 ret = 1; 451 break; 452 } 453 if (++j >= queue->tq_tcount) 454 break; 455 } 456 TQ_UNLOCK(queue); 457 return (ret); 458 } 459