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