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 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 49 static struct mtx taskqueue_queues_mutex; 50 51 struct taskqueue { 52 STAILQ_ENTRY(taskqueue) tq_link; 53 STAILQ_HEAD(, task) tq_queue; 54 const char *tq_name; 55 taskqueue_enqueue_fn tq_enqueue; 56 void *tq_context; 57 struct task *tq_running; 58 struct mtx tq_mutex; 59 struct proc **tq_pproc; 60 int tq_pcount; 61 int tq_spin; 62 int tq_flags; 63 }; 64 65 #define TQ_FLAGS_ACTIVE (1 << 0) 66 #define TQ_FLAGS_BLOCKED (1 << 1) 67 #define TQ_FLAGS_PENDING (1 << 2) 68 69 static __inline void 70 TQ_LOCK(struct taskqueue *tq) 71 { 72 if (tq->tq_spin) 73 mtx_lock_spin(&tq->tq_mutex); 74 else 75 mtx_lock(&tq->tq_mutex); 76 } 77 78 static __inline void 79 TQ_UNLOCK(struct taskqueue *tq) 80 { 81 if (tq->tq_spin) 82 mtx_unlock_spin(&tq->tq_mutex); 83 else 84 mtx_unlock(&tq->tq_mutex); 85 } 86 87 static void init_taskqueue_list(void *data); 88 89 static __inline int 90 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm, 91 int t) 92 { 93 if (tq->tq_spin) 94 return (msleep_spin(p, m, wm, t)); 95 return (msleep(p, m, pri, wm, t)); 96 } 97 98 static void 99 init_taskqueue_list(void *data __unused) 100 { 101 102 mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF); 103 STAILQ_INIT(&taskqueue_queues); 104 } 105 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list, 106 NULL); 107 108 static struct taskqueue * 109 _taskqueue_create(const char *name, int mflags, 110 taskqueue_enqueue_fn enqueue, void *context, 111 int mtxflags, const char *mtxname) 112 { 113 struct taskqueue *queue; 114 115 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 116 if (!queue) 117 return 0; 118 119 STAILQ_INIT(&queue->tq_queue); 120 queue->tq_name = name; 121 queue->tq_enqueue = enqueue; 122 queue->tq_context = context; 123 queue->tq_spin = (mtxflags & MTX_SPIN) != 0; 124 queue->tq_flags |= TQ_FLAGS_ACTIVE; 125 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags); 126 127 mtx_lock(&taskqueue_queues_mutex); 128 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 129 mtx_unlock(&taskqueue_queues_mutex); 130 131 return queue; 132 } 133 134 struct taskqueue * 135 taskqueue_create(const char *name, int mflags, 136 taskqueue_enqueue_fn enqueue, void *context) 137 { 138 return _taskqueue_create(name, mflags, enqueue, context, 139 MTX_DEF, "taskqueue"); 140 } 141 142 /* 143 * Signal a taskqueue thread to terminate. 144 */ 145 static void 146 taskqueue_terminate(struct proc **pp, struct taskqueue *tq) 147 { 148 149 while (tq->tq_pcount > 0) { 150 wakeup(tq); 151 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0); 152 } 153 } 154 155 void 156 taskqueue_free(struct taskqueue *queue) 157 { 158 159 mtx_lock(&taskqueue_queues_mutex); 160 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 161 mtx_unlock(&taskqueue_queues_mutex); 162 163 TQ_LOCK(queue); 164 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 165 taskqueue_run(queue); 166 taskqueue_terminate(queue->tq_pproc, queue); 167 mtx_destroy(&queue->tq_mutex); 168 free(queue->tq_pproc, M_TASKQUEUE); 169 free(queue, M_TASKQUEUE); 170 } 171 172 /* 173 * Returns with the taskqueue locked. 174 */ 175 struct taskqueue * 176 taskqueue_find(const char *name) 177 { 178 struct taskqueue *queue; 179 180 mtx_lock(&taskqueue_queues_mutex); 181 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 182 if (strcmp(queue->tq_name, name) == 0) { 183 TQ_LOCK(queue); 184 mtx_unlock(&taskqueue_queues_mutex); 185 return queue; 186 } 187 } 188 mtx_unlock(&taskqueue_queues_mutex); 189 return NULL; 190 } 191 192 int 193 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 194 { 195 struct task *ins; 196 struct task *prev; 197 198 TQ_LOCK(queue); 199 200 /* 201 * Count multiple enqueues. 202 */ 203 if (task->ta_pending) { 204 task->ta_pending++; 205 TQ_UNLOCK(queue); 206 return 0; 207 } 208 209 /* 210 * Optimise the case when all tasks have the same priority. 211 */ 212 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 213 if (!prev || prev->ta_priority >= task->ta_priority) { 214 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 215 } else { 216 prev = 0; 217 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 218 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 219 if (ins->ta_priority < task->ta_priority) 220 break; 221 222 if (prev) 223 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 224 else 225 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 226 } 227 228 task->ta_pending = 1; 229 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) 230 queue->tq_enqueue(queue->tq_context); 231 else 232 queue->tq_flags |= TQ_FLAGS_PENDING; 233 234 TQ_UNLOCK(queue); 235 236 return 0; 237 } 238 239 void 240 taskqueue_block(struct taskqueue *queue) 241 { 242 243 TQ_LOCK(queue); 244 queue->tq_flags |= TQ_FLAGS_BLOCKED; 245 TQ_UNLOCK(queue); 246 } 247 248 void 249 taskqueue_unblock(struct taskqueue *queue) 250 { 251 252 TQ_LOCK(queue); 253 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 254 if (queue->tq_flags & TQ_FLAGS_PENDING) { 255 queue->tq_flags &= ~TQ_FLAGS_PENDING; 256 queue->tq_enqueue(queue->tq_context); 257 } 258 TQ_UNLOCK(queue); 259 } 260 261 void 262 taskqueue_run(struct taskqueue *queue) 263 { 264 struct task *task; 265 int owned, pending; 266 267 owned = mtx_owned(&queue->tq_mutex); 268 if (!owned) 269 TQ_LOCK(queue); 270 while (STAILQ_FIRST(&queue->tq_queue)) { 271 /* 272 * Carefully remove the first task from the queue and 273 * zero its pending count. 274 */ 275 task = STAILQ_FIRST(&queue->tq_queue); 276 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 277 pending = task->ta_pending; 278 task->ta_pending = 0; 279 queue->tq_running = task; 280 TQ_UNLOCK(queue); 281 282 task->ta_func(task->ta_context, pending); 283 284 TQ_LOCK(queue); 285 queue->tq_running = NULL; 286 wakeup(task); 287 } 288 289 /* 290 * For compatibility, unlock on return if the queue was not locked 291 * on entry, although this opens a race window. 292 */ 293 if (!owned) 294 TQ_UNLOCK(queue); 295 } 296 297 void 298 taskqueue_drain(struct taskqueue *queue, struct task *task) 299 { 300 if (queue->tq_spin) { /* XXX */ 301 mtx_lock_spin(&queue->tq_mutex); 302 while (task->ta_pending != 0 || task == queue->tq_running) 303 msleep_spin(task, &queue->tq_mutex, "-", 0); 304 mtx_unlock_spin(&queue->tq_mutex); 305 } else { 306 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 307 308 mtx_lock(&queue->tq_mutex); 309 while (task->ta_pending != 0 || task == queue->tq_running) 310 msleep(task, &queue->tq_mutex, PWAIT, "-", 0); 311 mtx_unlock(&queue->tq_mutex); 312 } 313 } 314 315 static void 316 taskqueue_swi_enqueue(void *context) 317 { 318 swi_sched(taskqueue_ih, 0); 319 } 320 321 static void 322 taskqueue_swi_run(void *dummy) 323 { 324 taskqueue_run(taskqueue_swi); 325 } 326 327 static void 328 taskqueue_swi_giant_enqueue(void *context) 329 { 330 swi_sched(taskqueue_giant_ih, 0); 331 } 332 333 static void 334 taskqueue_swi_giant_run(void *dummy) 335 { 336 taskqueue_run(taskqueue_swi_giant); 337 } 338 339 int 340 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 341 const char *name, ...) 342 { 343 va_list ap; 344 struct taskqueue *tq; 345 struct thread *td; 346 char ktname[MAXCOMLEN]; 347 int i, error; 348 349 if (count <= 0) 350 return (EINVAL); 351 tq = *tqp; 352 353 va_start(ap, name); 354 vsnprintf(ktname, MAXCOMLEN, name, ap); 355 va_end(ap); 356 357 tq->tq_pproc = malloc(sizeof(struct proc *) * count, M_TASKQUEUE, 358 M_NOWAIT | M_ZERO); 359 if (tq->tq_pproc == NULL) { 360 printf("%s: no memory for %s threads\n", __func__, ktname); 361 return (ENOMEM); 362 } 363 364 for (i = 0; i < count; i++) { 365 if (count == 1) 366 error = kproc_create(taskqueue_thread_loop, tqp, 367 &tq->tq_pproc[i], RFSTOPPED, 0, ktname); 368 else 369 error = kproc_create(taskqueue_thread_loop, tqp, 370 &tq->tq_pproc[i], RFSTOPPED, 0, "%s_%d", ktname, i); 371 if (error) { 372 /* should be ok to continue, taskqueue_free will dtrt */ 373 printf("%s: kproc_create(%s): error %d", 374 __func__, ktname, error); 375 tq->tq_pproc[i] = NULL; /* paranoid */ 376 } else 377 tq->tq_pcount++; 378 } 379 for (i = 0; i < count; i++) { 380 if (tq->tq_pproc[i] == NULL) 381 continue; 382 td = FIRST_THREAD_IN_PROC(tq->tq_pproc[i]); 383 thread_lock(td); 384 sched_prio(td, pri); 385 sched_add(td, SRQ_BORING); 386 thread_unlock(td); 387 } 388 389 return (0); 390 } 391 392 void 393 taskqueue_thread_loop(void *arg) 394 { 395 struct taskqueue **tqp, *tq; 396 397 tqp = arg; 398 tq = *tqp; 399 TQ_LOCK(tq); 400 do { 401 taskqueue_run(tq); 402 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 403 } while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0); 404 405 /* rendezvous with thread that asked us to terminate */ 406 tq->tq_pcount--; 407 wakeup_one(tq->tq_pproc); 408 TQ_UNLOCK(tq); 409 kproc_exit(0); 410 } 411 412 void 413 taskqueue_thread_enqueue(void *context) 414 { 415 struct taskqueue **tqp, *tq; 416 417 tqp = context; 418 tq = *tqp; 419 420 mtx_assert(&tq->tq_mutex, MA_OWNED); 421 wakeup_one(tq); 422 } 423 424 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 425 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 426 INTR_MPSAFE, &taskqueue_ih)); 427 428 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0, 429 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 430 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 431 432 TASKQUEUE_DEFINE_THREAD(thread); 433 434 struct taskqueue * 435 taskqueue_create_fast(const char *name, int mflags, 436 taskqueue_enqueue_fn enqueue, void *context) 437 { 438 return _taskqueue_create(name, mflags, enqueue, context, 439 MTX_SPIN, "fast_taskqueue"); 440 } 441 442 /* NB: for backwards compatibility */ 443 int 444 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 445 { 446 return taskqueue_enqueue(queue, task); 447 } 448 449 static void *taskqueue_fast_ih; 450 451 static void 452 taskqueue_fast_enqueue(void *context) 453 { 454 swi_sched(taskqueue_fast_ih, 0); 455 } 456 457 static void 458 taskqueue_fast_run(void *dummy) 459 { 460 taskqueue_run(taskqueue_fast); 461 } 462 463 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, 0, 464 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL, 465 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 466