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/limits.h> 37#include <sys/lock.h> 38#include <sys/malloc.h> 39#include <sys/mutex.h> 40#include <sys/proc.h> 41#include <sys/sched.h> 42#include <sys/taskqueue.h> 43#include <sys/unistd.h> 44#include <machine/stdarg.h> 45 46static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 47static void *taskqueue_giant_ih; 48static void *taskqueue_ih; 49 50struct taskqueue_busy { 51 struct task *tb_running; 52 TAILQ_ENTRY(taskqueue_busy) tb_link; 53}; 54 55struct taskqueue { 56 STAILQ_HEAD(, task) tq_queue; 57 taskqueue_enqueue_fn tq_enqueue; 58 void *tq_context; 59 TAILQ_HEAD(, taskqueue_busy) tq_active; 60 struct mtx tq_mutex; 61 struct thread **tq_threads; 62 int tq_tcount; 63 int tq_spin; 64 int tq_flags; 65 int tq_callouts; 66}; 67 68#define TQ_FLAGS_ACTIVE (1 << 0) 69#define TQ_FLAGS_BLOCKED (1 << 1) 70#define TQ_FLAGS_PENDING (1 << 2) 71 72#define DT_CALLOUT_ARMED (1 << 0) 73 74#define TQ_LOCK(tq) \ 75 do { \ 76 if ((tq)->tq_spin) \ 77 mtx_lock_spin(&(tq)->tq_mutex); \ 78 else \ 79 mtx_lock(&(tq)->tq_mutex); \ 80 } while (0) 81 82#define TQ_UNLOCK(tq) \ 83 do { \ 84 if ((tq)->tq_spin) \ 85 mtx_unlock_spin(&(tq)->tq_mutex); \ 86 else \ 87 mtx_unlock(&(tq)->tq_mutex); \ 88 } while (0) 89 90void 91_timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task, 92 int priority, task_fn_t func, void *context) 93{ 94 95 TASK_INIT(&timeout_task->t, priority, func, context); 96 callout_init_mtx(&timeout_task->c, &queue->tq_mutex, 0); 97 timeout_task->q = queue; 98 timeout_task->f = 0; 99} 100 101static __inline int 102TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm, 103 int t) 104{ 105 if (tq->tq_spin) 106 return (msleep_spin(p, m, wm, t)); 107 return (msleep(p, m, pri, wm, t)); 108} 109 110static struct taskqueue * 111_taskqueue_create(const char *name __unused, int mflags, 112 taskqueue_enqueue_fn enqueue, void *context, 113 int mtxflags, const char *mtxname) 114{ 115 struct taskqueue *queue; 116 117 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 118 if (!queue) 119 return NULL; 120 121 STAILQ_INIT(&queue->tq_queue); 122 TAILQ_INIT(&queue->tq_active); 123 queue->tq_enqueue = enqueue; 124 queue->tq_context = context; 125 queue->tq_spin = (mtxflags & MTX_SPIN) != 0; 126 queue->tq_flags |= TQ_FLAGS_ACTIVE; 127 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags); 128 129 return queue; 130} 131 132struct taskqueue * 133taskqueue_create(const char *name, int mflags, 134 taskqueue_enqueue_fn enqueue, void *context) 135{ 136 return _taskqueue_create(name, mflags, enqueue, context, 137 MTX_DEF, "taskqueue"); 138} 139 140/* 141 * Signal a taskqueue thread to terminate. 142 */ 143static void 144taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 145{ 146 147 while (tq->tq_tcount > 0 || tq->tq_callouts > 0) { 148 wakeup(tq); 149 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0); 150 } 151} 152 153void 154taskqueue_free(struct taskqueue *queue) 155{ 156 157 TQ_LOCK(queue); 158 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 159 taskqueue_terminate(queue->tq_threads, queue); 160 KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?")); 161 KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks")); 162 mtx_destroy(&queue->tq_mutex); 163 free(queue->tq_threads, M_TASKQUEUE); 164 free(queue, M_TASKQUEUE); 165} 166 167static int 168taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task) 169{ 170 struct task *ins; 171 struct task *prev; 172 173 /* 174 * Count multiple enqueues. 175 */ 176 if (task->ta_pending) { 177 if (task->ta_pending < USHRT_MAX) 178 task->ta_pending++; 179 return (0); 180 } 181 182 /* 183 * Optimise the case when all tasks have the same priority. 184 */ 185 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 186 if (!prev || prev->ta_priority >= task->ta_priority) { 187 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 188 } else { 189 prev = NULL; 190 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 191 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 192 if (ins->ta_priority < task->ta_priority) 193 break; 194 195 if (prev) 196 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 197 else 198 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 199 } 200 201 task->ta_pending = 1; 202 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) 203 queue->tq_enqueue(queue->tq_context); 204 else 205 queue->tq_flags |= TQ_FLAGS_PENDING; 206 207 return (0); 208} 209int 210taskqueue_enqueue(struct taskqueue *queue, struct task *task) 211{ 212 int res; 213 214 TQ_LOCK(queue); 215 res = taskqueue_enqueue_locked(queue, task); 216 TQ_UNLOCK(queue); 217 218 return (res); 219} 220 221static void 222taskqueue_timeout_func(void *arg) 223{ 224 struct taskqueue *queue; 225 struct timeout_task *timeout_task; 226 227 timeout_task = arg; 228 queue = timeout_task->q; 229 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout")); 230 timeout_task->f &= ~DT_CALLOUT_ARMED; 231 queue->tq_callouts--; 232 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t); 233} 234 235int 236taskqueue_enqueue_timeout(struct taskqueue *queue, 237 struct timeout_task *timeout_task, int ticks) 238{ 239 int res; 240 241 TQ_LOCK(queue); 242 KASSERT(timeout_task->q == NULL || timeout_task->q == queue, 243 ("Migrated queue")); 244 KASSERT(!queue->tq_spin, ("Timeout for spin-queue")); 245 timeout_task->q = queue; 246 res = timeout_task->t.ta_pending; 247 if (ticks == 0) { 248 taskqueue_enqueue_locked(queue, &timeout_task->t); 249 } else { 250 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 251 res++; 252 } else { 253 queue->tq_callouts++; 254 timeout_task->f |= DT_CALLOUT_ARMED; 255 if (ticks < 0) 256 ticks = -ticks; /* Ignore overflow. */ 257 } 258 if (ticks > 0) { 259 callout_reset(&timeout_task->c, ticks, 260 taskqueue_timeout_func, timeout_task); 261 } 262 } 263 TQ_UNLOCK(queue); 264 return (res); 265} 266 267static void 268taskqueue_drain_running(struct taskqueue *queue) 269{ 270 271 while (!TAILQ_EMPTY(&queue->tq_active)) 272 TQ_SLEEP(queue, &queue->tq_active, &queue->tq_mutex, 273 PWAIT, "-", 0); 274} 275 276void 277taskqueue_block(struct taskqueue *queue) 278{ 279 280 TQ_LOCK(queue); 281 queue->tq_flags |= TQ_FLAGS_BLOCKED; 282 TQ_UNLOCK(queue); 283} 284 285void 286taskqueue_unblock(struct taskqueue *queue) 287{ 288 289 TQ_LOCK(queue); 290 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 291 if (queue->tq_flags & TQ_FLAGS_PENDING) { 292 queue->tq_flags &= ~TQ_FLAGS_PENDING; 293 queue->tq_enqueue(queue->tq_context); 294 } 295 TQ_UNLOCK(queue); 296} 297 298static void 299taskqueue_run_locked(struct taskqueue *queue) 300{ 301 struct taskqueue_busy tb; 302 struct task *task; 303 int pending; 304 305 mtx_assert(&queue->tq_mutex, MA_OWNED); 306 tb.tb_running = NULL; 307 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link); 308 309 while (STAILQ_FIRST(&queue->tq_queue)) { 310 /* 311 * Carefully remove the first task from the queue and 312 * zero its pending count. 313 */ 314 task = STAILQ_FIRST(&queue->tq_queue); 315 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 316 pending = task->ta_pending; 317 task->ta_pending = 0; 318 tb.tb_running = task; 319 TQ_UNLOCK(queue); 320 321 task->ta_func(task->ta_context, pending); 322 323 TQ_LOCK(queue); 324 tb.tb_running = NULL; 325 wakeup(task); 326 } 327 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link); 328 if (TAILQ_EMPTY(&queue->tq_active)) 329 wakeup(&queue->tq_active); 330} 331 332void 333taskqueue_run(struct taskqueue *queue) 334{ 335 336 TQ_LOCK(queue); 337 taskqueue_run_locked(queue); 338 TQ_UNLOCK(queue); 339} 340 341static int 342task_is_running(struct taskqueue *queue, struct task *task) 343{ 344 struct taskqueue_busy *tb; 345 346 mtx_assert(&queue->tq_mutex, MA_OWNED); 347 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) { 348 if (tb->tb_running == task) 349 return (1); 350 } 351 return (0); 352} 353 354static int 355taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 356 u_int *pendp) 357{ 358 359 if (task->ta_pending > 0) 360 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 361 if (pendp != NULL) 362 *pendp = task->ta_pending; 363 task->ta_pending = 0; 364 return (task_is_running(queue, task) ? EBUSY : 0); 365} 366 367int 368taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 369{ 370 int error; 371 372 TQ_LOCK(queue); 373 error = taskqueue_cancel_locked(queue, task, pendp); 374 TQ_UNLOCK(queue); 375 376 return (error); 377} 378 379int 380taskqueue_cancel_timeout(struct taskqueue *queue, 381 struct timeout_task *timeout_task, u_int *pendp) 382{ 383 u_int pending, pending1; 384 int error; 385 386 TQ_LOCK(queue); 387 pending = !!callout_stop(&timeout_task->c); 388 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 389 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 390 timeout_task->f &= ~DT_CALLOUT_ARMED; 391 queue->tq_callouts--; 392 } 393 TQ_UNLOCK(queue); 394 395 if (pendp != NULL) 396 *pendp = pending + pending1; 397 return (error); 398} 399 400void 401taskqueue_drain(struct taskqueue *queue, struct task *task) 402{ 403 404 if (!queue->tq_spin) 405 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 406 407 TQ_LOCK(queue); 408 while (task->ta_pending != 0 || task_is_running(queue, task)) 409 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0); 410 TQ_UNLOCK(queue); 411} 412 413void 414taskqueue_drain_all(struct taskqueue *queue) 415{ 416 struct task *task; 417 418 if (!queue->tq_spin) 419 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 420 421 TQ_LOCK(queue); 422 task = STAILQ_LAST(&queue->tq_queue, task, ta_link); 423 if (task != NULL) 424 while (task->ta_pending != 0) 425 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0); 426 taskqueue_drain_running(queue); 427 KASSERT(STAILQ_EMPTY(&queue->tq_queue), 428 ("taskqueue queue is not empty after draining")); 429 TQ_UNLOCK(queue); 430} 431 432void 433taskqueue_drain_timeout(struct taskqueue *queue, 434 struct timeout_task *timeout_task) 435{ 436 437 callout_drain(&timeout_task->c); 438 taskqueue_drain(queue, &timeout_task->t); 439} 440 441static void 442taskqueue_swi_enqueue(void *context) 443{ 444 swi_sched(taskqueue_ih, 0); 445} 446 447static void 448taskqueue_swi_run(void *dummy) 449{ 450 taskqueue_run(taskqueue_swi); 451} 452 453static void 454taskqueue_swi_giant_enqueue(void *context) 455{ 456 swi_sched(taskqueue_giant_ih, 0); 457} 458 459static void 460taskqueue_swi_giant_run(void *dummy) 461{ 462 taskqueue_run(taskqueue_swi_giant); 463} 464 465int 466taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 467 const char *name, ...) 468{ 469 va_list ap; 470 struct thread *td; 471 struct taskqueue *tq; 472 int i, error; 473 char ktname[MAXCOMLEN + 1]; 474 475 if (count <= 0) 476 return (EINVAL); 477 478 tq = *tqp; 479 480 va_start(ap, name); 481 vsnprintf(ktname, sizeof(ktname), name, ap); 482 va_end(ap); 483 484 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE, 485 M_NOWAIT | M_ZERO); 486 if (tq->tq_threads == NULL) { 487 printf("%s: no memory for %s threads\n", __func__, ktname); 488 return (ENOMEM); 489 } 490 491 for (i = 0; i < count; i++) { 492 if (count == 1) 493 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 494 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname); 495 else 496 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 497 &tq->tq_threads[i], RFSTOPPED, 0, 498 "%s_%d", ktname, i); 499 if (error) { 500 /* should be ok to continue, taskqueue_free will dtrt */ 501 printf("%s: kthread_add(%s): error %d", __func__, 502 ktname, error); 503 tq->tq_threads[i] = NULL; /* paranoid */ 504 } else 505 tq->tq_tcount++; 506 } 507 for (i = 0; i < count; i++) { 508 if (tq->tq_threads[i] == NULL) 509 continue; 510 td = tq->tq_threads[i]; 511 thread_lock(td); 512 sched_prio(td, pri); 513 sched_add(td, SRQ_BORING); 514 thread_unlock(td); 515 } 516 517 return (0); 518} 519 520void 521taskqueue_thread_loop(void *arg) 522{ 523 struct taskqueue **tqp, *tq; 524 525 tqp = arg; 526 tq = *tqp; 527 TQ_LOCK(tq); 528 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 529 taskqueue_run_locked(tq); 530 /* 531 * Because taskqueue_run() can drop tq_mutex, we need to 532 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the 533 * meantime, which means we missed a wakeup. 534 */ 535 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0) 536 break; 537 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 538 } 539 taskqueue_run_locked(tq); 540 541 /* rendezvous with thread that asked us to terminate */ 542 tq->tq_tcount--; 543 wakeup_one(tq->tq_threads); 544 TQ_UNLOCK(tq); 545 kthread_exit(); 546} 547 548void 549taskqueue_thread_enqueue(void *context) 550{ 551 struct taskqueue **tqp, *tq; 552 553 tqp = context; 554 tq = *tqp; 555 556 mtx_assert(&tq->tq_mutex, MA_OWNED); 557 wakeup_one(tq); 558} 559 560TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL, 561 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 562 INTR_MPSAFE, &taskqueue_ih)); 563 564TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL, 565 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 566 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 567 568TASKQUEUE_DEFINE_THREAD(thread); 569 570struct taskqueue * 571taskqueue_create_fast(const char *name, int mflags, 572 taskqueue_enqueue_fn enqueue, void *context) 573{ 574 return _taskqueue_create(name, mflags, enqueue, context, 575 MTX_SPIN, "fast_taskqueue"); 576} 577 578/* NB: for backwards compatibility */ 579int 580taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 581{ 582 return taskqueue_enqueue(queue, task); 583} 584 585static void *taskqueue_fast_ih; 586 587static void 588taskqueue_fast_enqueue(void *context) 589{ 590 swi_sched(taskqueue_fast_ih, 0); 591} 592 593static void 594taskqueue_fast_run(void *dummy) 595{ 596 taskqueue_run(taskqueue_fast); 597} 598 599TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL, 600 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL, 601 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 602 603int 604taskqueue_member(struct taskqueue *queue, struct thread *td) 605{ 606 int i, j, ret = 0; 607 608 for (i = 0, j = 0; ; i++) { 609 if (queue->tq_threads[i] == NULL) 610 continue; 611 if (queue->tq_threads[i] == td) { 612 ret = 1; 613 break; 614 } 615 if (++j >= queue->tq_tcount) 616 break; 617 } 618 return (ret); 619} 620