subr_taskqueue.c revision 256281
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: stable/10/sys/kern/subr_taskqueue.c 254787 2013-08-24 14:41:49Z mav $"); 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 taskqueue_callback_fn tq_callbacks[TASKQUEUE_NUM_CALLBACKS]; 67 void *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS]; 68}; 69 70#define TQ_FLAGS_ACTIVE (1 << 0) 71#define TQ_FLAGS_BLOCKED (1 << 1) 72#define TQ_FLAGS_PENDING (1 << 2) 73 74#define DT_CALLOUT_ARMED (1 << 0) 75 76#define TQ_LOCK(tq) \ 77 do { \ 78 if ((tq)->tq_spin) \ 79 mtx_lock_spin(&(tq)->tq_mutex); \ 80 else \ 81 mtx_lock(&(tq)->tq_mutex); \ 82 } while (0) 83#define TQ_ASSERT_LOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_OWNED) 84 85#define TQ_UNLOCK(tq) \ 86 do { \ 87 if ((tq)->tq_spin) \ 88 mtx_unlock_spin(&(tq)->tq_mutex); \ 89 else \ 90 mtx_unlock(&(tq)->tq_mutex); \ 91 } while (0) 92#define TQ_ASSERT_UNLOCKED(tq) mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED) 93 94void 95_timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task, 96 int priority, task_fn_t func, void *context) 97{ 98 99 TASK_INIT(&timeout_task->t, priority, func, context); 100 callout_init_mtx(&timeout_task->c, &queue->tq_mutex, 0); 101 timeout_task->q = queue; 102 timeout_task->f = 0; 103} 104 105static __inline int 106TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm, 107 int t) 108{ 109 if (tq->tq_spin) 110 return (msleep_spin(p, m, wm, t)); 111 return (msleep(p, m, pri, wm, t)); 112} 113 114static struct taskqueue * 115_taskqueue_create(const char *name __unused, int mflags, 116 taskqueue_enqueue_fn enqueue, void *context, 117 int mtxflags, const char *mtxname) 118{ 119 struct taskqueue *queue; 120 121 queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO); 122 if (!queue) 123 return NULL; 124 125 STAILQ_INIT(&queue->tq_queue); 126 TAILQ_INIT(&queue->tq_active); 127 queue->tq_enqueue = enqueue; 128 queue->tq_context = context; 129 queue->tq_spin = (mtxflags & MTX_SPIN) != 0; 130 queue->tq_flags |= TQ_FLAGS_ACTIVE; 131 mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags); 132 133 return queue; 134} 135 136struct taskqueue * 137taskqueue_create(const char *name, int mflags, 138 taskqueue_enqueue_fn enqueue, void *context) 139{ 140 return _taskqueue_create(name, mflags, enqueue, context, 141 MTX_DEF, "taskqueue"); 142} 143 144void 145taskqueue_set_callback(struct taskqueue *queue, 146 enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback, 147 void *context) 148{ 149 150 KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) && 151 (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)), 152 ("Callback type %d not valid, must be %d-%d", cb_type, 153 TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX)); 154 KASSERT((queue->tq_callbacks[cb_type] == NULL), 155 ("Re-initialization of taskqueue callback?")); 156 157 queue->tq_callbacks[cb_type] = callback; 158 queue->tq_cb_contexts[cb_type] = context; 159} 160 161/* 162 * Signal a taskqueue thread to terminate. 163 */ 164static void 165taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 166{ 167 168 while (tq->tq_tcount > 0 || tq->tq_callouts > 0) { 169 wakeup(tq); 170 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0); 171 } 172} 173 174void 175taskqueue_free(struct taskqueue *queue) 176{ 177 178 TQ_LOCK(queue); 179 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 180 taskqueue_terminate(queue->tq_threads, queue); 181 KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?")); 182 KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks")); 183 mtx_destroy(&queue->tq_mutex); 184 free(queue->tq_threads, M_TASKQUEUE); 185 free(queue, M_TASKQUEUE); 186} 187 188static int 189taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task) 190{ 191 struct task *ins; 192 struct task *prev; 193 194 /* 195 * Count multiple enqueues. 196 */ 197 if (task->ta_pending) { 198 if (task->ta_pending < USHRT_MAX) 199 task->ta_pending++; 200 return (0); 201 } 202 203 /* 204 * Optimise the case when all tasks have the same priority. 205 */ 206 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 207 if (!prev || prev->ta_priority >= task->ta_priority) { 208 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 209 } else { 210 prev = NULL; 211 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 212 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 213 if (ins->ta_priority < task->ta_priority) 214 break; 215 216 if (prev) 217 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 218 else 219 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 220 } 221 222 task->ta_pending = 1; 223 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) 224 queue->tq_enqueue(queue->tq_context); 225 else 226 queue->tq_flags |= TQ_FLAGS_PENDING; 227 228 return (0); 229} 230int 231taskqueue_enqueue(struct taskqueue *queue, struct task *task) 232{ 233 int res; 234 235 TQ_LOCK(queue); 236 res = taskqueue_enqueue_locked(queue, task); 237 TQ_UNLOCK(queue); 238 239 return (res); 240} 241 242static void 243taskqueue_timeout_func(void *arg) 244{ 245 struct taskqueue *queue; 246 struct timeout_task *timeout_task; 247 248 timeout_task = arg; 249 queue = timeout_task->q; 250 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout")); 251 timeout_task->f &= ~DT_CALLOUT_ARMED; 252 queue->tq_callouts--; 253 taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t); 254} 255 256int 257taskqueue_enqueue_timeout(struct taskqueue *queue, 258 struct timeout_task *timeout_task, int ticks) 259{ 260 int res; 261 262 TQ_LOCK(queue); 263 KASSERT(timeout_task->q == NULL || timeout_task->q == queue, 264 ("Migrated queue")); 265 KASSERT(!queue->tq_spin, ("Timeout for spin-queue")); 266 timeout_task->q = queue; 267 res = timeout_task->t.ta_pending; 268 if (ticks == 0) { 269 taskqueue_enqueue_locked(queue, &timeout_task->t); 270 } else { 271 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 272 res++; 273 } else { 274 queue->tq_callouts++; 275 timeout_task->f |= DT_CALLOUT_ARMED; 276 if (ticks < 0) 277 ticks = -ticks; /* Ignore overflow. */ 278 } 279 if (ticks > 0) { 280 callout_reset(&timeout_task->c, ticks, 281 taskqueue_timeout_func, timeout_task); 282 } 283 } 284 TQ_UNLOCK(queue); 285 return (res); 286} 287 288void 289taskqueue_block(struct taskqueue *queue) 290{ 291 292 TQ_LOCK(queue); 293 queue->tq_flags |= TQ_FLAGS_BLOCKED; 294 TQ_UNLOCK(queue); 295} 296 297void 298taskqueue_unblock(struct taskqueue *queue) 299{ 300 301 TQ_LOCK(queue); 302 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 303 if (queue->tq_flags & TQ_FLAGS_PENDING) { 304 queue->tq_flags &= ~TQ_FLAGS_PENDING; 305 queue->tq_enqueue(queue->tq_context); 306 } 307 TQ_UNLOCK(queue); 308} 309 310static void 311taskqueue_run_locked(struct taskqueue *queue) 312{ 313 struct taskqueue_busy tb; 314 struct task *task; 315 int pending; 316 317 TQ_ASSERT_LOCKED(queue); 318 tb.tb_running = NULL; 319 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link); 320 321 while (STAILQ_FIRST(&queue->tq_queue)) { 322 /* 323 * Carefully remove the first task from the queue and 324 * zero its pending count. 325 */ 326 task = STAILQ_FIRST(&queue->tq_queue); 327 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 328 pending = task->ta_pending; 329 task->ta_pending = 0; 330 tb.tb_running = task; 331 TQ_UNLOCK(queue); 332 333 task->ta_func(task->ta_context, pending); 334 335 TQ_LOCK(queue); 336 tb.tb_running = NULL; 337 wakeup(task); 338 } 339 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link); 340} 341 342void 343taskqueue_run(struct taskqueue *queue) 344{ 345 346 TQ_LOCK(queue); 347 taskqueue_run_locked(queue); 348 TQ_UNLOCK(queue); 349} 350 351static int 352task_is_running(struct taskqueue *queue, struct task *task) 353{ 354 struct taskqueue_busy *tb; 355 356 TQ_ASSERT_LOCKED(queue); 357 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) { 358 if (tb->tb_running == task) 359 return (1); 360 } 361 return (0); 362} 363 364static int 365taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 366 u_int *pendp) 367{ 368 369 if (task->ta_pending > 0) 370 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 371 if (pendp != NULL) 372 *pendp = task->ta_pending; 373 task->ta_pending = 0; 374 return (task_is_running(queue, task) ? EBUSY : 0); 375} 376 377int 378taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 379{ 380 u_int pending; 381 int error; 382 383 TQ_LOCK(queue); 384 pending = task->ta_pending; 385 error = taskqueue_cancel_locked(queue, task, pendp); 386 TQ_UNLOCK(queue); 387 388 return (error); 389} 390 391int 392taskqueue_cancel_timeout(struct taskqueue *queue, 393 struct timeout_task *timeout_task, u_int *pendp) 394{ 395 u_int pending, pending1; 396 int error; 397 398 TQ_LOCK(queue); 399 pending = !!callout_stop(&timeout_task->c); 400 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 401 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 402 timeout_task->f &= ~DT_CALLOUT_ARMED; 403 queue->tq_callouts--; 404 } 405 TQ_UNLOCK(queue); 406 407 if (pendp != NULL) 408 *pendp = pending + pending1; 409 return (error); 410} 411 412void 413taskqueue_drain(struct taskqueue *queue, struct task *task) 414{ 415 416 if (!queue->tq_spin) 417 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 418 419 TQ_LOCK(queue); 420 while (task->ta_pending != 0 || task_is_running(queue, task)) 421 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0); 422 TQ_UNLOCK(queue); 423} 424 425void 426taskqueue_drain_timeout(struct taskqueue *queue, 427 struct timeout_task *timeout_task) 428{ 429 430 callout_drain(&timeout_task->c); 431 taskqueue_drain(queue, &timeout_task->t); 432} 433 434static void 435taskqueue_swi_enqueue(void *context) 436{ 437 swi_sched(taskqueue_ih, 0); 438} 439 440static void 441taskqueue_swi_run(void *dummy) 442{ 443 taskqueue_run(taskqueue_swi); 444} 445 446static void 447taskqueue_swi_giant_enqueue(void *context) 448{ 449 swi_sched(taskqueue_giant_ih, 0); 450} 451 452static void 453taskqueue_swi_giant_run(void *dummy) 454{ 455 taskqueue_run(taskqueue_swi_giant); 456} 457 458int 459taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 460 const char *name, ...) 461{ 462 va_list ap; 463 struct thread *td; 464 struct taskqueue *tq; 465 int i, error; 466 char ktname[MAXCOMLEN + 1]; 467 468 if (count <= 0) 469 return (EINVAL); 470 471 tq = *tqp; 472 473 va_start(ap, name); 474 vsnprintf(ktname, sizeof(ktname), name, ap); 475 va_end(ap); 476 477 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE, 478 M_NOWAIT | M_ZERO); 479 if (tq->tq_threads == NULL) { 480 printf("%s: no memory for %s threads\n", __func__, ktname); 481 return (ENOMEM); 482 } 483 484 for (i = 0; i < count; i++) { 485 if (count == 1) 486 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 487 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname); 488 else 489 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 490 &tq->tq_threads[i], RFSTOPPED, 0, 491 "%s_%d", ktname, i); 492 if (error) { 493 /* should be ok to continue, taskqueue_free will dtrt */ 494 printf("%s: kthread_add(%s): error %d", __func__, 495 ktname, error); 496 tq->tq_threads[i] = NULL; /* paranoid */ 497 } else 498 tq->tq_tcount++; 499 } 500 for (i = 0; i < count; i++) { 501 if (tq->tq_threads[i] == NULL) 502 continue; 503 td = tq->tq_threads[i]; 504 thread_lock(td); 505 sched_prio(td, pri); 506 sched_add(td, SRQ_BORING); 507 thread_unlock(td); 508 } 509 510 return (0); 511} 512 513static inline void 514taskqueue_run_callback(struct taskqueue *tq, 515 enum taskqueue_callback_type cb_type) 516{ 517 taskqueue_callback_fn tq_callback; 518 519 TQ_ASSERT_UNLOCKED(tq); 520 tq_callback = tq->tq_callbacks[cb_type]; 521 if (tq_callback != NULL) 522 tq_callback(tq->tq_cb_contexts[cb_type]); 523} 524 525void 526taskqueue_thread_loop(void *arg) 527{ 528 struct taskqueue **tqp, *tq; 529 530 tqp = arg; 531 tq = *tqp; 532 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT); 533 TQ_LOCK(tq); 534 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 535 taskqueue_run_locked(tq); 536 /* 537 * Because taskqueue_run() can drop tq_mutex, we need to 538 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the 539 * meantime, which means we missed a wakeup. 540 */ 541 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0) 542 break; 543 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 544 } 545 taskqueue_run_locked(tq); 546 547 /* 548 * This thread is on its way out, so just drop the lock temporarily 549 * in order to call the shutdown callback. This allows the callback 550 * to look at the taskqueue, even just before it dies. 551 */ 552 TQ_UNLOCK(tq); 553 taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN); 554 TQ_LOCK(tq); 555 556 /* rendezvous with thread that asked us to terminate */ 557 tq->tq_tcount--; 558 wakeup_one(tq->tq_threads); 559 TQ_UNLOCK(tq); 560 kthread_exit(); 561} 562 563void 564taskqueue_thread_enqueue(void *context) 565{ 566 struct taskqueue **tqp, *tq; 567 568 tqp = context; 569 tq = *tqp; 570 571 TQ_ASSERT_LOCKED(tq); 572 wakeup_one(tq); 573} 574 575TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL, 576 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 577 INTR_MPSAFE, &taskqueue_ih)); 578 579TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL, 580 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 581 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 582 583TASKQUEUE_DEFINE_THREAD(thread); 584 585struct taskqueue * 586taskqueue_create_fast(const char *name, int mflags, 587 taskqueue_enqueue_fn enqueue, void *context) 588{ 589 return _taskqueue_create(name, mflags, enqueue, context, 590 MTX_SPIN, "fast_taskqueue"); 591} 592 593/* NB: for backwards compatibility */ 594int 595taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 596{ 597 return taskqueue_enqueue(queue, task); 598} 599 600static void *taskqueue_fast_ih; 601 602static void 603taskqueue_fast_enqueue(void *context) 604{ 605 swi_sched(taskqueue_fast_ih, 0); 606} 607 608static void 609taskqueue_fast_run(void *dummy) 610{ 611 taskqueue_run(taskqueue_fast); 612} 613 614TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL, 615 swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL, 616 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 617 618int 619taskqueue_member(struct taskqueue *queue, struct thread *td) 620{ 621 int i, j, ret = 0; 622 623 for (i = 0, j = 0; ; i++) { 624 if (queue->tq_threads[i] == NULL) 625 continue; 626 if (queue->tq_threads[i] == td) { 627 ret = 1; 628 break; 629 } 630 if (++j >= queue->tq_tcount) 631 break; 632 } 633 return (ret); 634} 635