subr_taskqueue.c revision 225570
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: head/sys/kern/subr_taskqueue.c 225570 2011-09-15 08:42:06Z adrian $"); 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 } 256 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func, 257 timeout_task); 258 } 259 TQ_UNLOCK(queue); 260 return (res); 261} 262 263void 264taskqueue_block(struct taskqueue *queue) 265{ 266 267 TQ_LOCK(queue); 268 queue->tq_flags |= TQ_FLAGS_BLOCKED; 269 TQ_UNLOCK(queue); 270} 271 272void 273taskqueue_unblock(struct taskqueue *queue) 274{ 275 276 TQ_LOCK(queue); 277 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 278 if (queue->tq_flags & TQ_FLAGS_PENDING) { 279 queue->tq_flags &= ~TQ_FLAGS_PENDING; 280 queue->tq_enqueue(queue->tq_context); 281 } 282 TQ_UNLOCK(queue); 283} 284 285static void 286taskqueue_run_locked(struct taskqueue *queue) 287{ 288 struct taskqueue_busy tb; 289 struct task *task; 290 int pending; 291 292 mtx_assert(&queue->tq_mutex, MA_OWNED); 293 tb.tb_running = NULL; 294 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link); 295 296 while (STAILQ_FIRST(&queue->tq_queue)) { 297 /* 298 * Carefully remove the first task from the queue and 299 * zero its pending count. 300 */ 301 task = STAILQ_FIRST(&queue->tq_queue); 302 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 303 pending = task->ta_pending; 304 task->ta_pending = 0; 305 tb.tb_running = task; 306 TQ_UNLOCK(queue); 307 308 task->ta_func(task->ta_context, pending); 309 310 TQ_LOCK(queue); 311 tb.tb_running = NULL; 312 wakeup(task); 313 } 314 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link); 315} 316 317void 318taskqueue_run(struct taskqueue *queue) 319{ 320 321 TQ_LOCK(queue); 322 taskqueue_run_locked(queue); 323 TQ_UNLOCK(queue); 324} 325 326static int 327task_is_running(struct taskqueue *queue, struct task *task) 328{ 329 struct taskqueue_busy *tb; 330 331 mtx_assert(&queue->tq_mutex, MA_OWNED); 332 TAILQ_FOREACH(tb, &queue->tq_active, tb_link) { 333 if (tb->tb_running == task) 334 return (1); 335 } 336 return (0); 337} 338 339static int 340taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 341 u_int *pendp) 342{ 343 344 if (task->ta_pending > 0) 345 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 346 if (pendp != NULL) 347 *pendp = task->ta_pending; 348 task->ta_pending = 0; 349 return (task_is_running(queue, task) ? EBUSY : 0); 350} 351 352int 353taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 354{ 355 u_int pending; 356 int error; 357 358 TQ_LOCK(queue); 359 pending = task->ta_pending; 360 error = taskqueue_cancel_locked(queue, task, pendp); 361 TQ_UNLOCK(queue); 362 363 return (error); 364} 365 366int 367taskqueue_cancel_timeout(struct taskqueue *queue, 368 struct timeout_task *timeout_task, u_int *pendp) 369{ 370 u_int pending, pending1; 371 int error; 372 373 TQ_LOCK(queue); 374 pending = !!callout_stop(&timeout_task->c); 375 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 376 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 377 timeout_task->f &= ~DT_CALLOUT_ARMED; 378 queue->tq_callouts--; 379 } 380 TQ_UNLOCK(queue); 381 382 if (pendp != NULL) 383 *pendp = pending + pending1; 384 return (error); 385} 386 387void 388taskqueue_drain(struct taskqueue *queue, struct task *task) 389{ 390 391 if (!queue->tq_spin) 392 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__); 393 394 TQ_LOCK(queue); 395 while (task->ta_pending != 0 || task_is_running(queue, task)) 396 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0); 397 TQ_UNLOCK(queue); 398} 399 400void 401taskqueue_drain_timeout(struct taskqueue *queue, 402 struct timeout_task *timeout_task) 403{ 404 405 callout_drain(&timeout_task->c); 406 taskqueue_drain(queue, &timeout_task->t); 407} 408 409static void 410taskqueue_swi_enqueue(void *context) 411{ 412 swi_sched(taskqueue_ih, 0); 413} 414 415static void 416taskqueue_swi_run(void *dummy) 417{ 418 taskqueue_run(taskqueue_swi); 419} 420 421static void 422taskqueue_swi_giant_enqueue(void *context) 423{ 424 swi_sched(taskqueue_giant_ih, 0); 425} 426 427static void 428taskqueue_swi_giant_run(void *dummy) 429{ 430 taskqueue_run(taskqueue_swi_giant); 431} 432 433int 434taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, 435 const char *name, ...) 436{ 437 va_list ap; 438 struct thread *td; 439 struct taskqueue *tq; 440 int i, error; 441 char ktname[MAXCOMLEN + 1]; 442 443 if (count <= 0) 444 return (EINVAL); 445 446 tq = *tqp; 447 448 va_start(ap, name); 449 vsnprintf(ktname, sizeof(ktname), name, ap); 450 va_end(ap); 451 452 tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE, 453 M_NOWAIT | M_ZERO); 454 if (tq->tq_threads == NULL) { 455 printf("%s: no memory for %s threads\n", __func__, ktname); 456 return (ENOMEM); 457 } 458 459 for (i = 0; i < count; i++) { 460 if (count == 1) 461 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 462 &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname); 463 else 464 error = kthread_add(taskqueue_thread_loop, tqp, NULL, 465 &tq->tq_threads[i], RFSTOPPED, 0, 466 "%s_%d", ktname, i); 467 if (error) { 468 /* should be ok to continue, taskqueue_free will dtrt */ 469 printf("%s: kthread_add(%s): error %d", __func__, 470 ktname, error); 471 tq->tq_threads[i] = NULL; /* paranoid */ 472 } else 473 tq->tq_tcount++; 474 } 475 for (i = 0; i < count; i++) { 476 if (tq->tq_threads[i] == NULL) 477 continue; 478 td = tq->tq_threads[i]; 479 thread_lock(td); 480 sched_prio(td, pri); 481 sched_add(td, SRQ_BORING); 482 thread_unlock(td); 483 } 484 485 return (0); 486} 487 488void 489taskqueue_thread_loop(void *arg) 490{ 491 struct taskqueue **tqp, *tq; 492 493 tqp = arg; 494 tq = *tqp; 495 TQ_LOCK(tq); 496 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 497 taskqueue_run_locked(tq); 498 /* 499 * Because taskqueue_run() can drop tq_mutex, we need to 500 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the 501 * meantime, which means we missed a wakeup. 502 */ 503 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0) 504 break; 505 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0); 506 } 507 taskqueue_run_locked(tq); 508 509 /* rendezvous with thread that asked us to terminate */ 510 tq->tq_tcount--; 511 wakeup_one(tq->tq_threads); 512 TQ_UNLOCK(tq); 513 kthread_exit(); 514} 515 516void 517taskqueue_thread_enqueue(void *context) 518{ 519 struct taskqueue **tqp, *tq; 520 521 tqp = context; 522 tq = *tqp; 523 524 mtx_assert(&tq->tq_mutex, MA_OWNED); 525 wakeup_one(tq); 526} 527 528TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL, 529 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 530 INTR_MPSAFE, &taskqueue_ih)); 531 532TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL, 533 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run, 534 NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 535 536TASKQUEUE_DEFINE_THREAD(thread); 537 538struct taskqueue * 539taskqueue_create_fast(const char *name, int mflags, 540 taskqueue_enqueue_fn enqueue, void *context) 541{ 542 return _taskqueue_create(name, mflags, enqueue, context, 543 MTX_SPIN, "fast_taskqueue"); 544} 545 546/* NB: for backwards compatibility */ 547int 548taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task) 549{ 550 return taskqueue_enqueue(queue, task); 551} 552 553static void *taskqueue_fast_ih; 554 555static void 556taskqueue_fast_enqueue(void *context) 557{ 558 swi_sched(taskqueue_fast_ih, 0); 559} 560 561static void 562taskqueue_fast_run(void *dummy) 563{ 564 taskqueue_run(taskqueue_fast); 565} 566 567TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL, 568 swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL, 569 SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih)); 570 571int 572taskqueue_member(struct taskqueue *queue, struct thread *td) 573{ 574 int i, j, ret = 0; 575 576 TQ_LOCK(queue); 577 for (i = 0, j = 0; ; i++) { 578 if (queue->tq_threads[i] == NULL) 579 continue; 580 if (queue->tq_threads[i] == td) { 581 ret = 1; 582 break; 583 } 584 if (++j >= queue->tq_tcount) 585 break; 586 } 587 TQ_UNLOCK(queue); 588 return (ret); 589} 590