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 * $FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.69 2012/08/28 13:35:37 jhb Exp $" 27 */ 28 29 #include <sys/param.h> 30 #include <sys/queue.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/taskqueue.h> 34 #include <sys/interrupt.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/kthread.h> 38 #include <sys/spinlock.h> 39 #include <sys/spinlock2.h> 40 #include <sys/serialize.h> 41 #include <sys/proc.h> 42 43 MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues"); 44 45 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues; 46 static struct lock taskqueue_queues_lock; 47 struct spinlock taskqueue_queues_spin; 48 49 struct taskqueue { 50 STAILQ_ENTRY(taskqueue) tq_link; 51 STAILQ_HEAD(, task) tq_queue; 52 const char *tq_name; 53 /* NOTE: tq must be locked before calling tq_enqueue */ 54 taskqueue_enqueue_fn tq_enqueue; 55 void *tq_context; 56 57 struct task *tq_running; 58 struct spinlock tq_lock; 59 struct thread **tq_threads; 60 int tq_tcount; 61 int tq_flags; 62 int tq_callouts; 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 #define DT_CALLOUT_ARMED (1 << 0) 70 71 void 72 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task, 73 int priority, task_fn_t func, void *context) 74 { 75 76 TASK_INIT(&timeout_task->t, priority, func, context); 77 callout_init(&timeout_task->c); /* XXX use callout_init_mp() */ 78 timeout_task->t.ta_queue = queue; 79 timeout_task->f = 0; 80 } 81 82 static void taskqueue_run(struct taskqueue *queue, int lock_held); 83 84 static __inline void 85 TQ_LOCK_INIT(struct taskqueue *tq) 86 { 87 spin_init(&tq->tq_lock, "tqlock"); 88 } 89 90 static __inline void 91 TQ_LOCK_UNINIT(struct taskqueue *tq) 92 { 93 spin_uninit(&tq->tq_lock); 94 } 95 96 static __inline void 97 TQ_LOCK(struct taskqueue *tq) 98 { 99 spin_lock(&tq->tq_lock); 100 } 101 102 static __inline void 103 TQ_UNLOCK(struct taskqueue *tq) 104 { 105 spin_unlock(&tq->tq_lock); 106 } 107 108 static __inline void 109 TQ_SLEEP(struct taskqueue *tq, void *ident, const char *wmesg) 110 { 111 ssleep(ident, &tq->tq_lock, 0, wmesg, 0); 112 } 113 114 struct taskqueue * 115 taskqueue_create(const char *name, int mflags, 116 taskqueue_enqueue_fn enqueue, void *context) 117 { 118 struct taskqueue *queue; 119 120 queue = kmalloc(sizeof(*queue), M_TASKQUEUE, mflags | M_ZERO); 121 if (!queue) 122 return NULL; 123 STAILQ_INIT(&queue->tq_queue); 124 queue->tq_name = name; 125 queue->tq_enqueue = enqueue; 126 queue->tq_context = context; 127 queue->tq_flags |= TQ_FLAGS_ACTIVE; 128 TQ_LOCK_INIT(queue); 129 130 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 131 STAILQ_INSERT_TAIL(&taskqueue_queues, queue, tq_link); 132 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 133 134 return queue; 135 } 136 137 /* NOTE: tq must be locked */ 138 static void 139 taskqueue_terminate(struct thread **pp, struct taskqueue *tq) 140 { 141 while(tq->tq_tcount > 0) { 142 /* Unlock spinlock before wakeup() */ 143 TQ_UNLOCK(tq); 144 wakeup(tq); 145 TQ_LOCK(tq); 146 TQ_SLEEP(tq, pp, "taskqueue_terminate"); 147 } 148 } 149 150 void 151 taskqueue_free(struct taskqueue *queue) 152 { 153 TQ_LOCK(queue); 154 queue->tq_flags &= ~TQ_FLAGS_ACTIVE; 155 taskqueue_run(queue, 1); 156 taskqueue_terminate(queue->tq_threads, queue); 157 TQ_UNLOCK(queue); 158 159 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 160 STAILQ_REMOVE(&taskqueue_queues, queue, taskqueue, tq_link); 161 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 162 163 TQ_LOCK_UNINIT(queue); 164 165 kfree(queue, M_TASKQUEUE); 166 } 167 168 struct taskqueue * 169 taskqueue_find(const char *name) 170 { 171 struct taskqueue *queue; 172 173 lockmgr(&taskqueue_queues_lock, LK_EXCLUSIVE); 174 STAILQ_FOREACH(queue, &taskqueue_queues, tq_link) { 175 if (!strcmp(queue->tq_name, name)) { 176 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 177 return queue; 178 } 179 } 180 lockmgr(&taskqueue_queues_lock, LK_RELEASE); 181 return NULL; 182 } 183 184 /* 185 * NOTE! If using the per-cpu taskqueues ``taskqueue_thread[mycpuid]'', 186 * be sure NOT TO SHARE the ``task'' between CPUs. TASKS ARE NOT LOCKED. 187 * So either use a throwaway task which will only be enqueued once, or 188 * use one task per CPU! 189 */ 190 static int 191 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task) 192 { 193 struct task *ins; 194 struct task *prev; 195 196 /* 197 * Don't allow new tasks on a queue which is being freed. 198 */ 199 if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0) 200 return EPIPE; 201 202 /* 203 * Count multiple enqueues. 204 */ 205 if (task->ta_pending) { 206 KKASSERT(queue == task->ta_queue); 207 task->ta_pending++; 208 return 0; 209 } 210 task->ta_queue = queue; 211 212 /* 213 * Optimise the case when all tasks have the same priority. 214 */ 215 prev = STAILQ_LAST(&queue->tq_queue, task, ta_link); 216 if (!prev || prev->ta_priority >= task->ta_priority) { 217 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link); 218 } else { 219 prev = NULL; 220 for (ins = STAILQ_FIRST(&queue->tq_queue); ins; 221 prev = ins, ins = STAILQ_NEXT(ins, ta_link)) 222 if (ins->ta_priority < task->ta_priority) 223 break; 224 225 if (prev) 226 STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link); 227 else 228 STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link); 229 } 230 231 task->ta_pending = 1; 232 if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0) { 233 if (queue->tq_enqueue) 234 queue->tq_enqueue(queue->tq_context); 235 } else { 236 queue->tq_flags |= TQ_FLAGS_PENDING; 237 } 238 239 return 0; 240 } 241 242 /* 243 * This version requires that the task not be moved between queues 244 * in an uncontrolled fashion. 245 */ 246 int 247 taskqueue_enqueue(struct taskqueue *queue, struct task *task) 248 { 249 int res; 250 251 TQ_LOCK(queue); 252 res = taskqueue_enqueue_locked(queue, task); 253 TQ_UNLOCK(queue); 254 255 return (res); 256 } 257 258 /* 259 * This version allows a task to be moved between queues in an uncontrolled 260 * fashion. (*qpp) is set to the queue the task is (possibly already) 261 * enqueued on, or the specified queue if it is possible to move the task. 262 */ 263 int 264 taskqueue_enqueue_optq(struct taskqueue *queue, struct taskqueue **qpp, 265 struct task *task) 266 { 267 struct taskqueue *qtmp; 268 int res; 269 270 /* 271 * Interlock for task structure check, handle the case where we 272 * are unable to safely shift the task to the specified queue. 273 */ 274 for (;;) { 275 qtmp = task->ta_queue; 276 cpu_ccfence(); 277 278 if (qtmp == NULL) { 279 spin_lock(&taskqueue_queues_spin); 280 if (task->ta_queue == NULL) 281 task->ta_queue = queue; 282 spin_unlock(&taskqueue_queues_spin); 283 } else { 284 TQ_LOCK(qtmp); 285 if (task->ta_queue == qtmp) { 286 if (qtmp == queue) 287 break; 288 289 /* 290 * If qtmp is pending on a different queue 291 * it must stay on that queue. 292 * 293 * WARNING: Once ta_queue is reassigned 294 * our qtmp lock is no longer 295 * sufficient and we lose control 296 * of the task. 297 */ 298 if (task->ta_pending) { 299 task->ta_pending++; 300 *qpp = qtmp; 301 TQ_UNLOCK(qtmp); 302 return 0; 303 } 304 cpu_sfence(); 305 task->ta_queue = queue; 306 cpu_ccfence(); 307 } 308 TQ_UNLOCK(qtmp); 309 } 310 /* retry */ 311 } 312 313 /* 314 * The task is assigned to (queue), enqueue it there. 315 */ 316 *qpp = queue; 317 res = taskqueue_enqueue_locked(queue, task); 318 TQ_UNLOCK(queue); 319 320 return (res); 321 } 322 323 static void 324 taskqueue_timeout_func(void *arg) 325 { 326 struct taskqueue *queue; 327 struct timeout_task *timeout_task; 328 329 timeout_task = arg; 330 queue = timeout_task->t.ta_queue; 331 332 TQ_LOCK(queue); 333 KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout")); 334 timeout_task->f &= ~DT_CALLOUT_ARMED; 335 queue->tq_callouts--; 336 taskqueue_enqueue_locked(queue, &timeout_task->t); 337 TQ_UNLOCK(queue); 338 } 339 340 int 341 taskqueue_enqueue_timeout(struct taskqueue *queue, 342 struct timeout_task *timeout_task, int ticks) 343 { 344 int res; 345 346 TQ_LOCK(queue); 347 KASSERT(timeout_task->t.ta_queue == NULL || 348 timeout_task->t.ta_queue == queue, 349 ("Migrated queue")); 350 timeout_task->t.ta_queue = queue; 351 res = timeout_task->t.ta_pending; 352 if (ticks == 0) { 353 taskqueue_enqueue_locked(queue, &timeout_task->t); 354 TQ_UNLOCK(queue); 355 } else { 356 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 357 res++; 358 } else { 359 queue->tq_callouts++; 360 timeout_task->f |= DT_CALLOUT_ARMED; 361 } 362 TQ_UNLOCK(queue); 363 callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func, 364 timeout_task); 365 } 366 return (res); 367 } 368 369 void 370 taskqueue_block(struct taskqueue *queue) 371 { 372 TQ_LOCK(queue); 373 queue->tq_flags |= TQ_FLAGS_BLOCKED; 374 TQ_UNLOCK(queue); 375 } 376 377 void 378 taskqueue_unblock(struct taskqueue *queue) 379 { 380 TQ_LOCK(queue); 381 queue->tq_flags &= ~TQ_FLAGS_BLOCKED; 382 if (queue->tq_flags & TQ_FLAGS_PENDING) { 383 queue->tq_flags &= ~TQ_FLAGS_PENDING; 384 if (queue->tq_enqueue) 385 queue->tq_enqueue(queue->tq_context); 386 } 387 TQ_UNLOCK(queue); 388 } 389 390 static void 391 taskqueue_run(struct taskqueue *queue, int lock_held) 392 { 393 struct task *task; 394 int pending; 395 396 if (lock_held == 0) 397 TQ_LOCK(queue); 398 while (STAILQ_FIRST(&queue->tq_queue)) { 399 /* 400 * Carefully remove the first task from the queue and 401 * zero its pending count. 402 */ 403 task = STAILQ_FIRST(&queue->tq_queue); 404 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link); 405 pending = task->ta_pending; 406 task->ta_pending = 0; 407 queue->tq_running = task; 408 409 TQ_UNLOCK(queue); 410 task->ta_func(task->ta_context, pending); 411 queue->tq_running = NULL; 412 wakeup(task); 413 TQ_LOCK(queue); 414 } 415 if (lock_held == 0) 416 TQ_UNLOCK(queue); 417 } 418 419 static int 420 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task, 421 u_int *pendp) 422 { 423 424 if (task->ta_pending > 0) 425 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link); 426 if (pendp != NULL) 427 *pendp = task->ta_pending; 428 task->ta_pending = 0; 429 return (task == queue->tq_running ? EBUSY : 0); 430 } 431 432 int 433 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp) 434 { 435 int error; 436 437 TQ_LOCK(queue); 438 error = taskqueue_cancel_locked(queue, task, pendp); 439 TQ_UNLOCK(queue); 440 441 return (error); 442 } 443 444 int 445 taskqueue_cancel_simple(struct task *task) 446 { 447 struct taskqueue *queue; 448 int error; 449 450 for (;;) { 451 queue = task->ta_queue; 452 cpu_ccfence(); 453 if (queue == NULL) { 454 error = 0; 455 break; 456 } 457 TQ_LOCK(queue); 458 if (queue == task->ta_queue) { 459 error = taskqueue_cancel_locked(queue, task, NULL); 460 TQ_UNLOCK(queue); 461 break; 462 } 463 TQ_UNLOCK(queue); 464 } 465 return error; 466 } 467 468 int 469 taskqueue_cancel_timeout(struct taskqueue *queue, 470 struct timeout_task *timeout_task, u_int *pendp) 471 { 472 u_int pending, pending1; 473 int error; 474 475 pending = !!callout_stop(&timeout_task->c); 476 TQ_LOCK(queue); 477 error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1); 478 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) { 479 timeout_task->f &= ~DT_CALLOUT_ARMED; 480 queue->tq_callouts--; 481 } 482 TQ_UNLOCK(queue); 483 484 if (pendp != NULL) 485 *pendp = pending + pending1; 486 return (error); 487 } 488 489 void 490 taskqueue_drain(struct taskqueue *queue, struct task *task) 491 { 492 TQ_LOCK(queue); 493 while (task->ta_pending != 0 || task == queue->tq_running) 494 TQ_SLEEP(queue, task, "-"); 495 TQ_UNLOCK(queue); 496 } 497 498 /* 499 * Wait for the task to drain and return 500 */ 501 void 502 taskqueue_drain_simple(struct task *task) 503 { 504 struct taskqueue *queue; 505 506 for (;;) { 507 queue = task->ta_queue; 508 cpu_ccfence(); 509 if (queue == NULL) 510 return; 511 TQ_LOCK(queue); 512 if (task->ta_pending == 0 && task != queue->tq_running) { 513 TQ_UNLOCK(queue); 514 return; 515 } 516 TQ_SLEEP(queue, task, "-"); 517 TQ_UNLOCK(queue); 518 } 519 } 520 521 void 522 taskqueue_drain_timeout(struct taskqueue *queue, 523 struct timeout_task *timeout_task) 524 { 525 callout_cancel(&timeout_task->c); 526 taskqueue_drain(queue, &timeout_task->t); 527 } 528 529 static void 530 taskqueue_swi_enqueue(void *context) 531 { 532 setsofttq(); 533 } 534 535 static void 536 taskqueue_swi_run(void *arg, void *frame) 537 { 538 taskqueue_run(taskqueue_swi, 0); 539 } 540 541 static void 542 taskqueue_swi_mp_run(void *arg, void *frame) 543 { 544 taskqueue_run(taskqueue_swi_mp, 0); 545 } 546 547 int 548 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri, int ncpu, 549 const char *fmt, ...) 550 { 551 __va_list ap; 552 struct thread *td; 553 struct taskqueue *tq; 554 int i, error, cpu; 555 char ktname[MAXCOMLEN]; 556 557 if (count <= 0) 558 return EINVAL; 559 /* catch call argument mistakes */ 560 KKASSERT(pri > 0 && pri < TDPRI_MAX); 561 562 tq = *tqp; 563 cpu = ncpu; 564 565 __va_start(ap, fmt); 566 kvsnprintf(ktname, MAXCOMLEN, fmt, ap); 567 __va_end(ap); 568 569 tq->tq_threads = kmalloc(sizeof(struct thread *) * count, M_TASKQUEUE, 570 M_WAITOK | M_ZERO); 571 572 for (i = 0; i < count; i++) { 573 /* 574 * If no specific cpu was specified and more than one thread 575 * is to be created, we distribute the threads amongst all 576 * cpus. 577 */ 578 if ((ncpu <= -1) && (count > 1)) 579 cpu = i%ncpus; 580 581 if (count == 1) { 582 error = lwkt_create(taskqueue_thread_loop, tqp, 583 &tq->tq_threads[i], NULL, 584 TDF_NOSTART, cpu, 585 "%s", ktname); 586 } else { 587 error = lwkt_create(taskqueue_thread_loop, tqp, 588 &tq->tq_threads[i], NULL, 589 TDF_NOSTART, cpu, 590 "%s_%d", ktname, i); 591 } 592 if (error) { 593 kprintf("%s: lwkt_create(%s): error %d", __func__, 594 ktname, error); 595 tq->tq_threads[i] = NULL; 596 } else { 597 td = tq->tq_threads[i]; 598 lwkt_setpri_initial(td, pri); 599 lwkt_schedule(td); 600 tq->tq_tcount++; 601 } 602 } 603 604 return 0; 605 } 606 607 void 608 taskqueue_thread_loop(void *arg) 609 { 610 struct taskqueue **tqp, *tq; 611 612 tqp = arg; 613 tq = *tqp; 614 TQ_LOCK(tq); 615 while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) { 616 taskqueue_run(tq, 1); 617 TQ_SLEEP(tq, tq, "tqthr"); 618 } 619 620 /* rendezvous with thread that asked us to terminate */ 621 tq->tq_tcount--; 622 TQ_UNLOCK(tq); 623 wakeup_one(tq->tq_threads); 624 lwkt_exit(); 625 } 626 627 /* NOTE: tq must be locked */ 628 void 629 taskqueue_thread_enqueue(void *context) 630 { 631 struct taskqueue **tqp, *tq; 632 633 tqp = context; 634 tq = *tqp; 635 636 /* Unlock spinlock before wakeup_one() */ 637 TQ_UNLOCK(tq); 638 wakeup_one(tq); 639 TQ_LOCK(tq); 640 } 641 642 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0, 643 register_swi(SWI_TQ, taskqueue_swi_run, NULL, "swi_taskq", NULL, -1)); 644 /* 645 * XXX: possibly use a different SWI_TQ_MP or so. 646 * related: sys/interrupt.h 647 * related: platform/XXX/isa/ipl_funcs.c 648 */ 649 TASKQUEUE_DEFINE(swi_mp, taskqueue_swi_enqueue, 0, 650 register_swi_mp(SWI_TQ, taskqueue_swi_mp_run, NULL, "swi_mp_taskq", NULL, 651 -1)); 652 653 struct taskqueue *taskqueue_thread[MAXCPU]; 654 655 static void 656 taskqueue_init(void) 657 { 658 int cpu; 659 660 lockinit(&taskqueue_queues_lock, "tqqueues", 0, 0); 661 spin_init(&taskqueue_queues_spin, "tqspin"); 662 STAILQ_INIT(&taskqueue_queues); 663 664 for (cpu = 0; cpu < ncpus; cpu++) { 665 taskqueue_thread[cpu] = taskqueue_create("thread", M_INTWAIT, 666 taskqueue_thread_enqueue, &taskqueue_thread[cpu]); 667 taskqueue_start_threads(&taskqueue_thread[cpu], 1, 668 TDPRI_KERN_DAEMON, cpu, "taskq_cpu %d", cpu); 669 } 670 } 671 672 SYSINIT(taskqueueinit, SI_SUB_PRE_DRIVERS, SI_ORDER_FIRST, taskqueue_init, NULL); 673