sys/kern/subr_taskqueue.c

   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/cpuset.h>
  34 #include <sys/interrupt.h>
  35 #include <sys/kernel.h>
  36 #include <sys/kthread.h>
  37 #include <sys/limits.h>
  38 #include <sys/lock.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/proc.h>
  42 #include <sys/sched.h>
  43 #include <sys/taskqueue.h>
  44 #include <sys/unistd.h>
  45 #include <machine/stdarg.h>
  46
  47 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  48 static void     *taskqueue_giant_ih;
  49 static void     *taskqueue_ih;
  50 static void      taskqueue_fast_enqueue(void *);
  51 static void      taskqueue_swi_enqueue(void *);
  52 static void      taskqueue_swi_giant_enqueue(void *);
  53
  54 struct taskqueue_busy {
  55         struct task     *tb_running;
  56         TAILQ_ENTRY(taskqueue_busy) tb_link;
  57 };
  58
  59 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
  60
  61 struct taskqueue {
  62         STAILQ_HEAD(, task)     tq_queue;
  63         taskqueue_enqueue_fn    tq_enqueue;
  64         void                    *tq_context;
  65         TAILQ_HEAD(, taskqueue_busy) tq_active;
  66         struct mtx              tq_mutex;
  67         struct thread           **tq_threads;
  68         int                     tq_tcount;
  69         int                     tq_spin;
  70         int                     tq_flags;
  71         int                     tq_callouts;
  72         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  73         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  74 };
  75
  76 #define TQ_FLAGS_ACTIVE         (1 << 0)
  77 #define TQ_FLAGS_BLOCKED        (1 << 1)
  78 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  79
  80 #define DT_CALLOUT_ARMED        (1 << 0)
  81
  82 #define TQ_LOCK(tq)                                                     \
  83         do {                                                            \
  84                 if ((tq)->tq_spin)                                      \
  85                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  86                 else                                                    \
  87                         mtx_lock(&(tq)->tq_mutex);                      \
  88         } while (0)
  89 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  90
  91 #define TQ_UNLOCK(tq)                                                   \
  92         do {                                                            \
  93                 if ((tq)->tq_spin)                                      \
  94                         mtx_unlock_spin(&(tq)->tq_mutex);               \
  95                 else                                                    \
  96                         mtx_unlock(&(tq)->tq_mutex);                    \
  97         } while (0)
  98 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
  99
 100 void
 101 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 102     int priority, task_fn_t func, void *context)
 103 {
 104
 105         TASK_INIT(&timeout_task->t, priority, func, context);
 106         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 107             CALLOUT_RETURNUNLOCKED);
 108         timeout_task->q = queue;
 109         timeout_task->f = 0;
 110 }
 111
 112 static __inline int
 113 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 114     int t)
 115 {
 116         if (tq->tq_spin)
 117                 return (msleep_spin(p, m, wm, t));
 118         return (msleep(p, m, pri, wm, t));
 119 }
 120
 121 static struct taskqueue *
 122 _taskqueue_create(const char *name __unused, int mflags,
 123                  taskqueue_enqueue_fn enqueue, void *context,
 124                  int mtxflags, const char *mtxname)
 125 {
 126         struct taskqueue *queue;
 127
 128         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 129         if (!queue)
 130                 return NULL;
 131
 132         STAILQ_INIT(&queue->tq_queue);
 133         TAILQ_INIT(&queue->tq_active);
 134         queue->tq_enqueue = enqueue;
 135         queue->tq_context = context;
 136         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 137         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 138         if (enqueue == taskqueue_fast_enqueue ||
 139             enqueue == taskqueue_swi_enqueue ||
 140             enqueue == taskqueue_swi_giant_enqueue ||
 141             enqueue == taskqueue_thread_enqueue)
 142                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 143         mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
 144
 145         return queue;
 146 }
 147
 148 struct taskqueue *
 149 taskqueue_create(const char *name, int mflags,
 150                  taskqueue_enqueue_fn enqueue, void *context)
 151 {
 152         return _taskqueue_create(name, mflags, enqueue, context,
 153                         MTX_DEF, "taskqueue");
 154 }
 155
 156 void
 157 taskqueue_set_callback(struct taskqueue *queue,
 158     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 159     void *context)
 160 {
 161
 162         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 163             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 164             ("Callback type %d not valid, must be %d-%d", cb_type,
 165             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 166         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 167             ("Re-initialization of taskqueue callback?"));
 168
 169         queue->tq_callbacks[cb_type] = callback;
 170         queue->tq_cb_contexts[cb_type] = context;
 171 }
 172
 173 /*
 174  * Signal a taskqueue thread to terminate.
 175  */
 176 static void
 177 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 178 {
 179
 180         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 181                 wakeup(tq);
 182                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 183         }
 184 }
 185
 186 void
 187 taskqueue_free(struct taskqueue *queue)
 188 {
 189
 190         TQ_LOCK(queue);
 191         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 192         taskqueue_terminate(queue->tq_threads, queue);
 193         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 194         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 195         mtx_destroy(&queue->tq_mutex);
 196         free(queue->tq_threads, M_TASKQUEUE);
 197         free(queue, M_TASKQUEUE);
 198 }
 199
 200 static int
 201 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 202 {
 203         struct task *ins;
 204         struct task *prev;
 205
 206         /*
 207          * Count multiple enqueues.
 208          */
 209         if (task->ta_pending) {
 210                 if (task->ta_pending < USHRT_MAX)
 211                         task->ta_pending++;
 212                 TQ_UNLOCK(queue);
 213                 return (0);
 214         }
 215
 216         /*
 217          * Optimise the case when all tasks have the same priority.
 218          */
 219         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 220         if (!prev || prev->ta_priority >= task->ta_priority) {
 221                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 222         } else {
 223                 prev = NULL;
 224                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 225                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 226                         if (ins->ta_priority < task->ta_priority)
 227                                 break;
 228
 229                 if (prev)
 230                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 231                 else
 232                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 233         }
 234
 235         task->ta_pending = 1;
 236         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 237                 TQ_UNLOCK(queue);
 238         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 239                 queue->tq_enqueue(queue->tq_context);
 240         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 241                 TQ_UNLOCK(queue);
 242
 243         /* Return with lock released. */
 244         return (0);
 245 }
 246
 247 int
 248 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 249 {
 250         int res;
 251
 252         TQ_LOCK(queue);
 253         res = taskqueue_enqueue_locked(queue, task);
 254         /* The lock is released inside. */
 255
 256         return (res);
 257 }
 258
 259 static void
 260 taskqueue_timeout_func(void *arg)
 261 {
 262         struct taskqueue *queue;
 263         struct timeout_task *timeout_task;
 264
 265         timeout_task = arg;
 266         queue = timeout_task->q;
 267         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 268         timeout_task->f &= ~DT_CALLOUT_ARMED;
 269         queue->tq_callouts--;
 270         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 271         /* The lock is released inside. */
 272 }
 273
 274 int
 275 taskqueue_enqueue_timeout(struct taskqueue *queue,
 276     struct timeout_task *timeout_task, int ticks)
 277 {
 278         int res;
 279
 280         TQ_LOCK(queue);
 281         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 282             ("Migrated queue"));
 283         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 284         timeout_task->q = queue;
 285         res = timeout_task->t.ta_pending;
 286         if (ticks == 0) {
 287                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 288                 /* The lock is released inside. */
 289         } else {
 290                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 291                         res++;
 292                 } else {
 293                         queue->tq_callouts++;
 294                         timeout_task->f |= DT_CALLOUT_ARMED;
 295                         if (ticks < 0)
 296                                 ticks = -ticks; /* Ignore overflow. */
 297                 }
 298                 if (ticks > 0) {
 299                         callout_reset(&timeout_task->c, ticks,
 300                             taskqueue_timeout_func, timeout_task);
 301                 }
 302                 TQ_UNLOCK(queue);
 303         }
 304         return (res);
 305 }
 306
 307 static void
 308 taskqueue_task_nop_fn(void *context, int pending)
 309 {
 310 }
 311
 312 /*
 313  * Block until all currently queued tasks in this taskqueue
 314  * have begun execution.  Tasks queued during execution of
 315  * this function are ignored.
 316  */
 317 static void
 318 taskqueue_drain_tq_queue(struct taskqueue *queue)
 319 {
 320         struct task t_barrier;
 321
 322         if (STAILQ_EMPTY(&queue->tq_queue))
 323                 return;
 324
 325         /*
 326          * Enqueue our barrier after all current tasks, but with
 327          * the highest priority so that newly queued tasks cannot
 328          * pass it.  Because of the high priority, we can not use
 329          * taskqueue_enqueue_locked directly (which drops the lock
 330          * anyway) so just insert it at tail while we have the
 331          * queue lock.
 332          */
 333         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
 334         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 335         t_barrier.ta_pending = 1;
 336
 337         /*
 338          * Once the barrier has executed, all previously queued tasks
 339          * have completed or are currently executing.
 340          */
 341         while (t_barrier.ta_pending != 0)
 342                 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
 343 }
 344
 345 /*
 346  * Block until all currently executing tasks for this taskqueue
 347  * complete.  Tasks that begin execution during the execution
 348  * of this function are ignored.
 349  */
 350 static void
 351 taskqueue_drain_tq_active(struct taskqueue *queue)
 352 {
 353         struct taskqueue_busy tb_marker, *tb_first;
 354
 355         if (TAILQ_EMPTY(&queue->tq_active))
 356                 return;
 357
 358         /* Block taskq_terminate().*/
 359         queue->tq_callouts++;
 360
 361         /*
 362          * Wait for all currently executing taskqueue threads
 363          * to go idle.
 364          */
 365         tb_marker.tb_running = TB_DRAIN_WAITER;
 366         TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
 367         while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
 368                 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
 369         TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
 370
 371         /*
 372          * Wakeup any other drain waiter that happened to queue up
 373          * without any intervening active thread.
 374          */
 375         tb_first = TAILQ_FIRST(&queue->tq_active);
 376         if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
 377                 wakeup(tb_first);
 378
 379         /* Release taskqueue_terminate(). */
 380         queue->tq_callouts--;
 381         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 382                 wakeup_one(queue->tq_threads);
 383 }
 384
 385 void
 386 taskqueue_block(struct taskqueue *queue)
 387 {
 388
 389         TQ_LOCK(queue);
 390         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 391         TQ_UNLOCK(queue);
 392 }
 393
 394 void
 395 taskqueue_unblock(struct taskqueue *queue)
 396 {
 397
 398         TQ_LOCK(queue);
 399         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 400         if (!STAILQ_EMPTY(&queue->tq_queue))
 401                 queue->tq_enqueue(queue->tq_context);
 402         TQ_UNLOCK(queue);
 403 }
 404
 405 static void
 406 taskqueue_run_locked(struct taskqueue *queue)
 407 {
 408         struct taskqueue_busy tb;
 409         struct taskqueue_busy *tb_first;
 410         struct task *task;
 411         int pending;
 412
 413         TQ_ASSERT_LOCKED(queue);
 414         tb.tb_running = NULL;
 415
 416         while (STAILQ_FIRST(&queue->tq_queue)) {
 417                 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 418
 419                 /*
 420                  * Carefully remove the first task from the queue and
 421                  * zero its pending count.
 422                  */
 423                 task = STAILQ_FIRST(&queue->tq_queue);
 424                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 425                 pending = task->ta_pending;
 426                 task->ta_pending = 0;
 427                 tb.tb_running = task;
 428                 TQ_UNLOCK(queue);
 429
 430                 task->ta_func(task->ta_context, pending);
 431
 432                 TQ_LOCK(queue);
 433                 tb.tb_running = NULL;
 434                 wakeup(task);
 435
 436                 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 437                 tb_first = TAILQ_FIRST(&queue->tq_active);
 438                 if (tb_first != NULL &&
 439                     tb_first->tb_running == TB_DRAIN_WAITER)
 440                         wakeup(tb_first);
 441         }
 442 }
 443
 444 void
 445 taskqueue_run(struct taskqueue *queue)
 446 {
 447
 448         TQ_LOCK(queue);
 449         taskqueue_run_locked(queue);
 450         TQ_UNLOCK(queue);
 451 }
 452
 453 static int
 454 task_is_running(struct taskqueue *queue, struct task *task)
 455 {
 456         struct taskqueue_busy *tb;
 457
 458         TQ_ASSERT_LOCKED(queue);
 459         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 460                 if (tb->tb_running == task)
 461                         return (1);
 462         }
 463         return (0);
 464 }
 465
 466 static int
 467 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 468     u_int *pendp)
 469 {
 470
 471         if (task->ta_pending > 0)
 472                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 473         if (pendp != NULL)
 474                 *pendp = task->ta_pending;
 475         task->ta_pending = 0;
 476         return (task_is_running(queue, task) ? EBUSY : 0);
 477 }
 478
 479 int
 480 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 481 {
 482         int error;
 483
 484         TQ_LOCK(queue);
 485         error = taskqueue_cancel_locked(queue, task, pendp);
 486         TQ_UNLOCK(queue);
 487
 488         return (error);
 489 }
 490
 491 int
 492 taskqueue_cancel_timeout(struct taskqueue *queue,
 493     struct timeout_task *timeout_task, u_int *pendp)
 494 {
 495         u_int pending, pending1;
 496         int error;
 497
 498         TQ_LOCK(queue);
 499         pending = !!callout_stop(&timeout_task->c);
 500         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 501         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 502                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 503                 queue->tq_callouts--;
 504         }
 505         TQ_UNLOCK(queue);
 506
 507         if (pendp != NULL)
 508                 *pendp = pending + pending1;
 509         return (error);
 510 }
 511
 512 void
 513 taskqueue_drain(struct taskqueue *queue, struct task *task)
 514 {
 515
 516         if (!queue->tq_spin)
 517                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 518
 519         TQ_LOCK(queue);
 520         while (task->ta_pending != 0 || task_is_running(queue, task))
 521                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 522         TQ_UNLOCK(queue);
 523 }
 524
 525 void
 526 taskqueue_drain_all(struct taskqueue *queue)
 527 {
 528
 529         if (!queue->tq_spin)
 530                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 531
 532         TQ_LOCK(queue);
 533         taskqueue_drain_tq_queue(queue);
 534         taskqueue_drain_tq_active(queue);
 535         TQ_UNLOCK(queue);
 536 }
 537
 538 void
 539 taskqueue_drain_timeout(struct taskqueue *queue,
 540     struct timeout_task *timeout_task)
 541 {
 542
 543         callout_drain(&timeout_task->c);
 544         taskqueue_drain(queue, &timeout_task->t);
 545 }
 546
 547 static void
 548 taskqueue_swi_enqueue(void *context)
 549 {
 550         swi_sched(taskqueue_ih, 0);
 551 }
 552
 553 static void
 554 taskqueue_swi_run(void *dummy)
 555 {
 556         taskqueue_run(taskqueue_swi);
 557 }
 558
 559 static void
 560 taskqueue_swi_giant_enqueue(void *context)
 561 {
 562         swi_sched(taskqueue_giant_ih, 0);
 563 }
 564
 565 static void
 566 taskqueue_swi_giant_run(void *dummy)
 567 {
 568         taskqueue_run(taskqueue_swi_giant);
 569 }
 570
 571 static int
 572 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 573     cpuset_t *mask, const char *name, va_list ap)
 574 {
 575         char ktname[MAXCOMLEN + 1];
 576         struct thread *td;
 577         struct taskqueue *tq;
 578         int i, error;
 579
 580         if (count <= 0)
 581                 return (EINVAL);
 582
 583         vsnprintf(ktname, sizeof(ktname), name, ap);
 584         tq = *tqp;
 585
 586         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 587             M_NOWAIT | M_ZERO);
 588         if (tq->tq_threads == NULL) {
 589                 printf("%s: no memory for %s threads\n", __func__, ktname);
 590                 return (ENOMEM);
 591         }
 592
 593         for (i = 0; i < count; i++) {
 594                 if (count == 1)
 595                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 596                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 597                 else
 598                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 599                             &tq->tq_threads[i], RFSTOPPED, 0,
 600                             "%s_%d", ktname, i);
 601                 if (error) {
 602                         /* should be ok to continue, taskqueue_free will dtrt */
 603                         printf("%s: kthread_add(%s): error %d", __func__,
 604                             ktname, error);
 605                         tq->tq_threads[i] = NULL;               /* paranoid */
 606                 } else
 607                         tq->tq_tcount++;
 608         }
 609         for (i = 0; i < count; i++) {
 610                 if (tq->tq_threads[i] == NULL)
 611                         continue;
 612                 td = tq->tq_threads[i];
 613                 if (mask) {
 614                         error = cpuset_setthread(td->td_tid, mask);
 615                         /*
 616                          * Failing to pin is rarely an actual fatal error;
 617                          * it'll just affect performance.
 618                          */
 619                         if (error)
 620                                 printf("%s: curthread=%llu: can't pin; "
 621                                     "error=%d\n",
 622                                     __func__,
 623                                     (unsigned long long) td->td_tid,
 624                                     error);
 625                 }
 626                 thread_lock(td);
 627                 sched_prio(td, pri);
 628                 sched_add(td, SRQ_BORING);
 629                 thread_unlock(td);
 630         }
 631
 632         return (0);
 633 }
 634
 635 int
 636 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 637     const char *name, ...)
 638 {
 639         va_list ap;
 640         int error;
 641
 642         va_start(ap, name);
 643         error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
 644         va_end(ap);
 645         return (error);
 646 }
 647
 648 int
 649 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 650     cpuset_t *mask, const char *name, ...)
 651 {
 652         va_list ap;
 653         int error;
 654
 655         va_start(ap, name);
 656         error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
 657         va_end(ap);
 658         return (error);
 659 }
 660
 661 static inline void
 662 taskqueue_run_callback(struct taskqueue *tq,
 663     enum taskqueue_callback_type cb_type)
 664 {
 665         taskqueue_callback_fn tq_callback;
 666
 667         TQ_ASSERT_UNLOCKED(tq);
 668         tq_callback = tq->tq_callbacks[cb_type];
 669         if (tq_callback != NULL)
 670                 tq_callback(tq->tq_cb_contexts[cb_type]);
 671 }
 672
 673 void
 674 taskqueue_thread_loop(void *arg)
 675 {
 676         struct taskqueue **tqp, *tq;
 677
 678         tqp = arg;
 679         tq = *tqp;
 680         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 681         TQ_LOCK(tq);
 682         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 683                 taskqueue_run_locked(tq);
 684                 /*
 685                  * Because taskqueue_run() can drop tq_mutex, we need to
 686                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 687                  * meantime, which means we missed a wakeup.
 688                  */
 689                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 690                         break;
 691                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 692         }
 693         taskqueue_run_locked(tq);
 694
 695         /*
 696          * This thread is on its way out, so just drop the lock temporarily
 697          * in order to call the shutdown callback.  This allows the callback
 698          * to look at the taskqueue, even just before it dies.
 699          */
 700         TQ_UNLOCK(tq);
 701         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 702         TQ_LOCK(tq);
 703
 704         /* rendezvous with thread that asked us to terminate */
 705         tq->tq_tcount--;
 706         wakeup_one(tq->tq_threads);
 707         TQ_UNLOCK(tq);
 708         kthread_exit();
 709 }
 710
 711 void
 712 taskqueue_thread_enqueue(void *context)
 713 {
 714         struct taskqueue **tqp, *tq;
 715
 716         tqp = context;
 717         tq = *tqp;
 718
 719         wakeup_one(tq);
 720 }
 721
 722 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 723                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 724                      INTR_MPSAFE, &taskqueue_ih));
 725
 726 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 727                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 728                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 729
 730 TASKQUEUE_DEFINE_THREAD(thread);
 731
 732 struct taskqueue *
 733 taskqueue_create_fast(const char *name, int mflags,
 734                  taskqueue_enqueue_fn enqueue, void *context)
 735 {
 736         return _taskqueue_create(name, mflags, enqueue, context,
 737                         MTX_SPIN, "fast_taskqueue");
 738 }
 739
 740 /* NB: for backwards compatibility */
 741 int
 742 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
 743 {
 744         return taskqueue_enqueue(queue, task);
 745 }
 746
 747 static void     *taskqueue_fast_ih;
 748
 749 static void
 750 taskqueue_fast_enqueue(void *context)
 751 {
 752         swi_sched(taskqueue_fast_ih, 0);
 753 }
 754
 755 static void
 756 taskqueue_fast_run(void *dummy)
 757 {
 758         taskqueue_run(taskqueue_fast);
 759 }
 760
 761 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 762         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 763         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 764
 765 int
 766 taskqueue_member(struct taskqueue *queue, struct thread *td)
 767 {
 768         int i, j, ret = 0;
 769
 770         for (i = 0, j = 0; ; i++) {
 771                 if (queue->tq_threads[i] == NULL)
 772                         continue;
 773                 if (queue->tq_threads[i] == td) {
 774                         ret = 1;
 775                         break;
 776                 }
 777                 if (++j >= queue->tq_tcount)
 778                         break;
 779         }
 780         return (ret);
 781 }