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/libkern.h>
  38 #include <sys/limits.h>
  39 #include <sys/lock.h>
  40 #include <sys/malloc.h>
  41 #include <sys/mutex.h>
  42 #include <sys/proc.h>
  43 #include <sys/sched.h>
  44 #include <sys/smp.h>
  45 #include <sys/taskqueue.h>
  46 #include <sys/unistd.h>
  47 #include <machine/stdarg.h>
  48
  49 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  50 static void     *taskqueue_giant_ih;
  51 static void     *taskqueue_ih;
  52 static void      taskqueue_fast_enqueue(void *);
  53 static void      taskqueue_swi_enqueue(void *);
  54 static void      taskqueue_swi_giant_enqueue(void *);
  55
  56 struct taskqueue_busy {
  57         struct task     *tb_running;
  58         TAILQ_ENTRY(taskqueue_busy) tb_link;
  59 };
  60
  61 struct task * const TB_DRAIN_WAITER = (struct task *)0x1;
  62
  63 struct taskqueue {
  64         STAILQ_HEAD(, task)     tq_queue;
  65         taskqueue_enqueue_fn    tq_enqueue;
  66         void                    *tq_context;
  67         char                    *tq_name;
  68         TAILQ_HEAD(, taskqueue_busy) tq_active;
  69         struct mtx              tq_mutex;
  70         struct thread           **tq_threads;
  71         int                     tq_tcount;
  72         int                     tq_spin;
  73         int                     tq_flags;
  74         int                     tq_callouts;
  75         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  76         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  77 };
  78
  79 #define TQ_FLAGS_ACTIVE         (1 << 0)
  80 #define TQ_FLAGS_BLOCKED        (1 << 1)
  81 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  82
  83 #define DT_CALLOUT_ARMED        (1 << 0)
  84
  85 #define TQ_LOCK(tq)                                                     \
  86         do {                                                            \
  87                 if ((tq)->tq_spin)                                      \
  88                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  89                 else                                                    \
  90                         mtx_lock(&(tq)->tq_mutex);                      \
  91         } while (0)
  92 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  93
  94 #define TQ_UNLOCK(tq)                                                   \
  95         do {                                                            \
  96                 if ((tq)->tq_spin)                                      \
  97                         mtx_unlock_spin(&(tq)->tq_mutex);               \
  98                 else                                                    \
  99                         mtx_unlock(&(tq)->tq_mutex);                    \
 100         } while (0)
 101 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 102
 103 void
 104 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 105     int priority, task_fn_t func, void *context)
 106 {
 107
 108         TASK_INIT(&timeout_task->t, priority, func, context);
 109         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 110             CALLOUT_RETURNUNLOCKED);
 111         timeout_task->q = queue;
 112         timeout_task->f = 0;
 113 }
 114
 115 static __inline int
 116 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 117     int t)
 118 {
 119         if (tq->tq_spin)
 120                 return (msleep_spin(p, m, wm, t));
 121         return (msleep(p, m, pri, wm, t));
 122 }
 123
 124 static struct taskqueue *
 125 _taskqueue_create(const char *name, int mflags,
 126                  taskqueue_enqueue_fn enqueue, void *context,
 127                  int mtxflags, const char *mtxname __unused)
 128 {
 129         struct taskqueue *queue;
 130         char *tq_name;
 131
 132         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
 133         if (tq_name == NULL)
 134                 return (NULL);
 135
 136         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 137         if (queue == NULL) {
 138                 free(tq_name, M_TASKQUEUE);
 139                 return (NULL);
 140         }
 141
 142         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 143
 144         STAILQ_INIT(&queue->tq_queue);
 145         TAILQ_INIT(&queue->tq_active);
 146         queue->tq_enqueue = enqueue;
 147         queue->tq_context = context;
 148         queue->tq_name = tq_name;
 149         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 150         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 151         if (enqueue == taskqueue_fast_enqueue ||
 152             enqueue == taskqueue_swi_enqueue ||
 153             enqueue == taskqueue_swi_giant_enqueue ||
 154             enqueue == taskqueue_thread_enqueue)
 155                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 156         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 157
 158         return (queue);
 159 }
 160
 161 struct taskqueue *
 162 taskqueue_create(const char *name, int mflags,
 163                  taskqueue_enqueue_fn enqueue, void *context)
 164 {
 165
 166         return _taskqueue_create(name, mflags, enqueue, context,
 167                         MTX_DEF, name);
 168 }
 169
 170 void
 171 taskqueue_set_callback(struct taskqueue *queue,
 172     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 173     void *context)
 174 {
 175
 176         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 177             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 178             ("Callback type %d not valid, must be %d-%d", cb_type,
 179             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 180         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 181             ("Re-initialization of taskqueue callback?"));
 182
 183         queue->tq_callbacks[cb_type] = callback;
 184         queue->tq_cb_contexts[cb_type] = context;
 185 }
 186
 187 /*
 188  * Signal a taskqueue thread to terminate.
 189  */
 190 static void
 191 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 192 {
 193
 194         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 195                 wakeup(tq);
 196                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 197         }
 198 }
 199
 200 void
 201 taskqueue_free(struct taskqueue *queue)
 202 {
 203
 204         TQ_LOCK(queue);
 205         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 206         taskqueue_terminate(queue->tq_threads, queue);
 207         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 208         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 209         mtx_destroy(&queue->tq_mutex);
 210         free(queue->tq_threads, M_TASKQUEUE);
 211         free(queue->tq_name, M_TASKQUEUE);
 212         free(queue, M_TASKQUEUE);
 213 }
 214
 215 static int
 216 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 217 {
 218         struct task *ins;
 219         struct task *prev;
 220
 221         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
 222         /*
 223          * Count multiple enqueues.
 224          */
 225         if (task->ta_pending) {
 226                 if (task->ta_pending < USHRT_MAX)
 227                         task->ta_pending++;
 228                 TQ_UNLOCK(queue);
 229                 return (0);
 230         }
 231
 232         /*
 233          * Optimise the case when all tasks have the same priority.
 234          */
 235         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 236         if (!prev || prev->ta_priority >= task->ta_priority) {
 237                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 238         } else {
 239                 prev = NULL;
 240                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 241                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 242                         if (ins->ta_priority < task->ta_priority)
 243                                 break;
 244
 245                 if (prev)
 246                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 247                 else
 248                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 249         }
 250
 251         task->ta_pending = 1;
 252         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 253                 TQ_UNLOCK(queue);
 254         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 255                 queue->tq_enqueue(queue->tq_context);
 256         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 257                 TQ_UNLOCK(queue);
 258
 259         /* Return with lock released. */
 260         return (0);
 261 }
 262
 263 int
 264 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 265 {
 266         int res;
 267
 268         TQ_LOCK(queue);
 269         res = taskqueue_enqueue_locked(queue, task);
 270         /* The lock is released inside. */
 271
 272         return (res);
 273 }
 274
 275 static void
 276 taskqueue_timeout_func(void *arg)
 277 {
 278         struct taskqueue *queue;
 279         struct timeout_task *timeout_task;
 280
 281         timeout_task = arg;
 282         queue = timeout_task->q;
 283         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 284         timeout_task->f &= ~DT_CALLOUT_ARMED;
 285         queue->tq_callouts--;
 286         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 287         /* The lock is released inside. */
 288 }
 289
 290 int
 291 taskqueue_enqueue_timeout(struct taskqueue *queue,
 292     struct timeout_task *timeout_task, int ticks)
 293 {
 294         int res;
 295
 296         TQ_LOCK(queue);
 297         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 298             ("Migrated queue"));
 299         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 300         timeout_task->q = queue;
 301         res = timeout_task->t.ta_pending;
 302         if (ticks == 0) {
 303                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 304                 /* The lock is released inside. */
 305         } else {
 306                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 307                         res++;
 308                 } else {
 309                         queue->tq_callouts++;
 310                         timeout_task->f |= DT_CALLOUT_ARMED;
 311                         if (ticks < 0)
 312                                 ticks = -ticks; /* Ignore overflow. */
 313                 }
 314                 if (ticks > 0) {
 315                         callout_reset(&timeout_task->c, ticks,
 316                             taskqueue_timeout_func, timeout_task);
 317                 }
 318                 TQ_UNLOCK(queue);
 319         }
 320         return (res);
 321 }
 322
 323 static void
 324 taskqueue_task_nop_fn(void *context, int pending)
 325 {
 326 }
 327
 328 /*
 329  * Block until all currently queued tasks in this taskqueue
 330  * have begun execution.  Tasks queued during execution of
 331  * this function are ignored.
 332  */
 333 static void
 334 taskqueue_drain_tq_queue(struct taskqueue *queue)
 335 {
 336         struct task t_barrier;
 337
 338         if (STAILQ_EMPTY(&queue->tq_queue))
 339                 return;
 340
 341         /*
 342          * Enqueue our barrier after all current tasks, but with
 343          * the highest priority so that newly queued tasks cannot
 344          * pass it.  Because of the high priority, we can not use
 345          * taskqueue_enqueue_locked directly (which drops the lock
 346          * anyway) so just insert it at tail while we have the
 347          * queue lock.
 348          */
 349         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
 350         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 351         t_barrier.ta_pending = 1;
 352
 353         /*
 354          * Once the barrier has executed, all previously queued tasks
 355          * have completed or are currently executing.
 356          */
 357         while (t_barrier.ta_pending != 0)
 358                 TQ_SLEEP(queue, &t_barrier, &queue->tq_mutex, PWAIT, "-", 0);
 359 }
 360
 361 /*
 362  * Block until all currently executing tasks for this taskqueue
 363  * complete.  Tasks that begin execution during the execution
 364  * of this function are ignored.
 365  */
 366 static void
 367 taskqueue_drain_tq_active(struct taskqueue *queue)
 368 {
 369         struct taskqueue_busy tb_marker, *tb_first;
 370
 371         if (TAILQ_EMPTY(&queue->tq_active))
 372                 return;
 373
 374         /* Block taskq_terminate().*/
 375         queue->tq_callouts++;
 376
 377         /*
 378          * Wait for all currently executing taskqueue threads
 379          * to go idle.
 380          */
 381         tb_marker.tb_running = TB_DRAIN_WAITER;
 382         TAILQ_INSERT_TAIL(&queue->tq_active, &tb_marker, tb_link);
 383         while (TAILQ_FIRST(&queue->tq_active) != &tb_marker)
 384                 TQ_SLEEP(queue, &tb_marker, &queue->tq_mutex, PWAIT, "-", 0);
 385         TAILQ_REMOVE(&queue->tq_active, &tb_marker, tb_link);
 386
 387         /*
 388          * Wakeup any other drain waiter that happened to queue up
 389          * without any intervening active thread.
 390          */
 391         tb_first = TAILQ_FIRST(&queue->tq_active);
 392         if (tb_first != NULL && tb_first->tb_running == TB_DRAIN_WAITER)
 393                 wakeup(tb_first);
 394
 395         /* Release taskqueue_terminate(). */
 396         queue->tq_callouts--;
 397         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 398                 wakeup_one(queue->tq_threads);
 399 }
 400
 401 void
 402 taskqueue_block(struct taskqueue *queue)
 403 {
 404
 405         TQ_LOCK(queue);
 406         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 407         TQ_UNLOCK(queue);
 408 }
 409
 410 void
 411 taskqueue_unblock(struct taskqueue *queue)
 412 {
 413
 414         TQ_LOCK(queue);
 415         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 416         if (!STAILQ_EMPTY(&queue->tq_queue))
 417                 queue->tq_enqueue(queue->tq_context);
 418         TQ_UNLOCK(queue);
 419 }
 420
 421 static void
 422 taskqueue_run_locked(struct taskqueue *queue)
 423 {
 424         struct taskqueue_busy tb;
 425         struct taskqueue_busy *tb_first;
 426         struct task *task;
 427         int pending;
 428
 429         KASSERT(queue != NULL, ("tq is NULL"));
 430         TQ_ASSERT_LOCKED(queue);
 431         tb.tb_running = NULL;
 432
 433         while (STAILQ_FIRST(&queue->tq_queue)) {
 434                 TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 435
 436                 /*
 437                  * Carefully remove the first task from the queue and
 438                  * zero its pending count.
 439                  */
 440                 task = STAILQ_FIRST(&queue->tq_queue);
 441                 KASSERT(task != NULL, ("task is NULL"));
 442                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 443                 pending = task->ta_pending;
 444                 task->ta_pending = 0;
 445                 tb.tb_running = task;
 446                 TQ_UNLOCK(queue);
 447
 448                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
 449                 task->ta_func(task->ta_context, pending);
 450
 451                 TQ_LOCK(queue);
 452                 tb.tb_running = NULL;
 453                 wakeup(task);
 454
 455                 TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 456                 tb_first = TAILQ_FIRST(&queue->tq_active);
 457                 if (tb_first != NULL &&
 458                     tb_first->tb_running == TB_DRAIN_WAITER)
 459                         wakeup(tb_first);
 460         }
 461 }
 462
 463 void
 464 taskqueue_run(struct taskqueue *queue)
 465 {
 466
 467         TQ_LOCK(queue);
 468         taskqueue_run_locked(queue);
 469         TQ_UNLOCK(queue);
 470 }
 471
 472 static int
 473 task_is_running(struct taskqueue *queue, struct task *task)
 474 {
 475         struct taskqueue_busy *tb;
 476
 477         TQ_ASSERT_LOCKED(queue);
 478         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 479                 if (tb->tb_running == task)
 480                         return (1);
 481         }
 482         return (0);
 483 }
 484
 485 static int
 486 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 487     u_int *pendp)
 488 {
 489
 490         if (task->ta_pending > 0)
 491                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 492         if (pendp != NULL)
 493                 *pendp = task->ta_pending;
 494         task->ta_pending = 0;
 495         return (task_is_running(queue, task) ? EBUSY : 0);
 496 }
 497
 498 int
 499 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 500 {
 501         int error;
 502
 503         TQ_LOCK(queue);
 504         error = taskqueue_cancel_locked(queue, task, pendp);
 505         TQ_UNLOCK(queue);
 506
 507         return (error);
 508 }
 509
 510 int
 511 taskqueue_cancel_timeout(struct taskqueue *queue,
 512     struct timeout_task *timeout_task, u_int *pendp)
 513 {
 514         u_int pending, pending1;
 515         int error;
 516
 517         TQ_LOCK(queue);
 518         pending = !!(callout_stop(&timeout_task->c) > 0);
 519         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 520         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 521                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 522                 queue->tq_callouts--;
 523         }
 524         TQ_UNLOCK(queue);
 525
 526         if (pendp != NULL)
 527                 *pendp = pending + pending1;
 528         return (error);
 529 }
 530
 531 void
 532 taskqueue_drain(struct taskqueue *queue, struct task *task)
 533 {
 534
 535         if (!queue->tq_spin)
 536                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 537
 538         TQ_LOCK(queue);
 539         while (task->ta_pending != 0 || task_is_running(queue, task))
 540                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 541         TQ_UNLOCK(queue);
 542 }
 543
 544 void
 545 taskqueue_drain_all(struct taskqueue *queue)
 546 {
 547
 548         if (!queue->tq_spin)
 549                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 550
 551         TQ_LOCK(queue);
 552         taskqueue_drain_tq_queue(queue);
 553         taskqueue_drain_tq_active(queue);
 554         TQ_UNLOCK(queue);
 555 }
 556
 557 void
 558 taskqueue_drain_timeout(struct taskqueue *queue,
 559     struct timeout_task *timeout_task)
 560 {
 561
 562         callout_drain(&timeout_task->c);
 563         taskqueue_drain(queue, &timeout_task->t);
 564 }
 565
 566 static void
 567 taskqueue_swi_enqueue(void *context)
 568 {
 569         swi_sched(taskqueue_ih, 0);
 570 }
 571
 572 static void
 573 taskqueue_swi_run(void *dummy)
 574 {
 575         taskqueue_run(taskqueue_swi);
 576 }
 577
 578 static void
 579 taskqueue_swi_giant_enqueue(void *context)
 580 {
 581         swi_sched(taskqueue_giant_ih, 0);
 582 }
 583
 584 static void
 585 taskqueue_swi_giant_run(void *dummy)
 586 {
 587         taskqueue_run(taskqueue_swi_giant);
 588 }
 589
 590 static int
 591 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 592     cpuset_t *mask, const char *name, va_list ap)
 593 {
 594         char ktname[MAXCOMLEN + 1];
 595         struct thread *td;
 596         struct taskqueue *tq;
 597         int i, error;
 598
 599         if (count <= 0)
 600                 return (EINVAL);
 601
 602         vsnprintf(ktname, sizeof(ktname), name, ap);
 603         tq = *tqp;
 604
 605         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 606             M_NOWAIT | M_ZERO);
 607         if (tq->tq_threads == NULL) {
 608                 printf("%s: no memory for %s threads\n", __func__, ktname);
 609                 return (ENOMEM);
 610         }
 611
 612         for (i = 0; i < count; i++) {
 613                 if (count == 1)
 614                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 615                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 616                 else
 617                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 618                             &tq->tq_threads[i], RFSTOPPED, 0,
 619                             "%s_%d", ktname, i);
 620                 if (error) {
 621                         /* should be ok to continue, taskqueue_free will dtrt */
 622                         printf("%s: kthread_add(%s): error %d", __func__,
 623                             ktname, error);
 624                         tq->tq_threads[i] = NULL;               /* paranoid */
 625                 } else
 626                         tq->tq_tcount++;
 627         }
 628         for (i = 0; i < count; i++) {
 629                 if (tq->tq_threads[i] == NULL)
 630                         continue;
 631                 td = tq->tq_threads[i];
 632                 if (mask) {
 633                         error = cpuset_setthread(td->td_tid, mask);
 634                         /*
 635                          * Failing to pin is rarely an actual fatal error;
 636                          * it'll just affect performance.
 637                          */
 638                         if (error)
 639                                 printf("%s: curthread=%llu: can't pin; "
 640                                     "error=%d\n",
 641                                     __func__,
 642                                     (unsigned long long) td->td_tid,
 643                                     error);
 644                 }
 645                 thread_lock(td);
 646                 sched_prio(td, pri);
 647                 sched_add(td, SRQ_BORING);
 648                 thread_unlock(td);
 649         }
 650
 651         return (0);
 652 }
 653
 654 int
 655 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 656     const char *name, ...)
 657 {
 658         va_list ap;
 659         int error;
 660
 661         va_start(ap, name);
 662         error = _taskqueue_start_threads(tqp, count, pri, NULL, name, ap);
 663         va_end(ap);
 664         return (error);
 665 }
 666
 667 int
 668 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 669     cpuset_t *mask, const char *name, ...)
 670 {
 671         va_list ap;
 672         int error;
 673
 674         va_start(ap, name);
 675         error = _taskqueue_start_threads(tqp, count, pri, mask, name, ap);
 676         va_end(ap);
 677         return (error);
 678 }
 679
 680 static inline void
 681 taskqueue_run_callback(struct taskqueue *tq,
 682     enum taskqueue_callback_type cb_type)
 683 {
 684         taskqueue_callback_fn tq_callback;
 685
 686         TQ_ASSERT_UNLOCKED(tq);
 687         tq_callback = tq->tq_callbacks[cb_type];
 688         if (tq_callback != NULL)
 689                 tq_callback(tq->tq_cb_contexts[cb_type]);
 690 }
 691
 692 void
 693 taskqueue_thread_loop(void *arg)
 694 {
 695         struct taskqueue **tqp, *tq;
 696
 697         tqp = arg;
 698         tq = *tqp;
 699         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 700         TQ_LOCK(tq);
 701         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 702                 /* XXX ? */
 703                 taskqueue_run_locked(tq);
 704                 /*
 705                  * Because taskqueue_run() can drop tq_mutex, we need to
 706                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 707                  * meantime, which means we missed a wakeup.
 708                  */
 709                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 710                         break;
 711                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 712         }
 713         taskqueue_run_locked(tq);
 714         /*
 715          * This thread is on its way out, so just drop the lock temporarily
 716          * in order to call the shutdown callback.  This allows the callback
 717          * to look at the taskqueue, even just before it dies.
 718          */
 719         TQ_UNLOCK(tq);
 720         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 721         TQ_LOCK(tq);
 722
 723         /* rendezvous with thread that asked us to terminate */
 724         tq->tq_tcount--;
 725         wakeup_one(tq->tq_threads);
 726         TQ_UNLOCK(tq);
 727         kthread_exit();
 728 }
 729
 730 void
 731 taskqueue_thread_enqueue(void *context)
 732 {
 733         struct taskqueue **tqp, *tq;
 734
 735         tqp = context;
 736         tq = *tqp;
 737         wakeup_one(tq);
 738 }
 739
 740 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 741                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 742                      INTR_MPSAFE, &taskqueue_ih));
 743
 744 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 745                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 746                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 747
 748 TASKQUEUE_DEFINE_THREAD(thread);
 749
 750 struct taskqueue *
 751 taskqueue_create_fast(const char *name, int mflags,
 752                  taskqueue_enqueue_fn enqueue, void *context)
 753 {
 754         return _taskqueue_create(name, mflags, enqueue, context,
 755                         MTX_SPIN, "fast_taskqueue");
 756 }
 757
 758 static void     *taskqueue_fast_ih;
 759
 760 static void
 761 taskqueue_fast_enqueue(void *context)
 762 {
 763         swi_sched(taskqueue_fast_ih, 0);
 764 }
 765
 766 static void
 767 taskqueue_fast_run(void *dummy)
 768 {
 769         taskqueue_run(taskqueue_fast);
 770 }
 771
 772 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 773         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 774         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 775
 776 int
 777 taskqueue_member(struct taskqueue *queue, struct thread *td)
 778 {
 779         int i, j, ret = 0;
 780
 781         for (i = 0, j = 0; ; i++) {
 782                 if (queue->tq_threads[i] == NULL)
 783                         continue;
 784                 if (queue->tq_threads[i] == td) {
 785                         ret = 1;
 786                         break;
 787                 }
 788                 if (++j >= queue->tq_tcount)
 789                         break;
 790         }
 791         return (ret);
 792 }