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/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
  46 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  47 static void     *taskqueue_giant_ih;
  48 static void     *taskqueue_ih;
  49 static void      taskqueue_fast_enqueue(void *);
  50 static void      taskqueue_swi_enqueue(void *);
  51 static void      taskqueue_swi_giant_enqueue(void *);
  52
  53 struct taskqueue_busy {
  54         struct task     *tb_running;
  55         TAILQ_ENTRY(taskqueue_busy) tb_link;
  56 };
  57
  58 struct taskqueue {
  59         STAILQ_HEAD(, task)     tq_queue;
  60         taskqueue_enqueue_fn    tq_enqueue;
  61         void                    *tq_context;
  62         TAILQ_HEAD(, taskqueue_busy) tq_active;
  63         struct mtx              tq_mutex;
  64         struct thread           **tq_threads;
  65         int                     tq_tcount;
  66         int                     tq_spin;
  67         int                     tq_flags;
  68         int                     tq_callouts;
  69         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  70         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  71 };
  72
  73 #define TQ_FLAGS_ACTIVE         (1 << 0)
  74 #define TQ_FLAGS_BLOCKED        (1 << 1)
  75 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  76
  77 #define DT_CALLOUT_ARMED        (1 << 0)
  78
  79 #define TQ_LOCK(tq)                                                     \
  80         do {                                                            \
  81                 if ((tq)->tq_spin)                                      \
  82                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  83                 else                                                    \
  84                         mtx_lock(&(tq)->tq_mutex);                      \
  85         } while (0)
  86 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  87
  88 #define TQ_UNLOCK(tq)                                                   \
  89         do {                                                            \
  90                 if ((tq)->tq_spin)                                      \
  91                         mtx_unlock_spin(&(tq)->tq_mutex);               \
  92                 else                                                    \
  93                         mtx_unlock(&(tq)->tq_mutex);                    \
  94         } while (0)
  95 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
  96
  97 void
  98 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
  99     int priority, task_fn_t func, void *context)
 100 {
 101
 102         TASK_INIT(&timeout_task->t, priority, func, context);
 103         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 104             CALLOUT_RETURNUNLOCKED);
 105         timeout_task->q = queue;
 106         timeout_task->f = 0;
 107 }
 108
 109 static __inline int
 110 TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
 111     int t)
 112 {
 113         if (tq->tq_spin)
 114                 return (msleep_spin(p, m, wm, t));
 115         return (msleep(p, m, pri, wm, t));
 116 }
 117
 118 static struct taskqueue *
 119 _taskqueue_create(const char *name __unused, int mflags,
 120                  taskqueue_enqueue_fn enqueue, void *context,
 121                  int mtxflags, const char *mtxname)
 122 {
 123         struct taskqueue *queue;
 124
 125         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 126         if (!queue)
 127                 return NULL;
 128
 129         STAILQ_INIT(&queue->tq_queue);
 130         TAILQ_INIT(&queue->tq_active);
 131         queue->tq_enqueue = enqueue;
 132         queue->tq_context = context;
 133         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 134         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 135         if (enqueue == taskqueue_fast_enqueue ||
 136             enqueue == taskqueue_swi_enqueue ||
 137             enqueue == taskqueue_swi_giant_enqueue ||
 138             enqueue == taskqueue_thread_enqueue)
 139                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 140         mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
 141
 142         return queue;
 143 }
 144
 145 struct taskqueue *
 146 taskqueue_create(const char *name, int mflags,
 147                  taskqueue_enqueue_fn enqueue, void *context)
 148 {
 149         return _taskqueue_create(name, mflags, enqueue, context,
 150                         MTX_DEF, "taskqueue");
 151 }
 152
 153 void
 154 taskqueue_set_callback(struct taskqueue *queue,
 155     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 156     void *context)
 157 {
 158
 159         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 160             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 161             ("Callback type %d not valid, must be %d-%d", cb_type,
 162             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 163         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 164             ("Re-initialization of taskqueue callback?"));
 165
 166         queue->tq_callbacks[cb_type] = callback;
 167         queue->tq_cb_contexts[cb_type] = context;
 168 }
 169
 170 /*
 171  * Signal a taskqueue thread to terminate.
 172  */
 173 static void
 174 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 175 {
 176
 177         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 178                 wakeup(tq);
 179                 TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
 180         }
 181 }
 182
 183 void
 184 taskqueue_free(struct taskqueue *queue)
 185 {
 186
 187         TQ_LOCK(queue);
 188         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 189         taskqueue_terminate(queue->tq_threads, queue);
 190         KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
 191         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 192         mtx_destroy(&queue->tq_mutex);
 193         free(queue->tq_threads, M_TASKQUEUE);
 194         free(queue, M_TASKQUEUE);
 195 }
 196
 197 static int
 198 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
 199 {
 200         struct task *ins;
 201         struct task *prev;
 202
 203         /*
 204          * Count multiple enqueues.
 205          */
 206         if (task->ta_pending) {
 207                 if (task->ta_pending < USHRT_MAX)
 208                         task->ta_pending++;
 209                 TQ_UNLOCK(queue);
 210                 return (0);
 211         }
 212
 213         /*
 214          * Optimise the case when all tasks have the same priority.
 215          */
 216         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 217         if (!prev || prev->ta_priority >= task->ta_priority) {
 218                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 219         } else {
 220                 prev = NULL;
 221                 for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
 222                      prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 223                         if (ins->ta_priority < task->ta_priority)
 224                                 break;
 225
 226                 if (prev)
 227                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 228                 else
 229                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 230         }
 231
 232         task->ta_pending = 1;
 233         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 234                 TQ_UNLOCK(queue);
 235         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 236                 queue->tq_enqueue(queue->tq_context);
 237         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 238                 TQ_UNLOCK(queue);
 239
 240         /* Return with lock released. */
 241         return (0);
 242 }
 243 int
 244 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 245 {
 246         int res;
 247
 248         TQ_LOCK(queue);
 249         res = taskqueue_enqueue_locked(queue, task);
 250         /* The lock is released inside. */
 251
 252         return (res);
 253 }
 254
 255 static void
 256 taskqueue_timeout_func(void *arg)
 257 {
 258         struct taskqueue *queue;
 259         struct timeout_task *timeout_task;
 260
 261         timeout_task = arg;
 262         queue = timeout_task->q;
 263         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 264         timeout_task->f &= ~DT_CALLOUT_ARMED;
 265         queue->tq_callouts--;
 266         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
 267         /* The lock is released inside. */
 268 }
 269
 270 int
 271 taskqueue_enqueue_timeout(struct taskqueue *queue,
 272     struct timeout_task *timeout_task, int ticks)
 273 {
 274         int res;
 275
 276         TQ_LOCK(queue);
 277         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 278             ("Migrated queue"));
 279         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
 280         timeout_task->q = queue;
 281         res = timeout_task->t.ta_pending;
 282         if (ticks == 0) {
 283                 taskqueue_enqueue_locked(queue, &timeout_task->t);
 284                 /* The lock is released inside. */
 285         } else {
 286                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 287                         res++;
 288                 } else {
 289                         queue->tq_callouts++;
 290                         timeout_task->f |= DT_CALLOUT_ARMED;
 291                         if (ticks < 0)
 292                                 ticks = -ticks; /* Ignore overflow. */
 293                 }
 294                 if (ticks > 0) {
 295                         callout_reset(&timeout_task->c, ticks,
 296                             taskqueue_timeout_func, timeout_task);
 297                 }
 298                 TQ_UNLOCK(queue);
 299         }
 300         return (res);
 301 }
 302
 303 static void
 304 taskqueue_drain_running(struct taskqueue *queue)
 305 {
 306
 307         while (!TAILQ_EMPTY(&queue->tq_active))
 308                 TQ_SLEEP(queue, &queue->tq_active, &queue->tq_mutex,
 309                     PWAIT, "-", 0);
 310 }
 311
 312 void
 313 taskqueue_block(struct taskqueue *queue)
 314 {
 315
 316         TQ_LOCK(queue);
 317         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 318         TQ_UNLOCK(queue);
 319 }
 320
 321 void
 322 taskqueue_unblock(struct taskqueue *queue)
 323 {
 324
 325         TQ_LOCK(queue);
 326         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 327         if (!STAILQ_EMPTY(&queue->tq_queue))
 328                 queue->tq_enqueue(queue->tq_context);
 329         TQ_UNLOCK(queue);
 330 }
 331
 332 static void
 333 taskqueue_run_locked(struct taskqueue *queue)
 334 {
 335         struct taskqueue_busy tb;
 336         struct task *task;
 337         int pending;
 338
 339         TQ_ASSERT_LOCKED(queue);
 340         tb.tb_running = NULL;
 341         TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
 342
 343         while (STAILQ_FIRST(&queue->tq_queue)) {
 344                 /*
 345                  * Carefully remove the first task from the queue and
 346                  * zero its pending count.
 347                  */
 348                 task = STAILQ_FIRST(&queue->tq_queue);
 349                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 350                 pending = task->ta_pending;
 351                 task->ta_pending = 0;
 352                 tb.tb_running = task;
 353                 TQ_UNLOCK(queue);
 354
 355                 task->ta_func(task->ta_context, pending);
 356
 357                 TQ_LOCK(queue);
 358                 tb.tb_running = NULL;
 359                 wakeup(task);
 360         }
 361         TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
 362         if (TAILQ_EMPTY(&queue->tq_active))
 363                 wakeup(&queue->tq_active);
 364 }
 365
 366 void
 367 taskqueue_run(struct taskqueue *queue)
 368 {
 369
 370         TQ_LOCK(queue);
 371         taskqueue_run_locked(queue);
 372         TQ_UNLOCK(queue);
 373 }
 374
 375 static int
 376 task_is_running(struct taskqueue *queue, struct task *task)
 377 {
 378         struct taskqueue_busy *tb;
 379
 380         TQ_ASSERT_LOCKED(queue);
 381         TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
 382                 if (tb->tb_running == task)
 383                         return (1);
 384         }
 385         return (0);
 386 }
 387
 388 static int
 389 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 390     u_int *pendp)
 391 {
 392
 393         if (task->ta_pending > 0)
 394                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 395         if (pendp != NULL)
 396                 *pendp = task->ta_pending;
 397         task->ta_pending = 0;
 398         return (task_is_running(queue, task) ? EBUSY : 0);
 399 }
 400
 401 int
 402 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 403 {
 404         int error;
 405
 406         TQ_LOCK(queue);
 407         error = taskqueue_cancel_locked(queue, task, pendp);
 408         TQ_UNLOCK(queue);
 409
 410         return (error);
 411 }
 412
 413 int
 414 taskqueue_cancel_timeout(struct taskqueue *queue,
 415     struct timeout_task *timeout_task, u_int *pendp)
 416 {
 417         u_int pending, pending1;
 418         int error;
 419
 420         TQ_LOCK(queue);
 421         pending = !!callout_stop(&timeout_task->c);
 422         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 423         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 424                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 425                 queue->tq_callouts--;
 426         }
 427         TQ_UNLOCK(queue);
 428
 429         if (pendp != NULL)
 430                 *pendp = pending + pending1;
 431         return (error);
 432 }
 433
 434 void
 435 taskqueue_drain(struct taskqueue *queue, struct task *task)
 436 {
 437
 438         if (!queue->tq_spin)
 439                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 440
 441         TQ_LOCK(queue);
 442         while (task->ta_pending != 0 || task_is_running(queue, task))
 443                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 444         TQ_UNLOCK(queue);
 445 }
 446
 447 void
 448 taskqueue_drain_all(struct taskqueue *queue)
 449 {
 450         struct task *task;
 451
 452         if (!queue->tq_spin)
 453                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 454
 455         TQ_LOCK(queue);
 456         task = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 457         while (task != NULL && task->ta_pending != 0) {
 458                 struct task *oldtask;
 459                 TQ_SLEEP(queue, task, &queue->tq_mutex, PWAIT, "-", 0);
 460                 /*
 461                  * While we were asleeep the last entry may have been freed.
 462                  * We need to check if it's still even in the queue.
 463                  * Not perfect, but it's better than referencing bad memory.
 464                  * first guess is the current 'end of queue' but if a new
 465                  * item has been added we need to take the expensive path
 466                  * Better fix in 11.
 467                  */
 468                 oldtask = task;
 469                 if (oldtask !=
 470                     (task = STAILQ_LAST(&queue->tq_queue, task, ta_link))) {
 471                         STAILQ_FOREACH(task, &queue->tq_queue, ta_link) {
 472                                 if (task == oldtask)
 473                                         break;
 474                         }
 475                 }
 476         }
 477         taskqueue_drain_running(queue);
 478         KASSERT(STAILQ_EMPTY(&queue->tq_queue),
 479             ("taskqueue queue is not empty after draining"));
 480         TQ_UNLOCK(queue);
 481 }
 482
 483 void
 484 taskqueue_drain_timeout(struct taskqueue *queue,
 485     struct timeout_task *timeout_task)
 486 {
 487
 488         callout_drain(&timeout_task->c);
 489         taskqueue_drain(queue, &timeout_task->t);
 490 }
 491
 492 static void
 493 taskqueue_swi_enqueue(void *context)
 494 {
 495         swi_sched(taskqueue_ih, 0);
 496 }
 497
 498 static void
 499 taskqueue_swi_run(void *dummy)
 500 {
 501         taskqueue_run(taskqueue_swi);
 502 }
 503
 504 static void
 505 taskqueue_swi_giant_enqueue(void *context)
 506 {
 507         swi_sched(taskqueue_giant_ih, 0);
 508 }
 509
 510 static void
 511 taskqueue_swi_giant_run(void *dummy)
 512 {
 513         taskqueue_run(taskqueue_swi_giant);
 514 }
 515
 516 int
 517 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 518                         const char *name, ...)
 519 {
 520         va_list ap;
 521         struct thread *td;
 522         struct taskqueue *tq;
 523         int i, error;
 524         char ktname[MAXCOMLEN + 1];
 525
 526         if (count <= 0)
 527                 return (EINVAL);
 528
 529         tq = *tqp;
 530
 531         va_start(ap, name);
 532         vsnprintf(ktname, sizeof(ktname), name, ap);
 533         va_end(ap);
 534
 535         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 536             M_NOWAIT | M_ZERO);
 537         if (tq->tq_threads == NULL) {
 538                 printf("%s: no memory for %s threads\n", __func__, ktname);
 539                 return (ENOMEM);
 540         }
 541
 542         for (i = 0; i < count; i++) {
 543                 if (count == 1)
 544                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 545                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 546                 else
 547                         error = kthread_add(taskqueue_thread_loop, tqp, NULL,
 548                             &tq->tq_threads[i], RFSTOPPED, 0,
 549                             "%s_%d", ktname, i);
 550                 if (error) {
 551                         /* should be ok to continue, taskqueue_free will dtrt */
 552                         printf("%s: kthread_add(%s): error %d", __func__,
 553                             ktname, error);
 554                         tq->tq_threads[i] = NULL;               /* paranoid */
 555                 } else
 556                         tq->tq_tcount++;
 557         }
 558         for (i = 0; i < count; i++) {
 559                 if (tq->tq_threads[i] == NULL)
 560                         continue;
 561                 td = tq->tq_threads[i];
 562                 thread_lock(td);
 563                 sched_prio(td, pri);
 564                 sched_add(td, SRQ_BORING);
 565                 thread_unlock(td);
 566         }
 567
 568         return (0);
 569 }
 570
 571 static inline void
 572 taskqueue_run_callback(struct taskqueue *tq,
 573     enum taskqueue_callback_type cb_type)
 574 {
 575         taskqueue_callback_fn tq_callback;
 576
 577         TQ_ASSERT_UNLOCKED(tq);
 578         tq_callback = tq->tq_callbacks[cb_type];
 579         if (tq_callback != NULL)
 580                 tq_callback(tq->tq_cb_contexts[cb_type]);
 581 }
 582
 583 void
 584 taskqueue_thread_loop(void *arg)
 585 {
 586         struct taskqueue **tqp, *tq;
 587
 588         tqp = arg;
 589         tq = *tqp;
 590         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 591         TQ_LOCK(tq);
 592         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 593                 taskqueue_run_locked(tq);
 594                 /*
 595                  * Because taskqueue_run() can drop tq_mutex, we need to
 596                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 597                  * meantime, which means we missed a wakeup.
 598                  */
 599                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 600                         break;
 601                 TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
 602         }
 603         taskqueue_run_locked(tq);
 604
 605         /*
 606          * This thread is on its way out, so just drop the lock temporarily
 607          * in order to call the shutdown callback.  This allows the callback
 608          * to look at the taskqueue, even just before it dies.
 609          */
 610         TQ_UNLOCK(tq);
 611         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 612         TQ_LOCK(tq);
 613
 614         /* rendezvous with thread that asked us to terminate */
 615         tq->tq_tcount--;
 616         wakeup_one(tq->tq_threads);
 617         TQ_UNLOCK(tq);
 618         kthread_exit();
 619 }
 620
 621 void
 622 taskqueue_thread_enqueue(void *context)
 623 {
 624         struct taskqueue **tqp, *tq;
 625
 626         tqp = context;
 627         tq = *tqp;
 628
 629         wakeup_one(tq);
 630 }
 631
 632 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 633                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 634                      INTR_MPSAFE, &taskqueue_ih));
 635
 636 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 637                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 638                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 639
 640 TASKQUEUE_DEFINE_THREAD(thread);
 641
 642 struct taskqueue *
 643 taskqueue_create_fast(const char *name, int mflags,
 644                  taskqueue_enqueue_fn enqueue, void *context)
 645 {
 646         return _taskqueue_create(name, mflags, enqueue, context,
 647                         MTX_SPIN, "fast_taskqueue");
 648 }
 649
 650 /* NB: for backwards compatibility */
 651 int
 652 taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
 653 {
 654         return taskqueue_enqueue(queue, task);
 655 }
 656
 657 static void     *taskqueue_fast_ih;
 658
 659 static void
 660 taskqueue_fast_enqueue(void *context)
 661 {
 662         swi_sched(taskqueue_fast_ih, 0);
 663 }
 664
 665 static void
 666 taskqueue_fast_run(void *dummy)
 667 {
 668         taskqueue_run(taskqueue_fast);
 669 }
 670
 671 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 672         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 673         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 674
 675 int
 676 taskqueue_member(struct taskqueue *queue, struct thread *td)
 677 {
 678         int i, j, ret = 0;
 679
 680         for (i = 0, j = 0; ; i++) {
 681                 if (queue->tq_threads[i] == NULL)
 682                         continue;
 683                 if (queue->tq_threads[i] == td) {
 684                         ret = 1;
 685                         break;
 686                 }
 687                 if (++j >= queue->tq_tcount)
 688                         break;
 689         }
 690         return (ret);
 691 }