sys/kern/subr_taskqueue.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   3  *
   4  * Copyright (c) 2000 Doug Rabson
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/systm.h>
  31 #include <sys/bus.h>
  32 #include <sys/cpuset.h>
  33 #include <sys/interrupt.h>
  34 #include <sys/kernel.h>
  35 #include <sys/kthread.h>
  36 #include <sys/libkern.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/epoch.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         u_int                    tb_seq;
  59         bool                     tb_canceling;
  60         LIST_ENTRY(taskqueue_busy) tb_link;
  61 };
  62
  63 struct taskqueue {
  64         STAILQ_HEAD(, task)     tq_queue;
  65         LIST_HEAD(, taskqueue_busy) tq_active;
  66         struct task             *tq_hint;
  67         u_int                   tq_seq;
  68         int                     tq_callouts;
  69         struct mtx_padalign     tq_mutex;
  70         taskqueue_enqueue_fn    tq_enqueue;
  71         void                    *tq_context;
  72         char                    *tq_name;
  73         struct thread           **tq_threads;
  74         int                     tq_tcount;
  75         int                     tq_spin;
  76         int                     tq_flags;
  77         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  78         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  79 };
  80
  81 #define TQ_FLAGS_ACTIVE         (1 << 0)
  82 #define TQ_FLAGS_BLOCKED        (1 << 1)
  83 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  84
  85 #define DT_CALLOUT_ARMED        (1 << 0)
  86 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  87
  88 #define TQ_LOCK(tq)                                                     \
  89         do {                                                            \
  90                 if ((tq)->tq_spin)                                      \
  91                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  92                 else                                                    \
  93                         mtx_lock(&(tq)->tq_mutex);                      \
  94         } while (0)
  95 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  96
  97 #define TQ_UNLOCK(tq)                                                   \
  98         do {                                                            \
  99                 if ((tq)->tq_spin)                                      \
 100                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 101                 else                                                    \
 102                         mtx_unlock(&(tq)->tq_mutex);                    \
 103         } while (0)
 104 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 105
 106 void
 107 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 108     int priority, task_fn_t func, void *context)
 109 {
 110
 111         TASK_INIT(&timeout_task->t, priority, func, context);
 112         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 113             CALLOUT_RETURNUNLOCKED);
 114         timeout_task->q = queue;
 115         timeout_task->f = 0;
 116 }
 117
 118 static __inline int
 119 TQ_SLEEP(struct taskqueue *tq, void *p, const char *wm)
 120 {
 121         if (tq->tq_spin)
 122                 return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
 123         return (msleep(p, &tq->tq_mutex, 0, wm, 0));
 124 }
 125
 126 static struct taskqueue_busy *
 127 task_get_busy(struct taskqueue *queue, struct task *task)
 128 {
 129         struct taskqueue_busy *tb;
 130
 131         TQ_ASSERT_LOCKED(queue);
 132         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 133                 if (tb->tb_running == task)
 134                         return (tb);
 135         }
 136         return (NULL);
 137 }
 138
 139 static struct taskqueue *
 140 _taskqueue_create(const char *name, int mflags,
 141                  taskqueue_enqueue_fn enqueue, void *context,
 142                  int mtxflags, const char *mtxname __unused)
 143 {
 144         struct taskqueue *queue;
 145         char *tq_name;
 146
 147         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
 148         if (tq_name == NULL)
 149                 return (NULL);
 150
 151         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 152         if (queue == NULL) {
 153                 free(tq_name, M_TASKQUEUE);
 154                 return (NULL);
 155         }
 156
 157         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 158
 159         STAILQ_INIT(&queue->tq_queue);
 160         LIST_INIT(&queue->tq_active);
 161         queue->tq_enqueue = enqueue;
 162         queue->tq_context = context;
 163         queue->tq_name = tq_name;
 164         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 165         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 166         if (enqueue == taskqueue_fast_enqueue ||
 167             enqueue == taskqueue_swi_enqueue ||
 168             enqueue == taskqueue_swi_giant_enqueue ||
 169             enqueue == taskqueue_thread_enqueue)
 170                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 171         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 172
 173         return (queue);
 174 }
 175
 176 struct taskqueue *
 177 taskqueue_create(const char *name, int mflags,
 178                  taskqueue_enqueue_fn enqueue, void *context)
 179 {
 180
 181         return _taskqueue_create(name, mflags, enqueue, context,
 182                         MTX_DEF, name);
 183 }
 184
 185 void
 186 taskqueue_set_callback(struct taskqueue *queue,
 187     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 188     void *context)
 189 {
 190
 191         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 192             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 193             ("Callback type %d not valid, must be %d-%d", cb_type,
 194             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 195         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 196             ("Re-initialization of taskqueue callback?"));
 197
 198         queue->tq_callbacks[cb_type] = callback;
 199         queue->tq_cb_contexts[cb_type] = context;
 200 }
 201
 202 /*
 203  * Signal a taskqueue thread to terminate.
 204  */
 205 static void
 206 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 207 {
 208
 209         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 210                 wakeup(tq);
 211                 TQ_SLEEP(tq, pp, "tq_destroy");
 212         }
 213 }
 214
 215 void
 216 taskqueue_free(struct taskqueue *queue)
 217 {
 218
 219         TQ_LOCK(queue);
 220         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 221         taskqueue_terminate(queue->tq_threads, queue);
 222         KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
 223         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 224         mtx_destroy(&queue->tq_mutex);
 225         free(queue->tq_threads, M_TASKQUEUE);
 226         free(queue->tq_name, M_TASKQUEUE);
 227         free(queue, M_TASKQUEUE);
 228 }
 229
 230 static int
 231 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task, int flags)
 232 {
 233         struct task *ins;
 234         struct task *prev;
 235         struct taskqueue_busy *tb;
 236
 237         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
 238         /*
 239          * Ignore canceling task if requested.
 240          */
 241         if (__predict_false((flags & TASKQUEUE_FAIL_IF_CANCELING) != 0)) {
 242                 tb = task_get_busy(queue, task);
 243                 if (tb != NULL && tb->tb_canceling) {
 244                         TQ_UNLOCK(queue);
 245                         return (ECANCELED);
 246                 }
 247         }
 248
 249         /*
 250          * Count multiple enqueues.
 251          */
 252         if (task->ta_pending) {
 253                 if (__predict_false((flags & TASKQUEUE_FAIL_IF_PENDING) != 0)) {
 254                         TQ_UNLOCK(queue);
 255                         return (EEXIST);
 256                 }
 257                 if (task->ta_pending < USHRT_MAX)
 258                         task->ta_pending++;
 259                 TQ_UNLOCK(queue);
 260                 return (0);
 261         }
 262
 263         /*
 264          * Optimise cases when all tasks use small set of priorities.
 265          * In case of only one priority we always insert at the end.
 266          * In case of two tq_hint typically gives the insertion point.
 267          * In case of more then two tq_hint should halve the search.
 268          */
 269         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 270         if (!prev || prev->ta_priority >= task->ta_priority) {
 271                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 272         } else {
 273                 prev = queue->tq_hint;
 274                 if (prev && prev->ta_priority >= task->ta_priority) {
 275                         ins = STAILQ_NEXT(prev, ta_link);
 276                 } else {
 277                         prev = NULL;
 278                         ins = STAILQ_FIRST(&queue->tq_queue);
 279                 }
 280                 for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 281                         if (ins->ta_priority < task->ta_priority)
 282                                 break;
 283
 284                 if (prev) {
 285                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 286                         queue->tq_hint = task;
 287                 } else
 288                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 289         }
 290
 291         task->ta_pending = 1;
 292         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 293                 TQ_UNLOCK(queue);
 294         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 295                 queue->tq_enqueue(queue->tq_context);
 296         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 297                 TQ_UNLOCK(queue);
 298
 299         /* Return with lock released. */
 300         return (0);
 301 }
 302
 303 int
 304 taskqueue_enqueue_flags(struct taskqueue *queue, struct task *task, int flags)
 305 {
 306         int res;
 307
 308         TQ_LOCK(queue);
 309         res = taskqueue_enqueue_locked(queue, task, flags);
 310         /* The lock is released inside. */
 311
 312         return (res);
 313 }
 314
 315 int
 316 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 317 {
 318         return (taskqueue_enqueue_flags(queue, task, 0));
 319 }
 320
 321 static void
 322 taskqueue_timeout_func(void *arg)
 323 {
 324         struct taskqueue *queue;
 325         struct timeout_task *timeout_task;
 326
 327         timeout_task = arg;
 328         queue = timeout_task->q;
 329         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 330         timeout_task->f &= ~DT_CALLOUT_ARMED;
 331         queue->tq_callouts--;
 332         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t, 0);
 333         /* The lock is released inside. */
 334 }
 335
 336 int
 337 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
 338     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
 339 {
 340         int res;
 341
 342         TQ_LOCK(queue);
 343         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 344             ("Migrated queue"));
 345         timeout_task->q = queue;
 346         res = timeout_task->t.ta_pending;
 347         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 348                 /* Do nothing */
 349                 TQ_UNLOCK(queue);
 350                 res = -1;
 351         } else if (sbt == 0) {
 352                 taskqueue_enqueue_locked(queue, &timeout_task->t, 0);
 353                 /* The lock is released inside. */
 354         } else {
 355                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 356                         res++;
 357                 } else {
 358                         queue->tq_callouts++;
 359                         timeout_task->f |= DT_CALLOUT_ARMED;
 360                         if (sbt < 0)
 361                                 sbt = -sbt; /* Ignore overflow. */
 362                 }
 363                 if (sbt > 0) {
 364                         if (queue->tq_spin)
 365                                 flags |= C_DIRECT_EXEC;
 366                         callout_reset_sbt(&timeout_task->c, sbt, pr,
 367                             taskqueue_timeout_func, timeout_task, flags);
 368                 }
 369                 TQ_UNLOCK(queue);
 370         }
 371         return (res);
 372 }
 373
 374 int
 375 taskqueue_enqueue_timeout(struct taskqueue *queue,
 376     struct timeout_task *ttask, int ticks)
 377 {
 378
 379         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
 380             0, C_HARDCLOCK));
 381 }
 382
 383 static void
 384 taskqueue_task_nop_fn(void *context, int pending)
 385 {
 386 }
 387
 388 /*
 389  * Block until all currently queued tasks in this taskqueue
 390  * have begun execution.  Tasks queued during execution of
 391  * this function are ignored.
 392  */
 393 static int
 394 taskqueue_drain_tq_queue(struct taskqueue *queue)
 395 {
 396         struct task t_barrier;
 397
 398         if (STAILQ_EMPTY(&queue->tq_queue))
 399                 return (0);
 400
 401         /*
 402          * Enqueue our barrier after all current tasks, but with
 403          * the highest priority so that newly queued tasks cannot
 404          * pass it.  Because of the high priority, we can not use
 405          * taskqueue_enqueue_locked directly (which drops the lock
 406          * anyway) so just insert it at tail while we have the
 407          * queue lock.
 408          */
 409         TASK_INIT(&t_barrier, UCHAR_MAX, taskqueue_task_nop_fn, &t_barrier);
 410         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 411         queue->tq_hint = &t_barrier;
 412         t_barrier.ta_pending = 1;
 413
 414         /*
 415          * Once the barrier has executed, all previously queued tasks
 416          * have completed or are currently executing.
 417          */
 418         while (t_barrier.ta_pending != 0)
 419                 TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
 420         return (1);
 421 }
 422
 423 /*
 424  * Block until all currently executing tasks for this taskqueue
 425  * complete.  Tasks that begin execution during the execution
 426  * of this function are ignored.
 427  */
 428 static int
 429 taskqueue_drain_tq_active(struct taskqueue *queue)
 430 {
 431         struct taskqueue_busy *tb;
 432         u_int seq;
 433
 434         if (LIST_EMPTY(&queue->tq_active))
 435                 return (0);
 436
 437         /* Block taskq_terminate().*/
 438         queue->tq_callouts++;
 439
 440         /* Wait for any active task with sequence from the past. */
 441         seq = queue->tq_seq;
 442 restart:
 443         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 444                 if ((int)(tb->tb_seq - seq) <= 0) {
 445                         TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
 446                         goto restart;
 447                 }
 448         }
 449
 450         /* Release taskqueue_terminate(). */
 451         queue->tq_callouts--;
 452         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 453                 wakeup_one(queue->tq_threads);
 454         return (1);
 455 }
 456
 457 void
 458 taskqueue_block(struct taskqueue *queue)
 459 {
 460
 461         TQ_LOCK(queue);
 462         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 463         TQ_UNLOCK(queue);
 464 }
 465
 466 void
 467 taskqueue_unblock(struct taskqueue *queue)
 468 {
 469
 470         TQ_LOCK(queue);
 471         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 472         if (!STAILQ_EMPTY(&queue->tq_queue))
 473                 queue->tq_enqueue(queue->tq_context);
 474         TQ_UNLOCK(queue);
 475 }
 476
 477 static void
 478 taskqueue_run_locked(struct taskqueue *queue)
 479 {
 480         struct epoch_tracker et;
 481         struct taskqueue_busy tb;
 482         struct task *task;
 483         bool in_net_epoch;
 484         int pending;
 485
 486         KASSERT(queue != NULL, ("tq is NULL"));
 487         TQ_ASSERT_LOCKED(queue);
 488         tb.tb_running = NULL;
 489         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
 490         in_net_epoch = false;
 491
 492         while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
 493                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 494                 if (queue->tq_hint == task)
 495                         queue->tq_hint = NULL;
 496                 pending = task->ta_pending;
 497                 task->ta_pending = 0;
 498                 tb.tb_running = task;
 499                 tb.tb_seq = ++queue->tq_seq;
 500                 tb.tb_canceling = false;
 501                 TQ_UNLOCK(queue);
 502
 503                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
 504                 if (!in_net_epoch && TASK_IS_NET(task)) {
 505                         in_net_epoch = true;
 506                         NET_EPOCH_ENTER(et);
 507                 } else if (in_net_epoch && !TASK_IS_NET(task)) {
 508                         NET_EPOCH_EXIT(et);
 509                         in_net_epoch = false;
 510                 }
 511                 task->ta_func(task->ta_context, pending);
 512
 513                 TQ_LOCK(queue);
 514                 wakeup(task);
 515         }
 516         if (in_net_epoch)
 517                 NET_EPOCH_EXIT(et);
 518         LIST_REMOVE(&tb, tb_link);
 519 }
 520
 521 void
 522 taskqueue_run(struct taskqueue *queue)
 523 {
 524
 525         TQ_LOCK(queue);
 526         taskqueue_run_locked(queue);
 527         TQ_UNLOCK(queue);
 528 }
 529
 530 /*
 531  * Only use this function in single threaded contexts. It returns
 532  * non-zero if the given task is either pending or running. Else the
 533  * task is idle and can be queued again or freed.
 534  */
 535 int
 536 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 537 {
 538         int retval;
 539
 540         TQ_LOCK(queue);
 541         retval = task->ta_pending > 0 || task_get_busy(queue, task) != NULL;
 542         TQ_UNLOCK(queue);
 543
 544         return (retval);
 545 }
 546
 547 static int
 548 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 549     u_int *pendp)
 550 {
 551         struct taskqueue_busy *tb;
 552         int retval = 0;
 553
 554         if (task->ta_pending > 0) {
 555                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 556                 if (queue->tq_hint == task)
 557                         queue->tq_hint = NULL;
 558         }
 559         if (pendp != NULL)
 560                 *pendp = task->ta_pending;
 561         task->ta_pending = 0;
 562         tb = task_get_busy(queue, task);
 563         if (tb != NULL) {
 564                 tb->tb_canceling = true;
 565                 retval = EBUSY;
 566         }
 567
 568         return (retval);
 569 }
 570
 571 int
 572 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 573 {
 574         int error;
 575
 576         TQ_LOCK(queue);
 577         error = taskqueue_cancel_locked(queue, task, pendp);
 578         TQ_UNLOCK(queue);
 579
 580         return (error);
 581 }
 582
 583 int
 584 taskqueue_cancel_timeout(struct taskqueue *queue,
 585     struct timeout_task *timeout_task, u_int *pendp)
 586 {
 587         u_int pending, pending1;
 588         int error;
 589
 590         TQ_LOCK(queue);
 591         pending = !!(callout_stop(&timeout_task->c) > 0);
 592         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 593         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 594                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 595                 queue->tq_callouts--;
 596         }
 597         TQ_UNLOCK(queue);
 598
 599         if (pendp != NULL)
 600                 *pendp = pending + pending1;
 601         return (error);
 602 }
 603
 604 void
 605 taskqueue_drain(struct taskqueue *queue, struct task *task)
 606 {
 607
 608         if (!queue->tq_spin)
 609                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 610
 611         TQ_LOCK(queue);
 612         while (task->ta_pending != 0 || task_get_busy(queue, task) != NULL)
 613                 TQ_SLEEP(queue, task, "tq_drain");
 614         TQ_UNLOCK(queue);
 615 }
 616
 617 void
 618 taskqueue_drain_all(struct taskqueue *queue)
 619 {
 620
 621         if (!queue->tq_spin)
 622                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 623
 624         TQ_LOCK(queue);
 625         (void)taskqueue_drain_tq_queue(queue);
 626         (void)taskqueue_drain_tq_active(queue);
 627         TQ_UNLOCK(queue);
 628 }
 629
 630 void
 631 taskqueue_drain_timeout(struct taskqueue *queue,
 632     struct timeout_task *timeout_task)
 633 {
 634
 635         /*
 636          * Set flag to prevent timer from re-starting during drain:
 637          */
 638         TQ_LOCK(queue);
 639         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 640             ("Drain already in progress"));
 641         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 642         TQ_UNLOCK(queue);
 643
 644         callout_drain(&timeout_task->c);
 645         taskqueue_drain(queue, &timeout_task->t);
 646
 647         /*
 648          * Clear flag to allow timer to re-start:
 649          */
 650         TQ_LOCK(queue);
 651         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 652         TQ_UNLOCK(queue);
 653 }
 654
 655 void
 656 taskqueue_quiesce(struct taskqueue *queue)
 657 {
 658         int ret;
 659
 660         TQ_LOCK(queue);
 661         do {
 662                 ret = taskqueue_drain_tq_queue(queue);
 663                 if (ret == 0)
 664                         ret = taskqueue_drain_tq_active(queue);
 665         } while (ret != 0);
 666         TQ_UNLOCK(queue);
 667 }
 668
 669 static void
 670 taskqueue_swi_enqueue(void *context)
 671 {
 672         swi_sched(taskqueue_ih, 0);
 673 }
 674
 675 static void
 676 taskqueue_swi_run(void *dummy)
 677 {
 678         taskqueue_run(taskqueue_swi);
 679 }
 680
 681 static void
 682 taskqueue_swi_giant_enqueue(void *context)
 683 {
 684         swi_sched(taskqueue_giant_ih, 0);
 685 }
 686
 687 static void
 688 taskqueue_swi_giant_run(void *dummy)
 689 {
 690         taskqueue_run(taskqueue_swi_giant);
 691 }
 692
 693 static int
 694 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 695     cpuset_t *mask, struct proc *p, const char *name, va_list ap)
 696 {
 697         char ktname[MAXCOMLEN + 1];
 698         struct thread *td;
 699         struct taskqueue *tq;
 700         int i, error;
 701
 702         if (count <= 0)
 703                 return (EINVAL);
 704
 705         vsnprintf(ktname, sizeof(ktname), name, ap);
 706         tq = *tqp;
 707
 708         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 709             M_NOWAIT | M_ZERO);
 710         if (tq->tq_threads == NULL) {
 711                 printf("%s: no memory for %s threads\n", __func__, ktname);
 712                 return (ENOMEM);
 713         }
 714
 715         for (i = 0; i < count; i++) {
 716                 if (count == 1)
 717                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 718                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 719                 else
 720                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 721                             &tq->tq_threads[i], RFSTOPPED, 0,
 722                             "%s_%d", ktname, i);
 723                 if (error) {
 724                         /* should be ok to continue, taskqueue_free will dtrt */
 725                         printf("%s: kthread_add(%s): error %d", __func__,
 726                             ktname, error);
 727                         tq->tq_threads[i] = NULL;               /* paranoid */
 728                 } else
 729                         tq->tq_tcount++;
 730         }
 731         if (tq->tq_tcount == 0) {
 732                 free(tq->tq_threads, M_TASKQUEUE);
 733                 tq->tq_threads = NULL;
 734                 return (ENOMEM);
 735         }
 736         for (i = 0; i < count; i++) {
 737                 if (tq->tq_threads[i] == NULL)
 738                         continue;
 739                 td = tq->tq_threads[i];
 740                 if (mask) {
 741                         error = cpuset_setthread(td->td_tid, mask);
 742                         /*
 743                          * Failing to pin is rarely an actual fatal error;
 744                          * it'll just affect performance.
 745                          */
 746                         if (error)
 747                                 printf("%s: curthread=%llu: can't pin; "
 748                                     "error=%d\n",
 749                                     __func__,
 750                                     (unsigned long long) td->td_tid,
 751                                     error);
 752                 }
 753                 thread_lock(td);
 754                 sched_prio(td, pri);
 755                 sched_add(td, SRQ_BORING);
 756         }
 757
 758         return (0);
 759 }
 760
 761 int
 762 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 763     const char *name, ...)
 764 {
 765         va_list ap;
 766         int error;
 767
 768         va_start(ap, name);
 769         error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
 770         va_end(ap);
 771         return (error);
 772 }
 773
 774 int
 775 taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
 776     struct proc *proc, const char *name, ...)
 777 {
 778         va_list ap;
 779         int error;
 780
 781         va_start(ap, name);
 782         error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
 783         va_end(ap);
 784         return (error);
 785 }
 786
 787 int
 788 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 789     cpuset_t *mask, const char *name, ...)
 790 {
 791         va_list ap;
 792         int error;
 793
 794         va_start(ap, name);
 795         error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
 796         va_end(ap);
 797         return (error);
 798 }
 799
 800 static inline void
 801 taskqueue_run_callback(struct taskqueue *tq,
 802     enum taskqueue_callback_type cb_type)
 803 {
 804         taskqueue_callback_fn tq_callback;
 805
 806         TQ_ASSERT_UNLOCKED(tq);
 807         tq_callback = tq->tq_callbacks[cb_type];
 808         if (tq_callback != NULL)
 809                 tq_callback(tq->tq_cb_contexts[cb_type]);
 810 }
 811
 812 void
 813 taskqueue_thread_loop(void *arg)
 814 {
 815         struct taskqueue **tqp, *tq;
 816
 817         tqp = arg;
 818         tq = *tqp;
 819         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 820         TQ_LOCK(tq);
 821         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 822                 /* XXX ? */
 823                 taskqueue_run_locked(tq);
 824                 /*
 825                  * Because taskqueue_run() can drop tq_mutex, we need to
 826                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 827                  * meantime, which means we missed a wakeup.
 828                  */
 829                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 830                         break;
 831                 TQ_SLEEP(tq, tq, "-");
 832         }
 833         taskqueue_run_locked(tq);
 834         /*
 835          * This thread is on its way out, so just drop the lock temporarily
 836          * in order to call the shutdown callback.  This allows the callback
 837          * to look at the taskqueue, even just before it dies.
 838          */
 839         TQ_UNLOCK(tq);
 840         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 841         TQ_LOCK(tq);
 842
 843         /* rendezvous with thread that asked us to terminate */
 844         tq->tq_tcount--;
 845         wakeup_one(tq->tq_threads);
 846         TQ_UNLOCK(tq);
 847         kthread_exit();
 848 }
 849
 850 void
 851 taskqueue_thread_enqueue(void *context)
 852 {
 853         struct taskqueue **tqp, *tq;
 854
 855         tqp = context;
 856         tq = *tqp;
 857         wakeup_any(tq);
 858 }
 859
 860 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 861                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 862                      INTR_MPSAFE, &taskqueue_ih));
 863
 864 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 865                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 866                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 867
 868 TASKQUEUE_DEFINE_THREAD(thread);
 869
 870 struct taskqueue *
 871 taskqueue_create_fast(const char *name, int mflags,
 872                  taskqueue_enqueue_fn enqueue, void *context)
 873 {
 874         return _taskqueue_create(name, mflags, enqueue, context,
 875                         MTX_SPIN, "fast_taskqueue");
 876 }
 877
 878 static void     *taskqueue_fast_ih;
 879
 880 static void
 881 taskqueue_fast_enqueue(void *context)
 882 {
 883         swi_sched(taskqueue_fast_ih, 0);
 884 }
 885
 886 static void
 887 taskqueue_fast_run(void *dummy)
 888 {
 889         taskqueue_run(taskqueue_fast);
 890 }
 891
 892 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 893         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 894         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 895
 896 int
 897 taskqueue_member(struct taskqueue *queue, struct thread *td)
 898 {
 899         int i, j, ret = 0;
 900
 901         for (i = 0, j = 0; ; i++) {
 902                 if (queue->tq_threads[i] == NULL)
 903                         continue;
 904                 if (queue->tq_threads[i] == td) {
 905                         ret = 1;
 906                         break;
 907                 }
 908                 if (++j >= queue->tq_tcount)
 909                         break;
 910         }
 911         return (ret);
 912 }