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/cdefs.h>
  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/epoch.h>
  44 #include <sys/sched.h>
  45 #include <sys/smp.h>
  46 #include <sys/taskqueue.h>
  47 #include <sys/unistd.h>
  48 #include <machine/stdarg.h>
  49
  50 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  51 static void     *taskqueue_giant_ih;
  52 static void     *taskqueue_ih;
  53 static void      taskqueue_fast_enqueue(void *);
  54 static void      taskqueue_swi_enqueue(void *);
  55 static void      taskqueue_swi_giant_enqueue(void *);
  56
  57 struct taskqueue_busy {
  58         struct task             *tb_running;
  59         u_int                    tb_seq;
  60         bool                     tb_canceling;
  61         LIST_ENTRY(taskqueue_busy) tb_link;
  62 };
  63
  64 struct taskqueue {
  65         STAILQ_HEAD(, task)     tq_queue;
  66         LIST_HEAD(, taskqueue_busy) tq_active;
  67         struct task             *tq_hint;
  68         u_int                   tq_seq;
  69         int                     tq_callouts;
  70         struct mtx_padalign     tq_mutex;
  71         taskqueue_enqueue_fn    tq_enqueue;
  72         void                    *tq_context;
  73         char                    *tq_name;
  74         struct thread           **tq_threads;
  75         int                     tq_tcount;
  76         int                     tq_spin;
  77         int                     tq_flags;
  78         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  79         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  80 };
  81
  82 #define TQ_FLAGS_ACTIVE         (1 << 0)
  83 #define TQ_FLAGS_BLOCKED        (1 << 1)
  84 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  85
  86 #define DT_CALLOUT_ARMED        (1 << 0)
  87 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  88
  89 #define TQ_LOCK(tq)                                                     \
  90         do {                                                            \
  91                 if ((tq)->tq_spin)                                      \
  92                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  93                 else                                                    \
  94                         mtx_lock(&(tq)->tq_mutex);                      \
  95         } while (0)
  96 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  97
  98 #define TQ_UNLOCK(tq)                                                   \
  99         do {                                                            \
 100                 if ((tq)->tq_spin)                                      \
 101                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 102                 else                                                    \
 103                         mtx_unlock(&(tq)->tq_mutex);                    \
 104         } while (0)
 105 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 106
 107 void
 108 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 109     int priority, task_fn_t func, void *context)
 110 {
 111
 112         TASK_INIT(&timeout_task->t, priority, func, context);
 113         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 114             CALLOUT_RETURNUNLOCKED);
 115         timeout_task->q = queue;
 116         timeout_task->f = 0;
 117 }
 118
 119 static __inline int
 120 TQ_SLEEP(struct taskqueue *tq, void *p, const char *wm)
 121 {
 122         if (tq->tq_spin)
 123                 return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
 124         return (msleep(p, &tq->tq_mutex, 0, wm, 0));
 125 }
 126
 127 static struct taskqueue_busy *
 128 task_get_busy(struct taskqueue *queue, struct task *task)
 129 {
 130         struct taskqueue_busy *tb;
 131
 132         TQ_ASSERT_LOCKED(queue);
 133         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 134                 if (tb->tb_running == task)
 135                         return (tb);
 136         }
 137         return (NULL);
 138 }
 139
 140 static struct taskqueue *
 141 _taskqueue_create(const char *name, int mflags,
 142                  taskqueue_enqueue_fn enqueue, void *context,
 143                  int mtxflags, const char *mtxname __unused)
 144 {
 145         struct taskqueue *queue;
 146         char *tq_name;
 147
 148         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
 149         if (tq_name == NULL)
 150                 return (NULL);
 151
 152         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 153         if (queue == NULL) {
 154                 free(tq_name, M_TASKQUEUE);
 155                 return (NULL);
 156         }
 157
 158         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 159
 160         STAILQ_INIT(&queue->tq_queue);
 161         LIST_INIT(&queue->tq_active);
 162         queue->tq_enqueue = enqueue;
 163         queue->tq_context = context;
 164         queue->tq_name = tq_name;
 165         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 166         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 167         if (enqueue == taskqueue_fast_enqueue ||
 168             enqueue == taskqueue_swi_enqueue ||
 169             enqueue == taskqueue_swi_giant_enqueue ||
 170             enqueue == taskqueue_thread_enqueue)
 171                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 172         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 173
 174         return (queue);
 175 }
 176
 177 struct taskqueue *
 178 taskqueue_create(const char *name, int mflags,
 179                  taskqueue_enqueue_fn enqueue, void *context)
 180 {
 181
 182         return _taskqueue_create(name, mflags, enqueue, context,
 183                         MTX_DEF, name);
 184 }
 185
 186 void
 187 taskqueue_set_callback(struct taskqueue *queue,
 188     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 189     void *context)
 190 {
 191
 192         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 193             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 194             ("Callback type %d not valid, must be %d-%d", cb_type,
 195             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 196         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 197             ("Re-initialization of taskqueue callback?"));
 198
 199         queue->tq_callbacks[cb_type] = callback;
 200         queue->tq_cb_contexts[cb_type] = context;
 201 }
 202
 203 /*
 204  * Signal a taskqueue thread to terminate.
 205  */
 206 static void
 207 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 208 {
 209
 210         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 211                 wakeup(tq);
 212                 TQ_SLEEP(tq, pp, "tq_destroy");
 213         }
 214 }
 215
 216 void
 217 taskqueue_free(struct taskqueue *queue)
 218 {
 219
 220         TQ_LOCK(queue);
 221         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 222         taskqueue_terminate(queue->tq_threads, queue);
 223         KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
 224         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 225         mtx_destroy(&queue->tq_mutex);
 226         free(queue->tq_threads, M_TASKQUEUE);
 227         free(queue->tq_name, M_TASKQUEUE);
 228         free(queue, M_TASKQUEUE);
 229 }
 230
 231 static int
 232 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task, int flags)
 233 {
 234         struct task *ins;
 235         struct task *prev;
 236         struct taskqueue_busy *tb;
 237
 238         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
 239         /*
 240          * Ignore canceling task if requested.
 241          */
 242         if (__predict_false((flags & TASKQUEUE_FAIL_IF_CANCELING) != 0)) {
 243                 tb = task_get_busy(queue, task);
 244                 if (tb != NULL && tb->tb_canceling) {
 245                         TQ_UNLOCK(queue);
 246                         return (ECANCELED);
 247                 }
 248         }
 249
 250         /*
 251          * Count multiple enqueues.
 252          */
 253         if (task->ta_pending) {
 254                 if (__predict_false((flags & TASKQUEUE_FAIL_IF_PENDING) != 0)) {
 255                         TQ_UNLOCK(queue);
 256                         return (EEXIST);
 257                 }
 258                 if (task->ta_pending < USHRT_MAX)
 259                         task->ta_pending++;
 260                 TQ_UNLOCK(queue);
 261                 return (0);
 262         }
 263
 264         /*
 265          * Optimise cases when all tasks use small set of priorities.
 266          * In case of only one priority we always insert at the end.
 267          * In case of two tq_hint typically gives the insertion point.
 268          * In case of more then two tq_hint should halve the search.
 269          */
 270         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 271         if (!prev || prev->ta_priority >= task->ta_priority) {
 272                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 273         } else {
 274                 prev = queue->tq_hint;
 275                 if (prev && prev->ta_priority >= task->ta_priority) {
 276                         ins = STAILQ_NEXT(prev, ta_link);
 277                 } else {
 278                         prev = NULL;
 279                         ins = STAILQ_FIRST(&queue->tq_queue);
 280                 }
 281                 for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 282                         if (ins->ta_priority < task->ta_priority)
 283                                 break;
 284
 285                 if (prev) {
 286                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 287                         queue->tq_hint = task;
 288                 } else
 289                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 290         }
 291
 292         task->ta_pending = 1;
 293         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 294                 TQ_UNLOCK(queue);
 295         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 296                 queue->tq_enqueue(queue->tq_context);
 297         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 298                 TQ_UNLOCK(queue);
 299
 300         /* Return with lock released. */
 301         return (0);
 302 }
 303
 304 int
 305 taskqueue_enqueue_flags(struct taskqueue *queue, struct task *task, int flags)
 306 {
 307         int res;
 308
 309         TQ_LOCK(queue);
 310         res = taskqueue_enqueue_locked(queue, task, flags);
 311         /* The lock is released inside. */
 312
 313         return (res);
 314 }
 315
 316 int
 317 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 318 {
 319         return (taskqueue_enqueue_flags(queue, task, 0));
 320 }
 321
 322 static void
 323 taskqueue_timeout_func(void *arg)
 324 {
 325         struct taskqueue *queue;
 326         struct timeout_task *timeout_task;
 327
 328         timeout_task = arg;
 329         queue = timeout_task->q;
 330         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 331         timeout_task->f &= ~DT_CALLOUT_ARMED;
 332         queue->tq_callouts--;
 333         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t, 0);
 334         /* The lock is released inside. */
 335 }
 336
 337 int
 338 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
 339     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
 340 {
 341         int res;
 342
 343         TQ_LOCK(queue);
 344         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 345             ("Migrated queue"));
 346         timeout_task->q = queue;
 347         res = timeout_task->t.ta_pending;
 348         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 349                 /* Do nothing */
 350                 TQ_UNLOCK(queue);
 351                 res = -1;
 352         } else if (sbt == 0) {
 353                 taskqueue_enqueue_locked(queue, &timeout_task->t, 0);
 354                 /* The lock is released inside. */
 355         } else {
 356                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 357                         res++;
 358                 } else {
 359                         queue->tq_callouts++;
 360                         timeout_task->f |= DT_CALLOUT_ARMED;
 361                         if (sbt < 0)
 362                                 sbt = -sbt; /* Ignore overflow. */
 363                 }
 364                 if (sbt > 0) {
 365                         if (queue->tq_spin)
 366                                 flags |= C_DIRECT_EXEC;
 367                         callout_reset_sbt(&timeout_task->c, sbt, pr,
 368                             taskqueue_timeout_func, timeout_task, flags);
 369                 }
 370                 TQ_UNLOCK(queue);
 371         }
 372         return (res);
 373 }
 374
 375 int
 376 taskqueue_enqueue_timeout(struct taskqueue *queue,
 377     struct timeout_task *ttask, int ticks)
 378 {
 379
 380         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
 381             0, C_HARDCLOCK));
 382 }
 383
 384 static void
 385 taskqueue_task_nop_fn(void *context, int pending)
 386 {
 387 }
 388
 389 /*
 390  * Block until all currently queued tasks in this taskqueue
 391  * have begun execution.  Tasks queued during execution of
 392  * this function are ignored.
 393  */
 394 static int
 395 taskqueue_drain_tq_queue(struct taskqueue *queue)
 396 {
 397         struct task t_barrier;
 398
 399         if (STAILQ_EMPTY(&queue->tq_queue))
 400                 return (0);
 401
 402         /*
 403          * Enqueue our barrier after all current tasks, but with
 404          * the highest priority so that newly queued tasks cannot
 405          * pass it.  Because of the high priority, we can not use
 406          * taskqueue_enqueue_locked directly (which drops the lock
 407          * anyway) so just insert it at tail while we have the
 408          * queue lock.
 409          */
 410         TASK_INIT(&t_barrier, UCHAR_MAX, taskqueue_task_nop_fn, &t_barrier);
 411         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 412         queue->tq_hint = &t_barrier;
 413         t_barrier.ta_pending = 1;
 414
 415         /*
 416          * Once the barrier has executed, all previously queued tasks
 417          * have completed or are currently executing.
 418          */
 419         while (t_barrier.ta_pending != 0)
 420                 TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
 421         return (1);
 422 }
 423
 424 /*
 425  * Block until all currently executing tasks for this taskqueue
 426  * complete.  Tasks that begin execution during the execution
 427  * of this function are ignored.
 428  */
 429 static int
 430 taskqueue_drain_tq_active(struct taskqueue *queue)
 431 {
 432         struct taskqueue_busy *tb;
 433         u_int seq;
 434
 435         if (LIST_EMPTY(&queue->tq_active))
 436                 return (0);
 437
 438         /* Block taskq_terminate().*/
 439         queue->tq_callouts++;
 440
 441         /* Wait for any active task with sequence from the past. */
 442         seq = queue->tq_seq;
 443 restart:
 444         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 445                 if ((int)(tb->tb_seq - seq) <= 0) {
 446                         TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
 447                         goto restart;
 448                 }
 449         }
 450
 451         /* Release taskqueue_terminate(). */
 452         queue->tq_callouts--;
 453         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 454                 wakeup_one(queue->tq_threads);
 455         return (1);
 456 }
 457
 458 void
 459 taskqueue_block(struct taskqueue *queue)
 460 {
 461
 462         TQ_LOCK(queue);
 463         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 464         TQ_UNLOCK(queue);
 465 }
 466
 467 void
 468 taskqueue_unblock(struct taskqueue *queue)
 469 {
 470
 471         TQ_LOCK(queue);
 472         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 473         if (!STAILQ_EMPTY(&queue->tq_queue))
 474                 queue->tq_enqueue(queue->tq_context);
 475         TQ_UNLOCK(queue);
 476 }
 477
 478 static void
 479 taskqueue_run_locked(struct taskqueue *queue)
 480 {
 481         struct epoch_tracker et;
 482         struct taskqueue_busy tb;
 483         struct task *task;
 484         bool in_net_epoch;
 485         int pending;
 486
 487         KASSERT(queue != NULL, ("tq is NULL"));
 488         TQ_ASSERT_LOCKED(queue);
 489         tb.tb_running = NULL;
 490         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
 491         in_net_epoch = false;
 492
 493         while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
 494                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 495                 if (queue->tq_hint == task)
 496                         queue->tq_hint = NULL;
 497                 pending = task->ta_pending;
 498                 task->ta_pending = 0;
 499                 tb.tb_running = task;
 500                 tb.tb_seq = ++queue->tq_seq;
 501                 tb.tb_canceling = false;
 502                 TQ_UNLOCK(queue);
 503
 504                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
 505                 if (!in_net_epoch && TASK_IS_NET(task)) {
 506                         in_net_epoch = true;
 507                         NET_EPOCH_ENTER(et);
 508                 } else if (in_net_epoch && !TASK_IS_NET(task)) {
 509                         NET_EPOCH_EXIT(et);
 510                         in_net_epoch = false;
 511                 }
 512                 task->ta_func(task->ta_context, pending);
 513
 514                 TQ_LOCK(queue);
 515                 wakeup(task);
 516         }
 517         if (in_net_epoch)
 518                 NET_EPOCH_EXIT(et);
 519         LIST_REMOVE(&tb, tb_link);
 520 }
 521
 522 void
 523 taskqueue_run(struct taskqueue *queue)
 524 {
 525
 526         TQ_LOCK(queue);
 527         taskqueue_run_locked(queue);
 528         TQ_UNLOCK(queue);
 529 }
 530
 531 /*
 532  * Only use this function in single threaded contexts. It returns
 533  * non-zero if the given task is either pending or running. Else the
 534  * task is idle and can be queued again or freed.
 535  */
 536 int
 537 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 538 {
 539         int retval;
 540
 541         TQ_LOCK(queue);
 542         retval = task->ta_pending > 0 || task_get_busy(queue, task) != NULL;
 543         TQ_UNLOCK(queue);
 544
 545         return (retval);
 546 }
 547
 548 static int
 549 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 550     u_int *pendp)
 551 {
 552         struct taskqueue_busy *tb;
 553         int retval = 0;
 554
 555         if (task->ta_pending > 0) {
 556                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 557                 if (queue->tq_hint == task)
 558                         queue->tq_hint = NULL;
 559         }
 560         if (pendp != NULL)
 561                 *pendp = task->ta_pending;
 562         task->ta_pending = 0;
 563         tb = task_get_busy(queue, task);
 564         if (tb != NULL) {
 565                 tb->tb_canceling = true;
 566                 retval = EBUSY;
 567         }
 568
 569         return (retval);
 570 }
 571
 572 int
 573 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 574 {
 575         int error;
 576
 577         TQ_LOCK(queue);
 578         error = taskqueue_cancel_locked(queue, task, pendp);
 579         TQ_UNLOCK(queue);
 580
 581         return (error);
 582 }
 583
 584 int
 585 taskqueue_cancel_timeout(struct taskqueue *queue,
 586     struct timeout_task *timeout_task, u_int *pendp)
 587 {
 588         u_int pending, pending1;
 589         int error;
 590
 591         TQ_LOCK(queue);
 592         pending = !!(callout_stop(&timeout_task->c) > 0);
 593         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 594         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 595                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 596                 queue->tq_callouts--;
 597         }
 598         TQ_UNLOCK(queue);
 599
 600         if (pendp != NULL)
 601                 *pendp = pending + pending1;
 602         return (error);
 603 }
 604
 605 void
 606 taskqueue_drain(struct taskqueue *queue, struct task *task)
 607 {
 608
 609         if (!queue->tq_spin)
 610                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 611
 612         TQ_LOCK(queue);
 613         while (task->ta_pending != 0 || task_get_busy(queue, task) != NULL)
 614                 TQ_SLEEP(queue, task, "tq_drain");
 615         TQ_UNLOCK(queue);
 616 }
 617
 618 void
 619 taskqueue_drain_all(struct taskqueue *queue)
 620 {
 621
 622         if (!queue->tq_spin)
 623                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 624
 625         TQ_LOCK(queue);
 626         (void)taskqueue_drain_tq_queue(queue);
 627         (void)taskqueue_drain_tq_active(queue);
 628         TQ_UNLOCK(queue);
 629 }
 630
 631 void
 632 taskqueue_drain_timeout(struct taskqueue *queue,
 633     struct timeout_task *timeout_task)
 634 {
 635
 636         /*
 637          * Set flag to prevent timer from re-starting during drain:
 638          */
 639         TQ_LOCK(queue);
 640         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 641             ("Drain already in progress"));
 642         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 643         TQ_UNLOCK(queue);
 644
 645         callout_drain(&timeout_task->c);
 646         taskqueue_drain(queue, &timeout_task->t);
 647
 648         /*
 649          * Clear flag to allow timer to re-start:
 650          */
 651         TQ_LOCK(queue);
 652         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 653         TQ_UNLOCK(queue);
 654 }
 655
 656 void
 657 taskqueue_quiesce(struct taskqueue *queue)
 658 {
 659         int ret;
 660
 661         TQ_LOCK(queue);
 662         do {
 663                 ret = taskqueue_drain_tq_queue(queue);
 664                 if (ret == 0)
 665                         ret = taskqueue_drain_tq_active(queue);
 666         } while (ret != 0);
 667         TQ_UNLOCK(queue);
 668 }
 669
 670 static void
 671 taskqueue_swi_enqueue(void *context)
 672 {
 673         swi_sched(taskqueue_ih, 0);
 674 }
 675
 676 static void
 677 taskqueue_swi_run(void *dummy)
 678 {
 679         taskqueue_run(taskqueue_swi);
 680 }
 681
 682 static void
 683 taskqueue_swi_giant_enqueue(void *context)
 684 {
 685         swi_sched(taskqueue_giant_ih, 0);
 686 }
 687
 688 static void
 689 taskqueue_swi_giant_run(void *dummy)
 690 {
 691         taskqueue_run(taskqueue_swi_giant);
 692 }
 693
 694 static int
 695 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 696     cpuset_t *mask, struct proc *p, const char *name, va_list ap)
 697 {
 698         char ktname[MAXCOMLEN + 1];
 699         struct thread *td;
 700         struct taskqueue *tq;
 701         int i, error;
 702
 703         if (count <= 0)
 704                 return (EINVAL);
 705
 706         vsnprintf(ktname, sizeof(ktname), name, ap);
 707         tq = *tqp;
 708
 709         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 710             M_NOWAIT | M_ZERO);
 711         if (tq->tq_threads == NULL) {
 712                 printf("%s: no memory for %s threads\n", __func__, ktname);
 713                 return (ENOMEM);
 714         }
 715
 716         for (i = 0; i < count; i++) {
 717                 if (count == 1)
 718                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 719                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 720                 else
 721                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 722                             &tq->tq_threads[i], RFSTOPPED, 0,
 723                             "%s_%d", ktname, i);
 724                 if (error) {
 725                         /* should be ok to continue, taskqueue_free will dtrt */
 726                         printf("%s: kthread_add(%s): error %d", __func__,
 727                             ktname, error);
 728                         tq->tq_threads[i] = NULL;               /* paranoid */
 729                 } else
 730                         tq->tq_tcount++;
 731         }
 732         if (tq->tq_tcount == 0) {
 733                 free(tq->tq_threads, M_TASKQUEUE);
 734                 tq->tq_threads = NULL;
 735                 return (ENOMEM);
 736         }
 737         for (i = 0; i < count; i++) {
 738                 if (tq->tq_threads[i] == NULL)
 739                         continue;
 740                 td = tq->tq_threads[i];
 741                 if (mask) {
 742                         error = cpuset_setthread(td->td_tid, mask);
 743                         /*
 744                          * Failing to pin is rarely an actual fatal error;
 745                          * it'll just affect performance.
 746                          */
 747                         if (error)
 748                                 printf("%s: curthread=%llu: can't pin; "
 749                                     "error=%d\n",
 750                                     __func__,
 751                                     (unsigned long long) td->td_tid,
 752                                     error);
 753                 }
 754                 thread_lock(td);
 755                 sched_prio(td, pri);
 756                 sched_add(td, SRQ_BORING);
 757         }
 758
 759         return (0);
 760 }
 761
 762 int
 763 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 764     const char *name, ...)
 765 {
 766         va_list ap;
 767         int error;
 768
 769         va_start(ap, name);
 770         error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
 771         va_end(ap);
 772         return (error);
 773 }
 774
 775 int
 776 taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
 777     struct proc *proc, const char *name, ...)
 778 {
 779         va_list ap;
 780         int error;
 781
 782         va_start(ap, name);
 783         error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
 784         va_end(ap);
 785         return (error);
 786 }
 787
 788 int
 789 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 790     cpuset_t *mask, const char *name, ...)
 791 {
 792         va_list ap;
 793         int error;
 794
 795         va_start(ap, name);
 796         error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
 797         va_end(ap);
 798         return (error);
 799 }
 800
 801 static inline void
 802 taskqueue_run_callback(struct taskqueue *tq,
 803     enum taskqueue_callback_type cb_type)
 804 {
 805         taskqueue_callback_fn tq_callback;
 806
 807         TQ_ASSERT_UNLOCKED(tq);
 808         tq_callback = tq->tq_callbacks[cb_type];
 809         if (tq_callback != NULL)
 810                 tq_callback(tq->tq_cb_contexts[cb_type]);
 811 }
 812
 813 void
 814 taskqueue_thread_loop(void *arg)
 815 {
 816         struct taskqueue **tqp, *tq;
 817
 818         tqp = arg;
 819         tq = *tqp;
 820         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 821         TQ_LOCK(tq);
 822         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 823                 /* XXX ? */
 824                 taskqueue_run_locked(tq);
 825                 /*
 826                  * Because taskqueue_run() can drop tq_mutex, we need to
 827                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 828                  * meantime, which means we missed a wakeup.
 829                  */
 830                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 831                         break;
 832                 TQ_SLEEP(tq, tq, "-");
 833         }
 834         taskqueue_run_locked(tq);
 835         /*
 836          * This thread is on its way out, so just drop the lock temporarily
 837          * in order to call the shutdown callback.  This allows the callback
 838          * to look at the taskqueue, even just before it dies.
 839          */
 840         TQ_UNLOCK(tq);
 841         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 842         TQ_LOCK(tq);
 843
 844         /* rendezvous with thread that asked us to terminate */
 845         tq->tq_tcount--;
 846         wakeup_one(tq->tq_threads);
 847         TQ_UNLOCK(tq);
 848         kthread_exit();
 849 }
 850
 851 void
 852 taskqueue_thread_enqueue(void *context)
 853 {
 854         struct taskqueue **tqp, *tq;
 855
 856         tqp = context;
 857         tq = *tqp;
 858         wakeup_any(tq);
 859 }
 860
 861 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 862                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 863                      INTR_MPSAFE, &taskqueue_ih));
 864
 865 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 866                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 867                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 868
 869 TASKQUEUE_DEFINE_THREAD(thread);
 870
 871 struct taskqueue *
 872 taskqueue_create_fast(const char *name, int mflags,
 873                  taskqueue_enqueue_fn enqueue, void *context)
 874 {
 875         return _taskqueue_create(name, mflags, enqueue, context,
 876                         MTX_SPIN, "fast_taskqueue");
 877 }
 878
 879 static void     *taskqueue_fast_ih;
 880
 881 static void
 882 taskqueue_fast_enqueue(void *context)
 883 {
 884         swi_sched(taskqueue_fast_ih, 0);
 885 }
 886
 887 static void
 888 taskqueue_fast_run(void *dummy)
 889 {
 890         taskqueue_run(taskqueue_fast);
 891 }
 892
 893 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 894         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 895         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 896
 897 int
 898 taskqueue_member(struct taskqueue *queue, struct thread *td)
 899 {
 900         int i, j, ret = 0;
 901
 902         for (i = 0, j = 0; ; i++) {
 903                 if (queue->tq_threads[i] == NULL)
 904                         continue;
 905                 if (queue->tq_threads[i] == td) {
 906                         ret = 1;
 907                         break;
 908                 }
 909                 if (++j >= queue->tq_tcount)
 910                         break;
 911         }
 912         return (ret);
 913 }