sys/kern/subr_taskqueue.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   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 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/bus.h>
  35 #include <sys/cpuset.h>
  36 #include <sys/interrupt.h>
  37 #include <sys/kernel.h>
  38 #include <sys/kthread.h>
  39 #include <sys/libkern.h>
  40 #include <sys/limits.h>
  41 #include <sys/lock.h>
  42 #include <sys/malloc.h>
  43 #include <sys/mutex.h>
  44 #include <sys/proc.h>
  45 #include <sys/epoch.h>
  46 #include <sys/sched.h>
  47 #include <sys/smp.h>
  48 #include <sys/taskqueue.h>
  49 #include <sys/unistd.h>
  50 #include <machine/stdarg.h>
  51
  52 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
  53 static void     *taskqueue_giant_ih;
  54 static void     *taskqueue_ih;
  55 static void      taskqueue_fast_enqueue(void *);
  56 static void      taskqueue_swi_enqueue(void *);
  57 static void      taskqueue_swi_giant_enqueue(void *);
  58
  59 struct taskqueue_busy {
  60         struct task             *tb_running;
  61         u_int                    tb_seq;
  62         bool                     tb_canceling;
  63         LIST_ENTRY(taskqueue_busy) tb_link;
  64 };
  65
  66 struct taskqueue {
  67         STAILQ_HEAD(, task)     tq_queue;
  68         LIST_HEAD(, taskqueue_busy) tq_active;
  69         struct task             *tq_hint;
  70         u_int                   tq_seq;
  71         int                     tq_callouts;
  72         struct mtx_padalign     tq_mutex;
  73         taskqueue_enqueue_fn    tq_enqueue;
  74         void                    *tq_context;
  75         char                    *tq_name;
  76         struct thread           **tq_threads;
  77         int                     tq_tcount;
  78         int                     tq_spin;
  79         int                     tq_flags;
  80         taskqueue_callback_fn   tq_callbacks[TASKQUEUE_NUM_CALLBACKS];
  81         void                    *tq_cb_contexts[TASKQUEUE_NUM_CALLBACKS];
  82 };
  83
  84 #define TQ_FLAGS_ACTIVE         (1 << 0)
  85 #define TQ_FLAGS_BLOCKED        (1 << 1)
  86 #define TQ_FLAGS_UNLOCKED_ENQUEUE       (1 << 2)
  87
  88 #define DT_CALLOUT_ARMED        (1 << 0)
  89 #define DT_DRAIN_IN_PROGRESS    (1 << 1)
  90
  91 #define TQ_LOCK(tq)                                                     \
  92         do {                                                            \
  93                 if ((tq)->tq_spin)                                      \
  94                         mtx_lock_spin(&(tq)->tq_mutex);                 \
  95                 else                                                    \
  96                         mtx_lock(&(tq)->tq_mutex);                      \
  97         } while (0)
  98 #define TQ_ASSERT_LOCKED(tq)    mtx_assert(&(tq)->tq_mutex, MA_OWNED)
  99
 100 #define TQ_UNLOCK(tq)                                                   \
 101         do {                                                            \
 102                 if ((tq)->tq_spin)                                      \
 103                         mtx_unlock_spin(&(tq)->tq_mutex);               \
 104                 else                                                    \
 105                         mtx_unlock(&(tq)->tq_mutex);                    \
 106         } while (0)
 107 #define TQ_ASSERT_UNLOCKED(tq)  mtx_assert(&(tq)->tq_mutex, MA_NOTOWNED)
 108
 109 void
 110 _timeout_task_init(struct taskqueue *queue, struct timeout_task *timeout_task,
 111     int priority, task_fn_t func, void *context)
 112 {
 113
 114         TASK_INIT(&timeout_task->t, priority, func, context);
 115         callout_init_mtx(&timeout_task->c, &queue->tq_mutex,
 116             CALLOUT_RETURNUNLOCKED);
 117         timeout_task->q = queue;
 118         timeout_task->f = 0;
 119 }
 120
 121 static __inline int
 122 TQ_SLEEP(struct taskqueue *tq, void *p, const char *wm)
 123 {
 124         if (tq->tq_spin)
 125                 return (msleep_spin(p, (struct mtx *)&tq->tq_mutex, wm, 0));
 126         return (msleep(p, &tq->tq_mutex, 0, wm, 0));
 127 }
 128
 129 static struct taskqueue_busy *
 130 task_get_busy(struct taskqueue *queue, struct task *task)
 131 {
 132         struct taskqueue_busy *tb;
 133
 134         TQ_ASSERT_LOCKED(queue);
 135         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 136                 if (tb->tb_running == task)
 137                         return (tb);
 138         }
 139         return (NULL);
 140 }
 141
 142 static struct taskqueue *
 143 _taskqueue_create(const char *name, int mflags,
 144                  taskqueue_enqueue_fn enqueue, void *context,
 145                  int mtxflags, const char *mtxname __unused)
 146 {
 147         struct taskqueue *queue;
 148         char *tq_name;
 149
 150         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
 151         if (tq_name == NULL)
 152                 return (NULL);
 153
 154         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
 155         if (queue == NULL) {
 156                 free(tq_name, M_TASKQUEUE);
 157                 return (NULL);
 158         }
 159
 160         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
 161
 162         STAILQ_INIT(&queue->tq_queue);
 163         LIST_INIT(&queue->tq_active);
 164         queue->tq_enqueue = enqueue;
 165         queue->tq_context = context;
 166         queue->tq_name = tq_name;
 167         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
 168         queue->tq_flags |= TQ_FLAGS_ACTIVE;
 169         if (enqueue == taskqueue_fast_enqueue ||
 170             enqueue == taskqueue_swi_enqueue ||
 171             enqueue == taskqueue_swi_giant_enqueue ||
 172             enqueue == taskqueue_thread_enqueue)
 173                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
 174         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
 175
 176         return (queue);
 177 }
 178
 179 struct taskqueue *
 180 taskqueue_create(const char *name, int mflags,
 181                  taskqueue_enqueue_fn enqueue, void *context)
 182 {
 183
 184         return _taskqueue_create(name, mflags, enqueue, context,
 185                         MTX_DEF, name);
 186 }
 187
 188 void
 189 taskqueue_set_callback(struct taskqueue *queue,
 190     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
 191     void *context)
 192 {
 193
 194         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
 195             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
 196             ("Callback type %d not valid, must be %d-%d", cb_type,
 197             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
 198         KASSERT((queue->tq_callbacks[cb_type] == NULL),
 199             ("Re-initialization of taskqueue callback?"));
 200
 201         queue->tq_callbacks[cb_type] = callback;
 202         queue->tq_cb_contexts[cb_type] = context;
 203 }
 204
 205 /*
 206  * Signal a taskqueue thread to terminate.
 207  */
 208 static void
 209 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
 210 {
 211
 212         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
 213                 wakeup(tq);
 214                 TQ_SLEEP(tq, pp, "tq_destroy");
 215         }
 216 }
 217
 218 void
 219 taskqueue_free(struct taskqueue *queue)
 220 {
 221
 222         TQ_LOCK(queue);
 223         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
 224         taskqueue_terminate(queue->tq_threads, queue);
 225         KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
 226         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
 227         mtx_destroy(&queue->tq_mutex);
 228         free(queue->tq_threads, M_TASKQUEUE);
 229         free(queue->tq_name, M_TASKQUEUE);
 230         free(queue, M_TASKQUEUE);
 231 }
 232
 233 static int
 234 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task, int flags)
 235 {
 236         struct task *ins;
 237         struct task *prev;
 238         struct taskqueue_busy *tb;
 239
 240         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
 241         /*
 242          * Ignore canceling task if requested.
 243          */
 244         if (__predict_false((flags & TASKQUEUE_FAIL_IF_CANCELING) != 0)) {
 245                 tb = task_get_busy(queue, task);
 246                 if (tb != NULL && tb->tb_canceling) {
 247                         TQ_UNLOCK(queue);
 248                         return (ECANCELED);
 249                 }
 250         }
 251
 252         /*
 253          * Count multiple enqueues.
 254          */
 255         if (task->ta_pending) {
 256                 if (__predict_false((flags & TASKQUEUE_FAIL_IF_PENDING) != 0)) {
 257                         TQ_UNLOCK(queue);
 258                         return (EEXIST);
 259                 }
 260                 if (task->ta_pending < USHRT_MAX)
 261                         task->ta_pending++;
 262                 TQ_UNLOCK(queue);
 263                 return (0);
 264         }
 265
 266         /*
 267          * Optimise cases when all tasks use small set of priorities.
 268          * In case of only one priority we always insert at the end.
 269          * In case of two tq_hint typically gives the insertion point.
 270          * In case of more then two tq_hint should halve the search.
 271          */
 272         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
 273         if (!prev || prev->ta_priority >= task->ta_priority) {
 274                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
 275         } else {
 276                 prev = queue->tq_hint;
 277                 if (prev && prev->ta_priority >= task->ta_priority) {
 278                         ins = STAILQ_NEXT(prev, ta_link);
 279                 } else {
 280                         prev = NULL;
 281                         ins = STAILQ_FIRST(&queue->tq_queue);
 282                 }
 283                 for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
 284                         if (ins->ta_priority < task->ta_priority)
 285                                 break;
 286
 287                 if (prev) {
 288                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
 289                         queue->tq_hint = task;
 290                 } else
 291                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
 292         }
 293
 294         task->ta_pending = 1;
 295         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
 296                 TQ_UNLOCK(queue);
 297         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
 298                 queue->tq_enqueue(queue->tq_context);
 299         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
 300                 TQ_UNLOCK(queue);
 301
 302         /* Return with lock released. */
 303         return (0);
 304 }
 305
 306 int
 307 taskqueue_enqueue_flags(struct taskqueue *queue, struct task *task, int flags)
 308 {
 309         int res;
 310
 311         TQ_LOCK(queue);
 312         res = taskqueue_enqueue_locked(queue, task, flags);
 313         /* The lock is released inside. */
 314
 315         return (res);
 316 }
 317
 318 int
 319 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
 320 {
 321         return (taskqueue_enqueue_flags(queue, task, 0));
 322 }
 323
 324 static void
 325 taskqueue_timeout_func(void *arg)
 326 {
 327         struct taskqueue *queue;
 328         struct timeout_task *timeout_task;
 329
 330         timeout_task = arg;
 331         queue = timeout_task->q;
 332         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
 333         timeout_task->f &= ~DT_CALLOUT_ARMED;
 334         queue->tq_callouts--;
 335         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t, 0);
 336         /* The lock is released inside. */
 337 }
 338
 339 int
 340 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
 341     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
 342 {
 343         int res;
 344
 345         TQ_LOCK(queue);
 346         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
 347             ("Migrated queue"));
 348         timeout_task->q = queue;
 349         res = timeout_task->t.ta_pending;
 350         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
 351                 /* Do nothing */
 352                 TQ_UNLOCK(queue);
 353                 res = -1;
 354         } else if (sbt == 0) {
 355                 taskqueue_enqueue_locked(queue, &timeout_task->t, 0);
 356                 /* The lock is released inside. */
 357         } else {
 358                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 359                         res++;
 360                 } else {
 361                         queue->tq_callouts++;
 362                         timeout_task->f |= DT_CALLOUT_ARMED;
 363                         if (sbt < 0)
 364                                 sbt = -sbt; /* Ignore overflow. */
 365                 }
 366                 if (sbt > 0) {
 367                         if (queue->tq_spin)
 368                                 flags |= C_DIRECT_EXEC;
 369                         callout_reset_sbt(&timeout_task->c, sbt, pr,
 370                             taskqueue_timeout_func, timeout_task, flags);
 371                 }
 372                 TQ_UNLOCK(queue);
 373         }
 374         return (res);
 375 }
 376
 377 int
 378 taskqueue_enqueue_timeout(struct taskqueue *queue,
 379     struct timeout_task *ttask, int ticks)
 380 {
 381
 382         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
 383             0, C_HARDCLOCK));
 384 }
 385
 386 static void
 387 taskqueue_task_nop_fn(void *context, int pending)
 388 {
 389 }
 390
 391 /*
 392  * Block until all currently queued tasks in this taskqueue
 393  * have begun execution.  Tasks queued during execution of
 394  * this function are ignored.
 395  */
 396 static int
 397 taskqueue_drain_tq_queue(struct taskqueue *queue)
 398 {
 399         struct task t_barrier;
 400
 401         if (STAILQ_EMPTY(&queue->tq_queue))
 402                 return (0);
 403
 404         /*
 405          * Enqueue our barrier after all current tasks, but with
 406          * the highest priority so that newly queued tasks cannot
 407          * pass it.  Because of the high priority, we can not use
 408          * taskqueue_enqueue_locked directly (which drops the lock
 409          * anyway) so just insert it at tail while we have the
 410          * queue lock.
 411          */
 412         TASK_INIT(&t_barrier, UCHAR_MAX, taskqueue_task_nop_fn, &t_barrier);
 413         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
 414         queue->tq_hint = &t_barrier;
 415         t_barrier.ta_pending = 1;
 416
 417         /*
 418          * Once the barrier has executed, all previously queued tasks
 419          * have completed or are currently executing.
 420          */
 421         while (t_barrier.ta_pending != 0)
 422                 TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
 423         return (1);
 424 }
 425
 426 /*
 427  * Block until all currently executing tasks for this taskqueue
 428  * complete.  Tasks that begin execution during the execution
 429  * of this function are ignored.
 430  */
 431 static int
 432 taskqueue_drain_tq_active(struct taskqueue *queue)
 433 {
 434         struct taskqueue_busy *tb;
 435         u_int seq;
 436
 437         if (LIST_EMPTY(&queue->tq_active))
 438                 return (0);
 439
 440         /* Block taskq_terminate().*/
 441         queue->tq_callouts++;
 442
 443         /* Wait for any active task with sequence from the past. */
 444         seq = queue->tq_seq;
 445 restart:
 446         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
 447                 if ((int)(tb->tb_seq - seq) <= 0) {
 448                         TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
 449                         goto restart;
 450                 }
 451         }
 452
 453         /* Release taskqueue_terminate(). */
 454         queue->tq_callouts--;
 455         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 456                 wakeup_one(queue->tq_threads);
 457         return (1);
 458 }
 459
 460 void
 461 taskqueue_block(struct taskqueue *queue)
 462 {
 463
 464         TQ_LOCK(queue);
 465         queue->tq_flags |= TQ_FLAGS_BLOCKED;
 466         TQ_UNLOCK(queue);
 467 }
 468
 469 void
 470 taskqueue_unblock(struct taskqueue *queue)
 471 {
 472
 473         TQ_LOCK(queue);
 474         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
 475         if (!STAILQ_EMPTY(&queue->tq_queue))
 476                 queue->tq_enqueue(queue->tq_context);
 477         TQ_UNLOCK(queue);
 478 }
 479
 480 static void
 481 taskqueue_run_locked(struct taskqueue *queue)
 482 {
 483         struct epoch_tracker et;
 484         struct taskqueue_busy tb;
 485         struct task *task;
 486         bool in_net_epoch;
 487         int pending;
 488
 489         KASSERT(queue != NULL, ("tq is NULL"));
 490         TQ_ASSERT_LOCKED(queue);
 491         tb.tb_running = NULL;
 492         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
 493         in_net_epoch = false;
 494
 495         while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
 496                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
 497                 if (queue->tq_hint == task)
 498                         queue->tq_hint = NULL;
 499                 pending = task->ta_pending;
 500                 task->ta_pending = 0;
 501                 tb.tb_running = task;
 502                 tb.tb_seq = ++queue->tq_seq;
 503                 tb.tb_canceling = false;
 504                 TQ_UNLOCK(queue);
 505
 506                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
 507                 if (!in_net_epoch && TASK_IS_NET(task)) {
 508                         in_net_epoch = true;
 509                         NET_EPOCH_ENTER(et);
 510                 } else if (in_net_epoch && !TASK_IS_NET(task)) {
 511                         NET_EPOCH_EXIT(et);
 512                         in_net_epoch = false;
 513                 }
 514                 task->ta_func(task->ta_context, pending);
 515
 516                 TQ_LOCK(queue);
 517                 wakeup(task);
 518         }
 519         if (in_net_epoch)
 520                 NET_EPOCH_EXIT(et);
 521         LIST_REMOVE(&tb, tb_link);
 522 }
 523
 524 void
 525 taskqueue_run(struct taskqueue *queue)
 526 {
 527
 528         TQ_LOCK(queue);
 529         taskqueue_run_locked(queue);
 530         TQ_UNLOCK(queue);
 531 }
 532
 533 /*
 534  * Only use this function in single threaded contexts. It returns
 535  * non-zero if the given task is either pending or running. Else the
 536  * task is idle and can be queued again or freed.
 537  */
 538 int
 539 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
 540 {
 541         int retval;
 542
 543         TQ_LOCK(queue);
 544         retval = task->ta_pending > 0 || task_get_busy(queue, task) != NULL;
 545         TQ_UNLOCK(queue);
 546
 547         return (retval);
 548 }
 549
 550 static int
 551 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
 552     u_int *pendp)
 553 {
 554         struct taskqueue_busy *tb;
 555         int retval = 0;
 556
 557         if (task->ta_pending > 0) {
 558                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
 559                 if (queue->tq_hint == task)
 560                         queue->tq_hint = NULL;
 561         }
 562         if (pendp != NULL)
 563                 *pendp = task->ta_pending;
 564         task->ta_pending = 0;
 565         tb = task_get_busy(queue, task);
 566         if (tb != NULL) {
 567                 tb->tb_canceling = true;
 568                 retval = EBUSY;
 569         }
 570
 571         return (retval);
 572 }
 573
 574 int
 575 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
 576 {
 577         int error;
 578
 579         TQ_LOCK(queue);
 580         error = taskqueue_cancel_locked(queue, task, pendp);
 581         TQ_UNLOCK(queue);
 582
 583         return (error);
 584 }
 585
 586 int
 587 taskqueue_cancel_timeout(struct taskqueue *queue,
 588     struct timeout_task *timeout_task, u_int *pendp)
 589 {
 590         u_int pending, pending1;
 591         int error;
 592
 593         TQ_LOCK(queue);
 594         pending = !!(callout_stop(&timeout_task->c) > 0);
 595         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
 596         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
 597                 timeout_task->f &= ~DT_CALLOUT_ARMED;
 598                 queue->tq_callouts--;
 599         }
 600         TQ_UNLOCK(queue);
 601
 602         if (pendp != NULL)
 603                 *pendp = pending + pending1;
 604         return (error);
 605 }
 606
 607 void
 608 taskqueue_drain(struct taskqueue *queue, struct task *task)
 609 {
 610
 611         if (!queue->tq_spin)
 612                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 613
 614         TQ_LOCK(queue);
 615         while (task->ta_pending != 0 || task_get_busy(queue, task) != NULL)
 616                 TQ_SLEEP(queue, task, "tq_drain");
 617         TQ_UNLOCK(queue);
 618 }
 619
 620 void
 621 taskqueue_drain_all(struct taskqueue *queue)
 622 {
 623
 624         if (!queue->tq_spin)
 625                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
 626
 627         TQ_LOCK(queue);
 628         (void)taskqueue_drain_tq_queue(queue);
 629         (void)taskqueue_drain_tq_active(queue);
 630         TQ_UNLOCK(queue);
 631 }
 632
 633 void
 634 taskqueue_drain_timeout(struct taskqueue *queue,
 635     struct timeout_task *timeout_task)
 636 {
 637
 638         /*
 639          * Set flag to prevent timer from re-starting during drain:
 640          */
 641         TQ_LOCK(queue);
 642         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
 643             ("Drain already in progress"));
 644         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
 645         TQ_UNLOCK(queue);
 646
 647         callout_drain(&timeout_task->c);
 648         taskqueue_drain(queue, &timeout_task->t);
 649
 650         /*
 651          * Clear flag to allow timer to re-start:
 652          */
 653         TQ_LOCK(queue);
 654         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
 655         TQ_UNLOCK(queue);
 656 }
 657
 658 void
 659 taskqueue_quiesce(struct taskqueue *queue)
 660 {
 661         int ret;
 662
 663         TQ_LOCK(queue);
 664         do {
 665                 ret = taskqueue_drain_tq_queue(queue);
 666                 if (ret == 0)
 667                         ret = taskqueue_drain_tq_active(queue);
 668         } while (ret != 0);
 669         TQ_UNLOCK(queue);
 670 }
 671
 672 static void
 673 taskqueue_swi_enqueue(void *context)
 674 {
 675         swi_sched(taskqueue_ih, 0);
 676 }
 677
 678 static void
 679 taskqueue_swi_run(void *dummy)
 680 {
 681         taskqueue_run(taskqueue_swi);
 682 }
 683
 684 static void
 685 taskqueue_swi_giant_enqueue(void *context)
 686 {
 687         swi_sched(taskqueue_giant_ih, 0);
 688 }
 689
 690 static void
 691 taskqueue_swi_giant_run(void *dummy)
 692 {
 693         taskqueue_run(taskqueue_swi_giant);
 694 }
 695
 696 static int
 697 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 698     cpuset_t *mask, struct proc *p, const char *name, va_list ap)
 699 {
 700         char ktname[MAXCOMLEN + 1];
 701         struct thread *td;
 702         struct taskqueue *tq;
 703         int i, error;
 704
 705         if (count <= 0)
 706                 return (EINVAL);
 707
 708         vsnprintf(ktname, sizeof(ktname), name, ap);
 709         tq = *tqp;
 710
 711         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
 712             M_NOWAIT | M_ZERO);
 713         if (tq->tq_threads == NULL) {
 714                 printf("%s: no memory for %s threads\n", __func__, ktname);
 715                 return (ENOMEM);
 716         }
 717
 718         for (i = 0; i < count; i++) {
 719                 if (count == 1)
 720                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 721                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
 722                 else
 723                         error = kthread_add(taskqueue_thread_loop, tqp, p,
 724                             &tq->tq_threads[i], RFSTOPPED, 0,
 725                             "%s_%d", ktname, i);
 726                 if (error) {
 727                         /* should be ok to continue, taskqueue_free will dtrt */
 728                         printf("%s: kthread_add(%s): error %d", __func__,
 729                             ktname, error);
 730                         tq->tq_threads[i] = NULL;               /* paranoid */
 731                 } else
 732                         tq->tq_tcount++;
 733         }
 734         if (tq->tq_tcount == 0) {
 735                 free(tq->tq_threads, M_TASKQUEUE);
 736                 tq->tq_threads = NULL;
 737                 return (ENOMEM);
 738         }
 739         for (i = 0; i < count; i++) {
 740                 if (tq->tq_threads[i] == NULL)
 741                         continue;
 742                 td = tq->tq_threads[i];
 743                 if (mask) {
 744                         error = cpuset_setthread(td->td_tid, mask);
 745                         /*
 746                          * Failing to pin is rarely an actual fatal error;
 747                          * it'll just affect performance.
 748                          */
 749                         if (error)
 750                                 printf("%s: curthread=%llu: can't pin; "
 751                                     "error=%d\n",
 752                                     __func__,
 753                                     (unsigned long long) td->td_tid,
 754                                     error);
 755                 }
 756                 thread_lock(td);
 757                 sched_prio(td, pri);
 758                 sched_add(td, SRQ_BORING);
 759         }
 760
 761         return (0);
 762 }
 763
 764 int
 765 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
 766     const char *name, ...)
 767 {
 768         va_list ap;
 769         int error;
 770
 771         va_start(ap, name);
 772         error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
 773         va_end(ap);
 774         return (error);
 775 }
 776
 777 int
 778 taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
 779     struct proc *proc, const char *name, ...)
 780 {
 781         va_list ap;
 782         int error;
 783
 784         va_start(ap, name);
 785         error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
 786         va_end(ap);
 787         return (error);
 788 }
 789
 790 int
 791 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
 792     cpuset_t *mask, const char *name, ...)
 793 {
 794         va_list ap;
 795         int error;
 796
 797         va_start(ap, name);
 798         error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
 799         va_end(ap);
 800         return (error);
 801 }
 802
 803 static inline void
 804 taskqueue_run_callback(struct taskqueue *tq,
 805     enum taskqueue_callback_type cb_type)
 806 {
 807         taskqueue_callback_fn tq_callback;
 808
 809         TQ_ASSERT_UNLOCKED(tq);
 810         tq_callback = tq->tq_callbacks[cb_type];
 811         if (tq_callback != NULL)
 812                 tq_callback(tq->tq_cb_contexts[cb_type]);
 813 }
 814
 815 void
 816 taskqueue_thread_loop(void *arg)
 817 {
 818         struct taskqueue **tqp, *tq;
 819
 820         tqp = arg;
 821         tq = *tqp;
 822         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
 823         TQ_LOCK(tq);
 824         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
 825                 /* XXX ? */
 826                 taskqueue_run_locked(tq);
 827                 /*
 828                  * Because taskqueue_run() can drop tq_mutex, we need to
 829                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
 830                  * meantime, which means we missed a wakeup.
 831                  */
 832                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
 833                         break;
 834                 TQ_SLEEP(tq, tq, "-");
 835         }
 836         taskqueue_run_locked(tq);
 837         /*
 838          * This thread is on its way out, so just drop the lock temporarily
 839          * in order to call the shutdown callback.  This allows the callback
 840          * to look at the taskqueue, even just before it dies.
 841          */
 842         TQ_UNLOCK(tq);
 843         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
 844         TQ_LOCK(tq);
 845
 846         /* rendezvous with thread that asked us to terminate */
 847         tq->tq_tcount--;
 848         wakeup_one(tq->tq_threads);
 849         TQ_UNLOCK(tq);
 850         kthread_exit();
 851 }
 852
 853 void
 854 taskqueue_thread_enqueue(void *context)
 855 {
 856         struct taskqueue **tqp, *tq;
 857
 858         tqp = context;
 859         tq = *tqp;
 860         wakeup_any(tq);
 861 }
 862
 863 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
 864                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
 865                      INTR_MPSAFE, &taskqueue_ih));
 866
 867 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
 868                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
 869                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
 870
 871 TASKQUEUE_DEFINE_THREAD(thread);
 872
 873 struct taskqueue *
 874 taskqueue_create_fast(const char *name, int mflags,
 875                  taskqueue_enqueue_fn enqueue, void *context)
 876 {
 877         return _taskqueue_create(name, mflags, enqueue, context,
 878                         MTX_SPIN, "fast_taskqueue");
 879 }
 880
 881 static void     *taskqueue_fast_ih;
 882
 883 static void
 884 taskqueue_fast_enqueue(void *context)
 885 {
 886         swi_sched(taskqueue_fast_ih, 0);
 887 }
 888
 889 static void
 890 taskqueue_fast_run(void *dummy)
 891 {
 892         taskqueue_run(taskqueue_fast);
 893 }
 894
 895 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
 896         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
 897         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
 898
 899 int
 900 taskqueue_member(struct taskqueue *queue, struct thread *td)
 901 {
 902         int i, j, ret = 0;
 903
 904         for (i = 0, j = 0; ; i++) {
 905                 if (queue->tq_threads[i] == NULL)
 906                         continue;
 907                 if (queue->tq_threads[i] == td) {
 908                         ret = 1;
 909                         break;
 910                 }
 911                 if (++j >= queue->tq_tcount)
 912                         break;
 913         }
 914         return (ret);
 915 }