subr_taskqueue.c

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    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 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_taskqueue.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_taskqueue.c
