subr_taskqueue.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
    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/sched.h>
   46 #include <sys/smp.h>
   47 #include <sys/taskqueue.h>
   48 #include <sys/unistd.h>
   49 #include <machine/stdarg.h>
   50 
   51 static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
   52 static void     *taskqueue_giant_ih;
   53 static void     *taskqueue_ih;
   54 static void      taskqueue_fast_enqueue(void *);
   55 static void      taskqueue_swi_enqueue(void *);
   56 static void      taskqueue_swi_giant_enqueue(void *);
   57 
   58 struct taskqueue_busy {
   59         struct task             *tb_running;
   60         u_int                    tb_seq;
   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 *
  128 _taskqueue_create(const char *name, int mflags,
  129                  taskqueue_enqueue_fn enqueue, void *context,
  130                  int mtxflags, const char *mtxname __unused)
  131 {
  132         struct taskqueue *queue;
  133         char *tq_name;
  134 
  135         tq_name = malloc(TASKQUEUE_NAMELEN, M_TASKQUEUE, mflags | M_ZERO);
  136         if (tq_name == NULL)
  137                 return (NULL);
  138 
  139         queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
  140         if (queue == NULL) {
  141                 free(tq_name, M_TASKQUEUE);
  142                 return (NULL);
  143         }
  144 
  145         snprintf(tq_name, TASKQUEUE_NAMELEN, "%s", (name) ? name : "taskqueue");
  146 
  147         STAILQ_INIT(&queue->tq_queue);
  148         LIST_INIT(&queue->tq_active);
  149         queue->tq_enqueue = enqueue;
  150         queue->tq_context = context;
  151         queue->tq_name = tq_name;
  152         queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
  153         queue->tq_flags |= TQ_FLAGS_ACTIVE;
  154         if (enqueue == taskqueue_fast_enqueue ||
  155             enqueue == taskqueue_swi_enqueue ||
  156             enqueue == taskqueue_swi_giant_enqueue ||
  157             enqueue == taskqueue_thread_enqueue)
  158                 queue->tq_flags |= TQ_FLAGS_UNLOCKED_ENQUEUE;
  159         mtx_init(&queue->tq_mutex, tq_name, NULL, mtxflags);
  160 
  161         return (queue);
  162 }
  163 
  164 struct taskqueue *
  165 taskqueue_create(const char *name, int mflags,
  166                  taskqueue_enqueue_fn enqueue, void *context)
  167 {
  168 
  169         return _taskqueue_create(name, mflags, enqueue, context,
  170                         MTX_DEF, name);
  171 }
  172 
  173 void
  174 taskqueue_set_callback(struct taskqueue *queue,
  175     enum taskqueue_callback_type cb_type, taskqueue_callback_fn callback,
  176     void *context)
  177 {
  178 
  179         KASSERT(((cb_type >= TASKQUEUE_CALLBACK_TYPE_MIN) &&
  180             (cb_type <= TASKQUEUE_CALLBACK_TYPE_MAX)),
  181             ("Callback type %d not valid, must be %d-%d", cb_type,
  182             TASKQUEUE_CALLBACK_TYPE_MIN, TASKQUEUE_CALLBACK_TYPE_MAX));
  183         KASSERT((queue->tq_callbacks[cb_type] == NULL),
  184             ("Re-initialization of taskqueue callback?"));
  185 
  186         queue->tq_callbacks[cb_type] = callback;
  187         queue->tq_cb_contexts[cb_type] = context;
  188 }
  189 
  190 /*
  191  * Signal a taskqueue thread to terminate.
  192  */
  193 static void
  194 taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
  195 {
  196 
  197         while (tq->tq_tcount > 0 || tq->tq_callouts > 0) {
  198                 wakeup(tq);
  199                 TQ_SLEEP(tq, pp, "tq_destroy");
  200         }
  201 }
  202 
  203 void
  204 taskqueue_free(struct taskqueue *queue)
  205 {
  206 
  207         TQ_LOCK(queue);
  208         queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
  209         taskqueue_terminate(queue->tq_threads, queue);
  210         KASSERT(LIST_EMPTY(&queue->tq_active), ("Tasks still running?"));
  211         KASSERT(queue->tq_callouts == 0, ("Armed timeout tasks"));
  212         mtx_destroy(&queue->tq_mutex);
  213         free(queue->tq_threads, M_TASKQUEUE);
  214         free(queue->tq_name, M_TASKQUEUE);
  215         free(queue, M_TASKQUEUE);
  216 }
  217 
  218 static int
  219 taskqueue_enqueue_locked(struct taskqueue *queue, struct task *task)
  220 {
  221         struct task *ins;
  222         struct task *prev;
  223 
  224         KASSERT(task->ta_func != NULL, ("enqueueing task with NULL func"));
  225         /*
  226          * Count multiple enqueues.
  227          */
  228         if (task->ta_pending) {
  229                 if (task->ta_pending < USHRT_MAX)
  230                         task->ta_pending++;
  231                 TQ_UNLOCK(queue);
  232                 return (0);
  233         }
  234 
  235         /*
  236          * Optimise cases when all tasks use small set of priorities.
  237          * In case of only one priority we always insert at the end.
  238          * In case of two tq_hint typically gives the insertion point.
  239          * In case of more then two tq_hint should halve the search.
  240          */
  241         prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
  242         if (!prev || prev->ta_priority >= task->ta_priority) {
  243                 STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
  244         } else {
  245                 prev = queue->tq_hint;
  246                 if (prev && prev->ta_priority >= task->ta_priority) {
  247                         ins = STAILQ_NEXT(prev, ta_link);
  248                 } else {
  249                         prev = NULL;
  250                         ins = STAILQ_FIRST(&queue->tq_queue);
  251                 }
  252                 for (; ins; prev = ins, ins = STAILQ_NEXT(ins, ta_link))
  253                         if (ins->ta_priority < task->ta_priority)
  254                                 break;
  255 
  256                 if (prev) {
  257                         STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
  258                         queue->tq_hint = task;
  259                 } else
  260                         STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
  261         }
  262 
  263         task->ta_pending = 1;
  264         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) != 0)
  265                 TQ_UNLOCK(queue);
  266         if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
  267                 queue->tq_enqueue(queue->tq_context);
  268         if ((queue->tq_flags & TQ_FLAGS_UNLOCKED_ENQUEUE) == 0)
  269                 TQ_UNLOCK(queue);
  270 
  271         /* Return with lock released. */
  272         return (0);
  273 }
  274 
  275 int
  276 taskqueue_enqueue(struct taskqueue *queue, struct task *task)
  277 {
  278         int res;
  279 
  280         TQ_LOCK(queue);
  281         res = taskqueue_enqueue_locked(queue, task);
  282         /* The lock is released inside. */
  283 
  284         return (res);
  285 }
  286 
  287 static void
  288 taskqueue_timeout_func(void *arg)
  289 {
  290         struct taskqueue *queue;
  291         struct timeout_task *timeout_task;
  292 
  293         timeout_task = arg;
  294         queue = timeout_task->q;
  295         KASSERT((timeout_task->f & DT_CALLOUT_ARMED) != 0, ("Stray timeout"));
  296         timeout_task->f &= ~DT_CALLOUT_ARMED;
  297         queue->tq_callouts--;
  298         taskqueue_enqueue_locked(timeout_task->q, &timeout_task->t);
  299         /* The lock is released inside. */
  300 }
  301 
  302 int
  303 taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
  304     struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr, int flags)
  305 {
  306         int res;
  307 
  308         TQ_LOCK(queue);
  309         KASSERT(timeout_task->q == NULL || timeout_task->q == queue,
  310             ("Migrated queue"));
  311         KASSERT(!queue->tq_spin, ("Timeout for spin-queue"));
  312         timeout_task->q = queue;
  313         res = timeout_task->t.ta_pending;
  314         if (timeout_task->f & DT_DRAIN_IN_PROGRESS) {
  315                 /* Do nothing */
  316                 TQ_UNLOCK(queue);
  317                 res = -1;
  318         } else if (sbt == 0) {
  319                 taskqueue_enqueue_locked(queue, &timeout_task->t);
  320                 /* The lock is released inside. */
  321         } else {
  322                 if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
  323                         res++;
  324                 } else {
  325                         queue->tq_callouts++;
  326                         timeout_task->f |= DT_CALLOUT_ARMED;
  327                         if (sbt < 0)
  328                                 sbt = -sbt; /* Ignore overflow. */
  329                 }
  330                 if (sbt > 0) {
  331                         callout_reset_sbt(&timeout_task->c, sbt, pr,
  332                             taskqueue_timeout_func, timeout_task, flags);
  333                 }
  334                 TQ_UNLOCK(queue);
  335         }
  336         return (res);
  337 }
  338 
  339 int
  340 taskqueue_enqueue_timeout(struct taskqueue *queue,
  341     struct timeout_task *ttask, int ticks)
  342 {
  343 
  344         return (taskqueue_enqueue_timeout_sbt(queue, ttask, ticks * tick_sbt,
  345             0, C_HARDCLOCK));
  346 }
  347 
  348 static void
  349 taskqueue_task_nop_fn(void *context, int pending)
  350 {
  351 }
  352 
  353 /*
  354  * Block until all currently queued tasks in this taskqueue
  355  * have begun execution.  Tasks queued during execution of
  356  * this function are ignored.
  357  */
  358 static int
  359 taskqueue_drain_tq_queue(struct taskqueue *queue)
  360 {
  361         struct task t_barrier;
  362 
  363         if (STAILQ_EMPTY(&queue->tq_queue))
  364                 return (0);
  365 
  366         /*
  367          * Enqueue our barrier after all current tasks, but with
  368          * the highest priority so that newly queued tasks cannot
  369          * pass it.  Because of the high priority, we can not use
  370          * taskqueue_enqueue_locked directly (which drops the lock
  371          * anyway) so just insert it at tail while we have the
  372          * queue lock.
  373          */
  374         TASK_INIT(&t_barrier, USHRT_MAX, taskqueue_task_nop_fn, &t_barrier);
  375         STAILQ_INSERT_TAIL(&queue->tq_queue, &t_barrier, ta_link);
  376         queue->tq_hint = &t_barrier;
  377         t_barrier.ta_pending = 1;
  378 
  379         /*
  380          * Once the barrier has executed, all previously queued tasks
  381          * have completed or are currently executing.
  382          */
  383         while (t_barrier.ta_pending != 0)
  384                 TQ_SLEEP(queue, &t_barrier, "tq_qdrain");
  385         return (1);
  386 }
  387 
  388 /*
  389  * Block until all currently executing tasks for this taskqueue
  390  * complete.  Tasks that begin execution during the execution
  391  * of this function are ignored.
  392  */
  393 static int
  394 taskqueue_drain_tq_active(struct taskqueue *queue)
  395 {
  396         struct taskqueue_busy *tb;
  397         u_int seq;
  398 
  399         if (LIST_EMPTY(&queue->tq_active))
  400                 return (0);
  401 
  402         /* Block taskq_terminate().*/
  403         queue->tq_callouts++;
  404 
  405         /* Wait for any active task with sequence from the past. */
  406         seq = queue->tq_seq;
  407 restart:
  408         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
  409                 if ((int)(tb->tb_seq - seq) <= 0) {
  410                         TQ_SLEEP(queue, tb->tb_running, "tq_adrain");
  411                         goto restart;
  412                 }
  413         }
  414 
  415         /* Release taskqueue_terminate(). */
  416         queue->tq_callouts--;
  417         if ((queue->tq_flags & TQ_FLAGS_ACTIVE) == 0)
  418                 wakeup_one(queue->tq_threads);
  419         return (1);
  420 }
  421 
  422 void
  423 taskqueue_block(struct taskqueue *queue)
  424 {
  425 
  426         TQ_LOCK(queue);
  427         queue->tq_flags |= TQ_FLAGS_BLOCKED;
  428         TQ_UNLOCK(queue);
  429 }
  430 
  431 void
  432 taskqueue_unblock(struct taskqueue *queue)
  433 {
  434 
  435         TQ_LOCK(queue);
  436         queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
  437         if (!STAILQ_EMPTY(&queue->tq_queue))
  438                 queue->tq_enqueue(queue->tq_context);
  439         TQ_UNLOCK(queue);
  440 }
  441 
  442 static void
  443 taskqueue_run_locked(struct taskqueue *queue)
  444 {
  445         struct taskqueue_busy tb;
  446         struct task *task;
  447         int pending;
  448 
  449         KASSERT(queue != NULL, ("tq is NULL"));
  450         TQ_ASSERT_LOCKED(queue);
  451         tb.tb_running = NULL;
  452         LIST_INSERT_HEAD(&queue->tq_active, &tb, tb_link);
  453 
  454         while ((task = STAILQ_FIRST(&queue->tq_queue)) != NULL) {
  455                 STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
  456                 if (queue->tq_hint == task)
  457                         queue->tq_hint = NULL;
  458                 pending = task->ta_pending;
  459                 task->ta_pending = 0;
  460                 tb.tb_running = task;
  461                 tb.tb_seq = ++queue->tq_seq;
  462                 TQ_UNLOCK(queue);
  463 
  464                 KASSERT(task->ta_func != NULL, ("task->ta_func is NULL"));
  465                 task->ta_func(task->ta_context, pending);
  466 
  467                 TQ_LOCK(queue);
  468                 wakeup(task);
  469         }
  470         LIST_REMOVE(&tb, tb_link);
  471 }
  472 
  473 void
  474 taskqueue_run(struct taskqueue *queue)
  475 {
  476 
  477         TQ_LOCK(queue);
  478         taskqueue_run_locked(queue);
  479         TQ_UNLOCK(queue);
  480 }
  481 
  482 static int
  483 task_is_running(struct taskqueue *queue, struct task *task)
  484 {
  485         struct taskqueue_busy *tb;
  486 
  487         TQ_ASSERT_LOCKED(queue);
  488         LIST_FOREACH(tb, &queue->tq_active, tb_link) {
  489                 if (tb->tb_running == task)
  490                         return (1);
  491         }
  492         return (0);
  493 }
  494 
  495 /*
  496  * Only use this function in single threaded contexts. It returns
  497  * non-zero if the given task is either pending or running. Else the
  498  * task is idle and can be queued again or freed.
  499  */
  500 int
  501 taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task)
  502 {
  503         int retval;
  504 
  505         TQ_LOCK(queue);
  506         retval = task->ta_pending > 0 || task_is_running(queue, task);
  507         TQ_UNLOCK(queue);
  508 
  509         return (retval);
  510 }
  511 
  512 static int
  513 taskqueue_cancel_locked(struct taskqueue *queue, struct task *task,
  514     u_int *pendp)
  515 {
  516 
  517         if (task->ta_pending > 0) {
  518                 STAILQ_REMOVE(&queue->tq_queue, task, task, ta_link);
  519                 if (queue->tq_hint == task)
  520                         queue->tq_hint = NULL;
  521         }
  522         if (pendp != NULL)
  523                 *pendp = task->ta_pending;
  524         task->ta_pending = 0;
  525         return (task_is_running(queue, task) ? EBUSY : 0);
  526 }
  527 
  528 int
  529 taskqueue_cancel(struct taskqueue *queue, struct task *task, u_int *pendp)
  530 {
  531         int error;
  532 
  533         TQ_LOCK(queue);
  534         error = taskqueue_cancel_locked(queue, task, pendp);
  535         TQ_UNLOCK(queue);
  536 
  537         return (error);
  538 }
  539 
  540 int
  541 taskqueue_cancel_timeout(struct taskqueue *queue,
  542     struct timeout_task *timeout_task, u_int *pendp)
  543 {
  544         u_int pending, pending1;
  545         int error;
  546 
  547         TQ_LOCK(queue);
  548         pending = !!(callout_stop(&timeout_task->c) > 0);
  549         error = taskqueue_cancel_locked(queue, &timeout_task->t, &pending1);
  550         if ((timeout_task->f & DT_CALLOUT_ARMED) != 0) {
  551                 timeout_task->f &= ~DT_CALLOUT_ARMED;
  552                 queue->tq_callouts--;
  553         }
  554         TQ_UNLOCK(queue);
  555 
  556         if (pendp != NULL)
  557                 *pendp = pending + pending1;
  558         return (error);
  559 }
  560 
  561 void
  562 taskqueue_drain(struct taskqueue *queue, struct task *task)
  563 {
  564 
  565         if (!queue->tq_spin)
  566                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
  567 
  568         TQ_LOCK(queue);
  569         while (task->ta_pending != 0 || task_is_running(queue, task))
  570                 TQ_SLEEP(queue, task, "tq_drain");
  571         TQ_UNLOCK(queue);
  572 }
  573 
  574 void
  575 taskqueue_drain_all(struct taskqueue *queue)
  576 {
  577 
  578         if (!queue->tq_spin)
  579                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
  580 
  581         TQ_LOCK(queue);
  582         (void)taskqueue_drain_tq_queue(queue);
  583         (void)taskqueue_drain_tq_active(queue);
  584         TQ_UNLOCK(queue);
  585 }
  586 
  587 void
  588 taskqueue_drain_timeout(struct taskqueue *queue,
  589     struct timeout_task *timeout_task)
  590 {
  591 
  592         /*
  593          * Set flag to prevent timer from re-starting during drain:
  594          */
  595         TQ_LOCK(queue);
  596         KASSERT((timeout_task->f & DT_DRAIN_IN_PROGRESS) == 0,
  597             ("Drain already in progress"));
  598         timeout_task->f |= DT_DRAIN_IN_PROGRESS;
  599         TQ_UNLOCK(queue);
  600 
  601         callout_drain(&timeout_task->c);
  602         taskqueue_drain(queue, &timeout_task->t);
  603 
  604         /*
  605          * Clear flag to allow timer to re-start:
  606          */
  607         TQ_LOCK(queue);
  608         timeout_task->f &= ~DT_DRAIN_IN_PROGRESS;
  609         TQ_UNLOCK(queue);
  610 }
  611 
  612 void
  613 taskqueue_quiesce(struct taskqueue *queue)
  614 {
  615         int ret;
  616 
  617         TQ_LOCK(queue);
  618         do {
  619                 ret = taskqueue_drain_tq_queue(queue);
  620                 if (ret == 0)
  621                         ret = taskqueue_drain_tq_active(queue);
  622         } while (ret != 0);
  623         TQ_UNLOCK(queue);
  624 }
  625 
  626 static void
  627 taskqueue_swi_enqueue(void *context)
  628 {
  629         swi_sched(taskqueue_ih, 0);
  630 }
  631 
  632 static void
  633 taskqueue_swi_run(void *dummy)
  634 {
  635         taskqueue_run(taskqueue_swi);
  636 }
  637 
  638 static void
  639 taskqueue_swi_giant_enqueue(void *context)
  640 {
  641         swi_sched(taskqueue_giant_ih, 0);
  642 }
  643 
  644 static void
  645 taskqueue_swi_giant_run(void *dummy)
  646 {
  647         taskqueue_run(taskqueue_swi_giant);
  648 }
  649 
  650 static int
  651 _taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
  652     cpuset_t *mask, struct proc *p, const char *name, va_list ap)
  653 {
  654         char ktname[MAXCOMLEN + 1];
  655         struct thread *td;
  656         struct taskqueue *tq;
  657         int i, error;
  658 
  659         if (count <= 0)
  660                 return (EINVAL);
  661 
  662         vsnprintf(ktname, sizeof(ktname), name, ap);
  663         tq = *tqp;
  664 
  665         tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
  666             M_NOWAIT | M_ZERO);
  667         if (tq->tq_threads == NULL) {
  668                 printf("%s: no memory for %s threads\n", __func__, ktname);
  669                 return (ENOMEM);
  670         }
  671 
  672         for (i = 0; i < count; i++) {
  673                 if (count == 1)
  674                         error = kthread_add(taskqueue_thread_loop, tqp, p,
  675                             &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
  676                 else
  677                         error = kthread_add(taskqueue_thread_loop, tqp, p,
  678                             &tq->tq_threads[i], RFSTOPPED, 0,
  679                             "%s_%d", ktname, i);
  680                 if (error) {
  681                         /* should be ok to continue, taskqueue_free will dtrt */
  682                         printf("%s: kthread_add(%s): error %d", __func__,
  683                             ktname, error);
  684                         tq->tq_threads[i] = NULL;               /* paranoid */
  685                 } else
  686                         tq->tq_tcount++;
  687         }
  688         if (tq->tq_tcount == 0) {
  689                 free(tq->tq_threads, M_TASKQUEUE);
  690                 tq->tq_threads = NULL;
  691                 return (ENOMEM);
  692         }
  693         for (i = 0; i < count; i++) {
  694                 if (tq->tq_threads[i] == NULL)
  695                         continue;
  696                 td = tq->tq_threads[i];
  697                 if (mask) {
  698                         error = cpuset_setthread(td->td_tid, mask);
  699                         /*
  700                          * Failing to pin is rarely an actual fatal error;
  701                          * it'll just affect performance.
  702                          */
  703                         if (error)
  704                                 printf("%s: curthread=%llu: can't pin; "
  705                                     "error=%d\n",
  706                                     __func__,
  707                                     (unsigned long long) td->td_tid,
  708                                     error);
  709                 }
  710                 thread_lock(td);
  711                 sched_prio(td, pri);
  712                 sched_add(td, SRQ_BORING);
  713                 thread_unlock(td);
  714         }
  715 
  716         return (0);
  717 }
  718 
  719 int
  720 taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
  721     const char *name, ...)
  722 {
  723         va_list ap;
  724         int error;
  725 
  726         va_start(ap, name);
  727         error = _taskqueue_start_threads(tqp, count, pri, NULL, NULL, name, ap);
  728         va_end(ap);
  729         return (error);
  730 }
  731 
  732 int
  733 taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count, int pri,
  734     struct proc *proc, const char *name, ...)
  735 {
  736         va_list ap;
  737         int error;
  738 
  739         va_start(ap, name);
  740         error = _taskqueue_start_threads(tqp, count, pri, NULL, proc, name, ap);
  741         va_end(ap);
  742         return (error);
  743 }
  744 
  745 int
  746 taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count, int pri,
  747     cpuset_t *mask, const char *name, ...)
  748 {
  749         va_list ap;
  750         int error;
  751 
  752         va_start(ap, name);
  753         error = _taskqueue_start_threads(tqp, count, pri, mask, NULL, name, ap);
  754         va_end(ap);
  755         return (error);
  756 }
  757 
  758 static inline void
  759 taskqueue_run_callback(struct taskqueue *tq,
  760     enum taskqueue_callback_type cb_type)
  761 {
  762         taskqueue_callback_fn tq_callback;
  763 
  764         TQ_ASSERT_UNLOCKED(tq);
  765         tq_callback = tq->tq_callbacks[cb_type];
  766         if (tq_callback != NULL)
  767                 tq_callback(tq->tq_cb_contexts[cb_type]);
  768 }
  769 
  770 void
  771 taskqueue_thread_loop(void *arg)
  772 {
  773         struct taskqueue **tqp, *tq;
  774 
  775         tqp = arg;
  776         tq = *tqp;
  777         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_INIT);
  778         TQ_LOCK(tq);
  779         while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
  780                 /* XXX ? */
  781                 taskqueue_run_locked(tq);
  782                 /*
  783                  * Because taskqueue_run() can drop tq_mutex, we need to
  784                  * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
  785                  * meantime, which means we missed a wakeup.
  786                  */
  787                 if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
  788                         break;
  789                 TQ_SLEEP(tq, tq, "-");
  790         }
  791         taskqueue_run_locked(tq);
  792         /*
  793          * This thread is on its way out, so just drop the lock temporarily
  794          * in order to call the shutdown callback.  This allows the callback
  795          * to look at the taskqueue, even just before it dies.
  796          */
  797         TQ_UNLOCK(tq);
  798         taskqueue_run_callback(tq, TASKQUEUE_CALLBACK_TYPE_SHUTDOWN);
  799         TQ_LOCK(tq);
  800 
  801         /* rendezvous with thread that asked us to terminate */
  802         tq->tq_tcount--;
  803         wakeup_one(tq->tq_threads);
  804         TQ_UNLOCK(tq);
  805         kthread_exit();
  806 }
  807 
  808 void
  809 taskqueue_thread_enqueue(void *context)
  810 {
  811         struct taskqueue **tqp, *tq;
  812 
  813         tqp = context;
  814         tq = *tqp;
  815         wakeup_any(tq);
  816 }
  817 
  818 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
  819                  swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
  820                      INTR_MPSAFE, &taskqueue_ih));
  821 
  822 TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
  823                  swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
  824                      NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));
  825 
  826 TASKQUEUE_DEFINE_THREAD(thread);
  827 
  828 struct taskqueue *
  829 taskqueue_create_fast(const char *name, int mflags,
  830                  taskqueue_enqueue_fn enqueue, void *context)
  831 {
  832         return _taskqueue_create(name, mflags, enqueue, context,
  833                         MTX_SPIN, "fast_taskqueue");
  834 }
  835 
  836 static void     *taskqueue_fast_ih;
  837 
  838 static void
  839 taskqueue_fast_enqueue(void *context)
  840 {
  841         swi_sched(taskqueue_fast_ih, 0);
  842 }
  843 
  844 static void
  845 taskqueue_fast_run(void *dummy)
  846 {
  847         taskqueue_run(taskqueue_fast);
  848 }
  849 
  850 TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
  851         swi_add(NULL, "fast taskq", taskqueue_fast_run, NULL,
  852         SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
  853 
  854 int
  855 taskqueue_member(struct taskqueue *queue, struct thread *td)
  856 {
  857         int i, j, ret = 0;
  858 
  859         for (i = 0, j = 0; ; i++) {
  860                 if (queue->tq_threads[i] == NULL)
  861                         continue;
  862                 if (queue->tq_threads[i] == td) {
  863                         ret = 1;
  864                         break;
  865                 }
  866                 if (++j >= queue->tq_tcount)
  867                         break;
  868         }
  869         return (ret);
  870 }
Cache object: af2a7d6db1065c183828b316c050306d
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.
FreeBSD/Linux Kernel Cross Reference sys/kern/subr_taskqueue.c

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