sys/sys/taskqueue.h

   1 /*-
   2  * Copyright (c) 2000 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/sys/taskqueue.h,v 1.31 2011/12/19 18:55:13 jhb Exp $
  27  */
  28
  29 #ifndef _SYS_TASKQUEUE_H_
  30 #define _SYS_TASKQUEUE_H_
  31
  32 #if !defined(_KERNEL)
  33 #error "This file should not be included by userland programs."
  34 #endif
  35
  36 #include <sys/queue.h>
  37 #include <sys/callout.h>
  38
  39 struct taskqueue;
  40
  41 /*
  42  * Each task includes a function which is called from
  43  * taskqueue_run().  The first argument is taken from the 'ta_context'
  44  * field of struct task and the second argument is a count of how many
  45  * times the task was enqueued before the call to taskqueue_run().
  46  */
  47 typedef void task_fn_t(void *context, int pending);
  48
  49 /*
  50  * A notification callback function which is called from
  51  * taskqueue_enqueue().  The context argument is given in the call to
  52  * taskqueue_create().  This function would normally be used to allow the
  53  * queue to arrange to run itself later (e.g., by scheduling a software
  54  * interrupt or waking a kernel thread).
  55  */
  56 typedef void (*taskqueue_enqueue_fn)(void *context);
  57
  58 struct task {
  59         STAILQ_ENTRY(task) ta_link;     /* link for queue */
  60         int     ta_pending;             /* count times queued */
  61         int     ta_priority;            /* priority of task in queue */
  62         task_fn_t *ta_func;             /* task handler */
  63         void    *ta_context;            /* argument for handler */
  64 };
  65
  66 struct timeout_task {
  67         struct taskqueue *q;
  68         struct task t;
  69         struct callout c;
  70         int    f;
  71 };
  72
  73 struct taskqueue *taskqueue_create(const char *name, int mflags,
  74                                     taskqueue_enqueue_fn enqueue,
  75                                     void *context);
  76 int     taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
  77                                 int ncpu, const char *name, ...)
  78                                 __printflike(5, 6);
  79 int     taskqueue_enqueue(struct taskqueue *queue, struct task *task);
  80 int     taskqueue_enqueue_timeout(struct taskqueue *queue,
  81             struct timeout_task *timeout_task, int ticks);
  82 int     taskqueue_cancel(struct taskqueue *queue, struct task *task,
  83             u_int *pendp);
  84 int     taskqueue_cancel_timeout(struct taskqueue *queue,
  85             struct timeout_task *timeout_task, u_int *pendp);
  86 void    taskqueue_drain(struct taskqueue *queue, struct task *task);
  87 void    taskqueue_drain_timeout(struct taskqueue *queue,
  88             struct timeout_task *timeout_task);
  89 struct  taskqueue *taskqueue_find(const char *name);
  90 void    taskqueue_free(struct taskqueue *queue);
  91 void    taskqueue_block(struct taskqueue *queue);
  92 void    taskqueue_unblock(struct taskqueue *queue);
  93
  94 #define TASK_INITIALIZER(priority, func, context)       \
  95         { .ta_pending = 0,                              \
  96           .ta_priority = (priority),                    \
  97           .ta_func = (func),                            \
  98           .ta_context = (context) }
  99
 100 /*
 101  * Functions for dedicated thread taskqueues
 102  */
 103 void    taskqueue_thread_loop(void *arg);
 104 void    taskqueue_thread_enqueue(void *context);
 105
 106 /*
 107  * Initialise a task structure.
 108  */
 109 #define TASK_INIT(task, priority, func, context) do {   \
 110         (task)->ta_pending = 0;                         \
 111         (task)->ta_priority = (priority);               \
 112         (task)->ta_func = (func);                       \
 113         (task)->ta_context = (context);                 \
 114 } while (0)
 115
 116 void _timeout_task_init(struct taskqueue *queue,
 117             struct timeout_task *timeout_task, int priority, task_fn_t func,
 118             void *context);
 119 #define TIMEOUT_TASK_INIT(queue, timeout_task, priority, func, context) \
 120         _timeout_task_init(queue, timeout_task, priority, func, context);
 121
 122 /*
 123  * Declare a reference to a taskqueue.
 124  */
 125 #define TASKQUEUE_DECLARE(name)                 \
 126 extern struct taskqueue *taskqueue_##name
 127
 128 /*
 129  * Define and initialise a taskqueue.
 130  */
 131 #define TASKQUEUE_DEFINE(name, enqueue, context, init)                  \
 132                                                                         \
 133 struct taskqueue *taskqueue_##name;                                     \
 134                                                                         \
 135 static void                                                             \
 136 taskqueue_define_##name(void *arg)                                      \
 137 {                                                                       \
 138         taskqueue_##name =                                              \
 139             taskqueue_create(#name, M_INTWAIT, (enqueue), (context));   \
 140         init;                                                           \
 141 }                                                                       \
 142                                                                         \
 143 SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND,            \
 144         taskqueue_define_##name, NULL);                                 \
 145                                                                         \
 146 struct __hack
 147
 148 #define TASKQUEUE_DEFINE_THREAD(name)                                   \
 149 TASKQUEUE_DEFINE(name, taskqueue_thread_enqueue, &taskqueue_##name,     \
 150         taskqueue_start_threads(&taskqueue_##name, 1, prio,             \
 151         "%s taskq", #name))
 152 /*
 153  * This queue is serviced by a software interrupt handler.  To enqueue
 154  * a task, call taskqueue_enqueue(taskqueue_swi, &task).
 155  */
 156 TASKQUEUE_DECLARE(swi);
 157 TASKQUEUE_DECLARE(swi_mp);
 158
 159 /*
 160  * This queue is serviced by a per-cpu kernel thread.  To enqueue a task, call
 161  * taskqueue_enqueue(taskqueue_thread[mycpuid], &task).
 162  */
 163 extern struct taskqueue *taskqueue_thread[];
 164
 165 #endif /* !_SYS_TASKQUEUE_H_ */