taskqueue.h revision 177621 
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: head/sys/sys/taskqueue.h 177621 2008-03-25 22:38:45Z scottl $
27 */
28
29#ifndef _SYS_TASKQUEUE_H_
30#define _SYS_TASKQUEUE_H_
31
32#ifndef _KERNEL
33#error "no user-servicable parts inside"
34#endif
35
36#include <sys/queue.h>
37#include <sys/_task.h>
38
39struct taskqueue;
40
41/*
42 * A notification callback function which is called from
43 * taskqueue_enqueue().  The context argument is given in the call to
44 * taskqueue_create().  This function would normally be used to allow the
45 * queue to arrange to run itself later (e.g., by scheduling a software
46 * interrupt or waking a kernel thread).
47 */
48typedef void (*taskqueue_enqueue_fn)(void *context);
49
50struct proc;
51struct taskqueue *taskqueue_create(const char *name, int mflags,
52				    taskqueue_enqueue_fn enqueue,
53				    void *context);
54int	taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
55				const char *name, ...) __printflike(4, 5);
56int	taskqueue_enqueue(struct taskqueue *queue, struct task *task);
57void	taskqueue_drain(struct taskqueue *queue, struct task *task);
58struct taskqueue *taskqueue_find(const char *name);
59void	taskqueue_free(struct taskqueue *queue);
60void	taskqueue_run(struct taskqueue *queue);
61void	taskqueue_block(struct taskqueue *queue);
62void	taskqueue_unblock(struct taskqueue *queue);
63
64/*
65 * Functions for dedicated thread taskqueues
66 */
67void	taskqueue_thread_loop(void *arg);
68void	taskqueue_thread_enqueue(void *context);
69
70/*
71 * Initialise a task structure.
72 */
73#define TASK_INIT(task, priority, func, context) do {	\
74	(task)->ta_pending = 0;				\
75	(task)->ta_priority = (priority);		\
76	(task)->ta_func = (func);			\
77	(task)->ta_context = (context);			\
78} while (0)
79
80/*
81 * Declare a reference to a taskqueue.
82 */
83#define TASKQUEUE_DECLARE(name)			\
84extern struct taskqueue *taskqueue_##name
85
86/*
87 * Define and initialise a global taskqueue that uses sleep mutexes.
88 */
89#define TASKQUEUE_DEFINE(name, enqueue, context, init)			\
90									\
91struct taskqueue *taskqueue_##name;					\
92									\
93static void								\
94taskqueue_define_##name(void *arg)					\
95{									\
96	taskqueue_##name =						\
97	    taskqueue_create(#name, M_NOWAIT, (enqueue), (context));	\
98	init;								\
99}									\
100									\
101SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND,		\
102	taskqueue_define_##name, NULL);					\
103									\
104struct __hack
105#define TASKQUEUE_DEFINE_THREAD(name)					\
106TASKQUEUE_DEFINE(name, taskqueue_thread_enqueue, &taskqueue_##name,	\
107	taskqueue_start_threads(&taskqueue_##name, 1, PWAIT,		\
108	"%s taskq", #name))
109
110/*
111 * Define and initialise a global taskqueue that uses spin mutexes.
112 */
113#define TASKQUEUE_FAST_DEFINE(name, enqueue, context, init)		\
114									\
115struct taskqueue *taskqueue_##name;					\
116									\
117static void								\
118taskqueue_define_##name(void *arg)					\
119{									\
120	taskqueue_##name =						\
121	    taskqueue_create_fast(#name, M_NOWAIT, (enqueue),		\
122	    (context));							\
123	init;								\
124}									\
125									\
126SYSINIT(taskqueue_##name, SI_SUB_CONFIGURE, SI_ORDER_SECOND,		\
127	taskqueue_define_##name, NULL);					\
128									\
129struct __hack
130#define TASKQUEUE_FAST_DEFINE_THREAD(name)				\
131TASKQUEUE_FAST_DEFINE(name, taskqueue_thread_enqueue,			\
132	&taskqueue_##name, taskqueue_start_threads(&taskqueue_##name	\
133	1, PWAIT, "%s taskq", #name))
134
135/*
136 * These queues are serviced by software interrupt handlers.  To enqueue
137 * a task, call taskqueue_enqueue(taskqueue_swi, &task) or
138 * taskqueue_enqueue(taskqueue_swi_giant, &task).
139 */
140TASKQUEUE_DECLARE(swi_giant);
141TASKQUEUE_DECLARE(swi);
142
143/*
144 * This queue is serviced by a kernel thread.  To enqueue a task, call
145 * taskqueue_enqueue(taskqueue_thread, &task).
146 */
147TASKQUEUE_DECLARE(thread);
148
149/*
150 * Queue for swi handlers dispatched from fast interrupt handlers.
151 * These are necessarily different from the above because the queue
152 * must be locked with spinlocks since sleep mutex's cannot be used
153 * from a fast interrupt handler context.
154 */
155TASKQUEUE_DECLARE(fast);
156int	taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task);
157struct taskqueue *taskqueue_create_fast(const char *name, int mflags,
158				    taskqueue_enqueue_fn enqueue,
159				    void *context);
160
161#endif /* !_SYS_TASKQUEUE_H_ */
162