FreeBSD/Linux Kernel Cross Reference
sys/sys/sleepqueue.h
1 /*-
2 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
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 * 3. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: releng/6.2/sys/sys/sleepqueue.h 164286 2006-11-14 20:42:41Z cvs2svn $
30 */
31
32 #ifndef _SYS_SLEEPQUEUE_H_
33 #define _SYS_SLEEPQUEUE_H_
34
35 /*
36 * Sleep queue interface. Sleep/wakeup and condition variables use a sleep
37 * queue for the queue of threads blocked on a sleep channel.
38 *
39 * A thread calls sleepq_lock() to lock the sleep queue chain associated
40 * with a given wait channel. A thread can then call call sleepq_add() to
41 * add themself onto a sleep queue and call one of the sleepq_wait()
42 * functions to actually go to sleep. If a thread needs to abort a sleep
43 * operation it should call sleepq_release() to unlock the associated sleep
44 * queue chain lock. If the thread also needs to remove itself from a queue
45 * it just enqueued itself on, it can use sleepq_remove() instead.
46 *
47 * If the thread only wishes to sleep for a limited amount of time, it can
48 * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It
49 * should then use one of the sleepq_timedwait() functions to block.
50 *
51 * If the thread wants to the sleep to be interruptible by signals, it can
52 * call sleepq_catch_signals() after sleepq_add(). It should then use
53 * one of the sleepq_wait_sig() functions to block. After the thread has
54 * been resumed, it should call sleepq_calc_signal_retval() to determine
55 * if it should return EINTR or ERESTART passing in the value returned from
56 * the earlier call to sleepq_catch_signals().
57 *
58 * A thread is normally resumed from a sleep queue by either the
59 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes
60 * the thread with the highest priority that is sleeping on the specified
61 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping
62 * on the specified wait channel. A thread sleeping in an interruptible
63 * sleep can be interrupted by calling sleepq_abort(). A thread can also
64 * be removed from a specified sleep queue using the sleepq_remove()
65 * function. Note that the sleep queue chain must first be locked via
66 * sleepq_lock() when calling sleepq_signal() and sleepq_broadcast().
67 *
68 * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
69 * and releases it at thread destruction via sleepq_free(). Note that
70 * a sleep queue is not tied to a specific thread and that the sleep queue
71 * released at thread destruction may not be the same sleep queue that the
72 * thread allocated when it was created.
73 *
74 * XXX: Some other parts of the kernel such as ithread sleeping may end up
75 * using this interface as well (death to TDI_IWAIT!)
76 */
77
78 struct mtx;
79 struct sleepqueue;
80 struct thread;
81
82 #ifdef _KERNEL
83
84 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */
85 #define SLEEPQ_MSLEEP 0x00 /* Used by msleep/wakeup. */
86 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */
87 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */
88
89 void init_sleepqueues(void);
90 void sleepq_abort(struct thread *td, int intrval);
91 void sleepq_add(void *, struct mtx *, const char *, int);
92 struct sleepqueue *sleepq_alloc(void);
93 void sleepq_broadcast(void *, int, int);
94 void sleepq_free(struct sleepqueue *);
95 void sleepq_lock(void *);
96 struct sleepqueue *sleepq_lookup(void *);
97 void sleepq_release(void *);
98 void sleepq_remove(struct thread *, void *);
99 void sleepq_signal(void *, int, int);
100 void sleepq_set_timeout(void *wchan, int timo);
101 int sleepq_timedwait(void *wchan);
102 int sleepq_timedwait_sig(void *wchan);
103 void sleepq_wait(void *);
104 int sleepq_wait_sig(void *wchan);
105
106 #endif /* _KERNEL */
107 #endif /* !_SYS_SLEEPQUEUE_H_ */
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