FreeBSD/Linux Kernel Cross Reference
2 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
3 * All rights reserved.
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.
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.
29 * $FreeBSD$
32 #ifndef _SYS_SLEEPQUEUE_H_
33 #define _SYS_SLEEPQUEUE_H_
36 * Sleep queue interface. Sleep/wakeup and condition variables use a sleep
37 * queue for the queue of threads blocked on a sleep channel.
39 * A thread calls sleepq_lookup() to look up the proper sleep queue in the
40 * hash table that is associated with a specified wait channel. This
41 * function returns a pointer to the queue and locks the associated sleep
42 * queue chain. A thread calls sleepq_add() to add themself onto a sleep
43 * queue and calls one of the sleepq_wait() functions to actually go to
44 * sleep. If a thread needs to abort a sleep operation it should call
45 * sleepq_release() to unlock the associated sleep queue chain lock. If
46 * the thread also needs to remove itself from a queue it just enqueued
47 * itself on, it can use sleepq_remove().
49 * If the thread only wishes to sleep for a limited amount of time, it can
50 * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It
51 * should then use one of the sleepq_timedwait() functions to block.
53 * If the thread wants to the sleep to be interruptible by signals, it can
54 * call sleepq_catch_signals() after sleepq_add(). It should then use
55 * one of the sleepq_wait_sig() functions to block. After the thread has
56 * been resumed, it should call sleepq_calc_signal_retval() to determine
57 * if it should return EINTR or ERESTART passing in the value returned from
58 * the earlier call to sleepq_catch_signals().
60 * A thread is normally resumed from a sleep queue by either the
61 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes
62 * the thread with the highest priority that is sleeping on the specified
63 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping
64 * on the specified wait channel. A thread sleeping in an interruptible
65 * sleep can be interrupted by calling sleepq_abort(). A thread can also
66 * be removed from a specified sleep queue using the sleepq_remove()
67 * function.
69 * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
70 * and releases it at thread destruction via sleepq_free(). Note that
71 * a sleep queue is not tied to a specific thread and that the sleep queue
72 * released at thread destruction may not be the same sleep queue that the
73 * thread allocated when it was created.
75 * XXX: Some other parts of the kernel such as ithread sleeping may end up
76 * using this interface as well (death to TDI_IWAIT!)
79 struct mtx;
80 struct sleepqueue;
81 struct thread;
83 #ifdef _KERNEL
85 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */
86 #define SLEEPQ_MSLEEP 0x00 /* Used by msleep/wakeup. */
87 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */
88 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */
90 void init_sleepqueues(void);
91 void sleepq_abort(struct thread *td);
92 void sleepq_add(struct sleepqueue *, void *, struct mtx *, const char *,
94 struct sleepqueue *sleepq_alloc(void);
95 void sleepq_broadcast(void *, int, int);
96 int sleepq_calc_signal_retval(int sig);
97 int sleepq_catch_signals(void *wchan);
98 void sleepq_free(struct sleepqueue *);
99 struct sleepqueue *sleepq_lookup(void *);
100 void sleepq_release(void *);
101 void sleepq_remove(struct thread *, void *);
102 void sleepq_signal(void *, int, int);
103 void sleepq_set_timeout(void *wchan, int timo);
104 int sleepq_timedwait(void *wchan);
105 int sleepq_timedwait_sig(void *wchan, int signal_caught);
106 void sleepq_wait(void *);
107 int sleepq_wait_sig(void *wchan);
109 #endif /* _KERNEL */
110 #endif /* !_SYS_SLEEPQUEUE_H_ */
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