sleepqueue.h revision 367457 
1/*-
2 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD: stable/11/sys/sys/sleepqueue.h 367457 2020-11-07 18:10:59Z dim $
26 */
27
28#ifndef _SYS_SLEEPQUEUE_H_
29#define _SYS_SLEEPQUEUE_H_
30
31/*
32 * Sleep queue interface.  Sleep/wakeup, condition variables, and sx
33 * locks use a sleep queue for the queue of threads blocked on a sleep
34 * channel.
35 *
36 * A thread calls sleepq_lock() to lock the sleep queue chain associated
37 * with a given wait channel.  A thread can then call call sleepq_add() to
38 * add themself onto a sleep queue and call one of the sleepq_wait()
39 * functions to actually go to sleep.  If a thread needs to abort a sleep
40 * operation it should call sleepq_release() to unlock the associated sleep
41 * queue chain lock.  If the thread also needs to remove itself from a queue
42 * it just enqueued itself on, it can use sleepq_remove() instead.
43 *
44 * If the thread only wishes to sleep for a limited amount of time, it can
45 * call sleepq_set_timeout() after sleepq_add() to setup a timeout.  It
46 * should then use one of the sleepq_timedwait() functions to block.
47 *
48 * A thread is normally resumed from a sleep queue by either the
49 * sleepq_signal() or sleepq_broadcast() functions.  Sleepq_signal() wakes
50 * the thread with the highest priority that is sleeping on the specified
51 * wait channel.  Sleepq_broadcast() wakes all threads that are sleeping
52 * on the specified wait channel.  A thread sleeping in an interruptible
53 * sleep can be interrupted by calling sleepq_abort().  A thread can also
54 * be removed from a specified sleep queue using the sleepq_remove()
55 * function.  Note that the sleep queue chain must first be locked via
56 * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or
57 * sleepq_signal().  These routines each return a boolean that will be true
58 * if at least one swapped-out thread was resumed.  In that case, the caller
59 * is responsible for waking up the swapper by calling kick_proc0() after
60 * releasing the sleep queue chain lock.
61 *
62 * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
63 * and releases it at thread destruction via sleepq_free().  Note that
64 * a sleep queue is not tied to a specific thread and that the sleep queue
65 * released at thread destruction may not be the same sleep queue that the
66 * thread allocated when it was created.
67 *
68 * XXX: Some other parts of the kernel such as ithread sleeping may end up
69 * using this interface as well (death to TDI_IWAIT!)
70 */
71
72struct lock_object;
73struct sleepqueue;
74struct thread;
75
76#ifdef _KERNEL
77
78#define	SLEEPQ_TYPE		0x0ff		/* Mask of sleep queue types. */
79#define	SLEEPQ_SLEEP		0x00		/* Used by sleep/wakeup. */
80#define	SLEEPQ_CONDVAR		0x01		/* Used for a cv. */
81#define	SLEEPQ_PAUSE		0x02		/* Used by pause. */
82#define	SLEEPQ_SX		0x03		/* Used by an sx lock. */
83#define	SLEEPQ_LK		0x04		/* Used by a lockmgr. */
84#define	SLEEPQ_INTERRUPTIBLE	0x100		/* Sleep is interruptible. */
85#define	SLEEPQ_UNFAIR		0x200		/* Unfair wakeup order. */
86
87void	init_sleepqueues(void);
88int	sleepq_abort(struct thread *td, int intrval);
89void	sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg,
90	    int flags, int queue);
91struct sleepqueue *sleepq_alloc(void);
92int	sleepq_broadcast(void *wchan, int flags, int pri, int queue);
93void	sleepq_chains_remove_matching(bool (*matches)(struct thread *));
94void	sleepq_free(struct sleepqueue *sq);
95void	sleepq_lock(void *wchan);
96struct sleepqueue *sleepq_lookup(void *wchan);
97void	sleepq_release(void *wchan);
98void	sleepq_remove(struct thread *td, void *wchan);
99int	sleepq_remove_matching(struct sleepqueue *sq, int queue,
100	    bool (*matches)(struct thread *), int pri);
101int	sleepq_signal(void *wchan, int flags, int pri, int queue);
102void	sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt,
103	    sbintime_t pr, int flags);
104#define	sleepq_set_timeout(wchan, timo)					\
105    sleepq_set_timeout_sbt((wchan), tick_sbt * (timo), 0, C_HARDCLOCK)
106u_int	sleepq_sleepcnt(void *wchan, int queue);
107int	sleepq_timedwait(void *wchan, int pri);
108int	sleepq_timedwait_sig(void *wchan, int pri);
109int	sleepq_type(void *wchan);
110void	sleepq_wait(void *wchan, int pri);
111int	sleepq_wait_sig(void *wchan, int pri);
112
113#ifdef STACK
114struct sbuf;
115int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue,
116    int *count_stacks_printed);
117#endif
118
119#endif	/* _KERNEL */
120#endif	/* !_SYS_SLEEPQUEUE_H_ */
121