1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
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#define SLEEPQ_DROP 0x400 /* Return without lock held. */
87
88void init_sleepqueues(void);
89void sleepq_abort(struct thread *td, int intrval);
90void sleepq_add(const void *wchan, struct lock_object *lock,
91 const char *wmesg, int flags, int queue);
92struct sleepqueue *sleepq_alloc(void);
93void sleepq_broadcast(const void *wchan, int flags, int pri, int queue);
94void sleepq_chains_remove_matching(bool (*matches)(struct thread *));
95void sleepq_free(struct sleepqueue *sq);
96void sleepq_lock(const void *wchan);
97struct sleepqueue *sleepq_lookup(const void *wchan);
98void sleepq_release(const void *wchan);
99void sleepq_remove(struct thread *td, const void *wchan);
100void sleepq_remove_matching(struct sleepqueue *sq, int queue,
101 bool (*matches)(struct thread *), int pri);
102void sleepq_remove_nested(struct thread *td);
103void sleepq_signal(const void *wchan, int flags, int pri, int queue);
104void sleepq_set_timeout_sbt(const void *wchan, sbintime_t sbt,
105 sbintime_t pr, int flags);
106#define sleepq_set_timeout(wchan, timo) \
107 sleepq_set_timeout_sbt((wchan), tick_sbt * (timo), 0, C_HARDCLOCK)
108u_int sleepq_sleepcnt(const void *wchan, int queue);
109int sleepq_timedwait(const void *wchan, int pri);
110int sleepq_timedwait_sig(const void *wchan, int pri);
111int sleepq_type(const void *wchan);
112void sleepq_wait(const void *wchan, int pri);
113int sleepq_wait_sig(const void *wchan, int pri);
114
115#ifdef STACK
116struct sbuf;
117int sleepq_sbuf_print_stacks(struct sbuf *sb, const void *wchan, int queue,
118 int *count_stacks_printed);
119#endif
120
121#endif /* _KERNEL */
122#endif /* !_SYS_SLEEPQUEUE_H_ */