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