2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
30 #ifndef _SYS_SLEEPQUEUE_H_
31 #define _SYS_SLEEPQUEUE_H_
34 * Sleep queue interface. Sleep/wakeup, condition variables, and sx
35 * locks use a sleep queue for the queue of threads blocked on a sleep
38 * A thread calls sleepq_lock() to lock the sleep queue chain associated
39 * with a given wait channel. A thread can then call call sleepq_add() to
40 * add themself onto a sleep queue and call one of the sleepq_wait()
41 * functions to actually go to sleep. If a thread needs to abort a sleep
42 * operation it should call sleepq_release() to unlock the associated sleep
43 * queue chain lock. If the thread also needs to remove itself from a queue
44 * it just enqueued itself on, it can use sleepq_remove() instead.
46 * If the thread only wishes to sleep for a limited amount of time, it can
47 * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It
48 * should then use one of the sleepq_timedwait() functions to block.
50 * A thread is normally resumed from a sleep queue by either the
51 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes
52 * the thread with the highest priority that is sleeping on the specified
53 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping
54 * on the specified wait channel. A thread sleeping in an interruptible
55 * sleep can be interrupted by calling sleepq_abort(). A thread can also
56 * be removed from a specified sleep queue using the sleepq_remove()
57 * function. Note that the sleep queue chain must first be locked via
58 * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or
59 * sleepq_signal(). These routines each return a boolean that will be true
60 * if at least one swapped-out thread was resumed. In that case, the caller
61 * is responsible for waking up the swapper by calling kick_proc0() after
62 * releasing the sleep queue chain lock.
64 * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
65 * and releases it at thread destruction via sleepq_free(). Note that
66 * a sleep queue is not tied to a specific thread and that the sleep queue
67 * released at thread destruction may not be the same sleep queue that the
68 * thread allocated when it was created.
70 * XXX: Some other parts of the kernel such as ithread sleeping may end up
71 * using this interface as well (death to TDI_IWAIT!)
80 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */
81 #define SLEEPQ_SLEEP 0x00 /* Used by sleep/wakeup. */
82 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */
83 #define SLEEPQ_PAUSE 0x02 /* Used by pause. */
84 #define SLEEPQ_SX 0x03 /* Used by an sx lock. */
85 #define SLEEPQ_LK 0x04 /* Used by a lockmgr. */
86 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */
87 #define SLEEPQ_UNFAIR 0x200 /* Unfair wakeup order. */
89 void init_sleepqueues(void);
90 int sleepq_abort(struct thread *td, int intrval);
91 void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg,
92 int flags, int queue);
93 struct sleepqueue *sleepq_alloc(void);
94 int sleepq_broadcast(void *wchan, int flags, int pri, int queue);
95 void sleepq_chains_remove_matching(bool (*matches)(struct thread *));
96 void sleepq_free(struct sleepqueue *sq);
97 void sleepq_lock(void *wchan);
98 struct sleepqueue *sleepq_lookup(void *wchan);
99 void sleepq_release(void *wchan);
100 void sleepq_remove(struct thread *td, void *wchan);
101 int sleepq_remove_matching(struct sleepqueue *sq, int queue,
102 bool (*matches)(struct thread *), int pri);
103 int sleepq_signal(void *wchan, int flags, int pri, int queue);
104 void sleepq_set_timeout_sbt(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)
108 u_int sleepq_sleepcnt(void *wchan, int queue);
109 int sleepq_timedwait(void *wchan, int pri);
110 int sleepq_timedwait_sig(void *wchan, int pri);
111 int sleepq_type(void *wchan);
112 void sleepq_wait(void *wchan, int pri);
113 int sleepq_wait_sig(void *wchan, int pri);
117 int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue,
118 int *count_stacks_printed);
122 #endif /* !_SYS_SLEEPQUEUE_H_ */