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