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.
13 * 3. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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32 #ifndef _SYS_SLEEPQUEUE_H_
33 #define _SYS_SLEEPQUEUE_H_
36 * Sleep queue interface. Sleep/wakeup, condition variables, and sx
37 * locks use a sleep queue for the queue of threads blocked on a sleep
40 * A thread calls sleepq_lock() to lock the sleep queue chain associated
41 * with a given wait channel. A thread can then call call sleepq_add() to
42 * add themself onto a sleep queue and call one of the sleepq_wait()
43 * functions to actually go to sleep. If a thread needs to abort a sleep
44 * operation it should call sleepq_release() to unlock the associated sleep
45 * queue chain lock. If the thread also needs to remove itself from a queue
46 * it just enqueued itself on, it can use sleepq_remove() instead.
48 * If the thread only wishes to sleep for a limited amount of time, it can
49 * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It
50 * should then use one of the sleepq_timedwait() functions to block.
52 * If the thread wants the sleep to be interruptible by signals, it can
53 * call sleepq_catch_signals() after sleepq_add(). It should then use
54 * one of the sleepq_wait_sig() functions to block. After the thread has
55 * been resumed, it should call sleepq_calc_signal_retval() to determine
56 * if it should return EINTR or ERESTART passing in the value returned from
57 * the earlier call to sleepq_catch_signals().
59 * A thread is normally resumed from a sleep queue by either the
60 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes
61 * the thread with the highest priority that is sleeping on the specified
62 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping
63 * on the specified wait channel. A thread sleeping in an interruptible
64 * sleep can be interrupted by calling sleepq_abort(). A thread can also
65 * be removed from a specified sleep queue using the sleepq_remove()
66 * function. Note that the sleep queue chain must first be locked via
67 * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or
68 * sleepq_signal(). These routines each return a boolean that will be true
69 * if at least one swapped-out thread was resumed. In that case, the caller
70 * is responsible for waking up the swapper by calling kick_proc0() after
71 * releasing the sleep queue chain lock.
73 * Each thread allocates a sleep queue at thread creation via sleepq_alloc()
74 * and releases it at thread destruction via sleepq_free(). Note that
75 * a sleep queue is not tied to a specific thread and that the sleep queue
76 * released at thread destruction may not be the same sleep queue that the
77 * thread allocated when it was created.
79 * XXX: Some other parts of the kernel such as ithread sleeping may end up
80 * using this interface as well (death to TDI_IWAIT!)
89 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */
90 #define SLEEPQ_SLEEP 0x00 /* Used by sleep/wakeup. */
91 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */
92 #define SLEEPQ_PAUSE 0x02 /* Used by pause. */
93 #define SLEEPQ_SX 0x03 /* Used by an sx lock. */
94 #define SLEEPQ_LK 0x04 /* Used by a lockmgr. */
95 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */
97 void init_sleepqueues(void);
98 int sleepq_abort(struct thread *td, int intrval);
99 void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg,
100 int flags, int queue);
101 struct sleepqueue *sleepq_alloc(void);
102 int sleepq_broadcast(void *wchan, int flags, int pri, int queue);
103 void sleepq_free(struct sleepqueue *sq);
104 void sleepq_lock(void *wchan);
105 struct sleepqueue *sleepq_lookup(void *wchan);
106 void sleepq_release(void *wchan);
107 void sleepq_remove(struct thread *td, void *wchan);
108 int sleepq_signal(void *wchan, int flags, int pri, int queue);
109 void sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt,
110 sbintime_t pr, int flags);
111 #define sleepq_set_timeout(wchan, timo) \
112 sleepq_set_timeout_sbt((wchan), tick_sbt * (timo), 0, C_HARDCLOCK)
113 u_int sleepq_sleepcnt(void *wchan, int queue);
114 int sleepq_timedwait(void *wchan, int pri);
115 int sleepq_timedwait_sig(void *wchan, int pri);
116 int sleepq_type(void *wchan);
117 void sleepq_wait(void *wchan, int pri);
118 int sleepq_wait_sig(void *wchan, int pri);
121 #endif /* !_SYS_SLEEPQUEUE_H_ */