1 /*- 2 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 16 * 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 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 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 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 #ifndef _SYS_SLEEPQUEUE_H_ 33 #define _SYS_SLEEPQUEUE_H_ 34 35 /* 36 * Sleep queue interface. Sleep/wakeup and condition variables use a sleep 37 * queue for the queue of threads blocked on a sleep channel. 38 * 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. 46 * 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. 50 * 51 * If the thread wants to the sleep to be interruptible by signals, it can 52 * call sleepq_catch_signals() after sleepq_add(). It should then use 53 * one of the sleepq_wait_sig() functions to block. After the thread has 54 * been resumed, it should call sleepq_calc_signal_retval() to determine 55 * if it should return EINTR or ERESTART passing in the value returned from 56 * the earlier call to sleepq_catch_signals(). 57 * 58 * A thread is normally resumed from a sleep queue by either the 59 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes 60 * the thread with the highest priority that is sleeping on the specified 61 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping 62 * on the specified wait channel. A thread sleeping in an interruptible 63 * sleep can be interrupted by calling sleepq_abort(). A thread can also 64 * be removed from a specified sleep queue using the sleepq_remove() 65 * function. Note that the sleep queue chain must first be locked via 66 * sleepq_lock() when calling sleepq_signal() and sleepq_broadcast(). 67 * 68 * Each thread allocates a sleep queue at thread creation via sleepq_alloc() 69 * and releases it at thread destruction via sleepq_free(). Note that 70 * a sleep queue is not tied to a specific thread and that the sleep queue 71 * released at thread destruction may not be the same sleep queue that the 72 * thread allocated when it was created. 73 * 74 * XXX: Some other parts of the kernel such as ithread sleeping may end up 75 * using this interface as well (death to TDI_IWAIT!) 76 */ 77 78 struct lock_object; 79 struct sleepqueue; 80 struct thread; 81 82 #ifdef _KERNEL 83 84 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */ 85 #define SLEEPQ_MSLEEP 0x00 /* Used by msleep/wakeup. */ 86 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */ 87 #define SLEEPQ_PAUSE 0x02 /* Used by pause. */ 88 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */ 89 90 void init_sleepqueues(void); 91 void 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 void sleepq_broadcast(void *wchan, int flags, int pri, int queue); 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 void sleepq_signal(void *wchan, int flags, int pri, int queue); 102 void sleepq_set_timeout(void *wchan, int timo); 103 int sleepq_timedwait(void *wchan); 104 int sleepq_timedwait_sig(void *wchan); 105 void sleepq_wait(void *wchan); 106 int sleepq_wait_sig(void *wchan); 107 108 #endif /* _KERNEL */ 109 #endif /* !_SYS_SLEEPQUEUE_H_ */ 110