sleepqueue.h revision 262192
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 * 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 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: stable/10/sys/sys/sleepqueue.h 262192 2014-02-18 20:27:17Z jhb $ 27 */ 28 29#ifndef _SYS_SLEEPQUEUE_H_ 30#define _SYS_SLEEPQUEUE_H_ 31 32/* 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 35 * channel. 36 * 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. 44 * 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. 48 * 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(). 55 * 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. 69 * 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. 75 * 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!) 78 */ 79 80struct lock_object; 81struct sleepqueue; 82struct thread; 83 84#ifdef _KERNEL 85 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. */ 93 94void init_sleepqueues(void); 95int sleepq_abort(struct thread *td, int intrval); 96void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg, 97 int flags, int queue); 98struct sleepqueue *sleepq_alloc(void); 99int sleepq_broadcast(void *wchan, int flags, int pri, int queue); 100void sleepq_free(struct sleepqueue *sq); 101void sleepq_lock(void *wchan); 102struct sleepqueue *sleepq_lookup(void *wchan); 103void sleepq_release(void *wchan); 104void sleepq_remove(struct thread *td, void *wchan); 105int sleepq_signal(void *wchan, int flags, int pri, int queue); 106void 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) 110u_int sleepq_sleepcnt(void *wchan, int queue); 111int sleepq_timedwait(void *wchan, int pri); 112int sleepq_timedwait_sig(void *wchan, int pri); 113int sleepq_type(void *wchan); 114void sleepq_wait(void *wchan, int pri); 115int sleepq_wait_sig(void *wchan, int pri); 116 117#endif /* _KERNEL */ 118#endif /* !_SYS_SLEEPQUEUE_H_ */ 119