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, condition variables, and sx 37 * locks use a sleep queue for the queue of threads blocked on a sleep 38 * channel. 39 * 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. 47 * 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. 51 * 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(). 58 * 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. 72 * 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. 78 * 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!) 81 */ 82 83 struct lock_object; 84 struct sleepqueue; 85 struct thread; 86 87 #ifdef _KERNEL 88 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. */ 96 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); 119 120 #endif /* _KERNEL */ 121 #endif /* !_SYS_SLEEPQUEUE_H_ */ 122