1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #ifndef _SYS_SLEEPQUEUE_H_ 31 #define _SYS_SLEEPQUEUE_H_ 32 33 /* 34 * Sleep queue interface. Sleep/wakeup, condition variables, and sx 35 * locks use a sleep queue for the queue of threads blocked on a sleep 36 * channel. 37 * 38 * A thread calls sleepq_lock() to lock the sleep queue chain associated 39 * with a given wait channel. A thread can then call call sleepq_add() to 40 * add themself onto a sleep queue and call one of the sleepq_wait() 41 * functions to actually go to sleep. If a thread needs to abort a sleep 42 * operation it should call sleepq_release() to unlock the associated sleep 43 * queue chain lock. If the thread also needs to remove itself from a queue 44 * it just enqueued itself on, it can use sleepq_remove() instead. 45 * 46 * If the thread only wishes to sleep for a limited amount of time, it can 47 * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It 48 * should then use one of the sleepq_timedwait() functions to block. 49 * 50 * A thread is normally resumed from a sleep queue by either the 51 * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes 52 * the thread with the highest priority that is sleeping on the specified 53 * wait channel. Sleepq_broadcast() wakes all threads that are sleeping 54 * on the specified wait channel. A thread sleeping in an interruptible 55 * sleep can be interrupted by calling sleepq_abort(). A thread can also 56 * be removed from a specified sleep queue using the sleepq_remove() 57 * function. Note that the sleep queue chain must first be locked via 58 * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or 59 * sleepq_signal(). These routines each return a boolean that will be true 60 * if at least one swapped-out thread was resumed. In that case, the caller 61 * is responsible for waking up the swapper by calling kick_proc0() after 62 * releasing the sleep queue chain lock. 63 * 64 * Each thread allocates a sleep queue at thread creation via sleepq_alloc() 65 * and releases it at thread destruction via sleepq_free(). Note that 66 * a sleep queue is not tied to a specific thread and that the sleep queue 67 * released at thread destruction may not be the same sleep queue that the 68 * thread allocated when it was created. 69 * 70 * XXX: Some other parts of the kernel such as ithread sleeping may end up 71 * using this interface as well (death to TDI_IWAIT!) 72 */ 73 74 struct lock_object; 75 struct sleepqueue; 76 struct thread; 77 78 #ifdef _KERNEL 79 80 #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */ 81 #define SLEEPQ_SLEEP 0x00 /* Used by sleep/wakeup. */ 82 #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */ 83 #define SLEEPQ_PAUSE 0x02 /* Used by pause. */ 84 #define SLEEPQ_SX 0x03 /* Used by an sx lock. */ 85 #define SLEEPQ_LK 0x04 /* Used by a lockmgr. */ 86 #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */ 87 #define SLEEPQ_UNFAIR 0x200 /* Unfair wakeup order. */ 88 #define SLEEPQ_DROP 0x400 /* Return without lock held. */ 89 90 void init_sleepqueues(void); 91 int sleepq_abort(struct thread *td, int intrval); 92 void sleepq_add(const void *wchan, struct lock_object *lock, 93 const char *wmesg, int flags, int queue); 94 struct sleepqueue *sleepq_alloc(void); 95 int sleepq_broadcast(const void *wchan, int flags, int pri, int queue); 96 void sleepq_chains_remove_matching(bool (*matches)(struct thread *)); 97 void sleepq_free(struct sleepqueue *sq); 98 void sleepq_lock(const void *wchan); 99 struct sleepqueue *sleepq_lookup(const void *wchan); 100 void sleepq_release(const void *wchan); 101 void sleepq_remove(struct thread *td, const void *wchan); 102 int sleepq_remove_matching(struct sleepqueue *sq, int queue, 103 bool (*matches)(struct thread *), int pri); 104 void sleepq_remove_nested(struct thread *td); 105 int sleepq_signal(const void *wchan, int flags, int pri, int queue); 106 void sleepq_set_timeout_sbt(const 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(const void *wchan, int queue); 111 int sleepq_timedwait(const void *wchan, int pri); 112 int sleepq_timedwait_sig(const void *wchan, int pri); 113 int sleepq_type(const void *wchan); 114 void sleepq_wait(const void *wchan, int pri); 115 int sleepq_wait_sig(const void *wchan, int pri); 116 117 #ifdef STACK 118 struct sbuf; 119 int sleepq_sbuf_print_stacks(struct sbuf *sb, const void *wchan, int queue, 120 int *count_stacks_printed); 121 #endif 122 123 #endif /* _KERNEL */ 124 #endif /* !_SYS_SLEEPQUEUE_H_ */ 125