thr_pspinlock.c revision 161068
1144518Sdavidxu/*- 2144518Sdavidxu * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 3144518Sdavidxu * All rights reserved. 4144518Sdavidxu * 5144518Sdavidxu * Redistribution and use in source and binary forms, with or without 6144518Sdavidxu * modification, are permitted provided that the following conditions 7144518Sdavidxu * are met: 8144518Sdavidxu * 1. Redistributions of source code must retain the above copyright 9144518Sdavidxu * notice, this list of conditions and the following disclaimer. 10144518Sdavidxu * 2. Redistributions in binary form must reproduce the above copyright 11144518Sdavidxu * notice, this list of conditions and the following disclaimer in the 12144518Sdavidxu * documentation and/or other materials provided with the distribution. 13144518Sdavidxu * 14144518Sdavidxu * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15144518Sdavidxu * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16144518Sdavidxu * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17144518Sdavidxu * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18144518Sdavidxu * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19144518Sdavidxu * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20144518Sdavidxu * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21144518Sdavidxu * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22144518Sdavidxu * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23144518Sdavidxu * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24144518Sdavidxu * SUCH DAMAGE. 25144518Sdavidxu * 26144518Sdavidxu * $FreeBSD: head/lib/libthr/thread/thr_pspinlock.c 161068 2006-08-08 04:42:41Z davidxu $ 27144518Sdavidxu */ 28144518Sdavidxu 29157457Sdavidxu#include "namespace.h" 30144518Sdavidxu#include <errno.h> 31144518Sdavidxu#include <stdlib.h> 32144518Sdavidxu#include <pthread.h> 33157457Sdavidxu#include "un-namespace.h" 34157457Sdavidxu 35144518Sdavidxu#include "thr_private.h" 36144518Sdavidxu 37144518Sdavidxu#define SPIN_COUNT 100000 38144518Sdavidxu 39144518Sdavidxu__weak_reference(_pthread_spin_init, pthread_spin_init); 40144518Sdavidxu__weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 41144518Sdavidxu__weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 42144518Sdavidxu__weak_reference(_pthread_spin_lock, pthread_spin_lock); 43144518Sdavidxu__weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 44144518Sdavidxu 45144518Sdavidxuint 46144518Sdavidxu_pthread_spin_init(pthread_spinlock_t *lock, int pshared) 47144518Sdavidxu{ 48144518Sdavidxu struct pthread_spinlock *lck; 49144518Sdavidxu int ret; 50144518Sdavidxu 51144518Sdavidxu if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE) 52144518Sdavidxu ret = EINVAL; 53144518Sdavidxu else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL) 54144518Sdavidxu ret = ENOMEM; 55144518Sdavidxu else { 56144518Sdavidxu _thr_umtx_init(&lck->s_lock); 57144518Sdavidxu *lock = lck; 58144518Sdavidxu ret = 0; 59144518Sdavidxu } 60144518Sdavidxu 61144518Sdavidxu return (ret); 62144518Sdavidxu} 63144518Sdavidxu 64144518Sdavidxuint 65144518Sdavidxu_pthread_spin_destroy(pthread_spinlock_t *lock) 66144518Sdavidxu{ 67144518Sdavidxu int ret; 68144518Sdavidxu 69144518Sdavidxu if (lock == NULL || *lock == NULL) 70144518Sdavidxu ret = EINVAL; 71144518Sdavidxu else { 72144518Sdavidxu free(*lock); 73144518Sdavidxu *lock = NULL; 74144518Sdavidxu ret = 0; 75144518Sdavidxu } 76144518Sdavidxu 77144518Sdavidxu return (ret); 78144518Sdavidxu} 79144518Sdavidxu 80144518Sdavidxuint 81144518Sdavidxu_pthread_spin_trylock(pthread_spinlock_t *lock) 82144518Sdavidxu{ 83144518Sdavidxu struct pthread *curthread = _get_curthread(); 84144518Sdavidxu struct pthread_spinlock *lck; 85144518Sdavidxu int ret; 86144518Sdavidxu 87144518Sdavidxu if (lock == NULL || (lck = *lock) == NULL) 88144518Sdavidxu ret = EINVAL; 89144518Sdavidxu else 90144518Sdavidxu ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock); 91144518Sdavidxu return (ret); 92144518Sdavidxu} 93144518Sdavidxu 94144518Sdavidxuint 95144518Sdavidxu_pthread_spin_lock(pthread_spinlock_t *lock) 96144518Sdavidxu{ 97144518Sdavidxu struct pthread *curthread = _get_curthread(); 98144518Sdavidxu struct pthread_spinlock *lck; 99144518Sdavidxu int ret, count; 100144518Sdavidxu 101144518Sdavidxu if (lock == NULL || (lck = *lock) == NULL) 102144518Sdavidxu ret = EINVAL; 103144518Sdavidxu else { 104144518Sdavidxu count = SPIN_COUNT; 105144518Sdavidxu while ((ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock)) != 0) { 106144518Sdavidxu while (lck->s_lock) { 107161068Sdavidxu if (_thr_smp_cpus <= 1) { 108161068Sdavidxu _pthread_yield(); 109161068Sdavidxu } else { 110161068Sdavidxu#if defined(__i386__) || defined(__x86_64__) 111161068Sdavidxu /* tell cpu we are spinning */ 112161068Sdavidxu __asm __volatile("pause"); 113144518Sdavidxu#endif 114161068Sdavidxu if (--count <= 0) { 115161068Sdavidxu count = SPIN_COUNT; 116161068Sdavidxu _pthread_yield(); 117161068Sdavidxu } 118144518Sdavidxu } 119144518Sdavidxu } 120144518Sdavidxu } 121144518Sdavidxu ret = 0; 122144518Sdavidxu } 123144518Sdavidxu 124144518Sdavidxu return (ret); 125144518Sdavidxu} 126144518Sdavidxu 127144518Sdavidxuint 128144518Sdavidxu_pthread_spin_unlock(pthread_spinlock_t *lock) 129144518Sdavidxu{ 130144518Sdavidxu struct pthread *curthread = _get_curthread(); 131144518Sdavidxu struct pthread_spinlock *lck; 132144518Sdavidxu int ret; 133144518Sdavidxu 134144518Sdavidxu if (lock == NULL || (lck = *lock) == NULL) 135144518Sdavidxu ret = EINVAL; 136144518Sdavidxu else { 137144518Sdavidxu ret = THR_UMTX_UNLOCK(curthread, &lck->s_lock); 138144518Sdavidxu } 139144518Sdavidxu return (ret); 140144518Sdavidxu} 141