"Sync" threading libaries.
[dragonfly.git] / lib / libthread_xu / thread / thr_pspinlock.c
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1/*-
2 * Copyright (c) 2003 David Xu <davidxu@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 *
fc71f871 26 * $DragonFly: src/lib/libthread_xu/thread/thr_pspinlock.c,v 1.4 2006/04/06 13:03:09 davidxu Exp $
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27 */
28
fc71f871 29#include "namespace.h"
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30#include <machine/tls.h>
31
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32#include <errno.h>
33#include <stdlib.h>
34#include <pthread.h>
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35#include <pthread_np.h>
36#include "un-namespace.h"
37
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38#include "thr_private.h"
39
40#define SPIN_COUNT 100000
41
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42int
43_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
44{
45 struct pthread_spinlock *lck;
46 int ret;
47
48 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
49 ret = EINVAL;
50 else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
51 ret = ENOMEM;
52 else {
53 _thr_umtx_init(&lck->s_lock);
54 *lock = lck;
55 ret = 0;
56 }
57
58 return (ret);
59}
60
61int
62_pthread_spin_destroy(pthread_spinlock_t *lock)
63{
64 int ret;
65
66 if (lock == NULL || *lock == NULL)
67 ret = EINVAL;
68 else {
69 free(*lock);
70 *lock = NULL;
71 ret = 0;
72 }
73
74 return (ret);
75}
76
77int
78_pthread_spin_trylock(pthread_spinlock_t *lock)
79{
9e2ee207 80 struct pthread *curthread = tls_get_curthread();
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81 struct pthread_spinlock *lck;
82 int ret;
83
84 if (lock == NULL || (lck = *lock) == NULL)
85 ret = EINVAL;
86 else
87 ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock);
88 return (ret);
89}
90
91int
92_pthread_spin_lock(pthread_spinlock_t *lock)
93{
9e2ee207 94 struct pthread *curthread = tls_get_curthread();
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95 struct pthread_spinlock *lck;
96 int ret, count;
97
98 if (lock == NULL || (lck = *lock) == NULL)
99 ret = EINVAL;
100 else {
101 count = SPIN_COUNT;
102 while ((ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock)) != 0) {
103 while (lck->s_lock) {
104#ifdef __i386__
105 /* tell cpu we are spinning */
106 __asm __volatile("pause");
107#endif
108 if (--count <= 0) {
109 count = SPIN_COUNT;
110 _pthread_yield();
111 }
112 }
113 }
114 ret = 0;
115 }
116
117 return (ret);
118}
119
120int
121_pthread_spin_unlock(pthread_spinlock_t *lock)
122{
9e2ee207 123 struct pthread *curthread = tls_get_curthread();
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124 struct pthread_spinlock *lck;
125 int ret;
126
127 if (lock == NULL || (lck = *lock) == NULL)
128 ret = EINVAL;
129 else {
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130 THR_UMTX_UNLOCK(curthread, &lck->s_lock);
131 ret = 0;
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132 }
133 return (ret);
134}
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135
136__strong_reference(_pthread_spin_init, pthread_spin_init);
137__strong_reference(_pthread_spin_destroy, pthread_spin_destroy);
138__strong_reference(_pthread_spin_trylock, pthread_spin_trylock);
139__strong_reference(_pthread_spin_lock, pthread_spin_lock);
140__strong_reference(_pthread_spin_unlock, pthread_spin_unlock);
141