freebsd-nq/lib/libthr/thread/thr_pspinlock.c
David Xu d99f6dac14 - Remove variable _thr_scope_system, all threads are system scope.
- Rename _thr_smp_cpus to boolean variable _thr_is_smp.
- Define CPU_SPINWAIT macro for each arch, only X86 supports it.
2006-12-15 11:52:01 +00:00

139 lines
3.4 KiB
C

/*-
* Copyright (c) 2003 David Xu <davidxu@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include "namespace.h"
#include <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"
#define SPIN_COUNT 100000
__weak_reference(_pthread_spin_init, pthread_spin_init);
__weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
__weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
__weak_reference(_pthread_spin_lock, pthread_spin_lock);
__weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
int
_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
ret = EINVAL;
else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
ret = ENOMEM;
else {
_thr_umutex_init(&lck->s_lock);
*lock = lck;
ret = 0;
}
return (ret);
}
int
_pthread_spin_destroy(pthread_spinlock_t *lock)
{
int ret;
if (lock == NULL || *lock == NULL)
ret = EINVAL;
else {
free(*lock);
*lock = NULL;
ret = 0;
}
return (ret);
}
int
_pthread_spin_trylock(pthread_spinlock_t *lock)
{
struct pthread *curthread = _get_curthread();
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else
ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock);
return (ret);
}
int
_pthread_spin_lock(pthread_spinlock_t *lock)
{
struct pthread *curthread = _get_curthread();
struct pthread_spinlock *lck;
int ret, count;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else {
count = SPIN_COUNT;
while ((ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock)) != 0) {
while (lck->s_lock.m_owner) {
if (_thr_is_smp) {
_pthread_yield();
} else {
CPU_SPINWAIT;
if (--count <= 0) {
count = SPIN_COUNT;
_pthread_yield();
}
}
}
}
ret = 0;
}
return (ret);
}
int
_pthread_spin_unlock(pthread_spinlock_t *lock)
{
struct pthread *curthread = _get_curthread();
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else {
ret = THR_UMUTEX_UNLOCK(curthread, &lck->s_lock);
}
return (ret);
}