mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 04:50:07 +00:00
129 lines
3.4 KiB
C
129 lines
3.4 KiB
C
/* POSIX barrier implementation for LinuxThreads.
|
|
Copyright (C) 2000, 2003 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Kaz Kylheku <kaz@ashi.footprints.net>, 2000.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#include <errno.h>
|
|
#include "pthread.h"
|
|
#include "internals.h"
|
|
#include "spinlock.h"
|
|
#include "queue.h"
|
|
#include "restart.h"
|
|
|
|
int
|
|
pthread_barrier_wait(pthread_barrier_t *barrier)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
pthread_descr temp_wake_queue, th;
|
|
int result = 0;
|
|
|
|
__pthread_lock(&barrier->__ba_lock, self);
|
|
|
|
/* If the required number of threads have achieved rendezvous... */
|
|
if (barrier->__ba_present >= barrier->__ba_required - 1)
|
|
{
|
|
/* ... then this last caller shall be the serial thread */
|
|
result = PTHREAD_BARRIER_SERIAL_THREAD;
|
|
/* Copy and clear wait queue and reset barrier. */
|
|
temp_wake_queue = barrier->__ba_waiting;
|
|
barrier->__ba_waiting = NULL;
|
|
barrier->__ba_present = 0;
|
|
}
|
|
else
|
|
{
|
|
result = 0;
|
|
barrier->__ba_present++;
|
|
enqueue(&barrier->__ba_waiting, self);
|
|
}
|
|
|
|
__pthread_unlock(&barrier->__ba_lock);
|
|
|
|
if (result == 0)
|
|
{
|
|
/* Non-serial threads have to suspend */
|
|
suspend(self);
|
|
/* We don't bother dealing with cancellation because the POSIX
|
|
spec for barriers doesn't mention that pthread_barrier_wait
|
|
is a cancellation point. */
|
|
}
|
|
else
|
|
{
|
|
/* Serial thread wakes up all others. */
|
|
while ((th = dequeue(&temp_wake_queue)) != NULL)
|
|
restart(th);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
int
|
|
pthread_barrier_init(pthread_barrier_t *barrier,
|
|
const pthread_barrierattr_t *attr,
|
|
unsigned int count)
|
|
{
|
|
if (count == 0)
|
|
return EINVAL;
|
|
|
|
__pthread_init_lock(&barrier->__ba_lock);
|
|
barrier->__ba_required = count;
|
|
barrier->__ba_present = 0;
|
|
barrier->__ba_waiting = NULL;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pthread_barrier_destroy(pthread_barrier_t *barrier)
|
|
{
|
|
if (barrier->__ba_waiting != NULL) return EBUSY;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pthread_barrierattr_init(pthread_barrierattr_t *attr)
|
|
{
|
|
attr->__pshared = PTHREAD_PROCESS_PRIVATE;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pthread_barrierattr_destroy(pthread_barrierattr_t *attr)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
__pthread_barrierattr_getpshared(const pthread_barrierattr_t *attr,
|
|
int *pshared)
|
|
{
|
|
*pshared = PTHREAD_PROCESS_PRIVATE;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared)
|
|
{
|
|
if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED)
|
|
return EINVAL;
|
|
|
|
/* For now it is not possible to shared a conditional variable. */
|
|
if (pshared != PTHREAD_PROCESS_PRIVATE)
|
|
return ENOSYS;
|
|
|
|
return 0;
|
|
}
|