mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
79 lines
2.6 KiB
C
79 lines
2.6 KiB
C
/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
|
|
|
|
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; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <sysdep.h>
|
|
#include <lowlevellock.h>
|
|
#include <pthreadP.h>
|
|
|
|
|
|
/* Wait on barrier. */
|
|
int
|
|
pthread_barrier_wait (barrier)
|
|
pthread_barrier_t *barrier;
|
|
{
|
|
struct pthread_barrier *ibarrier = (struct pthread_barrier *) barrier;
|
|
int result = 0;
|
|
|
|
/* Make sure we are alone. */
|
|
lll_lock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
|
|
|
|
/* One more arrival. */
|
|
--ibarrier->left;
|
|
|
|
/* Are these all? */
|
|
if (ibarrier->left == 0)
|
|
{
|
|
/* Yes. Increment the event counter to avoid invalid wake-ups and
|
|
tell the current waiters that it is their turn. */
|
|
++ibarrier->curr_event;
|
|
|
|
/* Wake up everybody. */
|
|
lll_futex_wake (&ibarrier->curr_event, INT_MAX,
|
|
ibarrier->private ^ FUTEX_PRIVATE_FLAG);
|
|
|
|
/* This is the thread which finished the serialization. */
|
|
result = PTHREAD_BARRIER_SERIAL_THREAD;
|
|
}
|
|
else
|
|
{
|
|
/* The number of the event we are waiting for. The barrier's event
|
|
number must be bumped before we continue. */
|
|
unsigned int event = ibarrier->curr_event;
|
|
|
|
/* Before suspending, make the barrier available to others. */
|
|
lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
|
|
|
|
/* Wait for the event counter of the barrier to change. */
|
|
do
|
|
lll_futex_wait (&ibarrier->curr_event, event,
|
|
ibarrier->private ^ FUTEX_PRIVATE_FLAG);
|
|
while (event == ibarrier->curr_event);
|
|
}
|
|
|
|
/* Make sure the init_count is stored locally or in a register. */
|
|
unsigned int init_count = ibarrier->init_count;
|
|
|
|
/* If this was the last woken thread, unlock. */
|
|
if (atomic_increment_val (&ibarrier->left) == init_count)
|
|
/* We are done. */
|
|
lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
|
|
|
|
return result;
|
|
}
|