mirror of
https://gcc.gnu.org/git/gcc.git
synced 2024-11-27 05:44:15 +08:00
8ed501f167
2015-05-27 Uros Bizjak <ubizjak@gmail.com> * config/linux/wait.h (gomp_futex_wait, gomp_futex_wake): Declare as int. (FUTEX_PRIVATE_FLAG): Remove L suffix. * config/linux/mutex.c (gomp_futex_wait, gomp_futex_wake): Declare as int. 2015-05-27 Uros Bizjak <ubizjak@gmail.com> * config/linux/ia64/futex.h (sys_futex0) Change operand "op" to int. 2015-05-27 Uros Bizjak <ubizjak@gmail.com> Revert: * config/linux/x86/futex.h (sys_futex0) [!__x86_64__]: Change operand "op" to long. From-SVN: r223780
71 lines
2.3 KiB
C
71 lines
2.3 KiB
C
/* Copyright (C) 2005-2015 Free Software Foundation, Inc.
|
|
Contributed by Richard Henderson <rth@redhat.com>.
|
|
|
|
This file is part of the GNU Offloading and Multi Processing Library
|
|
(libgomp).
|
|
|
|
Libgomp is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3, or (at your option)
|
|
any later version.
|
|
|
|
Libgomp 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 General Public License for
|
|
more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* This is a Linux specific implementation of a mutex synchronization
|
|
mechanism for libgomp. This type is private to the library. This
|
|
implementation uses atomic instructions and the futex syscall. */
|
|
|
|
#include "wait.h"
|
|
|
|
int gomp_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
|
|
int gomp_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
|
|
|
|
void
|
|
gomp_mutex_lock_slow (gomp_mutex_t *mutex, int oldval)
|
|
{
|
|
/* First loop spins a while. */
|
|
while (oldval == 1)
|
|
{
|
|
if (do_spin (mutex, 1))
|
|
{
|
|
/* Spin timeout, nothing changed. Set waiting flag. */
|
|
oldval = __atomic_exchange_n (mutex, -1, MEMMODEL_ACQUIRE);
|
|
if (oldval == 0)
|
|
return;
|
|
futex_wait (mutex, -1);
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
/* Something changed. If now unlocked, we're good to go. */
|
|
oldval = 0;
|
|
if (__atomic_compare_exchange_n (mutex, &oldval, 1, false,
|
|
MEMMODEL_ACQUIRE, MEMMODEL_RELAXED))
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Second loop waits until mutex is unlocked. We always exit this
|
|
loop with wait flag set, so next unlock will awaken a thread. */
|
|
while ((oldval = __atomic_exchange_n (mutex, -1, MEMMODEL_ACQUIRE)))
|
|
do_wait (mutex, -1);
|
|
}
|
|
|
|
void
|
|
gomp_mutex_unlock_slow (gomp_mutex_t *mutex)
|
|
{
|
|
futex_wake (mutex, 1);
|
|
}
|