1/* Copyright (C) 2008, 2009 Free Software Foundation, Inc. 2 Contributed by Jakub Jelinek <jakub@redhat.com>. 3 4 This file is part of the GNU OpenMP Library (libgomp). 5 6 Libgomp is free software; you can redistribute it and/or modify it 7 under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25/* This is a Linux specific implementation of a mutex synchronization 26 mechanism for libgomp. This type is private to the library. This 27 implementation uses atomic instructions and the futex syscall. */ 28 29#ifndef GOMP_WAIT_H 30#define GOMP_WAIT_H 1 31 32#include "libgomp.h" 33#include <errno.h> 34 35#define FUTEX_WAIT 0 36#define FUTEX_WAKE 1 37#define FUTEX_PRIVATE_FLAG 128L 38 39#ifdef HAVE_ATTRIBUTE_VISIBILITY 40# pragma GCC visibility push(hidden) 41#endif 42 43extern long int gomp_futex_wait, gomp_futex_wake; 44 45#include "futex.h" 46 47static inline void do_wait (int *addr, int val) 48{ 49 unsigned long long i, count = gomp_spin_count_var; 50 51 if (__builtin_expect (gomp_managed_threads > gomp_available_cpus, 0)) 52 count = gomp_throttled_spin_count_var; 53 for (i = 0; i < count; i++) 54 if (__builtin_expect (*addr != val, 0)) 55 return; 56 else 57 cpu_relax (); 58 futex_wait (addr, val); 59} 60 61#ifdef HAVE_ATTRIBUTE_VISIBILITY 62# pragma GCC visibility pop 63#endif 64 65#endif /* GOMP_WAIT_H */ 66