/* Copyright (C) 2008-2018 Free Software Foundation, Inc. Contributed by Jakub Jelinek . 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 . */ /* 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. */ #ifndef GOMP_WAIT_H #define GOMP_WAIT_H 1 #include "libgomp.h" #include #define FUTEX_WAIT 0 #define FUTEX_WAKE 1 #define FUTEX_PRIVATE_FLAG 128 #ifdef HAVE_ATTRIBUTE_VISIBILITY # pragma GCC visibility push(hidden) #endif extern int gomp_futex_wait, gomp_futex_wake; #include static inline int do_spin (int *addr, int val) { unsigned long long i, count = gomp_spin_count_var; if (__builtin_expect (__atomic_load_n (&gomp_managed_threads, MEMMODEL_RELAXED) > gomp_available_cpus, 0)) count = gomp_throttled_spin_count_var; for (i = 0; i < count; i++) if (__builtin_expect (__atomic_load_n (addr, MEMMODEL_RELAXED) != val, 0)) return 0; else cpu_relax (); return 1; } static inline void do_wait (int *addr, int val) { if (do_spin (addr, val)) futex_wait (addr, val); } #ifdef HAVE_ATTRIBUTE_VISIBILITY # pragma GCC visibility pop #endif #endif /* GOMP_WAIT_H */