1 /* 2 * Distributed under the Boost Software License, Version 1.0. 3 * (See accompanying file LICENSE_1_0.txt or copy at 4 * http://www.boost.org/LICENSE_1_0.txt) 5 * 6 * Copyright (c) 2020 Andrey Semashev 7 */ 8 /*! 9 * \file atomic/detail/wait_ops_dragonfly_umtx.hpp 10 * 11 * This header contains implementation of the waiting/notifying atomic operations based on DragonFly BSD umtx. 12 * https://man.dragonflybsd.org/?command=umtx§ion=2 13 */ 14 15 #ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_ 16 #define BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_ 17 18 #include <unistd.h> 19 #include <boost/memory_order.hpp> 20 #include <boost/atomic/detail/config.hpp> 21 #include <boost/atomic/detail/wait_operations_fwd.hpp> 22 #include <boost/atomic/detail/header.hpp> 23 24 #ifdef BOOST_HAS_PRAGMA_ONCE 25 #pragma once 26 #endif 27 28 namespace boost { 29 namespace atomics { 30 namespace detail { 31 32 template< typename Base, bool Interprocess > 33 struct wait_operations< Base, sizeof(int), true, Interprocess > : 34 public Base 35 { 36 typedef Base base_type; 37 typedef typename base_type::storage_type storage_type; 38 39 static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = true; 40 has_native_wait_notifyboost::atomics::detail::wait_operations41 static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT 42 { 43 return true; 44 } 45 waitboost::atomics::detail::wait_operations46 static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT 47 { 48 storage_type new_val = base_type::load(storage, order); 49 while (new_val == old_val) 50 { 51 ::umtx_sleep(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), static_cast< int >(old_val), 0); 52 new_val = base_type::load(storage, order); 53 } 54 55 return new_val; 56 } 57 notify_oneboost::atomics::detail::wait_operations58 static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT 59 { 60 ::umtx_wakeup(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), 1); 61 } 62 notify_allboost::atomics::detail::wait_operations63 static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT 64 { 65 ::umtx_wakeup(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), 0); 66 } 67 }; 68 69 } // namespace detail 70 } // namespace atomics 71 } // namespace boost 72 73 #include <boost/atomic/detail/footer.hpp> 74 75 #endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_ 76