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Added futex-based implementation for waiting/notifying operations.

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This commit is contained in:
Andrey Semashev
2020-05-30 14:47:28 +03:00
parent 76e25f36a3
commit bf182818f4
2 changed files with 73 additions and 0 deletions
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9
include/boost/atomic/detail/platform.hpp
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@@ -133,6 +133,15 @@
#endif // !defined(BOOST_ATOMIC_DETAIL_CORE_BACKEND)
// Waiting and notifying operations backends
#if !defined(BOOST_WINDOWS)
#include <boost/atomic/detail/futex.hpp>
#if defined(BOOST_ATOMIC_DETAIL_HAS_FUTEX)
#define BOOST_ATOMIC_DETAIL_WAIT_BACKEND futex
#endif
#endif // !defined(BOOST_WINDOWS)
#endif // !defined(BOOST_ATOMIC_FORCE_FALLBACK)
#if !defined(BOOST_ATOMIC_DETAIL_CORE_BACKEND)

64
include/boost/atomic/detail/wait_ops_futex.hpp Normal file
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@@ -0,0 +1,64 @@
/*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* Copyright (c) 2020 Andrey Semashev
*/
/*!
* \file atomic/detail/wait_ops_futex.hpp
*
* This header contains implementation of the wait/notify atomic operations based on futexes.
*/
#ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_FUTEX_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_WAIT_OPS_FUTEX_HPP_INCLUDED_
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/futex.hpp>
#include <boost/atomic/detail/wait_operations_fwd.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
template< typename Base >
struct wait_operations< Base, 4u, true > :
public Base
{
typedef Base base_type;
typedef typename base_type::storage_type storage_type;
static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
{
storage_type new_val = base_type::load(storage, order);
while (new_val == old_val)
{
atomics::detail::futex_wait_private(const_cast< storage_type* >(&storage), old_val);
new_val = base_type::load(storage, order);
}
return new_val;
}
static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
{
atomics::detail::futex_signal_private(const_cast< storage_type* >(&storage));
}
static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
{
atomics::detail::futex_broadcast_private(const_cast< storage_type* >(&storage));
}
};
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_FUTEX_HPP_INCLUDED_