145 lines
4.4 KiB
C++
145 lines
4.4 KiB
C++
/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2020-2025 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/wait_ops_dragonfly_umtx.hpp
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*
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* This header contains implementation of the waiting/notifying atomic operations based on DragonFly BSD umtx.
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* https://man.dragonflybsd.org/?command=umtx§ion=2
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*/
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#ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_
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#include <unistd.h>
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#include <cstdint>
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#include <limits>
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#include <chrono>
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#include <boost/memory_order.hpp>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/chrono.hpp>
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#include <boost/atomic/detail/wait_operations_fwd.hpp>
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#include <boost/atomic/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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template< typename Base, bool Interprocess >
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struct wait_operations< Base, sizeof(int), true, Interprocess > :
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public Base
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{
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using base_type = Base;
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using storage_type = typename base_type::storage_type;
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public:
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static constexpr bool always_has_native_wait_notify = true;
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static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) noexcept
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{
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return true;
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}
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static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) noexcept
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{
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storage_type new_val = base_type::load(storage, order);
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while (new_val == old_val)
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{
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umtx_sleep(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), static_cast< int >(old_val), 0);
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new_val = base_type::load(storage, order);
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}
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return new_val;
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}
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private:
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template< typename Clock >
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static BOOST_FORCEINLINE storage_type wait_until_impl
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(
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storage_type const volatile& storage,
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storage_type old_val,
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typename Clock::time_point timeout,
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typename Clock::time_point now,
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memory_order order,
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bool& timed_out
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) noexcept(noexcept(Clock::now()))
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{
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storage_type new_val = base_type::load(storage, order);
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while (new_val == old_val)
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{
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const std::int64_t usec = atomics::detail::chrono::ceil< std::chrono::microseconds >(timeout - now).count();
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if (usec <= 0)
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{
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timed_out = true;
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break;
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}
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umtx_sleep
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(
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reinterpret_cast< int* >(const_cast< storage_type* >(&storage)),
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static_cast< int >(old_val),
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usec <= (std::numeric_limits< int >::max)() ? static_cast< int >(usec) : (std::numeric_limits< int >::max)()
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);
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now = Clock::now();
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new_val = base_type::load(storage, order);
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}
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return new_val;
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}
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public:
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template< typename Clock, typename Duration >
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static BOOST_FORCEINLINE storage_type wait_until
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(
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storage_type const volatile& storage,
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storage_type old_val,
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std::chrono::time_point< Clock, Duration > timeout,
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memory_order order,
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bool& timed_out
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) noexcept(noexcept(Clock::now()))
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{
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return wait_until_impl< Clock >(storage, old_val, timeout, Clock::now(), order, timed_out);
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}
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template< typename Rep, typename Period >
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static BOOST_FORCEINLINE storage_type wait_for
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(
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storage_type const volatile& storage,
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storage_type old_val,
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std::chrono::duration< Rep, Period > timeout,
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memory_order order,
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bool& timed_out
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) noexcept
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{
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const std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
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return wait_until_impl< std::chrono::steady_clock >(storage, old_val, now + timeout, now, order, timed_out);
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}
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static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) noexcept
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{
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umtx_wakeup(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), 1);
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}
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static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) noexcept
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{
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umtx_wakeup(reinterpret_cast< int* >(const_cast< storage_type* >(&storage)), 0);
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}
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};
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_DRAGONFLY_UMTX_HPP_INCLUDED_
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