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129 lines
3.1 KiB
C++
129 lines
3.1 KiB
C++
/*
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* naive_spin_mutex.hpp
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*
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* MIT License
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*
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* Copyright (c) 2017 yohhoy
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef YAMC_NAIVE_SPIN_MUTEX_HPP_
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#define YAMC_NAIVE_SPIN_MUTEX_HPP_
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#include <atomic>
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#include "yamc_backoff_spin.hpp"
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namespace yamc {
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/*
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* naive Test-And-Swap(TAS) spinlock implementation (with memory_order_seq_cst)
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*
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* - yamc::spin::mutex
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* - yamc::spin::basic_mutex<BackoffPolicy>
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*/
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namespace spin {
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template <typename BackoffPolicy>
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class basic_mutex {
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std::atomic<int> state_{0};
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public:
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basic_mutex() = default;
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~basic_mutex() = default;
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basic_mutex(const basic_mutex&) = delete;
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basic_mutex& operator=(const basic_mutex&) = delete;
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void lock()
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{
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typename BackoffPolicy::state state;
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int expected = 0;
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while (!state_.compare_exchange_weak(expected, 1)) {
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BackoffPolicy::wait(state);
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expected = 0;
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}
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}
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bool try_lock()
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{
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int expected = 0;
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return state_.compare_exchange_weak(expected, 1);
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}
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void unlock()
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{
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state_.store(0);
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}
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};
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using mutex = basic_mutex<YAMC_BACKOFF_SPIN_DEFAULT>;
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} // namespace spin
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/*
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* naive Test-And-Swap(TAS) spinlock implementation for weak hardware memory model
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*
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* - yamc::spin_weak::mutex
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* - yamc::spin_weak::basic_mutex<BackoffPolicy>
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*/
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namespace spin_weak {
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template <typename BackoffPolicy>
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class basic_mutex {
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std::atomic<int> state_{0};
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public:
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basic_mutex() = default;
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~basic_mutex() = default;
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basic_mutex(const basic_mutex&) = delete;
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basic_mutex& operator=(const basic_mutex&) = delete;
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void lock()
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{
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typename BackoffPolicy::state state;
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int expected = 0;
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while (!state_.compare_exchange_weak(expected, 1, std::memory_order_acquire, std::memory_order_relaxed)) {
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BackoffPolicy::wait(state);
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expected = 0;
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}
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}
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bool try_lock()
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{
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int expected = 0;
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return state_.compare_exchange_weak(expected, 1, std::memory_order_acquire, std::memory_order_relaxed);
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}
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void unlock()
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{
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state_.store(0, std::memory_order_release);
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}
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};
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using mutex = basic_mutex<YAMC_BACKOFF_SPIN_DEFAULT>;
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} // namespace spin_weak
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} // namespace yamc
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#endif
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