mirror of
https://github.com/darlinghq/darling-bmalloc.git
synced 2024-11-23 12:29:43 +00:00
96 lines
2.6 KiB
C++
96 lines
2.6 KiB
C++
/*
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* Copyright (C) 2014 Apple Inc. All rights reserved.
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* Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include "BAssert.h"
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#include <atomic>
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#include <mutex>
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#include <thread>
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// A fast replacement for std::mutex.
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namespace bmalloc {
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class Mutex;
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using UniqueLockHolder = std::unique_lock<Mutex>;
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using LockHolder = std::scoped_lock<Mutex>;
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class Mutex {
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public:
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constexpr Mutex() = default;
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void lock();
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bool try_lock();
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void unlock();
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private:
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BEXPORT void lockSlowCase();
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std::atomic<bool> m_flag { false };
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std::atomic<bool> m_isSpinning { false };
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};
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static inline void sleep(
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UniqueLockHolder& lock, std::chrono::milliseconds duration)
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{
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if (duration == std::chrono::milliseconds(0))
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return;
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lock.unlock();
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std::this_thread::sleep_for(duration);
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lock.lock();
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}
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static inline void waitUntilFalse(
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UniqueLockHolder& lock, std::chrono::milliseconds sleepDuration,
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bool& condition)
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{
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while (condition) {
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condition = false;
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sleep(lock, sleepDuration);
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}
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}
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inline bool Mutex::try_lock()
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{
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return !m_flag.exchange(true, std::memory_order_acquire);
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}
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inline void Mutex::lock()
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{
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if (!try_lock())
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lockSlowCase();
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}
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inline void Mutex::unlock()
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{
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m_flag.store(false, std::memory_order_release);
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}
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} // namespace bmalloc
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