mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2025-04-27 09:23:51 +02:00
72 lines
1.7 KiB
C++
72 lines
1.7 KiB
C++
/*
|
|
* Copyright (c)2013-2021 ZeroTier, Inc.
|
|
*
|
|
* Use of this software is governed by the Business Source License included
|
|
* in the LICENSE.TXT file in the project's root directory.
|
|
*
|
|
* Change Date: 2026-01-01
|
|
*
|
|
* On the date above, in accordance with the Business Source License, use
|
|
* of this software will be governed by version 2.0 of the Apache License.
|
|
*/
|
|
/****/
|
|
|
|
#ifndef ZT_SPINLOCK_HPP
|
|
#define ZT_SPINLOCK_HPP
|
|
|
|
#include "Constants.hpp"
|
|
#include "Mutex.hpp"
|
|
|
|
#ifdef __LINUX__
|
|
#include <sched.h>
|
|
#else
|
|
#include <thread>
|
|
#endif
|
|
|
|
/**
|
|
* Simple spinlock
|
|
*
|
|
* This can be used in place of Mutex to lock things that are extremely fast
|
|
* to access. It should be used very sparingly.
|
|
*/
|
|
class Spinlock {
|
|
public:
|
|
/**
|
|
* Pause current thread using whatever methods might be available
|
|
*
|
|
* This is broken out since it's used in a few other places where
|
|
* spinlock-like constructions are used.
|
|
*/
|
|
ZT_INLINE static void pause() noexcept
|
|
{
|
|
#ifdef ZT_ARCH_X64
|
|
_mm_pause();
|
|
#endif
|
|
#ifdef __LINUX__
|
|
sched_yield();
|
|
#else
|
|
std::this_thread::yield();
|
|
#endif
|
|
}
|
|
|
|
ZT_INLINE Spinlock() noexcept : m_locked(false) {}
|
|
|
|
ZT_INLINE void lock() noexcept
|
|
{
|
|
if (unlikely(m_locked.test_and_set(std::memory_order_acquire))) {
|
|
do {
|
|
Spinlock::pause();
|
|
} while (m_locked.test_and_set(std::memory_order_acquire));
|
|
}
|
|
}
|
|
|
|
ZT_INLINE void unlock() noexcept { m_locked.clear(std::memory_order_release); }
|
|
|
|
private:
|
|
ZT_INLINE Spinlock(const Spinlock &) noexcept {}
|
|
ZT_INLINE const Spinlock &operator=(const Spinlock &) noexcept { return *this; }
|
|
|
|
std::atomic_flag m_locked;
|
|
};
|
|
|
|
#endif
|