spinlock.hpp

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#ifndef SPINLOCK_HPP
#define SPINLOCK_HPP

#include <atomic>

class __attribute__((aligned(64))) SpinLock {
private:
    std::atomic_flag latch = ATOMIC_FLAG_INIT;

public:
    SpinLock(){};

    bool trylock() { return !latch.test_and_set(std::memory_order::memory_order_acquire); }

    void lock() {
        while (!trylock()) {
            __asm__("pause;");
        }
    };

    void unlock() { latch.clear(std::memory_order::memory_order_release); }
};

class SpinLockCLSize {
private:
    // The useful part
    std::atomic_flag latch = ATOMIC_FLAG_INIT;

    // The padding, assumes 64 byte cacheline
    // This should prevent false sharing
    volatile char c[64 - sizeof(std::atomic_flag)];

public:
    SpinLockCLSize() {
        // This cast is just to silence clang
        (void)c;
    };

    bool trylock() { return !latch.test_and_set(std::memory_order::memory_order_acquire); }

    void lock() {
        while (!trylock()) {
            __asm__("pause;");
        }
    };

    void unlock() { latch.clear(std::memory_order::memory_order_release); }
};

#endif /* SPINLOCK_HPP */