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#pragma once
#include "public.h"
#include "spin_lock_base.h"
#include <library/cpp/yt/misc/port.h>
#include <library/cpp/yt/system/thread_id.h>
#include <library/cpp/yt/memory/public.h>
#include <util/system/src_location.h>
#include <util/system/types.h>
#include <atomic>
namespace NYT::NThreading {
////////////////////////////////////////////////////////////////////////////////
//! A slightly modified version of TAdaptiveLock.
/*!
* The lock is unfair.
*/
class TSpinLock
: public TSpinLockBase
{
public:
using TSpinLockBase::TSpinLockBase;
//! Acquires the lock.
void Acquire() noexcept;
//! Tries acquiring the lock.
//! Returns |true| on success.
bool TryAcquire() noexcept;
//! Releases the lock.
void Release() noexcept;
//! Returns true if the lock is taken.
/*!
* This is inherently racy.
* Only use for debugging and diagnostic purposes.
*/
bool IsLocked() const noexcept;
private:
#ifdef YT_ENABLE_SPIN_LOCK_OWNERSHIP_TRACKING
using TValue = TSequentialThreadId;
static constexpr TValue UnlockedValue = InvalidSequentialThreadId;
#else
using TValue = ui32;
static constexpr TValue UnlockedValue = 0;
static constexpr TValue LockedValue = 1;
#endif
std::atomic<TValue> Value_ = UnlockedValue;
bool TryAndTryAcquire() noexcept;
void AcquireSlow() noexcept;
};
////////////////////////////////////////////////////////////////////////////////
//! A variant of TReaderWriterSpinLock occupyig the whole cache line.
class TPaddedSpinLock
: public TSpinLock
{
private:
[[maybe_unused]]
char Padding_[CacheLineSize - sizeof(TSpinLock)];
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT::NThreading
#define SPIN_LOCK_INL_H_
#include "spin_lock-inl.h"
#undef SPIN_LOCK_INL_H_
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