Spinlock Class Reference

By the use of Spinlocks, it is possible to serialize blocks of code that might run parallel on multiple CPU cores. More...

#include <sync/spinlock.h>

Public Member Functions
	Spinlock ()
	Constructor; Initializes as unlocked.
void	lock ()
	Enters the critical area. In case the area is already locked, lock() will actively wait for the area can be entered.
void	unlock ()
	Unblocks the critical area.

Private Member Functions
	Spinlock (const Spinlock &copy)=delete
Spinlock &	operator= (const Spinlock &)=delete

Private Attributes
cache_aligned bool	lock_status

Detailed Description

By the use of Spinlocks, it is possible to serialize blocks of code that might run parallel on multiple CPU cores.

Synchronization is implemented using a lock variable. Once a thread enters the critical area, it sets the lock variable (to a non-zero value); when this thread leaves the critical area, it resets the lock variable to zero. When trying to enter an already locked critical area, the trying thread actively waits until the critical area is free again.

Use the following two GCC intrinsics

• bool __atomic_test_and_set(void *ptr, int memorder)
• void __atomic_clear (bool *ptr, int memorder)

These intrinsics are translated into atomic, architecture-specific CPU instructions.

Note

If you want that things just work, choose __ATOMIC_SEQ_CST as memorder. This is not the most efficient memory order but works reasonably well.

Atomic Builtins in GCC manual

Constructor & Destructor Documentation

Spinlock() [1/2]

Spinlock::Spinlock ( const Spinlock &  copy )

privatedelete

Spinlock() [2/2]

Spinlock::Spinlock ( )

inline

Constructor; Initializes as unlocked.

Member Function Documentation

operator=()

Spinlock & Spinlock::operator= ( const Spinlock &  )

privatedelete

lock()

void Spinlock::lock ( )

inline

Enters the critical area. In case the area is already locked, lock() will actively wait for the area can be entered.

unlock()

void Spinlock::unlock ( )

inline

Unblocks the critical area.

Member Data Documentation

lock_status

cache_aligned bool Spinlock::lock_status

private

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The documentation for this class was generated from the following file:

• sync/spinlock.h