cds::sync::spin_lock< Backoff > Class Template Reference

Spin lock. More...

#include <cds/sync/spinlock.h>

Public Types
typedef Backoff	backoff_strategy
	back-off strategy type

Public Member Functions
	spin_lock () noexcept
	Construct free (unlocked) spin-lock.
	spin_lock (bool bLocked) noexcept
	Construct spin-lock in specified state. More...
	spin_lock (const spin_lock< Backoff > &) noexcept
	Dummy copy constructor. More...
	~spin_lock ()
	Destructor. On debug time it checks whether spin-lock is free.
bool	is_locked () const noexcept
	Check if the spin is locked.
bool	try_lock () noexcept
	Try to lock the object. More...
bool	try_lock (unsigned int nTryCount) noexcept(noexcept(backoff_strategy()()))
	Try to lock the object, repeat nTryCount times if failed. More...
void	lock () noexcept(noexcept(backoff_strategy()()))
	Lock the spin-lock. Waits infinitely while spin-lock is locked. Debug version: deadlock may be detected.
void	unlock () noexcept
	Unlock the spin-lock. Debug version: deadlock may be detected.

Private Attributes
atomics::atomic< bool >	m_spin
	Spin.

Detailed Description

template<typename Backoff>
class cds::sync::spin_lock< Backoff >

Spin lock.

Simple and light-weight spin-lock critical section It is useful to gain access to small (short-timed) code

Algorithm:

TATAS (test-and-test-and-lock) [1984] L. Rudolph, Z. Segall. Dynamic Decentralized Cache Schemes for MIMD Parallel Processors.

No serialization performed - any of waiting threads may owns the spin-lock. This spin-lock is NOT recursive: the thread owned the lock cannot call lock() method without deadlock. The method unlock() can call any thread

DEBUG version: The spinlock stores owner thead id. Assertion is raised when:

• double lock attempt encountered by same thread (deadlock)
• unlock by another thread

If spin-lock is locked the Backoff algorithm is called. Predefined backoff::LockDefault class yields current thread and repeats lock attempts later

Template parameters:

• Backoff - backoff strategy. Used when spin lock is locked

Constructor & Destructor Documentation

spin_lock() [1/2]

template<typename Backoff >

cds::sync::spin_lock< Backoff >::spin_lock ( bool  bLocked )

inlineexplicitnoexcept

Construct spin-lock in specified state.

In debug mode: if bLocked = true then spin-lock is made owned by current thread

spin_lock() [2/2]

template<typename Backoff >

cds::sync::spin_lock< Backoff >::spin_lock ( const spin_lock< Backoff > &  )

inlinenoexcept

Dummy copy constructor.

The ctor initializes the spin to free (unlocked) state like the default ctor.

Member Function Documentation

try_lock() [1/2]

template<typename Backoff >

bool cds::sync::spin_lock< Backoff >::try_lock ( )

inlinenoexcept

Try to lock the object.

Returns true if locking is succeeded otherwise (if the spin is already locked) returns false

Debug version: deadlock can be detected

try_lock() [2/2]

template<typename Backoff >

bool cds::sync::spin_lock< Backoff >::try_lock ( unsigned int  nTryCount )

inlinenoexcept

Try to lock the object, repeat nTryCount times if failed.

Returns true if locking is succeeded otherwise (if the spin is already locked) returns false

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

• cds/sync/spinlock.h