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RemotePlugin: use atomic operation for lock

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Use GCC's builtin atomic add/subtract operation for incrementing/
decrementing the recursive lock variable. This is needed to avoid race
conditions and is much faster than using mutexes etc.

Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>
This commit is contained in:
Jens Lang
2012-11-26 22:58:27 +01:00
committed by Tobias Doerffel
parent 6817631c91
commit da87fd4e55
1 changed files with 5 additions and 8 deletions
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13
include/RemotePlugin.h
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@@ -284,7 +284,7 @@ public:
// recursive lock
inline void lock()
{
if( !isInvalid() && ++m_lockDepth == 1 )
if( !isInvalid() && __sync_add_and_fetch( &m_lockDepth, 1 ) == 1 )
{
#ifdef USE_QT_SEMAPHORES
m_dataSem.acquire();
@@ -297,16 +297,13 @@ public:
// recursive unlock
inline void unlock()
{
if( m_lockDepth > 0 )
if( __sync_sub_and_fetch( &m_lockDepth, 1) <= 0 )
{
if( --m_lockDepth == 0 )
{
#ifdef USE_QT_SEMAPHORES
m_dataSem.release();
m_dataSem.release();
#else
sem_post( m_dataSem );
sem_post( m_dataSem );
#endif
}
}
}
@@ -484,7 +481,7 @@ private:
sem_t * m_dataSem;
sem_t * m_messageSem;
#endif
int m_lockDepth;
volatile int m_lockDepth;
} ;