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Use the new 3-operand testAndSet functions in QMutex

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This allows us to get the current value of the QMutex / QBasicMutex
after the testAndSet operation failed. It saves an extra load from
memory.

Change-Id: I4922a8b3df15e342b177b13f56cf4f1184314520
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
This commit is contained in:
Thiago Macieira 2012-08-16 17:15:33 +02:00 committed by The Qt Project
parent 0ebfd0866d
commit d84da39964
2 changed files with 12 additions and 6 deletions
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12
src/corelib/thread/qmutex.cpp
View File

@ -216,9 +216,9 @@ QMutex::~QMutex()
*/ */
void QMutex::lock() QT_MUTEX_LOCK_NOEXCEPT void QMutex::lock() QT_MUTEX_LOCK_NOEXCEPT
{ {
if (fastTryLock()) QMutexData *current;
if (fastTryLock(current))
return; return;
QMutexData *current = d_ptr.loadAcquire();
if (QT_PREPEND_NAMESPACE(isRecursive)(current)) if (QT_PREPEND_NAMESPACE(isRecursive)(current))
static_cast<QRecursiveMutexPrivate *>(current)->lock(-1); static_cast<QRecursiveMutexPrivate *>(current)->lock(-1);
else else
@ -250,9 +250,9 @@ void QMutex::lock() QT_MUTEX_LOCK_NOEXCEPT
*/ */
bool QMutex::tryLock(int timeout) QT_MUTEX_LOCK_NOEXCEPT bool QMutex::tryLock(int timeout) QT_MUTEX_LOCK_NOEXCEPT
{ {
if (fastTryLock()) QMutexData *current;
if (fastTryLock(current))
return true; return true;
QMutexData *current = d_ptr.loadAcquire();
if (QT_PREPEND_NAMESPACE(isRecursive)(current)) if (QT_PREPEND_NAMESPACE(isRecursive)(current))
return static_cast<QRecursiveMutexPrivate *>(current)->lock(timeout); return static_cast<QRecursiveMutexPrivate *>(current)->lock(timeout);
else else
@ -268,9 +268,9 @@ bool QMutex::tryLock(int timeout) QT_MUTEX_LOCK_NOEXCEPT
*/ */
void QMutex::unlock() Q_DECL_NOTHROW void QMutex::unlock() Q_DECL_NOTHROW
{ {
if (fastTryUnlock()) QMutexData *current;
if (fastTryUnlock(current))
return; return;
QMutexData *current = d_ptr.loadAcquire();
if (QT_PREPEND_NAMESPACE(isRecursive)(current)) if (QT_PREPEND_NAMESPACE(isRecursive)(current))
static_cast<QRecursiveMutexPrivate *>(current)->unlock(); static_cast<QRecursiveMutexPrivate *>(current)->unlock();
else else

6
src/corelib/thread/qmutex.h
View File

@ -86,6 +86,12 @@ private:
inline bool fastTryUnlock() Q_DECL_NOTHROW { inline bool fastTryUnlock() Q_DECL_NOTHROW {
return d_ptr.testAndSetRelease(dummyLocked(), 0); return d_ptr.testAndSetRelease(dummyLocked(), 0);
} }
inline bool fastTryLock(QMutexData *&current) Q_DECL_NOTHROW {
return d_ptr.testAndSetAcquire(0, dummyLocked(), current);
}
inline bool fastTryUnlock(QMutexData *&current) Q_DECL_NOTHROW {
return d_ptr.testAndSetRelease(dummyLocked(), 0, current);
}
void lockInternal() QT_MUTEX_LOCK_NOEXCEPT; void lockInternal() QT_MUTEX_LOCK_NOEXCEPT;
bool lockInternal(int timeout) QT_MUTEX_LOCK_NOEXCEPT; bool lockInternal(int timeout) QT_MUTEX_LOCK_NOEXCEPT;