From ddf444d31a7cb961b79190131cb679fd7a6351fd Mon Sep 17 00:00:00 2001
From: Olivier Goffart <olivier.goffart@nokia.com>
Date: Tue, 26 Jul 2011 10:44:55 +0200
Subject: Simplify the mutexpool used in QObject.

Since we now have QBasicMutex as a POD, we can simplify the mutexpool.
This remove the call the the Q_GLOBAL_STATIC and some others tests that
are taking CPU cycles when activating a signal.

The QMutexPool class itself can't be simplified because its mutex are
recursive mutexes, and the size is dynamic. also it is harder to get all
the mutexes initialized to 0.

Change-Id: Ie781655635907d2ad620eb189099cba14638414f
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-on: http://codereview.qt.nokia.com/2171
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>
---
 src/corelib/kernel/qobject.cpp | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index ab9314ce53..076744ee00 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -60,7 +60,6 @@
 #include <qsharedpointer.h>
 
 #include <private/qorderedmutexlocker_p.h>
-#include <private/qmutexpool_p.h>
 
 #include <new>
 
@@ -95,35 +94,22 @@ static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
     return types;
 }
 
-static QBasicAtomicPointer<QMutexPool> signalSlotMutexes = Q_BASIC_ATOMIC_INITIALIZER(0);
-static QBasicAtomicInt objectCount = Q_BASIC_ATOMIC_INITIALIZER(0);
+static QBasicMutex _q_ObjectMutexPool[131];
 
 /** \internal
  * mutex to be locked when accessing the connectionlists or the senders list
  */
 static inline QMutex *signalSlotLock(const QObject *o)
 {
-    if (!signalSlotMutexes) {
-        QMutexPool *mp = new QMutexPool;
-        if (!signalSlotMutexes.testAndSetOrdered(0, mp)) {
-            delete mp;
-        }
-    }
-    return signalSlotMutexes->get(o);
+    return static_cast<QMutex *>(&_q_ObjectMutexPool[
+        uint(quintptr(o)) % sizeof(_q_ObjectMutexPool)/sizeof(QBasicMutex)]);
 }
 
 extern "C" Q_CORE_EXPORT void qt_addObject(QObject *)
-{
-    objectCount.ref();
-}
+{}
 
 extern "C" Q_CORE_EXPORT void qt_removeObject(QObject *)
-{
-    if(!objectCount.deref()) {
-        QMutexPool *old = signalSlotMutexes.fetchAndStoreAcquire(0);
-        delete old;
-    }
-}
+{}
 
 struct QConnectionSenderSwitcher {
     QObject *receiver;
-- 
cgit v1.2.3