Optimize QOrderedMutexLocker

try first to lock without releasing the second mutex.
If it succees at first (likely), we should not have deadlock,
and we do not need to unlock and relock the first mutex

Should help in ~QObject

Reviewed-by: brad

1 files changed, 5 insertions, 3 deletions

diff --git a/src/corelib/thread/qorderedmutexlocker_p.h b/src/corelib/thread/qorderedmutexlocker_p.h
index c22ee5c..946d306 100644
--- a/src/corelib/thread/qorderedmutexlocker_p.h
+++ b/src/corelib/thread/qorderedmutexlocker_p.h
@@ -103,9 +103,11 @@ public:
             mtx2->lock();
             return true;
         }
-        mtx1->unlock();
-        mtx2->lock();
-        mtx1->lock();
+        if (!mtx2->tryLock()) {
+            mtx1->unlock();
+            mtx2->lock();
+            mtx1->lock();
+        }
         return true;
     }