From 1b42084217410ceac534636f3b183acbfde43afc Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 8 Dec 2010 09:52:58 +0000
Subject: [PATCH] Fixes for benign threading memory contentions.

---
 src/osgDB/DatabasePager.cpp | 39 +++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 17 deletions(-)

diff --git a/src/osgDB/DatabasePager.cpp b/src/osgDB/DatabasePager.cpp
index 4adaa564d..33a69fb25 100644
--- a/src/osgDB/DatabasePager.cpp
+++ b/src/osgDB/DatabasePager.cpp
@@ -777,20 +777,7 @@ double DatabasePager::DatabaseThread::getTimeSinceStartOfIteration() const
 void DatabasePager::DatabaseThread::run()
 {
     OSG_INFO<<_name<<": DatabasePager::DatabaseThread::run"<<std::endl;
-    
-#if 1
-    // need to set the texture object manager to be able to reuse textures
-    osg::Texture::setMinimumNumberOfTextureObjectsToRetainInCache(100);
-    
-    // need to set the display list manager to be able to reuse display lists
-    osg::Drawable::setMinimumNumberOfDisplayListsToRetainInCache(100);
-#else
-    // need to set the texture object manager to be able to reuse textures
-    osg::Texture::setMinimumNumberOfTextureObjectsToRetainInCache(0);
-    
-    // need to set the display list manager to be able to reuse display lists
-    osg::Drawable::setMinimumNumberOfDisplayListsToRetainInCache(0);
-#endif
+
 
     bool firstTime = true;
     
@@ -827,17 +814,21 @@ void DatabasePager::DatabaseThread::run()
         OSG_INFO<<_name<<": _pager->size()= "<<read_queue->size()<<" to delete = "<<read_queue->_childrenToDeleteList.size()<<std::endl;
 
 
+        
         //
         // delete any children if required.
         //
-        if (_pager->_deleteRemovedSubgraphsInDatabaseThread && !(read_queue->_childrenToDeleteList.empty()))
+        if (_pager->_deleteRemovedSubgraphsInDatabaseThread/* && !(read_queue->_childrenToDeleteList.empty())*/)
         {
             ObjectList deleteList;
 
             {
                 OpenThreads::ScopedLock<OpenThreads::Mutex> lock(read_queue->_childrenToDeleteListMutex);
-                deleteList.swap(read_queue->_childrenToDeleteList);
-                read_queue->updateBlock();
+                if (!read_queue->_childrenToDeleteList.empty())
+                {
+                    deleteList.swap(read_queue->_childrenToDeleteList);
+                    read_queue->updateBlock();
+                }
             }
         }
 
@@ -1296,6 +1287,20 @@ DatabasePager::DatabasePager(const DatabasePager& rhs)
     _activePagedLODList = rhs._activePagedLODList->clone();
     _inactivePagedLODList = rhs._inactivePagedLODList->clone();
 
+#if 1
+    // need to set the texture object manager to be able to reuse textures
+    osg::Texture::setMinimumNumberOfTextureObjectsToRetainInCache(100);
+
+    // need to set the display list manager to be able to reuse display lists
+    osg::Drawable::setMinimumNumberOfDisplayListsToRetainInCache(100);
+#else
+    // need to set the texture object manager to be able to reuse textures
+    osg::Texture::setMinimumNumberOfTextureObjectsToRetainInCache(0);
+
+    // need to set the display list manager to be able to reuse display lists
+    osg::Drawable::setMinimumNumberOfDisplayListsToRetainInCache(0);
+#endif
+
     // initialize the stats variables
     resetStats();
 }