Whenever LDUpdates are applied, track to see if any links are updated. In...

Whenever LDUpdates are applied, track to see if any links are updated. In addition, track if direct and tunnel links are updated.  createNewInstance will create a new topology instance only when links are updated.

src/main/java/net/floodlightcontroller/topology/TopologyManager.java

@@ -106,7 +106,17 @@ public class TopologyManager implements
     
     protected SingletonTask newInstanceTask;
     private Date lastUpdateTime;
-    protected boolean recomputeTopologyFlag;
+
+    /**
+     * Flag that indicates if links (direct/tunnel/multihop links) were
+     * updated as part of LDUpdate.
+     */
+    protected boolean linksUpdated;
+    /**
+     * Flag that indicates if direct or tunnel links were updated as
+     * part of LDUpdate.
+     */
+    protected boolean dtLinksUpdated;
 
     /**
      * Thread for recomputing topology.  The thread is always running, 
@@ -130,12 +140,14 @@ public class TopologyManager implements
     }
 
     public boolean updateTopology() {
-        recomputeTopologyFlag = false;
+        boolean newInstanceFlag;
+        linksUpdated = false;
+        dtLinksUpdated = false;
         applyUpdates();
-        createNewInstance();
+        newInstanceFlag = createNewInstance();
         lastUpdateTime = new Date();
         informListeners();
-        return recomputeTopologyFlag;
+        return newInstanceFlag;
     }
 
     // **********************
@@ -864,12 +876,13 @@ public class TopologyManager implements
     /**
      * This function computes a new topology instance.
      * It ignores links connected to all broadcast domain ports
-     * and tunnel ports.
+     * and tunnel ports. The method returns if a new instance of
+     * topology was created or not.
      */
-    protected void createNewInstance() {
+    protected boolean createNewInstance() {
         Set<NodePortTuple> blockedPorts = new HashSet<NodePortTuple>();
 
-        if (!recomputeTopologyFlag) return;
+        if (!linksUpdated) return false;
 
         Map<NodePortTuple, Set<Link>> openflowLinks;
         openflowLinks = 
@@ -897,6 +910,7 @@ public class TopologyManager implements
         // If needed, we may compute them differently.
         currentInstance = nt;
         currentInstanceWithoutTunnels = nt;
+        return true;
     }
 
 
@@ -1015,18 +1029,19 @@ public class TopologyManager implements
             addLinkToStructure(portBroadcastDomainLinks, link);
             flag1 = removeLinkFromStructure(tunnelLinks, link);
             flag2 = removeLinkFromStructure(directLinks, link);
-            recomputeTopologyFlag = flag1 || flag2;
+            dtLinksUpdated = flag1 || flag2;
         } else if (type.equals(LinkType.TUNNEL)) {
             addLinkToStructure(tunnelLinks, link);
             removeLinkFromStructure(portBroadcastDomainLinks, link);
             removeLinkFromStructure(directLinks, link);
-            recomputeTopologyFlag = true;
+            dtLinksUpdated = true;
         } else if (type.equals(LinkType.DIRECT_LINK)) {
             addLinkToStructure(directLinks, link);
             removeLinkFromStructure(tunnelLinks, link);
             removeLinkFromStructure(portBroadcastDomainLinks, link);
-            recomputeTopologyFlag = true;
+            dtLinksUpdated = true;
         }
+        linksUpdated = true;
     }
 
     public void removeLink(Link link)  {
@@ -1035,7 +1050,8 @@ public class TopologyManager implements
         flag1 = removeLinkFromStructure(directLinks, link);
         flag2 = removeLinkFromStructure(tunnelLinks, link);
 
-        recomputeTopologyFlag = flag1 || flag2;
+        linksUpdated = true;
+        dtLinksUpdated = flag1 || flag2;
 
         removeLinkFromStructure(portBroadcastDomainLinks, link);
         removeLinkFromStructure(switchPortLinks, link);
@@ -1066,7 +1082,7 @@ public class TopologyManager implements
         }
     }
 
-    public void removeLink(long srcId, short srcPort, 
+    public void removeLink(long srcId, short srcPort,
                            long dstId, short dstPort) {
         Link link = new Link(srcId, srcPort, dstId, dstPort);
         removeLink(link);
@@ -1087,6 +1103,8 @@ public class TopologyManager implements
     */
     private void clearCurrentTopology() {
         this.clear();
+        linksUpdated = true;
+        dtLinksUpdated = true;
         createNewInstance();
         lastUpdateTime = new Date();
     }