Bug 1118686 - TraceLogger: Cap the maximum number of entries in the graph tree, r=bbouvier

js/src/vm/TraceLoggingGraph.cpp

@@ -284,7 +284,7 @@ TraceLoggerGraph::startEvent(uint32_t id, uint64_t timestamp)
         return;
 
     if (!tree.hasSpaceForAdd()) {
-        if (!tree.ensureSpaceBeforeAdd()) {
+        if (tree.size() >= treeSizeFlushLimit() || !tree.ensureSpaceBeforeAdd()) {
             if (!flush()) {
                 fprintf(stderr, "TraceLogging: Couldn't write the data to disk.\n");
                 enabled = 0;

js/src/vm/TraceLoggingGraph.h

@@ -202,6 +202,11 @@ class TraceLoggerGraph
     // Create a tree out of all the given events.
     void log(ContinuousSpace<EventEntry> &events);
 
+    static size_t treeSizeFlushLimit() {
+        // Allow tree size to grow to 100MB.
+        return 100 * 1024 * 1024 / sizeof(TreeEntry);
+    }
+
   private:
     bool failed;
     bool enabled;