--- old/src/share/vm/gc/g1/concurrentMark.hpp	2015-12-14 21:50:29.194701599 -0800
+++ new/src/share/vm/gc/g1/concurrentMark.hpp	2015-12-14 21:50:29.102701602 -0800
@@ -353,6 +353,11 @@
   // time of remark.
   volatile bool           _concurrent_marking_in_progress;
 
+  // True only inside of markFromRoots().
+  // Similar to _concurrent_marking_in_progress but this is set to false
+  // when CMConcurrentMarkingTask is finished.
+  volatile bool           _concurrent_marking_from_roots;
+
   // All of these times are in ms
   NumberSeq _init_times;
   NumberSeq _remark_times;
@@ -459,6 +464,12 @@
   void enter_first_sync_barrier(uint worker_id);
   void enter_second_sync_barrier(uint worker_id);
 
+  // Start measuring concurrent mark from ConcurrentMark::markFromRoots().
+  void register_mark_from_roots_phase_start();
+
+  // End measuring concurrent mark from ConcurrentMark::markFromRoots().
+  void register_mark_from_roots_phase_end();
+
   // Live Data Counting data structures...
   // These data structures are initialized at the start of
   // marking. They are written to while marking is active.
@@ -516,6 +527,10 @@
     _concurrent_marking_in_progress = false;
   }
 
+  bool concurrent_marking_from_roots() const {
+    return _concurrent_marking_from_roots;
+  }
+
   void update_accum_task_vtime(int i, double vtime) {
     _accum_task_vtime[i] += vtime;
   }