--- a/src/hotspot/share/gc/g1/g1ConcurrentRefine.cpp	Tue Oct 08 20:47:46 2019 +0200
+++ b/src/hotspot/share/gc/g1/g1ConcurrentRefine.cpp	Tue Oct 08 15:15:50 2019 -0400
@@ -412,6 +412,22 @@
   dcqs.notify_if_necessary();
 }
 
+G1ConcurrentRefine::RefinementStats G1ConcurrentRefine::total_refinement_stats() const {
+  struct CollectData : public ThreadClosure {
+    Tickspan _total_time;
+    size_t _total_cards;
+    CollectData() : _total_time(), _total_cards(0) {}
+    virtual void do_thread(Thread* t) {
+      G1ConcurrentRefineThread* crt = static_cast<G1ConcurrentRefineThread*>(t);
+      _total_time += crt->total_refinement_time();
+      _total_cards += crt->total_refined_cards();
+    }
+  } collector;
+  // Cast away const so we can call non-modifying closure on threads.
+  const_cast<G1ConcurrentRefine*>(this)->threads_do(&collector);
+  return RefinementStats(collector._total_time, collector._total_cards);
+}
+
 size_t G1ConcurrentRefine::activation_threshold(uint worker_id) const {
   Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
   return activation_level(thresholds);
@@ -432,7 +448,8 @@
   }
 }
 
-bool G1ConcurrentRefine::do_refinement_step(uint worker_id) {
+bool G1ConcurrentRefine::do_refinement_step(uint worker_id,
+                                            size_t* total_refined_cards) {
   G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
 
   size_t curr_cards = dcqs.num_cards();
@@ -448,5 +465,6 @@
 
   // Process the next buffer, if there are enough left.
   return dcqs.refine_completed_buffer_concurrently(worker_id + worker_id_offset(),
-                                                   deactivation_threshold(worker_id));
+                                                   deactivation_threshold(worker_id),
+                                                   total_refined_cards);
 }