--- a/hotspot/src/share/vm/gc/g1/g1RemSet.cpp	Tue Jul 04 09:15:45 2017 +0200
+++ b/hotspot/src/share/vm/gc/g1/g1RemSet.cpp	Tue Jul 04 09:16:26 2017 +0200
@@ -282,7 +282,7 @@
                    G1HotCardCache* hot_card_cache) :
   _g1(g1),
   _scan_state(new G1RemSetScanState()),
-  _conc_refine_cards(0),
+  _num_conc_refined_cards(0),
   _ct_bs(ct_bs),
   _g1p(_g1->g1_policy()),
   _hot_card_cache(hot_card_cache),
@@ -724,7 +724,7 @@
       sdcq->enqueue(card_ptr);
     }
   } else {
-    _conc_refine_cards++;
+    _num_conc_refined_cards++; // Unsynchronized update, only used for logging.
   }
 }
 
@@ -768,7 +768,6 @@
 
   bool card_processed = r->oops_on_card_seq_iterate_careful<true>(dirty_region, update_rs_cl);
   assert(card_processed, "must be");
-  _conc_refine_cards++;
 
   return update_rs_cl->has_refs_into_cset();
 }

--- a/hotspot/src/share/vm/gc/g1/g1RemSet.hpp	Tue Jul 04 09:15:45 2017 +0200
+++ b/hotspot/src/share/vm/gc/g1/g1RemSet.hpp	Tue Jul 04 09:16:26 2017 +0200
@@ -76,7 +76,7 @@
   void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParScanThreadState* pss, uint worker_i);
 
   G1CollectedHeap* _g1;
-  size_t _conc_refine_cards;
+  size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.
 
   CardTableModRefBS*     _ct_bs;
   G1Policy*              _g1p;
@@ -145,7 +145,7 @@
   // Print accumulated summary info from the last time called.
   void print_periodic_summary_info(const char* header, uint period_count);
 
-  size_t conc_refine_cards() const { return _conc_refine_cards; }
+  size_t num_conc_refined_cards() const { return _num_conc_refined_cards; }
 
   void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
   void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);

--- a/hotspot/src/share/vm/gc/g1/g1RemSetSummary.cpp	Tue Jul 04 09:15:45 2017 +0200
+++ b/hotspot/src/share/vm/gc/g1/g1RemSetSummary.cpp	Tue Jul 04 09:16:26 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -52,7 +52,7 @@
 };
 
 void G1RemSetSummary::update() {
-  _num_refined_cards = remset()->conc_refine_cards();
+  _num_conc_refined_cards = remset()->num_conc_refined_cards();
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   _num_processed_buf_mutator = dcqs.processed_buffers_mut();
   _num_processed_buf_rs_threads = dcqs.processed_buffers_rs_thread();
@@ -93,7 +93,7 @@
 
 G1RemSetSummary::G1RemSetSummary() :
   _remset(NULL),
-  _num_refined_cards(0),
+  _num_conc_refined_cards(0),
   _num_processed_buf_mutator(0),
   _num_processed_buf_rs_threads(0),
   _num_coarsenings(0),
@@ -113,7 +113,7 @@
   assert(remset() == other->remset(), "just checking");
   assert(_num_vtimes == other->_num_vtimes, "just checking");
 
-  _num_refined_cards = other->num_concurrent_refined_cards();
+  _num_conc_refined_cards = other->num_conc_refined_cards();
 
   _num_processed_buf_mutator = other->num_processed_buf_mutator();
   _num_processed_buf_rs_threads = other->num_processed_buf_rs_threads();
@@ -130,7 +130,7 @@
   assert(remset() == other->remset(), "just checking");
   assert(_num_vtimes == other->_num_vtimes, "just checking");
 
-  _num_refined_cards = other->num_concurrent_refined_cards() - _num_refined_cards;
+  _num_conc_refined_cards = other->num_conc_refined_cards() - _num_conc_refined_cards;
 
   _num_processed_buf_mutator = other->num_processed_buf_mutator() - _num_processed_buf_mutator;
   _num_processed_buf_rs_threads = other->num_processed_buf_rs_threads() - _num_processed_buf_rs_threads;
@@ -352,8 +352,7 @@
 
 void G1RemSetSummary::print_on(outputStream* out) {
   out->print_cr(" Recent concurrent refinement statistics");
-  out->print_cr("  Processed " SIZE_FORMAT " cards",
-                num_concurrent_refined_cards());
+  out->print_cr("  Processed " SIZE_FORMAT " cards concurrently", num_conc_refined_cards());
   out->print_cr("  Of " SIZE_FORMAT " completed buffers:", num_processed_buf_total());
   out->print_cr("     " SIZE_FORMAT_W(8) " (%5.1f%%) by concurrent RS threads.",
                 num_processed_buf_total(),

--- a/hotspot/src/share/vm/gc/g1/g1RemSetSummary.hpp	Tue Jul 04 09:15:45 2017 +0200
+++ b/hotspot/src/share/vm/gc/g1/g1RemSetSummary.hpp	Tue Jul 04 09:16:26 2017 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,7 @@
     return _remset;
   }
 
-  size_t _num_refined_cards;
+  size_t _num_conc_refined_cards;
   size_t _num_processed_buf_mutator;
   size_t _num_processed_buf_rs_threads;
 
@@ -82,8 +82,8 @@
     return _sampling_thread_vtime;
   }
 
-  size_t num_concurrent_refined_cards() const {
-    return _num_refined_cards;
+  size_t num_conc_refined_cards() const {
+    return _num_conc_refined_cards;
   }
 
   size_t num_processed_buf_mutator() const {