--- old/src/share/vm/gc/g1/g1RemSet.hpp	2017-07-03 15:54:23.565037930 +0200
+++ new/src/share/vm/gc/g1/g1RemSet.hpp	2017-07-03 15:54:23.434033893 +0200
@@ -76,7 +76,7 @@
   void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParScanThreadState* pss, uint worker_i);
 
   G1CollectedHeap* _g1;
-  size_t _num_conc_refined_cards;
+  size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.
 
   CardTableModRefBS*     _ct_bs;
   G1Policy*              _g1p;