--- a/hotspot/src/share/vm/memory/cardTableRS.cpp	Thu Apr 09 17:39:42 2015 +0200
+++ b/hotspot/src/share/vm/memory/cardTableRS.cpp	Wed Apr 08 09:35:25 2015 +0200
@@ -180,6 +180,10 @@
   return (((intptr_t)entry) & (BytesPerWord-1)) == 0;
 }
 
+// The regions are visited in *decreasing* address order.
+// This order aids with imprecise card marking, where a dirty
+// card may cause scanning, and summarization marking, of objects
+// that extend onto subsequent cards.
 void ClearNoncleanCardWrapper::do_MemRegion(MemRegion mr) {
   assert(mr.word_size() > 0, "Error");
   assert(_ct->is_aligned(mr.start()), "mr.start() should be card aligned");