--- old/src/hotspot/share/oops/markOop.hpp	2019-04-18 22:07:19.560307076 -0400
+++ new/src/hotspot/share/oops/markOop.hpp	2019-04-18 22:07:18.932307087 -0400
@@ -209,6 +209,10 @@
   bool is_unlocked() const {
     return (mask_bits(value(), biased_lock_mask_in_place) == unlocked_value);
   }
+  // ObjectMonitor::install_displaced_markword_in_object() uses
+  // is_marked() on ObjectMonitor::_header as part of the restoration
+  // protocol for an object's header. In this usage, the mark bits are
+  // only ever set (and cleared) on the ObjectMonitor::_header field.
   bool is_marked()   const {
     return (mask_bits(value(), lock_mask_in_place) == marked_value);
   }