--- old/src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp	2018-11-21 22:49:36.447163500 -0800
+++ new/src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp	2018-11-21 22:49:35.729251000 -0800
@@ -61,6 +61,9 @@
   static PSGCAdaptivePolicyCounters* _gc_policy_counters;
 
   GenerationSizer* _collector_policy;
+  
+  // is the heap backed by two different memories?
+  bool _is_hetero_heap;
 
   SoftRefPolicy _soft_ref_policy;
 
@@ -93,7 +96,7 @@
 
  public:
   ParallelScavengeHeap(GenerationSizer* policy) :
-    CollectedHeap(), _collector_policy(policy), _death_march_count(0) { }
+    CollectedHeap(), _collector_policy(policy), _is_hetero_heap(false), _death_march_count(0) { }
 
   // For use by VM operations
   enum CollectionType {
@@ -147,6 +150,9 @@
     return CollectorPolicy::compute_heap_alignment();
   }
 
+  // is the heap backed by two different memories?
+  bool is_hetero_heap() { return _is_hetero_heap; }
+
   size_t capacity() const;
   size_t used() const;