--- old/src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp	2013-05-15 16:50:03.000000000 -0700
+++ new/src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp	2013-05-15 16:50:03.000000000 -0700
@@ -131,6 +131,8 @@
   inline size_t    region_size() const;
   inline size_t    size() const;
 
+  size_t reserved_byte_size() const { return _reserved_byte_size; }
+
   // Convert a heap address to/from a bit index.
   inline idx_t     addr_to_bit(HeapWord* addr) const;
   inline HeapWord* bit_to_addr(idx_t bit) const;
@@ -176,10 +178,11 @@
   BitMap          _beg_bits;
   BitMap          _end_bits;
   PSVirtualSpace* _virtual_space;
+  size_t          _reserved_byte_size;
 };
 
 inline ParMarkBitMap::ParMarkBitMap():
-  _beg_bits(), _end_bits(), _region_start(NULL), _region_size(0), _virtual_space(NULL)
+  _beg_bits(), _end_bits(), _region_start(NULL), _region_size(0), _virtual_space(NULL), _reserved_byte_size(0)
 { }
 
 inline void ParMarkBitMap::clear_range(idx_t beg, idx_t end)