233   HeapRegion* _hr;
 234 
 235   enum SomeAdditionalPrivateConstants {
 236     InitialCapacity = 16
 237   };
 238 
 239   void expand();
 240 
 241   bool _expanded;
 242 
 243   bool expanded() { return _expanded; }
 244   void set_expanded(bool b) { _expanded = b; }
 245 
 246   SparsePRT* _next_expanded;
 247 
 248   SparsePRT* next_expanded() { return _next_expanded; }
 249   void set_next_expanded(SparsePRT* nxt) { _next_expanded = nxt; }
 250 
 251   bool should_be_on_expanded_list();
 252 
 253   static SparsePRT* _head_expanded_list;
 254 
 255 public:
 256   SparsePRT(HeapRegion* hr);
 257 
 258   ~SparsePRT();
 259 
 260   size_t occupied() const { return _next->occupied_cards(); }
 261   size_t mem_size() const;
 262 
 263   // Attempts to ensure that the given card_index in the given region is in
 264   // the sparse table.  If successful (because the card was already
 265   // present, or because it was successfully added) returns "true".
 266   // Otherwise, returns "false" to indicate that the addition would
 267   // overflow the entry for the region.  The caller must transfer these
 268   // entries to a larger-capacity representation.
 269   bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
 270 
 271   // Return the pointer to the entry associated with the given region.
 272   SparsePRTEntry* get_entry(RegionIdx_t region_ind);
 273 

 233   HeapRegion* _hr;
 234 
 235   enum SomeAdditionalPrivateConstants {
 236     InitialCapacity = 16
 237   };
 238 
 239   void expand();
 240 
 241   bool _expanded;
 242 
 243   bool expanded() { return _expanded; }
 244   void set_expanded(bool b) { _expanded = b; }
 245 
 246   SparsePRT* _next_expanded;
 247 
 248   SparsePRT* next_expanded() { return _next_expanded; }
 249   void set_next_expanded(SparsePRT* nxt) { _next_expanded = nxt; }
 250 
 251   bool should_be_on_expanded_list();
 252 
 253   static SparsePRT* volatile _head_expanded_list;
 254 
 255 public:
 256   SparsePRT(HeapRegion* hr);
 257 
 258   ~SparsePRT();
 259 
 260   size_t occupied() const { return _next->occupied_cards(); }
 261   size_t mem_size() const;
 262 
 263   // Attempts to ensure that the given card_index in the given region is in
 264   // the sparse table.  If successful (because the card was already
 265   // present, or because it was successfully added) returns "true".
 266   // Otherwise, returns "false" to indicate that the addition would
 267   // overflow the entry for the region.  The caller must transfer these
 268   // entries to a larger-capacity representation.
 269   bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
 270 
 271   // Return the pointer to the entry associated with the given region.
 272   SparsePRTEntry* get_entry(RegionIdx_t region_ind);
 273