144 
 145   // When it's appropriate to recalculate the various sizes (at the
 146   // end of a GC, when a new eden region is allocated, etc.) we store
 147   // them here so that we can easily report them when needed and not
 148   // have to recalculate them every time.
 149 
 150   size_t _overall_reserved;
 151   size_t _overall_committed;
 152   size_t _overall_used;
 153 
 154   uint   _young_region_num;
 155   size_t _young_gen_committed;
 156   size_t _eden_committed;
 157   size_t _eden_used;
 158   size_t _survivor_committed;
 159   size_t _survivor_used;
 160 
 161   size_t _old_committed;
 162   size_t _old_used;
 163 
 164   G1CollectedHeap* g1h() { return _g1h; }
 165 
 166   // It returns x - y if x > y, 0 otherwise.
 167   // As described in the comment above, some of the inputs to the
 168   // calculations we have to do are obtained concurrently and hence
 169   // may be inconsistent with each other. So, this provides a
 170   // defensive way of performing the subtraction and avoids the value
 171   // going negative (which would mean a very large result, given that
 172   // the parameter are size_t).
 173   static size_t subtract_up_to_zero(size_t x, size_t y) {
 174     if (x > y) {
 175       return x - y;
 176     } else {
 177       return 0;
 178     }
 179   }
 180 
 181   // Recalculate all the sizes.
 182   void recalculate_sizes();
 183   // Recalculate only what's necessary when a new eden region is allocated.
 184   void recalculate_eden_size();
 185 

 144 
 145   // When it's appropriate to recalculate the various sizes (at the
 146   // end of a GC, when a new eden region is allocated, etc.) we store
 147   // them here so that we can easily report them when needed and not
 148   // have to recalculate them every time.
 149 
 150   size_t _overall_reserved;
 151   size_t _overall_committed;
 152   size_t _overall_used;
 153 
 154   uint   _young_region_num;
 155   size_t _young_gen_committed;
 156   size_t _eden_committed;
 157   size_t _eden_used;
 158   size_t _survivor_committed;
 159   size_t _survivor_used;
 160 
 161   size_t _old_committed;
 162   size_t _old_used;
 163 


 164   // It returns x - y if x > y, 0 otherwise.
 165   // As described in the comment above, some of the inputs to the
 166   // calculations we have to do are obtained concurrently and hence
 167   // may be inconsistent with each other. So, this provides a
 168   // defensive way of performing the subtraction and avoids the value
 169   // going negative (which would mean a very large result, given that
 170   // the parameter are size_t).
 171   static size_t subtract_up_to_zero(size_t x, size_t y) {
 172     if (x > y) {
 173       return x - y;
 174     } else {
 175       return 0;
 176     }
 177   }
 178 
 179   // Recalculate all the sizes.
 180   void recalculate_sizes();
 181   // Recalculate only what's necessary when a new eden region is allocated.
 182   void recalculate_eden_size();
 183