224   HeapWord** end_addr() const;
 225 
 226   // Thread-local allocation buffers
 227   bool supports_tlab_allocation() const { return true; }
 228   size_t tlab_capacity() const;
 229   size_t tlab_used() const;
 230   size_t unsafe_max_tlab_alloc() const;
 231 
 232   // Grow the generation by the specified number of bytes.
 233   // The size of bytes is assumed to be properly aligned.
 234   // Return true if the expansion was successful.
 235   bool expand(size_t bytes);
 236 
 237   // DefNewGeneration cannot currently expand except at
 238   // a GC.
 239   virtual bool is_maximal_no_gc() const { return true; }
 240 
 241   // Iteration
 242   void object_iterate(ObjectClosure* blk);
 243 
 244   void younger_refs_iterate(OopsInGenClosure* cl, uint n_threads);
 245 
 246   void space_iterate(SpaceClosure* blk, bool usedOnly = false);
 247 
 248   // Allocation support
 249   virtual bool should_allocate(size_t word_size, bool is_tlab) {
 250     assert(UseTLAB || !is_tlab, "Should not allocate tlab");
 251 
 252     size_t overflow_limit    = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
 253 
 254     const bool non_zero      = word_size > 0;
 255     const bool overflows     = word_size >= overflow_limit;
 256     const bool check_too_big = _pretenure_size_threshold_words > 0;
 257     const bool not_too_big   = word_size < _pretenure_size_threshold_words;
 258     const bool size_ok       = is_tlab || !check_too_big || not_too_big;
 259 
 260     bool result = !overflows &&
 261                   non_zero   &&
 262                   size_ok;
 263 
 264     return result;
 265   }

 224   HeapWord** end_addr() const;
 225 
 226   // Thread-local allocation buffers
 227   bool supports_tlab_allocation() const { return true; }
 228   size_t tlab_capacity() const;
 229   size_t tlab_used() const;
 230   size_t unsafe_max_tlab_alloc() const;
 231 
 232   // Grow the generation by the specified number of bytes.
 233   // The size of bytes is assumed to be properly aligned.
 234   // Return true if the expansion was successful.
 235   bool expand(size_t bytes);
 236 
 237   // DefNewGeneration cannot currently expand except at
 238   // a GC.
 239   virtual bool is_maximal_no_gc() const { return true; }
 240 
 241   // Iteration
 242   void object_iterate(ObjectClosure* blk);
 243 


 244   void space_iterate(SpaceClosure* blk, bool usedOnly = false);
 245 
 246   // Allocation support
 247   virtual bool should_allocate(size_t word_size, bool is_tlab) {
 248     assert(UseTLAB || !is_tlab, "Should not allocate tlab");
 249 
 250     size_t overflow_limit    = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
 251 
 252     const bool non_zero      = word_size > 0;
 253     const bool overflows     = word_size >= overflow_limit;
 254     const bool check_too_big = _pretenure_size_threshold_words > 0;
 255     const bool not_too_big   = word_size < _pretenure_size_threshold_words;
 256     const bool size_ok       = is_tlab || !check_too_big || not_too_big;
 257 
 258     bool result = !overflows &&
 259                   non_zero   &&
 260                   size_ok;
 261 
 262     return result;
 263   }