/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 *

 */

class PSMarkSweepDecorator;

class PSOldGen : public CHeapObj {

  friend class VMStructs;

  friend class PSPromotionManager; // Uses the cas_allocate methods

  friend class ParallelScavengeHeap;

  friend class AdjoiningGenerations;

 protected:

  MemRegion                _reserved;          // Used for simple containment tests

  PSVirtualSpace*          _virtual_space;     // Controls mapping and unmapping of virtual mem

  ObjectStartArray         _start_array;       // Keeps track of where objects start in a 512b block

  MutableSpace*            _object_space;      // Where all the objects live

  PSMarkSweepDecorator*    _object_mark_sweep; // The mark sweep view of _object_space

  const char* const        _name;              // Name of this generation.

  // Performance Counters

  PSGenerationCounters*    _gen_counters;

  SpaceCounters*           _space_counters;

  // Sizing information, in bytes, set in constructor

  const size_t _init_gen_size;

  const size_t _min_gen_size;

  const size_t _max_gen_size;

  // Used when initializing the _name field.

  static inline const char* select_name();

  HeapWord* allocate_noexpand(size_t word_size, bool is_tlab) {

    // We assume the heap lock is held here.

    assert(!is_tlab, "Does not support TLAB allocation");

    assert_locked_or_safepoint(Heap_lock);

    HeapWord* res = object_space()->allocate(word_size);

    if (res != NULL) {

      _start_array.allocate_block(res);

    }

    return res;

  }

  // Support for MT garbage collection. CAS allocation is lower overhead than grabbing

  // and releasing the heap lock, which is held during gc's anyway. This method is not

  // safe for use at the same time as allocate_noexpand()!

  HeapWord* cas_allocate_noexpand(size_t word_size) {

    assert(SafepointSynchronize::is_at_safepoint(), "Must only be called at safepoint");

    HeapWord* res = object_space()->cas_allocate(word_size);

    if (res != NULL) {

      _start_array.allocate_block(res);

    }

    return res;

  }

  // Support for MT garbage collection. See above comment.

  HeapWord* cas_allocate(size_t word_size) {

    HeapWord* res = cas_allocate_noexpand(word_size);

    return (res == NULL) ? expand_and_cas_allocate(word_size) : res;

  }

  HeapWord* expand_and_allocate(size_t word_size, bool is_tlab);

  HeapWord* expand_and_cas_allocate(size_t word_size);

  void expand(size_t bytes);

  bool expand_by(size_t bytes);

  bool expand_to_reserved();

  void shrink(size_t bytes);

  void post_resize();

 public:

  // Initialize the generation.

  PSOldGen(ReservedSpace rs, size_t alignment,

           size_t initial_size, size_t min_size, size_t max_size,

           const char* perf_data_name, int level);

  PSOldGen(size_t initial_size, size_t min_size, size_t max_size,

           const char* perf_data_name, int level);

  void initialize(ReservedSpace rs, size_t alignment,

                  const char* perf_data_name, int level);

  void initialize_virtual_space(ReservedSpace rs, size_t alignment);

  void initialize_work(const char* perf_data_name, int level);

  MemRegion reserved() const                { return _reserved; }

  virtual size_t max_gen_size()             { return _max_gen_size; }

  size_t min_gen_size()                     { return _min_gen_size; }

  // Returns limit on the maximum size of the generation.  This

  // is the same as _max_gen_size for PSOldGen but need not be

  // for a derived class.

  virtual size_t gen_size_limit();

  bool is_in(const void* p) const           {

    return _virtual_space->contains((void *)p);

  }

  bool is_in_reserved(const void* p) const {

    return reserved().contains(p);

  }

  MutableSpace*         object_space() const      { return _object_space; }

  PSMarkSweepDecorator* object_mark_sweep() const { return _object_mark_sweep; }

  ObjectStartArray*     start_array()             { return &_start_array; }

  PSVirtualSpace*       virtual_space() const     { return _virtual_space;}

  // Has the generation been successfully allocated?

  bool is_allocated();

  // MarkSweep methods

  virtual void precompact();

  void adjust_pointers();

  void compact();

  // Parallel old

  virtual void move_and_update(ParCompactionManager* cm);

  // Size info

  size_t capacity_in_bytes() const        { return object_space()->capacity_in_bytes(); }

  size_t used_in_bytes() const            { return object_space()->used_in_bytes(); }

  size_t free_in_bytes() const            { return object_space()->free_in_bytes(); }

  size_t capacity_in_words() const        { return object_space()->capacity_in_words(); }

  size_t used_in_words() const            { return object_space()->used_in_words(); }

  size_t free_in_words() const            { return object_space()->free_in_words(); }

  // Includes uncommitted memory

  size_t contiguous_available() const;

  bool is_maximal_no_gc() const {

    return virtual_space()->uncommitted_size() == 0;

  }

  // Calculating new sizes

  void resize(size_t desired_free_space);

  // Allocation. We report all successful allocations to the size policy

  // Note that the perm gen does not use this method, and should not!

  HeapWord* allocate(size_t word_size, bool is_tlab);

  // Iteration.

  void oop_iterate(OopClosure* cl) { object_space()->oop_iterate(cl); }

  void object_iterate(ObjectClosure* cl) { object_space()->object_iterate(cl); }

  // Debugging - do not use for time critical operations

  virtual void print() const;

  virtual void print_on(outputStream* st) const;

  void print_used_change(size_t prev_used) const;

  void verify(bool allow_dirty);

  void verify_object_start_array();

  // These should not used

  virtual void reset_after_change();

  // These should not used

  virtual size_t available_for_expansion();

  virtual size_t available_for_contraction();

  void space_invariants() PRODUCT_RETURN;

  // Performace Counter support

  void update_counters();

  // Printing support

  virtual const char* name() const { return _name; }

  // Debugging support

  // Save the tops of all spaces for later use during mangling.

  void record_spaces_top() PRODUCT_RETURN;

};