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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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#ifndef SHARE_GC_PARALLEL_PSYOUNGGEN_HPP
#define SHARE_GC_PARALLEL_PSYOUNGGEN_HPP

#include "gc/parallel/mutableSpace.hpp"
#include "gc/parallel/objectStartArray.hpp"
#include "gc/parallel/psVirtualspace.hpp"
#include "gc/parallel/spaceCounters.hpp"

class ReservedSpace;

class PSYoungGen : public CHeapObj<mtGC> {
  friend class VMStructs;
  friend class ParallelScavengeHeap;

 private:
  MemRegion       _reserved;
  PSVirtualSpace* _virtual_space;

  // Spaces
  MutableSpace* _eden_space;
  MutableSpace* _from_space;
  MutableSpace* _to_space;

  // Sizing information, in bytes, set in constructor
  const size_t _min_gen_size;
  const size_t _max_gen_size;

  // Performance counters
  GenerationCounters*   _gen_counters;
  SpaceCounters*        _eden_counters;
  SpaceCounters*        _from_counters;
  SpaceCounters*        _to_counters;

  // Initialize the space boundaries
  void compute_initial_space_boundaries();

  // Space boundary helper
  void set_space_boundaries(size_t eden_size, size_t survivor_size);

  bool resize_generation(size_t desired_young_gen_size);
  void resize_spaces(size_t requested_eden_size,
                     size_t requested_survivor_size);

  // Try to expand eden to hold at least word_size.
  // Return true iff the expansion is successful.
  bool try_expand_to_hold(size_t word_size);

  // Adjust the spaces to be consistent with the virtual space.
  void post_resize();

  void initialize(ReservedSpace rs, size_t inital_size, size_t alignment);
  void initialize_work();
  void initialize_virtual_space(ReservedSpace rs, size_t initial_size, size_t alignment);

  void compute_desired_sizes(bool is_survivor_overflowing,
                             size_t& eden_size,
                             size_t& survivor_size);

  void resize_inner(size_t desired_eden_size,
                    size_t desired_survivor_size);

 public:
  // Initialize the generation.
  PSYoungGen(ReservedSpace rs,
             size_t initial_byte_size,
             size_t minimum_byte_size,
             size_t maximum_byte_size);

  MemRegion reserved() const { return _reserved; }

  bool is_in(const void* p) const {
    return _virtual_space->is_in_committed(p);
  }

  bool is_in_reserved(const void* p) const {
    return reserved().contains((void *)p);
  }

  MutableSpace*   eden_space() const    { return _eden_space; }
  MutableSpace*   from_space() const    { return _from_space; }
  MutableSpace*   to_space() const      { return _to_space; }
  PSVirtualSpace* virtual_space() const { return _virtual_space; }

  // Called during/after GC
  void swap_spaces();

  bool is_from_to_layout() const {
    return from_space()->bottom() < to_space()->bottom();
  }

  void resize_after_young_gc(bool is_survivor_overflowing);

  // Size info
  size_t capacity_in_bytes() const;
  size_t used_in_bytes() const;
  size_t free_in_bytes() const;

  size_t capacity_in_words() const;
  size_t used_in_words() const;
  size_t free_in_words() const;

  size_t min_gen_size() const { return _min_gen_size; }
  size_t max_gen_size() const { return _max_gen_size; }

  // Allocation
  HeapWord* allocate(size_t word_size) {
    HeapWord* result = eden_space()->cas_allocate(word_size);
    return result;
  }

  HeapWord* expand_and_allocate(size_t word_size);

  // Iteration.
  void object_iterate(ObjectClosure* cl);

  // Performance Counter support
  void update_counters();

  // Debugging - do not use for time critical operations
  void print() const;
  virtual void print_on(outputStream* st) const;
  const char* name() const { return "PSYoungGen"; }

  void verify();

  // Space boundary invariant checker
  void space_invariants() PRODUCT_RETURN;
};

#endif // SHARE_GC_PARALLEL_PSYOUNGGEN_HPP