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

 *

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 * 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.

 *

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP

#include "gc_implementation/g1/g1BiasedArray.hpp"

#include "gc_implementation/g1/heapRegionSet.hpp"

class HeapRegion;

class HeapRegionClosure;

class FreeRegionList;

class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {

 protected:

  virtual HeapRegion* default_value() const { return NULL; }

};

//

// We create a HeapRegion when we commit the region's address space

// for the first time. When we uncommit the address space of a

// region we retain the HeapRegion to be able to re-use it in the

// future (in case we recommit it).

//

// We keep track of three lengths:

//

// * max_length() returns the maximum number of regions the heap can have.

//

class HeapRegionSeq: public CHeapObj<mtGC> {

  friend class VMStructs;

  G1HeapRegionTable _regions;

  FreeRegionList _free_list;

  uint _num_committed;

  // Internal only. The highest heap region +1 we allocated a HeapRegion instance for.

  uint _allocated_heapregions_length;

  HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }

  HeapWord* heap_end() const {return _regions.end_address_mapped(); }

  void make_regions_available(uint index, uint num_regions = 1);

  // Pass down commit calls to the VirtualSpace.

  void commit_regions(uint index, size_t num_regions = 1);

  void uncommit_regions(uint index, size_t num_regions = 1);

  // Notify other data structures about change in the heap layout.

  void update_committed_space(HeapWord* old_end, HeapWord* new_end);

  // Calculate the starting region for each worker during parallel iteration so

  // that they do not all start from the same region.

  uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const;

  // Finds the next sequence of unavailable regions starting from start_idx. Returns the

  // length of the sequence found. If this result is zero, no such sequence could be found,

  // otherwise res_idx indicates the start index of these regions.

  uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const;

  // Finds the next sequence of empty regions starting from start_idx, going backwards in

  // the heap. Returns the length of the sequence found. If this value is zero, no

  // sequence could be found, otherwise res_idx contains the start index of this range.

  uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const;

#ifdef ASSERT

public:

  bool is_free(HeapRegion* hr) const;

#endif

  // Returns whether the given region is available for allocation.

  bool is_available(uint region) const;

 public:

  // Empty constructor, we'll initialize it with the initialize() method.

  { }

  // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired

  // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit

  // the heap from the lowest address, this region (and its associated data

  // structures) are available and we do not need to check further.

  HeapRegion* get_dummy_region() { return new_heap_region(0); }

  // Return the HeapRegion at the given index. Assume that the index

  // is valid.

  inline HeapRegion* at(uint index) const;

  // If addr is within the committed space return its corresponding

  // HeapRegion, otherwise return NULL.

  inline HeapRegion* addr_to_region(HeapWord* addr) const;

  // Insert the given region into the free region list.

  inline void insert_into_free_list(HeapRegion* hr);

  // Insert the given region list into the global free region list.

  void insert_list_into_free_list(FreeRegionList* list) {

    _free_list.add_ordered(list);

  }

  HeapRegion* allocate_free_region(bool is_old) {

    HeapRegion* hr = _free_list.remove_region(is_old);

    if (hr != NULL) {

      assert(hr->next() == NULL, "Single region should not have next");

      assert(is_available(hr->hrs_index()), "Must be committed");

    }

    return hr;

  }

  inline void allocate_free_regions_starting_at(uint first, uint num_regions);

  // Remove all regions from the free list.

  void remove_all_free_regions() {

    _free_list.remove_all();

  }

  // Return the number of committed free regions in the heap.

  uint num_free_regions() const {

    return _free_list.length();

  }

  size_t total_capacity_bytes() const {

    return num_free_regions() * HeapRegion::GrainBytes;

  }

  // Return the number of available (uncommitted) regions.

  uint available() const { return max_length() - length(); }

  // Return the number of regions that have been committed in the heap.

  uint length() const { return _num_committed; }

  // Return the maximum number of regions in the heap.

  uint max_length() const { return (uint)_regions.length(); }

  MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); }

  // Expand the sequence to reflect that the heap has grown. Either create new

  // HeapRegions, or re-use existing ones. Returns the number of regions the

  // sequence was expanded by. If a HeapRegion allocation fails, the resulting

  // number of regions might be smaller than what's desired.

  uint expand_by(uint num_regions);

  // Makes sure that the regions from start to start+num_regions-1 are available

  // for allocation. Returns the number of regions that were committed to achieve

  // this.

  uint expand_at(uint start, uint num_regions);

  HeapRegion* next_region_in_heap(const HeapRegion* r) const;

  // Apply blk->doHeapRegion() on all committed regions in address order,

  // terminating the iteration early if doHeapRegion() returns true.

  void iterate(HeapRegionClosure* blk) const;

  void par_iterate(HeapRegionClosure* blk, uint worker_id, uint no_of_par_workers, jint claim_value) const;

  // Uncommit up to num_regions_to_remove regions that are completely free.

  // Return the actual number of uncommitted regions.

  uint shrink_by(uint num_regions_to_remove);

  void verify();

  // Do some sanity checking.

  void verify_optional() PRODUCT_RETURN;

};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP