src/hotspot/share/gc/g1/heapRegionManager.hpp

rev 51649 : version 1
rev 51650 : added comments
rev 52017 : All changes for G1 GC moved from 'combined' repo folder

@@ -69,20 +69,23 @@
 
 class HeapRegionManager: public CHeapObj<mtGC> {
   friend class VMStructs;
   friend class HeapRegionClaimer;
 
+  protected:
   G1HeapRegionTable _regions;
-
   G1RegionToSpaceMapper* _heap_mapper;
+  private:
   G1RegionToSpaceMapper* _prev_bitmap_mapper;
   G1RegionToSpaceMapper* _next_bitmap_mapper;
   G1RegionToSpaceMapper* _bot_mapper;
   G1RegionToSpaceMapper* _cardtable_mapper;
   G1RegionToSpaceMapper* _card_counts_mapper;
 
+  protected:
   FreeRegionList _free_list;
+  private:
 
   // Each bit in this bitmap indicates that the corresponding region is available
   // for allocation.
   CHeapBitMap _available_map;
 

@@ -93,15 +96,16 @@
   uint _allocated_heapregions_length;
 
   HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }
   HeapWord* heap_end() const {return _regions.end_address_mapped(); }
 
+  protected:
   void make_regions_available(uint index, uint num_regions = 1, WorkGang* pretouch_gang = NULL);
-
+  void uncommit_regions(uint index, size_t num_regions = 1);
+  private:
   // Pass down commit calls to the VirtualSpace.
   void commit_regions(uint index, size_t num_regions = 1, WorkGang* pretouch_gang = NULL);
-  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);
 
   // Find a contiguous set of empty or uncommitted regions of length num and return

@@ -115,18 +119,21 @@
   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;
-  // Allocate a new HeapRegion for the given index.
-  HeapRegion* new_heap_region(uint hrm_index);
 #ifdef ASSERT
 public:
   bool is_free(HeapRegion* hr) const;
-#endif
+  bool is_available(uint region) const;
+#else
   // Returns whether the given region is available for allocation.
+protected:
   bool is_available(uint region) const;
+#endif
+  // Allocate a new HeapRegion for the given index.
+  HeapRegion* new_heap_region(uint hrm_index);
 
  public:
   // Empty constructor, we'll initialize it with the initialize() method.
   HeapRegionManager();
 

@@ -139,11 +146,11 @@
 
   // 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); }
+  virtual 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;
 

@@ -161,11 +168,11 @@
   // 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) {
+  virtual 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->hrm_index()), "Must be committed");

@@ -196,38 +203,41 @@
   uint length() const { return _num_committed; }
 
   // Return the maximum number of regions in the heap.
   uint max_length() const { return (uint)_regions.length(); }
 
+  // Return maximum number of regions that heap can expand to.
+  virtual uint max_expandable_length() const { return (uint)_regions.length(); }
+
   MemoryUsage get_auxiliary_data_memory_usage() const;
 
   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, WorkGang* pretouch_workers);
+  virtual uint expand_by(uint num_regions, WorkGang* pretouch_workers);
 
   // 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, WorkGang* pretouch_workers);
+  virtual uint expand_at(uint start, uint num_regions, WorkGang* pretouch_workers);
 
   // Find a contiguous set of empty regions of length num. Returns the start index of
   // that set, or G1_NO_HRM_INDEX.
-  uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); }
+  virtual uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); }
   // Find a contiguous set of empty or unavailable regions of length num. Returns the
   // start index of that set, or G1_NO_HRM_INDEX.
-  uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); }
+  virtual uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); }
 
   HeapRegion* next_region_in_heap(const HeapRegion* r) const;
 
   // Find the highest free or uncommitted region in the reserved heap,
   // and if uncommitted, commit it. If none are available, return G1_NO_HRM_INDEX.
   // Set the 'expanded' boolean true if a new region was committed.
-  uint find_highest_free(bool* expanded);
+  virtual uint find_highest_free(bool* expanded);
 
   // Allocate the regions that contain the address range specified, committing the
   // regions if necessary. Return false if any of the regions is already committed
   // and not free, and return the number of regions newly committed in commit_count.
   bool allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers);

@@ -238,17 +248,17 @@
 
   void par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) 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);
+  virtual uint shrink_by(uint num_regions_to_remove);
 
   // Uncommit a number of regions starting at the specified index, which must be available,
   // empty, and free.
   void shrink_at(uint index, size_t num_regions);
 
-  void verify();
+  virtual void verify();
 
   // Do some sanity checking.
   void verify_optional() PRODUCT_RETURN;
 };