src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

rev 6668 : 8048112: G1 Full GC needs to support the case when the very first region is not available
Summary: To allow uncommit of regions within the heap, G1 Full GC should correctly handle the case when the very first region is not available (uncommitted). Provide support for that by lazily initializing the compaction point during iteration of the list of heap regions. Further refactor the code to let the G1CollectedHeap handle finding the next region to compact into.
Reviewed-by:

@@ -1151,11 +1151,11 @@
   virtual bool is_maximal_no_gc() const {
     return _g1_storage.uncommitted_size() == 0;
   }
 
   // The total number of regions in the heap.
-  uint n_regions() { return _hrs.length(); }
+  uint n_regions() const { return _hrs.length(); }
 
   // The max number of regions in the heap.
   uint max_regions() { return _hrs.max_length(); }
 
   // The number of regions that are completely free.

@@ -1385,12 +1385,11 @@
   void collection_set_iterate(HeapRegionClosure* blk);
 
   // As above but starting from region r
   void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk);
 
-  // Returns the first (lowest address) compactible space in the heap.
-  virtual CompactibleSpace* first_compactible_space();
+  HeapRegion* next_compaction_region(const HeapRegion* from) const;
 
   // A CollectedHeap will contain some number of spaces.  This finds the
   // space containing a given address, or else returns NULL.
   virtual Space* space_containing(const void* addr) const;