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

rev 6589 : 8047818: G1 HeapRegions can no longer be ContiguousSpaces
Reviewed-by:

@@ -23,11 +23,11 @@
  */
 
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
 
-#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
+#include "gc_implementation/g1/g1BlockOffsetTable.hpp"
 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
 #include "gc_implementation/g1/survRateGroup.hpp"
 #include "gc_implementation/shared/ageTable.hpp"
 #include "gc_implementation/shared/spaceDecorator.hpp"
 #include "memory/space.inline.hpp"

@@ -44,12 +44,10 @@
 // The problem is that the existence of this method breaks
 // the independence of barrier sets from remembered sets.
 // The solution is to remove this method from the definition
 // of a Space.
 
-class CompactibleSpace;
-class ContiguousSpace;
 class HeapRegionRemSet;
 class HeapRegionRemSetIterator;
 class HeapRegion;
 class HeapRegionSetBase;
 class nmethod;

@@ -123,14 +121,16 @@
 // invalid. Time stamps (on the regions and also on the
 // G1CollectedHeap) are reset at every cleanup (we iterate over
 // the regions anyway) and at the end of a Full GC. The current scheme
 // that uses sequential unsigned ints will fail only if we have 4b
 // evacuation pauses between two cleanups, which is _highly_ unlikely.
-
-class G1OffsetTableContigSpace: public ContiguousSpace {
+class G1OffsetTableContigSpace: public CompactibleSpace {
   friend class VMStructs;
+  HeapWord* _top;
  protected:
+  inline HeapWord* cas_allocate_inner(size_t size);
+  inline HeapWord* allocate_inner(size_t size);
   G1BlockOffsetArrayContigSpace _offsets;
   Mutex _par_alloc_lock;
   volatile unsigned _gc_time_stamp;
   // When we need to retire an allocation region, while other threads
   // are also concurrently trying to allocate into it, we typically

@@ -142,10 +142,23 @@
 
  public:
   G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
                            MemRegion mr);
 
+  inline void set_top(HeapWord* value) { _top = value; }
+  HeapWord* top() const { return _top; }
+  void reset_after_compaction() { set_top(compaction_top()); }
+
+  size_t used() const { return byte_size(bottom(), top()); }
+  size_t free() const { return byte_size(top(), end()); }
+  bool is_free_block(const HeapWord* p) const { return p >= top(); }
+
+  MemRegion used_region() const { return MemRegion(bottom(), top()); }
+
+  void object_iterate(ObjectClosure* blk);
+  void safe_object_iterate(ObjectClosure* blk);
+
   void set_bottom(HeapWord* value);
   void set_end(HeapWord* value);
 
   virtual HeapWord* saved_mark_word() const;
   void record_top_and_timestamp();

@@ -166,10 +179,12 @@
   virtual void clear(bool mangle_space);
 
   HeapWord* block_start(const void* p);
   HeapWord* block_start_const(const void* p) const;
 
+  void prepare_for_compaction(CompactPoint* cp);
+
   // Add offset table update.
   virtual HeapWord* allocate(size_t word_size);
   HeapWord* par_allocate(size_t word_size);
 
   // MarkSweep support phase3

@@ -351,18 +366,15 @@
     AggregateCountClaimValue   = 7,
     VerifyCountClaimValue      = 8,
     ParMarkRootClaimValue      = 9
   };
 
-  inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
-    assert(is_young(), "we can only skip BOT updates on young regions");
-    return ContiguousSpace::par_allocate(word_size);
-  }
-  inline HeapWord* allocate_no_bot_updates(size_t word_size) {
-    assert(is_young(), "we can only skip BOT updates on young regions");
-    return ContiguousSpace::allocate(word_size);
-  }
+  bool block_is_obj(const HeapWord* p) const;
+  size_t block_size(const HeapWord* p) const;
+
+  inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
+  inline HeapWord* allocate_no_bot_updates(size_t word_size);
 
   // If this region is a member of a HeapRegionSeq, the index in that
   // sequence, otherwise -1.
   uint hrs_index() const { return _hrs_index; }