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

rev 7056 : [mq]: 8058298
rev 7057 : imported patch review

*** 29,38 ****
--- 29,39 ----
  #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"
  #include "gc_implementation/g1/heapRegionSet.hpp"
  
  class HeapRegion;
  class HeapRegionClosure;
+ class HeapRegionClaimer;
  class FreeRegionList;
  
  class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
   protected:
    virtual HeapRegion* default_value() const { return NULL; }
*** 231,237 ****
--- 232,277 ----
  
    // Do some sanity checking.
    void verify_optional() PRODUCT_RETURN;
  };
  
+ // The HeapRegionClaimer is used during parallel iteration over heap regions,
+ // allowing workers to claim heap regions, gaining exclusive rights to these regions.
+ class HeapRegionClaimer : public StackObj {
+   uint  _n_workers;
+   uint  _n_regions;
+   uint* _claims;
+ 
+   static const uint Unclaimed = 0;
+   static const uint Claimed   = 1;
+ 
+  public:
+   HeapRegionClaimer() : _n_workers(0), _n_regions(0), _claims(NULL) {}
+ 
+   HeapRegionClaimer(uint n_workers) : _n_workers(n_workers), _n_regions(0), _claims(NULL) {
+     initialize(n_workers);
+   }
+ 
+   ~HeapRegionClaimer() {
+     if (_claims != NULL) {
+       FREE_C_HEAP_ARRAY(uint, _claims, mtGC);
+     }
+   }
+ 
+   inline uint n_regions() const {
+     return _n_regions;
+   }
+ 
+   void initialize(uint n_workers);
+ 
+   // Calculate the starting region for given worker so
+   // that they do not all start from the same region.
+   uint start_region_for_worker(uint worker_id) const;
+ 
+   // Check if region has been claimed with this HRClaimer.
+   bool is_region_claimed(uint region_index) const;
+ 
+   // Claim the given region, returns true if successfully claimed.
+   bool claim_region(uint region_index);
+ };
  #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP