src/share/vm/gc_implementation/g1/concurrentMark.cpp

rev 6927 : 8054808: Bitmap verification sometimes fails after Full GC aborts concurrent mark.
Summary: The verification code that checked whether no bitmap mark had been found re-read HeapRegion::end() after the check on the bitmap. Concurrent humongous object allocation could have changed HeapRegion::end() in the meantime. Fix this by using the actual end of the region instead of HeapRegion::end() for comparison.
Reviewed-by:

*** 886,896 ****
   public:
    CheckBitmapClearHRClosure(CMBitMap* bitmap) : _bitmap(bitmap) {
    }
  
    virtual bool doHeapRegion(HeapRegion* r) {
!     return _bitmap->getNextMarkedWordAddress(r->bottom(), r->end()) != r->end();
    }
  };
  
  bool ConcurrentMark::nextMarkBitmapIsClear() {
    CheckBitmapClearHRClosure cl(_nextMarkBitMap);
--- 886,900 ----
   public:
    CheckBitmapClearHRClosure(CMBitMap* bitmap) : _bitmap(bitmap) {
    }
  
    virtual bool doHeapRegion(HeapRegion* r) {
!     HeapWord* end = r->bottom() + HeapRegion::GrainWords;
!     // There cannot be a race when comparing to "end" after the call even if the
!     // compiler duplicates the calculation of "end" because r->bottom() is always
!     // constant.
!     return _bitmap->getNextMarkedWordAddress(r->bottom(), end) != end;
    }
  };
  
  bool ConcurrentMark::nextMarkBitmapIsClear() {
    CheckBitmapClearHRClosure cl(_nextMarkBitMap);