src/hotspot/share/gc/shared/markBitMap.cpp

*** 58,10 ***
--- 58,21 ---
    } else {
      _bm.clear_range(beg, end);
    }
  }
  
+ size_t MarkBitMap::count_marked(MemRegion mr) {
+   MemRegion intersection = mr.intersection(_covered);
+   assert(!intersection.is_empty(),
+          "Given range from " PTR_FORMAT " to " PTR_FORMAT " is completely outside the heap",
+          p2i(mr.start()), p2i(mr.end()));
+   // convert address range into offset range
+   size_t beg = addr_to_offset(intersection.start());
+   size_t end = addr_to_offset(intersection.end());
+   return _bm.count_one_bits(beg, end);
+ }
+ 
  #ifdef ASSERT
  void MarkBitMap::check_mark(HeapWord* addr) {
    assert(Universe::heap()->is_in(addr),
           "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.",
           p2i(this), p2i(addr));