src/hotspot/share/gc/shenandoah/shenandoahMarkBitMap.cpp

*** 118,10 ***
--- 118,29 ---
    size_t beg = address_to_index(intersection.start());
    size_t end = address_to_index(intersection.end());
    clear_large_range(beg, end);
  }
  
+ size_t ShenandoahMarkBitMap::count_marked(MemRegion mr) const {
+   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
+   HeapWord* beg = intersection.start();
+   HeapWord* end = intersection.end();
+   size_t sum = 0;
+   // We could probably be smarter here, but the complication is that we use
+   // two bits per object for strong vs weak marking.
+   for (HeapWord* current = beg; current < end; current++) {
+     if (is_marked(current)) {
+       sum++;
+     }
+   }
+   return sum;
+ }
+ 
  #ifdef ASSERT
  void ShenandoahMarkBitMap::check_mark(HeapWord* addr) const {
    assert(ShenandoahHeap::heap()->is_in(addr),
           "Trying to access bitmap " PTR_FORMAT " for address " PTR_FORMAT " not in the heap.",
           p2i(this), p2i(addr));