--- old/src/hotspot/share/gc/g1/g1OopStarChunkedList.cpp	2019-03-13 14:03:07.475203007 +0100
+++ new/src/hotspot/share/gc/g1/g1OopStarChunkedList.cpp	2019-03-13 14:03:07.265197304 +0100
@@ -32,9 +32,11 @@
   delete_list(_coops);
 }
 
-void G1OopStarChunkedList::oops_do(OopClosure* obj_cl, OopClosure* root_cl) {
-  chunks_do(_roots, root_cl);
-  chunks_do(_croots, root_cl);
-  chunks_do(_oops, obj_cl);
-  chunks_do(_coops, obj_cl);
+size_t G1OopStarChunkedList::oops_do(OopClosure* obj_cl, OopClosure* root_cl) {
+  size_t result = 0;
+  result += chunks_do(_roots, root_cl);
+  result += chunks_do(_croots, root_cl);
+  result += chunks_do(_oops, obj_cl);
+  result += chunks_do(_coops, obj_cl);
+  return result;
 }