--- old/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Nov  8 08:12:28 2017
+++ new/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Wed Nov  8 08:12:27 2017
@@ -2630,13 +2630,9 @@
 
 size_t G1CollectedHeap::pending_card_num() {
   size_t extra_cards = 0;
-  {
-    ThreadsListHandle tlh;
-    JavaThreadIterator jti(tlh.list());
-    for (JavaThread *curr = jti.first(); curr != NULL; curr = jti.next()) {
-      DirtyCardQueue& dcq = curr->dirty_card_queue();
-      extra_cards += dcq.size();
-    }
+  for (JavaThreadIteratorWithHandle jtiwh; JavaThread *curr = jtiwh.next(); ) {
+    DirtyCardQueue& dcq = curr->dirty_card_queue();
+    extra_cards += dcq.size();
   }
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   size_t buffer_size = dcqs.buffer_size();