--- old/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	2018-10-04 12:19:52.534629727 +0200
+++ new/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp	2018-10-04 12:19:52.119616882 +0200
@@ -1178,6 +1178,8 @@
       ClassLoaderDataGraph::purge();
     }
 
+    _g1h->resize_heap_if_necessary();
+
     compute_new_sizes();
 
     verify_during_pause(G1HeapVerifier::G1VerifyRemark, VerifyOption_G1UsePrevMarking, "Remark after");