--- old/src/hotspot/share/gc/shared/gcCause.cpp	2018-11-12 10:37:46.939875219 +0100
+++ new/src/hotspot/share/gc/shared/gcCause.cpp	2018-11-12 10:37:46.519862211 +0100
@@ -102,6 +102,9 @@
     case _g1_humongous_allocation:
       return "G1 Humongous Allocation";
 
+    case _g1_periodic_collection:
+      return "G1 Periodic Collection";
+
     case _dcmd_gc_run:
       return "Diagnostic Command";