diff -r 9f75dc382445 -r 4e325f8b50ce src/hotspot/share/gc/z/zDriver.hpp
--- a/src/hotspot/share/gc/z/zDriver.hpp	Tue Jan 29 10:23:38 2019 +0100
+++ b/src/hotspot/share/gc/z/zDriver.hpp	Tue Jan 29 10:23:38 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,18 +28,31 @@
 #include "gc/shared/gcCause.hpp"
 #include "gc/z/zMessagePort.hpp"
 
-class ZOperationClosure;
+class VM_ZOperation;
 
 class ZDriver : public ConcurrentGCThread {
 private:
   ZMessagePort<GCCause::Cause> _gc_cycle_port;
   ZRendezvousPort              _gc_locker_port;
 
-  bool vm_operation(ZOperationClosure* cl);
+  template <typename T> bool pause();
 
-  GCCause::Cause start_gc_cycle();
-  void run_gc_cycle(GCCause::Cause cause);
-  void end_gc_cycle();
+  void pause_mark_start();
+  void concurrent_mark();
+  bool pause_mark_end();
+  void concurrent_mark_continue();
+  void concurrent_process_non_strong_references();
+  void concurrent_reset_relocation_set();
+  void concurrent_destroy_detached_pages();
+  void pause_verify();
+  void concurrent_select_relocation_set();
+  void concurrent_prepare_relocation_set();
+  void pause_relocate_start();
+  void concurrent_relocate();
+
+  void check_out_of_memory();
+
+  void gc(GCCause::Cause cause);
 
 protected:
   virtual void run_service();