--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zVirtualMemory.hpp	2018-06-08 19:46:48.158933853 +0200
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2015, 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef SHARE_GC_Z_ZVIRTUALMEMORY_HPP
+#define SHARE_GC_Z_ZVIRTUALMEMORY_HPP
+
+#include "gc/z/zMemory.hpp"
+#include "memory/allocation.hpp"
+
+class ZVirtualMemory {
+  friend class VMStructs;
+
+private:
+  uintptr_t _start;
+  uintptr_t _end;
+
+public:
+  ZVirtualMemory();
+  ZVirtualMemory(uintptr_t start, size_t size);
+
+  bool is_null() const;
+  uintptr_t start() const;
+  uintptr_t end() const;
+  size_t size() const;
+  ZVirtualMemory split(size_t size);
+  void clear();
+};
+
+class ZVirtualMemoryManager {
+private:
+  ZMemoryManager _manager;
+  bool           _initialized;
+
+  bool reserve(uintptr_t start, size_t size);
+  void nmt_reserve(uintptr_t start, size_t size);
+
+public:
+  ZVirtualMemoryManager();
+
+  bool is_initialized() const;
+
+  ZVirtualMemory alloc(size_t size, bool alloc_from_front = false);
+  void free(ZVirtualMemory vmem);
+};
+
+#endif // SHARE_GC_Z_ZVIRTUALMEMORY_HPP