--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zMemory.hpp	2018-06-08 19:46:20.673741371 +0200
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2015, 2017, 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_ZMEMORY_HPP
+#define SHARE_GC_Z_ZMEMORY_HPP
+
+#include "gc/z/zList.hpp"
+#include "memory/allocation.hpp"
+
+class ZMemory : public CHeapObj<mtGC> {
+  friend class ZList<ZMemory>;
+
+private:
+  uintptr_t          _start;
+  uintptr_t          _end;
+  ZListNode<ZMemory> _node;
+
+public:
+  ZMemory(uintptr_t start, size_t size);
+
+  uintptr_t start() const;
+  uintptr_t end() const;
+  size_t size() const;
+
+  void shrink_from_front(size_t size);
+  void shrink_from_back(size_t size);
+  void grow_from_front(size_t size);
+  void grow_from_back(size_t size);
+};
+
+class ZMemoryManager {
+private:
+  ZList<ZMemory> _freelist;
+
+public:
+  uintptr_t alloc_from_front(size_t size);
+  uintptr_t alloc_from_back(size_t size);
+  void free(uintptr_t start, size_t size);
+};
+
+#endif // SHARE_GC_Z_ZMEMORY_HPP