--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zPhysicalMemory.hpp	2018-06-06 00:42:15.391629947 +0200
@@ -0,0 +1,99 @@
+/*
+ * 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_ZPHYSICALMEMORY_HPP
+#define SHARE_GC_Z_ZPHYSICALMEMORY_HPP
+
+#include "memory/allocation.hpp"
+#include OS_CPU_HEADER(gc/z/zPhysicalMemoryBacking)
+
+class ZPhysicalMemorySegment {
+private:
+  uintptr_t _start;
+  uintptr_t _end;
+
+public:
+  ZPhysicalMemorySegment(uintptr_t start, size_t size);
+
+  uintptr_t start() const;
+  uintptr_t end() const;
+  size_t size() const;
+
+  void expand(size_t size);
+  ZPhysicalMemorySegment split(size_t size);
+};
+
+class ZPhysicalMemory {
+private:
+  size_t                  _nsegments;
+  ZPhysicalMemorySegment* _segments;
+
+public:
+  ZPhysicalMemory();
+  ZPhysicalMemory(size_t size);
+  ZPhysicalMemory(const ZPhysicalMemorySegment& segment);
+
+  bool is_null() const;
+  size_t size() const;
+
+  size_t nsegments() const;
+  ZPhysicalMemorySegment segment(size_t index) const;
+  void add_segment(ZPhysicalMemorySegment segment);
+
+  ZPhysicalMemory split(size_t size);
+  void clear();
+};
+
+class ZPhysicalMemoryManager {
+  friend class VMStructs;
+
+private:
+  ZPhysicalMemoryBacking _backing;
+  const size_t           _max_capacity;
+  size_t                 _capacity;
+  size_t                 _used;
+
+  bool ensure_available(size_t size);
+
+  void nmt_commit(ZPhysicalMemory pmem, uintptr_t offset);
+  void nmt_uncommit(ZPhysicalMemory pmem, uintptr_t offset);
+
+public:
+  ZPhysicalMemoryManager(size_t max_capacity, size_t granule_size);
+
+  bool is_initialized() const;
+
+  size_t max_capacity() const;
+  size_t capacity() const;
+  size_t used() const;
+  size_t available() const;
+
+  ZPhysicalMemory alloc(size_t size);
+  void free(ZPhysicalMemory pmem);
+
+  void map(ZPhysicalMemory pmem, uintptr_t offset);
+  void unmap(ZPhysicalMemory pmem, uintptr_t offset);
+  void flip(ZPhysicalMemory pmem, uintptr_t offset);
+};
+
+#endif // SHARE_GC_Z_ZPHYSICALMEMORY_HPP