--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zRelocationSetSelector.hpp	2018-06-08 19:46:38.170500491 +0200
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 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_ZRELOCATIONSETSELECTOR_HPP
+#define SHARE_GC_Z_ZRELOCATIONSETSELECTOR_HPP
+
+#include "gc/z/zArray.hpp"
+#include "memory/allocation.hpp"
+
+class ZPage;
+class ZRelocationSet;
+
+class ZRelocationSetSelectorGroup {
+private:
+  const char* const    _name;
+  const size_t         _page_size;
+  const size_t         _object_size_limit;
+  const size_t         _fragmentation_limit;
+
+  ZArray<const ZPage*> _registered_pages;
+  const ZPage**        _sorted_pages;
+  size_t               _nselected;
+  size_t               _relocating;
+  size_t               _fragmentation;
+
+  void semi_sort();
+
+public:
+  ZRelocationSetSelectorGroup(const char* name,
+                              size_t page_size,
+                              size_t object_size_limit);
+  ~ZRelocationSetSelectorGroup();
+
+  void register_live_page(const ZPage* page, size_t garbage);
+  void select();
+
+  const ZPage* const* selected() const;
+  size_t nselected() const;
+  size_t relocating() const;
+  size_t fragmentation() const;
+};
+
+class ZRelocationSetSelector : public StackObj {
+private:
+  ZRelocationSetSelectorGroup _small;
+  ZRelocationSetSelectorGroup _medium;
+  size_t                      _live;
+  size_t                      _garbage;
+  size_t                      _fragmentation;
+
+public:
+  ZRelocationSetSelector();
+
+  void register_live_page(const ZPage* page);
+  void register_garbage_page(const ZPage* page);
+  void select(ZRelocationSet* relocation_set);
+
+  size_t live() const;
+  size_t garbage() const;
+  size_t relocating() const;
+  size_t fragmentation() const;
+};
+
+#endif // SHARE_GC_Z_ZRELOCATIONSETSELECTOR_HPP