diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/shared/ageTable.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shared/ageTable.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 1997, 2016, 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_VM_GC_SHARED_AGETABLE_HPP
+#define SHARE_VM_GC_SHARED_AGETABLE_HPP
+
+#include "oops/markOop.hpp"
+#include "oops/oop.hpp"
+#include "runtime/perfData.hpp"
+
+/* Copyright (c) 1992, 2016, Oracle and/or its affiliates, and Stanford University.
+   See the LICENSE file for license information. */
+
+// Age table for adaptive feedback-mediated tenuring (scavenging)
+//
+// Note: all sizes are in oops
+
+class AgeTable VALUE_OBJ_CLASS_SPEC {
+  friend class VMStructs;
+
+ public:
+  // constants
+  enum { table_size = markOopDesc::max_age + 1 };
+
+  // instance variables
+  size_t sizes[table_size];
+
+  // constructor.  "global" indicates that this is the global age table
+  // (as opposed to gc-thread-local)
+  AgeTable(bool global = true);
+
+  // clear table
+  void clear();
+
+  // add entry
+  inline void add(oop p, size_t oop_size);
+
+  void add(uint age, size_t oop_size) {
+    assert(age > 0 && age < table_size, "invalid age of object");
+    sizes[age] += oop_size;
+  }
+
+  // Merge another age table with the current one.  Used
+  // for parallel young generation gc.
+  void merge(AgeTable* subTable);
+
+  // Calculate new tenuring threshold based on age information.
+  uint compute_tenuring_threshold(size_t desired_survivor_size);
+  void print_age_table(uint tenuring_threshold);
+
+ private:
+
+  PerfVariable* _perf_sizes[table_size];
+};
+
+#endif // SHARE_VM_GC_SHARED_AGETABLE_HPP