--- /dev/null	2020-09-04 12:37:41.765504620 +0200
+++ new/src/hotspot/share/memory/metaspace/msArenaGrowthPolicy.hpp	2020-09-04 13:57:40.725286536 +0200
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020 SAP SE. 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_MEMORY_METASPACE_MSARENAGROWTHPOLICY_HPP
+#define SHARE_MEMORY_METASPACE_MSARENAGROWTHPOLICY_HPP
+
+#include "memory/metaspace/msChunklevel.hpp"
+#include "memory/metaspace.hpp" // For Metaspace::MetaspaceType
+#include "utilities/debug.hpp"
+
+namespace metaspace {
+
+// ArenaGrowthPolicy encodes the growth policy of a MetaspaceArena.
+//
+// These arenas grow in steps (by allocating new chunks). The coarseness of growth
+// (chunk size, level) depends on what the arena is used for. Used for a class loader
+// which is expected to load only one or very few classes should grow in tiny steps.
+// For normal classloaders, it can grow in coarser steps, and arenas used by
+// the boot loader will grow in even larger steps since we expect it to load a lot of
+// classes.
+// Note that when growing in large steps (in steps larger than a commit granule,
+// by default 64K), costs diminish somewhat since we do not commit the whole space
+// immediately.
+
+class ArenaGrowthPolicy {
+
+  // const array specifying chunk level allocation progression (growth steps). Last
+  //  chunk is to be an endlessly repeated allocation.
+  const chunklevel_t* const _entries;
+  const int _num_entries;
+
+public:
+
+  ArenaGrowthPolicy(const chunklevel_t* array, int num_entries)
+    : _entries(array), _num_entries(num_entries) {
+    assert(_num_entries > 0, "must not be empty.");
+  }
+
+  chunklevel_t get_level_at_step(int num_allocated) const {
+    if (num_allocated >= _num_entries) {
+      // Caller shall repeat last allocation
+      return _entries[_num_entries - 1];
+    }
+    return _entries[num_allocated];
+  }
+
+  // Given a space type, return the correct policy to use.
+  // The returned object is static and read only.
+  static const ArenaGrowthPolicy* policy_for_space_type(Metaspace::MetaspaceType space_type, bool is_class);
+
+};
+
+} // namespace metaspace
+
+#endif // SHARE_MEMORY_METASPACE_MSARENAGROWTHPOLICY_HPP