diff -r 7a2a740815b7 -r caf115bb98ad src/hotspot/share/jfr/leakprofiler/sampling/objectSampler.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/leakprofiler/sampling/objectSampler.hpp	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2014, 2018, 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_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
+#define SHARE_VM_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP
+
+#include "memory/allocation.hpp"
+#include "jfr/utilities/jfrTime.hpp"
+
+class BoolObjectClosure;
+class OopClosure;
+class ObjectSample;
+class ObjectSampler;
+class SampleList;
+class SamplePriorityQueue;
+class Thread;
+
+// Class reponsible for holding samples and
+// making sure the samples are evenly distributed as
+// new entries are added and removed.
+class ObjectSampler : public CHeapObj<mtTracing> {
+  friend class LeakProfiler;
+  friend class ObjectSampleCheckpoint;
+  friend class StartOperation;
+  friend class StopOperation;
+  friend class EmitEventOperation;
+ private:
+  SamplePriorityQueue* _priority_queue;
+  SampleList* _list;
+  JfrTicks _last_sweep;
+  size_t _total_allocated;
+  size_t _threshold;
+  size_t _size;
+  volatile int _tryLock;
+  bool _dead_samples;
+
+  explicit ObjectSampler(size_t size);
+  ~ObjectSampler();
+
+  void add(HeapWord* object, size_t size, JavaThread* thread);
+  void remove_dead(ObjectSample* sample);
+  void scavenge();
+
+  // Called by GC
+  void oops_do(BoolObjectClosure* is_alive, OopClosure* f);
+
+ public:
+  const ObjectSample* item_at(int index) const;
+  ObjectSample* item_at(int index);
+  int item_count() const;
+  const ObjectSample* last() const;
+  const ObjectSample* last_resolved() const;
+  void set_last_resolved(const ObjectSample* sample);
+  const JfrTicks& last_sweep() const;
+};
+
+#endif // SHARE_VM_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP