--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/src/hotspot/share/jfr/leakprofiler/sampling/sampleList.cpp	2018-04-09 14:44:54.332405069 +0200
@@ -0,0 +1,142 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "jfr/leakprofiler/sampling/objectSample.hpp"
+#include "jfr/leakprofiler/sampling/sampleList.hpp"
+#include "oops/oop.inline.hpp"
+
+SampleList::SampleList(size_t limit, size_t cache_size) :
+  _free_list(),
+  _in_use_list(),
+  _last_resolved(NULL),
+  _limit(limit),
+  _cache_size(cache_size),
+  _allocated(0) {
+}
+
+SampleList::~SampleList() {
+  deallocate_samples(_free_list);
+  deallocate_samples(_in_use_list);
+}
+
+ObjectSample* SampleList::last() const {
+  return _in_use_list.head();
+}
+
+const ObjectSample* SampleList::last_resolved() const {
+  return _last_resolved;
+}
+
+void SampleList::set_last_resolved(const ObjectSample* sample) {
+  assert(last() == sample, "invariant");
+  _last_resolved = sample;
+}
+
+void SampleList::link(ObjectSample* sample) {
+  assert(sample != NULL, "invariant");
+  _in_use_list.prepend(sample);
+}
+
+void SampleList::unlink(ObjectSample* sample) {
+  assert(sample != NULL, "invariant");
+  if (_last_resolved == sample) {
+    _last_resolved = sample->next();
+  }
+  reset(_in_use_list.remove(sample));
+}
+
+ObjectSample* SampleList::reuse(ObjectSample* sample) {
+  assert(sample != NULL, "invariant");
+  unlink(sample);
+  link(sample);
+  return sample;
+}
+
+void SampleList::populate_cache() {
+  if (_free_list.count() < _cache_size) {
+    const size_t cache_delta = _cache_size - _free_list.count();
+    for (size_t i = 0; i < cache_delta; ++i) {
+      ObjectSample* sample = newSample();
+      if (sample != NULL) {
+        _free_list.append(sample);
+      }
+    }
+  }
+}
+
+ObjectSample* SampleList::newSample() const {
+  if (_limit == _allocated) {
+    return NULL;
+  }
+  ++_allocated;
+  return new ObjectSample();
+}
+
+ObjectSample* SampleList::get() {
+  ObjectSample* sample = _free_list.head();
+  if (sample != NULL) {
+    link(_free_list.remove(sample));
+  } else {
+    sample = newSample();
+    if (sample != NULL) {
+      _in_use_list.prepend(sample);
+    }
+  }
+  if (_cache_size > 0 && sample != NULL) {
+    populate_cache();
+  }
+  return sample;
+}
+
+void SampleList::release(ObjectSample* sample) {
+  assert(sample != NULL, "invariant");
+  unlink(sample);
+  _free_list.append(sample);
+}
+
+void SampleList::deallocate_samples(List& list) {
+  if (list.count() > 0) {
+    ObjectSample* sample = list.head();
+    while (sample != NULL) {
+      list.remove(sample);
+      delete sample;
+      sample = list.head();
+    }
+  }
+  assert(list.count() == 0, "invariant");
+}
+
+void SampleList::reset(ObjectSample* sample) {
+  assert(sample != NULL, "invariant");
+  sample->reset();
+}
+
+bool SampleList::is_full() const {
+  return _in_use_list.count() == _limit;
+}
+
+size_t SampleList::count() const {
+  return _in_use_list.count();
+}