--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/recorder/storage/jfrMemorySpaceRetrieval.hpp	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 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_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP
+#define SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP
+
+#include "memory/allocation.hpp"
+#include "jfr/recorder/repository/jfrChunkWriter.hpp"
+#include "jfr/recorder/storage/jfrBuffer.hpp"
+#include "jfr/utilities/jfrAllocation.hpp"
+#include "jfr/utilities/jfrTypes.hpp"
+
+/*
+* Some policy classes for getting mspace memory
+*/
+
+template <typename Mspace>
+class JfrMspaceRetrieval : AllStatic {
+ public:
+  typedef typename Mspace::Type Type;
+  static Type* get(size_t size, Mspace* mspace, typename Mspace::Iterator& iterator, Thread* thread) {
+    while (iterator.has_next()) {
+      Type* const t = iterator.next();
+      if (t->retired()) continue;
+      if (t->try_acquire(thread)) {
+        assert(!t->retired(), "invariant");
+        if (t->free_size() >= size) {
+          return t;
+        }
+        t->set_retired();
+        mspace->register_full(t, thread);
+      }
+    }
+    return NULL;
+  }
+};
+
+template <typename Mspace>
+class JfrMspaceAlternatingRetrieval {
+ private:
+   // provides stochastic distribution over "deque" endpoints; racy is ok here
+  static bool _last_access;
+ public:
+  typedef typename Mspace::Type Type;
+  static Type* get(size_t size, Mspace* mspace, Thread* thread) {
+    typename Mspace::Iterator iterator(mspace->free(), (_last_access = !_last_access) ? forward : backward);
+    return JfrMspaceRetrieval<Mspace>::get(size, mspace, iterator, thread);
+  }
+};
+
+template <typename Mspace>
+bool JfrMspaceAlternatingRetrieval<Mspace>::_last_access = false;
+
+template <typename Mspace>
+class JfrMspaceSequentialRetrieval {
+ public:
+  typedef typename Mspace::Type Type;
+  static Type* get(size_t size, Mspace* mspace, Thread* thread) {
+    typename Mspace::Iterator iterator(mspace->free());
+    return JfrMspaceRetrieval<Mspace>::get(size, mspace, iterator, thread);
+  }
+};
+
+template <typename Mspace>
+class JfrExclusiveRetrieval : AllStatic {
+public:
+  typedef typename Mspace::Type Type;
+  static Type* get(size_t size, Mspace* mspace, typename Mspace::Iterator& iterator, Thread* thread) {
+    assert(mspace->is_locked(), "invariant");
+    if (iterator.has_next()) {
+      Type* const t = iterator.next();
+      assert(!t->retired(), "invariant");
+      assert(t->identity() == NULL, "invariant");
+      assert(t->free_size() >= size, "invariant");
+      t->acquire(thread);
+      return t;
+    }
+    return NULL;
+  }
+};
+
+template <typename Mspace>
+class JfrThreadLocalRetrieval {
+public:
+  typedef typename Mspace::Type Type;
+  static Type* get(size_t size, Mspace* mspace, Thread* thread) {
+    typename Mspace::Iterator iterator(mspace->free(), forward);
+    return JfrExclusiveRetrieval<Mspace>::get(size, mspace, iterator, thread);
+  }
+};
+
+#endif // SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACERETRIEVAL_HPP