--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/threadCritical.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2001, 2010, 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_RUNTIME_THREADCRITICAL_HPP
+#define SHARE_VM_RUNTIME_THREADCRITICAL_HPP
+
+#include "memory/allocation.hpp"
+
+// ThreadCritical is used to protect short non-blocking critical sections.
+// This class must use no vm facilities that require initialization.
+// It is used very early in the vm's initialization, in allocation
+// code and other areas. ThreadCritical regions are reentrant.
+//
+// Due to race conditions during vm exit, some of the os level
+// synchronization primitives may not be deallocated at exit. It
+// is a good plan to implement the platform dependent sections of
+// code with resources that are recoverable during process
+// cleanup by the os. Calling the initialize method before use
+// is also problematic, it is best to use preinitialized primitives
+// if possible. As an example:
+//
+// mutex_t  mp  =  DEFAULTMUTEX;
+//
+// Also note that this class is declared as a StackObj to enforce
+// block structured short locks. It cannot be declared a ResourceObj
+// or CHeapObj, due to initialization issues.
+
+class ThreadCritical : public StackObj {
+ friend class os;
+ private:
+  static void initialize();
+  static void release();
+
+ public:
+  ThreadCritical();
+  ~ThreadCritical();
+};
+
+#endif // SHARE_VM_RUNTIME_THREADCRITICAL_HPP