--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/runtime/threadCritical.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2001-2002 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// 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 dependant 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();
+};