1 /*
 2  * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHSTACKCHUNKGCDATA_HPP
25 #define SHARE_GC_SHENANDOAH_SHENANDOAHSTACKCHUNKGCDATA_HPP
26 
27 #include "oops/oopsHierarchy.hpp"
28 #include "runtime/atomic.hpp"
29 
30 class ShenandoahStackChunkGCData {
31 private:
32   // Monotonically increasing epoch counter.
33   // Must not wrap to track the epoch accurately.
34   static Atomic<int64_t> _epoch_id_counter;
35 
36   // The GC epoch when chunk was allocated.
37   int64_t _epoch;
38 
39   static ShenandoahStackChunkGCData* data(stackChunkOop chunk);
40 
41 public:
42   static void change_epoch_id();
43 
44   static void initialize(stackChunkOop chunk);
45   static bool is_different_epoch(stackChunkOop chunk);
46 };
47 
48 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHSTACKCHUNKGCDATA_HPP