1 /*
 2  * Copyright (c) 2021, Red Hat, Inc. 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 
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHGC_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHGC_HPP
27 
28 #include "memory/allocation.hpp"
29 #include "gc/shared/gcCause.hpp"
30 
31 /*
32  * Base class of three Shenandoah GC modes
33  *
34  * The relationship of the GCs:
35  *
36  * ("normal" mode) ----> Concurrent GC ----> (finish)
37  *                            |
38  *                            | <upgrade>
39  *                            v
40  * ("passive" mode) ---> Degenerated GC ---> (finish)
41  *                            |
42  *                            | <upgrade>
43  *                            v
44  *                         Full GC --------> (finish)
45  */
46 
47 class ShenandoahGC : public StackObj {
48 public:
49   // Fail point from concurrent GC
50   enum ShenandoahDegenPoint {
51     _degenerated_unset,
52     _degenerated_outside_cycle,
53     _degenerated_roots,
54     _degenerated_mark,
55     _degenerated_evac,
56     _degenerated_updaterefs,
57     _DEGENERATED_LIMIT
58   };
59 
60   // Returns false if the collection was cancelled, true otherwise.
61   virtual bool collect(GCCause::Cause cause) = 0;
62   static const char* degen_point_to_string(ShenandoahDegenPoint point);
63 
64 protected:
65   static void update_roots(bool full_gc);
66 };
67 
68 #endif  // SHARE_GC_SHENANDOAH_SHENANDOAHGC_HPP