1 /*
2 * Copyright (c) 2015, Oracle and/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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1COLLECTORSTATE_HPP
26 #define SHARE_VM_GC_G1_G1COLLECTORSTATE_HPP
27
28 #include "utilities/globalDefinitions.hpp"
29 #include "gc/g1/g1YCTypes.hpp"
30
31 // Various state variables that indicate
32 // the phase of the G1 collection.
33 class G1CollectorState VALUE_OBJ_CLASS_SPEC {
34 // Indicates whether we are in "full young" or "mixed" GC mode.
35 bool _gcs_are_young;
36 // Was the last GC "young"?
37 bool _last_gc_was_young;
38 // Is this the "last young GC" before we start doing mixed GCs?
39 // Set after a concurrent mark has completed.
40 bool _last_young_gc;
41
42 // If initiate_conc_mark_if_possible() is set at the beginning of a
43 // pause, it is a suggestion that the pause should start a marking
44 // cycle by doing the initial-mark work. However, it is possible
45 // that the concurrent marking thread is still finishing up the
46 // previous marking cycle (e.g., clearing the next marking
47 // bitmap). If that is the case we cannot start a new cycle and
48 // we'll have to wait for the concurrent marking thread to finish
49 // what it is doing. In this case we will postpone the marking cycle
50 // initiation decision for the next pause. When we eventually decide
51 // to start a cycle, we will set _during_initial_mark_pause which
52 // will stay true until the end of the initial-mark pause and it's
53 // the condition that indicates that a pause is doing the
54 // initial-mark work.
55 volatile bool _during_initial_mark_pause;
56
57 // At the end of a pause we check the heap occupancy and we decide
58 // whether we will start a marking cycle during the next pause. If
59 // we decide that we want to do that, we will set this parameter to
60 // true. So, this parameter will stay true between the end of a
61 // pause and the beginning of a subsequent pause (not necessarily
62 // the next one, see the comments on the next field) when we decide
63 // that we will indeed start a marking cycle and do the initial-mark
64 // work.
65 volatile bool _initiate_conc_mark_if_possible;
66
67 // NOTE: if some of these are synonyms for others,
68 // the redundant fields should be eliminated. XXX
69 bool _during_marking;
70 bool _mark_in_progress;
71 bool _in_marking_window;
72 bool _in_marking_window_im;
73
74 bool _concurrent_cycle_started;
75 bool _full_collection;
76
77 public:
78 G1CollectorState() :
79 _gcs_are_young(true),
80 _last_gc_was_young(false),
81 _last_young_gc(false),
82
83 _during_initial_mark_pause(false),
84 _initiate_conc_mark_if_possible(false),
85
86 _during_marking(false),
87 _mark_in_progress(false),
88 _in_marking_window(false),
89 _in_marking_window_im(false),
90 _concurrent_cycle_started(false),
91 _full_collection(false) {}
92
93 // Setters
94 void set_gcs_are_young(bool v) { _gcs_are_young = v; }
95 void set_last_gc_was_young(bool v) { _last_gc_was_young = v; }
96 void set_last_young_gc(bool v) { _last_young_gc = v; }
97 void set_during_initial_mark_pause(bool v) { _during_initial_mark_pause = v; }
98 void set_initiate_conc_mark_if_possible(bool v) { _initiate_conc_mark_if_possible = v; }
99 void set_during_marking(bool v) { _during_marking = v; }
100 void set_mark_in_progress(bool v) { _mark_in_progress = v; }
101 void set_in_marking_window(bool v) { _in_marking_window = v; }
102 void set_in_marking_window_im(bool v) { _in_marking_window_im = v; }
103 void set_concurrent_cycle_started(bool v) { _concurrent_cycle_started = v; }
104 void set_full_collection(bool v) { _full_collection = v; }
105
106 // Getters
107 bool gcs_are_young() const { return _gcs_are_young; }
108 bool last_gc_was_young() const { return _last_gc_was_young; }
109 bool last_young_gc() const { return _last_young_gc; }
110 bool during_initial_mark_pause() const { return _during_initial_mark_pause; }
111 bool initiate_conc_mark_if_possible() const { return _initiate_conc_mark_if_possible; }
112 bool during_marking() const { return _during_marking; }
113 bool mark_in_progress() const { return _mark_in_progress; }
114 bool in_marking_window() const { return _in_marking_window; }
115 bool in_marking_window_im() const { return _in_marking_window_im; }
116 bool concurrent_cycle_started() const { return _concurrent_cycle_started; }
117 bool full_collection() const { return _full_collection; }
118
119 // Composite booleans (clients worry about flickering)
120 bool during_concurrent_mark() const {
121 return (_in_marking_window && !_in_marking_window_im);
122 }
123
124 G1YCType yc_type() const {
125 if (during_initial_mark_pause()) {
126 return InitialMark;
127 } else if (mark_in_progress()) {
128 return DuringMark;
129 } else if (gcs_are_young()) {
130 return Normal;
131 } else {
132 return Mixed;
133 }
134 }
135 };
136
137 #endif // SHARE_VM_GC_G1_G1COLLECTORSTATE_HPP