1 /*
2 * Copyright (c) 2016, 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.
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_VM_GC_G1_G1COLLECTIONSET_HPP
26 #define SHARE_VM_GC_G1_G1COLLECTIONSET_HPP
27
28 #include "gc/g1/collectionSetChooser.hpp"
29 #include "gc/g1/g1FixedSizeStack.hpp"
30 #include "memory/allocation.hpp"
31 #include "utilities/debug.hpp"
32 #include "utilities/globalDefinitions.hpp"
33
34 class G1CollectedHeap;
35 class G1CollectorState;
36 class G1GCPhaseTimes;
37 class G1Policy;
38 class G1SurvivorRegions;
39 class HeapRegion;
40
41 class G1CollectionSet VALUE_OBJ_CLASS_SPEC {
42 G1CollectedHeap* _g1;
43 G1Policy* _policy;
44
45 CollectionSetChooser* _cset_chooser;
46
47 uint _eden_region_length;
48 uint _survivor_region_length;
49 uint _old_region_length;
50
51 // The actual collection set as a set of region indices.
52 G1FixedSizeStack<uint> _collection_set_regions;
53
54 // The number of bytes in the collection set before the pause. Set from
55 // the incrementally built collection set at the start of an evacuation
56 // pause, and incremented in finalize_old_part() when adding old regions
57 // (if any) to the collection set.
58 size_t _bytes_used_before;
59
60 size_t _recorded_rs_lengths;
61
62 // The associated information that is maintained while the incremental
63 // collection set is being built with young regions. Used to populate
64 // the recorded info for the evacuation pause.
65
66 enum CSetBuildType {
67 Active, // We are actively building the collection set
68 Inactive // We are not actively building the collection set
69 };
70
71 CSetBuildType _inc_build_state;
72
73 // The number of bytes in the incrementally built collection set.
74 // Used to set _collection_set_bytes_used_before at the start of
75 // an evacuation pause.
76 size_t _inc_bytes_used_before;
77
78 // The RSet lengths recorded for regions in the CSet. It is updated
79 // by the thread that adds a new region to the CSet. We assume that
80 // only one thread can be allocating a new CSet region (currently,
81 // it does so after taking the Heap_lock) hence no need to
82 // synchronize updates to this field.
83 size_t _inc_recorded_rs_lengths;
84
85 // A concurrent refinement thread periodically samples the young
86 // region RSets and needs to update _inc_recorded_rs_lengths as
87 // the RSets grow. Instead of having to synchronize updates to that
88 // field we accumulate them in this field and add it to
89 // _inc_recorded_rs_lengths_diffs at the start of a GC.
90 ssize_t _inc_recorded_rs_lengths_diffs;
91
92 // The predicted elapsed time it will take to collect the regions in
93 // the CSet. This is updated by the thread that adds a new region to
94 // the CSet. See the comment for _inc_recorded_rs_lengths about
95 // MT-safety assumptions.
96 double _inc_predicted_elapsed_time_ms;
97
98 // See the comment for _inc_recorded_rs_lengths_diffs.
99 double _inc_predicted_elapsed_time_ms_diffs;
100
101 G1CollectorState* collector_state();
102 G1GCPhaseTimes* phase_times();
103
104 double predict_region_elapsed_time_ms(HeapRegion* hr);
105
106 void verify_young_cset_indices() const NOT_DEBUG_RETURN;
107 public:
108 G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy);
109 ~G1CollectionSet();
110
111 // Set the maximum possible length of the collection set.
112 void set_max_length(uint max_region_length);
113
114 CollectionSetChooser* cset_chooser();
115
116 void init_region_lengths(uint eden_cset_region_length,
117 uint survivor_cset_region_length);
118
119 void set_recorded_rs_lengths(size_t rs_lengths);
120
121 uint region_length() const { return young_region_length() +
122 old_region_length(); }
123 uint young_region_length() const { return eden_region_length() +
124 survivor_region_length(); }
125
126 uint eden_region_length() const { return _eden_region_length; }
127 uint survivor_region_length() const { return _survivor_region_length; }
128 uint old_region_length() const { return _old_region_length; }
129
130 // Incremental collection set Support
131
132 // Initialize incremental collection set info.
133 void start_incremental_building();
134
135 // Perform any final calculations on the incremental collection set fields
136 // before we can use them.
137 void finalize_incremental_building();
138
139 // Reset the contents of the collection set.
140 void clear() {
141 _collection_set_regions.clear();
142 }
143
144 // Iterate over the collection set, applying the given HeapRegionClosure on all of them.
145 void iterate(HeapRegionClosure* cl);
146
147 // Iterate over the collection set, applying the given HeapRegionClosure on all of them,
148 // trying to optimally spread out starting position of total_workers workers given the
149 // caller's worker_id.
150 // If may_be_aborted is true, iteration may be aborted using the return value of the
151 // called closure method.
152 void iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers, bool may_be_aborted = false);
153
154 // Stop adding regions to the incremental collection set.
155 void stop_incremental_building() { _inc_build_state = Inactive; }
156
157 size_t recorded_rs_lengths() { return _recorded_rs_lengths; }
158
159 size_t bytes_used_before() const {
160 return _bytes_used_before;
161 }
162
163 void reset_bytes_used_before() {
164 _bytes_used_before = 0;
165 }
166
167 // Choose a new collection set. Marks the chosen regions as being
168 // "in_collection_set".
169 double finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors);
170 void finalize_old_part(double time_remaining_ms);
171
172 // Add old region "hr" to the collection set.
173 void add_old_region(HeapRegion* hr);
174
175 // Update information about hr in the aggregated information for
176 // the incrementally built collection set.
177 void update_young_region_prediction(HeapRegion* hr, size_t new_rs_length);
178
179 // Add eden region to the collection set.
180 void add_eden_region(HeapRegion* hr);
181
182 // Add survivor region to the collection set.
183 void add_survivor_regions(HeapRegion* hr);
184
185 #ifndef PRODUCT
186 bool verify_young_ages();
187
188 void print(outputStream* st);
189 #endif // !PRODUCT
190
191 private:
192 // Update the incremental collection set information when adding a region.
193 void add_young_region_common(HeapRegion* hr);
194 };
195
196 #endif // SHARE_VM_GC_G1_G1COLLECTIONSET_HPP
197