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 "memory/allocation.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 class G1CollectedHeap;
34 class G1CollectorState;
35 class G1GCPhaseTimes;
36 class G1Policy;
37 class G1SurvivorRegions;
38 class HeapRegion;
39
40 class G1CollectionSet VALUE_OBJ_CLASS_SPEC {
41 G1CollectedHeap* _g1;
42 G1Policy* _policy;
43
44 CollectionSetChooser* _cset_chooser;
45
46 uint _eden_region_length;
47 uint _survivor_region_length;
48 uint _old_region_length;
49
50 // The actual collection set as a set of region indices.
51 uint* _collection_set_regions;
52 volatile size_t _collection_set_cur_length;
53 size_t _collection_set_max_length;
54
55 // The number of bytes in the collection set before the pause. Set from
56 // the incrementally built collection set at the start of an evacuation
57 // pause, and incremented in finalize_old_part() when adding old regions
58 // (if any) to the collection set.
59 size_t _bytes_used_before;
60
61 size_t _recorded_rs_lengths;
62
63 // The associated information that is maintained while the incremental
64 // collection set is being built with young regions. Used to populate
65 // the recorded info for the evacuation pause.
66
67 enum CSetBuildType {
68 Active, // We are actively building the collection set
69 Inactive // We are not actively building the collection set
70 };
71
72 CSetBuildType _inc_build_state;
73
74 // The number of bytes in the incrementally built collection set.
75 // Used to set _collection_set_bytes_used_before at the start of
76 // an evacuation pause.
77 size_t _inc_bytes_used_before;
78
79 // The RSet lengths recorded for regions in the CSet. It is updated
80 // by the thread that adds a new region to the CSet. We assume that
81 // only one thread can be allocating a new CSet region (currently,
82 // it does so after taking the Heap_lock) hence no need to
83 // synchronize updates to this field.
84 size_t _inc_recorded_rs_lengths;
85
86 // A concurrent refinement thread periodically samples the young
87 // region RSets and needs to update _inc_recorded_rs_lengths as
88 // the RSets grow. Instead of having to synchronize updates to that
89 // field we accumulate them in this field and add it to
90 // _inc_recorded_rs_lengths_diffs at the start of a GC.
91 ssize_t _inc_recorded_rs_lengths_diffs;
92
93 // The predicted elapsed time it will take to collect the regions in
94 // the CSet. This is updated by the thread that adds a new region to
95 // the CSet. See the comment for _inc_recorded_rs_lengths about
96 // MT-safety assumptions.
97 double _inc_predicted_elapsed_time_ms;
98
99 // See the comment for _inc_recorded_rs_lengths_diffs.
100 double _inc_predicted_elapsed_time_ms_diffs;
101
102 G1CollectorState* collector_state();
103 G1GCPhaseTimes* phase_times();
104
105 double predict_region_elapsed_time_ms(HeapRegion* hr);
106
107 void verify_young_cset_indices() const NOT_DEBUG_RETURN;
108 public:
109 G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy);
110 ~G1CollectionSet();
111
112 // Set the maximum possible length of the collection set.
113 void set_max_length(uint max_region_length);
114
115 CollectionSetChooser* cset_chooser();
116
117 void init_region_lengths(uint eden_cset_region_length,
118 uint survivor_cset_region_length);
119
120 void set_recorded_rs_lengths(size_t rs_lengths);
121
122 uint region_length() const { return young_region_length() +
123 old_region_length(); }
124 uint young_region_length() const { return eden_region_length() +
125 survivor_region_length(); }
126
127 uint eden_region_length() const { return _eden_region_length; }
128 uint survivor_region_length() const { return _survivor_region_length; }
129 uint old_region_length() const { return _old_region_length; }
130
131 // Incremental collection set support
132
133 // Initialize incremental collection set info.
134 void start_incremental_building();
135
136 // Perform any final calculations on the incremental collection set fields
137 // before we can use them.
138 void finalize_incremental_building();
139
140 // Reset the contents of the collection set.
141 void clear();
142
143 // Iterate over the collection set, applying the given HeapRegionClosure on all of them.
144 // If may_be_aborted is true, iteration may be aborted using the return value of the
145 // called closure method.
146 void iterate(HeapRegionClosure* cl, bool may_be_aborted = false);
147
148 // Iterate over the collection set, applying the given HeapRegionClosure on all of them,
149 // trying to optimally spread out starting position of total_workers workers given the
150 // caller's worker_id.
151 // If may_be_aborted is true, iteration may be aborted using the return value of the
152 // called closure method.
153 void iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers, bool may_be_aborted = false);
154
155 // Stop adding regions to the incremental collection set.
156 void stop_incremental_building() { _inc_build_state = Inactive; }
157
158 size_t recorded_rs_lengths() { return _recorded_rs_lengths; }
159
160 size_t bytes_used_before() const {
161 return _bytes_used_before;
162 }
163
164 void reset_bytes_used_before() {
165 _bytes_used_before = 0;
166 }
167
168 // Choose a new collection set. Marks the chosen regions as being
169 // "in_collection_set".
170 double finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors);
171 void finalize_old_part(double time_remaining_ms);
172
173 // Add old region "hr" to the collection set.
174 void add_old_region(HeapRegion* hr);
175
176 // Update information about hr in the aggregated information for
177 // the incrementally built collection set.
178 void update_young_region_prediction(HeapRegion* hr, size_t new_rs_length);
179
180 // Add eden region to the collection set.
181 void add_eden_region(HeapRegion* hr);
182
183 // Add survivor region to the collection set.
184 void add_survivor_regions(HeapRegion* hr);
185
186 #ifndef PRODUCT
187 bool verify_young_ages();
188
189 void print(outputStream* st);
190 #endif // !PRODUCT
191
192 private:
193 // Update the incremental collection set information when adding a region.
194 void add_young_region_common(HeapRegion* hr);
195 };
196
197 #endif // SHARE_VM_GC_G1_G1COLLECTIONSET_HPP
198