1 /*
2 * Copyright (c) 2001, 2018, 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.
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1REMSET_HPP
26 #define SHARE_VM_GC_G1_G1REMSET_HPP
27
28 #include "gc/g1/dirtyCardQueue.hpp"
29 #include "gc/g1/g1CardTable.hpp"
30 #include "gc/g1/g1OopClosures.hpp"
31 #include "gc/g1/g1RemSetSummary.hpp"
32 #include "gc/g1/heapRegion.hpp"
33 #include "memory/allocation.hpp"
34 #include "memory/iterator.hpp"
35 #include "utilities/ticks.hpp"
36
37 // A G1RemSet provides ways of iterating over pointers into a selected
38 // collection set.
39
40 class BitMap;
41 class CardTableBarrierSet;
42 class G1BlockOffsetTable;
43 class CodeBlobClosure;
44 class G1CollectedHeap;
45 class G1CMBitMap;
46 class G1HotCardCache;
47 class G1RemSetScanState;
48 class G1ParScanThreadState;
49 class G1Policy;
50 class G1ScanObjsDuringScanRSClosure;
51 class G1ScanObjsDuringUpdateRSClosure;
52 class HeapRegionClaimer;
53
54 // A G1RemSet in which each heap region has a rem set that records the
55 // external heap references into it. Uses a mod ref bs to track updates,
56 // so that they can be used to update the individual region remsets.
57 class G1RemSet: public CHeapObj<mtGC> {
58 private:
59 G1RemSetScanState* _scan_state;
60
61 G1RemSetSummary _prev_period_summary;
62
63 // Scan all remembered sets of the collection set for references into the collection
64 // set.
65 void scan_rem_set(G1ParScanThreadState* pss, uint worker_i);
66
67 // Flush remaining refinement buffers for cross-region references to either evacuate references
68 // into the collection set or update the remembered set.
69 void update_rem_set(G1ParScanThreadState* pss, uint worker_i);
70
71 G1CollectedHeap* _g1h;
72 size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.
73
74 G1CardTable* _ct;
75 G1Policy* _g1p;
76 G1HotCardCache* _hot_card_cache;
77
78 public:
79 // Gives an approximation on how many threads can be expected to add records to
80 // a remembered set in parallel. This can be used for sizing data structures to
81 // decrease performance losses due to data structure sharing.
82 // Examples for quantities that influence this value are the maximum number of
83 // mutator threads, maximum number of concurrent refinement or GC threads.
84 static uint num_par_rem_sets();
85
86 // Initialize data that depends on the heap size being known.
87 void initialize(size_t capacity, uint max_regions);
88
89 G1RemSet(G1CollectedHeap* g1h,
90 G1CardTable* ct,
91 G1HotCardCache* hot_card_cache);
92 ~G1RemSet();
93
94 // Process all oops in the collection set from the cards in the refinement buffers and
95 // remembered sets using pss.
96 //
97 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code
98 // roots list for each region in the collection set.
99 void oops_into_collection_set_do(G1ParScanThreadState* pss, uint worker_i);
100
101 // Prepare for and cleanup after an oops_into_collection_set_do
102 // call. Must call each of these once before and after (in sequential
103 // code) any thread calls oops_into_collection_set_do.
104 void prepare_for_oops_into_collection_set_do();
105 void cleanup_after_oops_into_collection_set_do();
106
107 G1RemSetScanState* scan_state() const { return _scan_state; }
108
109 // Refine the card corresponding to "card_ptr". Safe to be called concurrently
110 // to the mutator.
111 void refine_card_concurrently(jbyte* card_ptr,
112 uint worker_i);
113
114 // Refine the card corresponding to "card_ptr", applying the given closure to
115 // all references found. Must only be called during gc.
116 // Returns whether the card has been scanned.
117 bool refine_card_during_gc(jbyte* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl);
118
119 // Print accumulated summary info from the start of the VM.
120 void print_summary_info();
121
122 // Print accumulated summary info from the last time called.
123 void print_periodic_summary_info(const char* header, uint period_count);
124
125 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; }
126
127 // Rebuilds the remembered set by scanning from bottom to TARS for all regions
128 // using the given work gang.
129 void rebuild_rem_set(G1ConcurrentMark* cm, WorkGang* workers, uint worker_id_offset);
130 };
131
132 class G1ScanRSForRegionClosure : public HeapRegionClosure {
133 G1CollectedHeap* _g1h;
134 G1CardTable *_ct;
135
136 G1ParScanThreadState* _pss;
137 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl;
138
139 G1RemSetScanState* _scan_state;
140
141 uint _worker_i;
142
143 size_t _cards_scanned;
144 size_t _cards_claimed;
145 size_t _cards_skipped;
146
147 Tickspan _rem_set_root_scan_time;
148 Tickspan _rem_set_trim_partially_time;
149
150 Tickspan _strong_code_root_scan_time;
151 Tickspan _strong_code_trim_partially_time;
152
153 void claim_card(size_t card_index, const uint region_idx_for_card);
154 void scan_card(MemRegion mr, uint region_idx_for_card);
155
156 void scan_rem_set_roots(HeapRegion* r);
157 void scan_strong_code_roots(HeapRegion* r);
158 public:
159 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state,
160 G1ScanObjsDuringScanRSClosure* scan_obj_on_card,
161 G1ParScanThreadState* pss,
162 uint worker_i);
163
164 bool do_heap_region(HeapRegion* r);
165
166 Tickspan rem_set_root_scan_time() const { return _rem_set_root_scan_time; }
167 Tickspan rem_set_trim_partially_time() const { return _rem_set_trim_partially_time; }
168
169 Tickspan strong_code_root_scan_time() const { return _strong_code_root_scan_time; }
170 Tickspan strong_code_root_trim_partially_time() const { return _strong_code_trim_partially_time; }
171
172 size_t cards_scanned() const { return _cards_scanned; }
173 size_t cards_claimed() const { return _cards_claimed; }
174 size_t cards_skipped() const { return _cards_skipped; }
175 };
176
177 #endif // SHARE_VM_GC_G1_G1REMSET_HPP