1 /*
2 * Copyright (c) 2001, 2017, 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
20 * or visit www.oracle.com if you need additional information or have any
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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/g1CardLiveData.hpp"
30 #include "gc/g1/g1RemSetSummary.hpp"
31 #include "gc/g1/heapRegion.hpp"
32 #include "memory/allocation.hpp"
33 #include "memory/iterator.hpp"
34
35 // A G1RemSet provides ways of iterating over pointers into a selected
36 // collection set.
37
38 class BitMap;
39 class CardTableModRefBS;
40 class G1BlockOffsetTable;
41 class CodeBlobClosure;
42 class G1CollectedHeap;
43 class G1HotCardCache;
44 class G1RemSetScanState;
45 class G1ParScanThreadState;
46 class G1Policy;
47 class G1SATBCardTableModRefBS;
48 class G1ScanObjsDuringScanRSClosure;
49 class G1ScanObjsDuringUpdateRSClosure;
50 class HeapRegionClaimer;
51
52 // A G1RemSet in which each heap region has a rem set that records the
53 // external heap references into it. Uses a mod ref bs to track updates,
54 // so that they can be used to update the individual region remsets.
55 class G1RemSet: public CHeapObj<mtGC> {
56 private:
57 G1RemSetScanState* _scan_state;
58 G1CardLiveData _card_live_data;
59
60 G1RemSetSummary _prev_period_summary;
61
62 // Scan all remembered sets of the collection set for references into the collection
63 // set.
64 void scan_rem_set(G1ParScanThreadState* pss,
65 CodeBlobClosure* heap_region_codeblobs,
66 uint worker_i);
67
68 // Flush remaining refinement buffers for cross-region references to either evacuate references
69 // into the collection set or update the remembered set.
70 void update_rem_set(G1ParScanThreadState* pss, uint worker_i);
71
72 G1CollectedHeap* _g1;
73 size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.
74
75 CardTableModRefBS* _ct_bs;
76 G1Policy* _g1p;
77 G1HotCardCache* _hot_card_cache;
78
79 public:
80 // Gives an approximation on how many threads can be expected to add records to
81 // a remembered set in parallel. This can be used for sizing data structures to
82 // decrease performance losses due to data structure sharing.
83 // Examples for quantities that influence this value are the maximum number of
84 // mutator threads, maximum number of concurrent refinement or GC threads.
85 static uint num_par_rem_sets();
86
87 // Initialize data that depends on the heap size being known.
88 void initialize(size_t capacity, uint max_regions);
89
90 // This is called to reset dual hash tables after the gc pause
91 // is finished and the initial hash table is no longer being
92 // scanned.
93 void cleanupHRRS();
94
95 G1RemSet(G1CollectedHeap* g1,
96 CardTableModRefBS* ct_bs,
97 G1HotCardCache* hot_card_cache);
98 ~G1RemSet();
99
100 // Process all oops in the collection set from the cards in the refinement buffers and
101 // remembered sets using pss.
102 //
103 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code
104 // roots list for each region in the collection set.
105 void oops_into_collection_set_do(G1ParScanThreadState* pss,
106 CodeBlobClosure* heap_region_codeblobs,
107 uint worker_i);
108
109 // Prepare for and cleanup after an oops_into_collection_set_do
110 // call. Must call each of these once before and after (in sequential
111 // code) any thread calls oops_into_collection_set_do.
112 void prepare_for_oops_into_collection_set_do();
113 void cleanup_after_oops_into_collection_set_do();
114
115 G1RemSetScanState* scan_state() const { return _scan_state; }
116
117 // Eliminates any remembered set entries that correspond to dead heap ranges.
118 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer);
119
120 // Refine the card corresponding to "card_ptr". Safe to be called concurrently
121 // to the mutator.
122 void refine_card_concurrently(jbyte* card_ptr,
123 uint worker_i);
124
125 // Refine the card corresponding to "card_ptr", applying the given closure to
126 // all references found. Must only be called during gc.
127 // Returns whether the card has been scanned.
128 bool refine_card_during_gc(jbyte* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl);
129
130 // Print accumulated summary info from the start of the VM.
131 void print_summary_info();
132
133 // Print accumulated summary info from the last time called.
134 void print_periodic_summary_info(const char* header, uint period_count);
135
136 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; }
137
138 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
139 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
140
141 // Verify that the liveness count data created concurrently matches one created
142 // during this safepoint.
143 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap);
144
145 void clear_card_live_data(WorkGang* workers);
146
147 #ifdef ASSERT
148 void verify_card_live_data_is_clear();
149 #endif
150 };
151
152 class G1ScanRSForRegionClosure : public HeapRegionClosure {
153 G1RemSetScanState* _scan_state;
154
155 size_t _cards_scanned;
156 size_t _cards_claimed;
157 size_t _cards_skipped;
158
159 G1CollectedHeap* _g1h;
160
161 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl;
162 CodeBlobClosure* _code_root_cl;
163
164 G1BlockOffsetTable* _bot;
165 G1SATBCardTableModRefBS *_ct_bs;
166
167 double _strong_code_root_scan_time_sec;
168 uint _worker_i;
169
170 void claim_card(size_t card_index, const uint region_idx_for_card);
171 void scan_card(MemRegion mr, uint region_idx_for_card);
172 void scan_strong_code_roots(HeapRegion* r);
173 public:
174 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state,
175 G1ScanObjsDuringScanRSClosure* scan_obj_on_card,
176 CodeBlobClosure* code_root_cl,
177 uint worker_i);
178
179 bool do_heap_region(HeapRegion* r);
180
181 double strong_code_root_scan_time_sec() {
182 return _strong_code_root_scan_time_sec;
183 }
184
185 size_t cards_scanned() const { return _cards_scanned; }
186 size_t cards_claimed() const { return _cards_claimed; }
187 size_t cards_skipped() const { return _cards_skipped; }
188 };
189
190 #endif // SHARE_VM_GC_G1_G1REMSET_HPP