1 /*
2 * Copyright (c) 2001, 2019, 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_GC_G1_G1REMSET_HPP
26 #define SHARE_GC_G1_G1REMSET_HPP
27
28 #include "gc/g1/g1CardTable.hpp"
29 #include "gc/g1/g1OopClosures.hpp"
30 #include "gc/g1/g1GCPhaseTimes.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 G1ParScanThreadStateSet;
50 class G1Policy;
51 class G1ScanCardClosure;
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 G1CollectedHeap* _g1h;
64
65 G1CardTable* _ct;
66 G1Policy* _g1p;
67 G1HotCardCache* _hot_card_cache;
68
69 void print_merge_heap_roots_stats();
70 public:
71
72 typedef CardTable::CardValue CardValue;
73 // Gives an approximation on how many threads can be expected to add records to
74 // a remembered set in parallel. This can be used for sizing data structures to
75 // decrease performance losses due to data structure sharing.
76 // Examples for quantities that influence this value are the maximum number of
77 // mutator threads, maximum number of concurrent refinement or GC threads.
78 static uint num_par_rem_sets();
79
80 // Initialize data that depends on the heap size being known.
81 void initialize(size_t capacity, uint max_regions);
82
83 G1RemSet(G1CollectedHeap* g1h,
84 G1CardTable* ct,
85 G1HotCardCache* hot_card_cache);
86 ~G1RemSet();
87
88 // Scan all cards in the non-collection set regions that potentially contain
89 // references into the current whole collection set.
90 void scan_heap_roots(G1ParScanThreadState* pss,
91 uint worker_id,
92 G1GCPhaseTimes::GCParPhases scan_phase,
93 G1GCPhaseTimes::GCParPhases objcopy_phase);
94
95 // Merge cards from various sources (remembered sets, hot card cache, log buffers)
96 // and calculate the cards that need to be scanned later (via scan_heap_roots()).
97 // If initial_evacuation is set, this is called during the initial evacuation.
98 void merge_heap_roots(bool initial_evacuation);
99
100 // Prepare for and cleanup after scanning the heap roots. Must be called
101 // once before and after in sequential code.
102 void prepare_for_scan_heap_roots();
103 // Cleans the card table from temporary duplicate detection information.
104 void cleanup_after_scan_heap_roots();
105 // Excludes the given region from heap root scanning.
106 void exclude_region_from_scan(uint region_idx);
107 // Creates a snapshot of the current _top values at the start of collection to
108 // filter out card marks that we do not want to scan.
109 void prepare_region_for_scan(HeapRegion* region);
110
111 // Do work for regions in the current increment of the collection set, scanning
112 // non-card based (heap) roots.
113 void scan_collection_set_regions(G1ParScanThreadState* pss,
114 uint worker_id,
115 G1GCPhaseTimes::GCParPhases scan_phase,
116 G1GCPhaseTimes::GCParPhases coderoots_phase,
117 G1GCPhaseTimes::GCParPhases objcopy_phase);
118
119 // Refine the card corresponding to "card_ptr". Safe to be called concurrently
120 // to the mutator.
121 void refine_card_concurrently(CardValue* card_ptr,
122 uint worker_id);
123
124 // Print accumulated summary info from the start of the VM.
125 void print_summary_info();
126
127 // Print accumulated summary info from the last time called.
128 void print_periodic_summary_info(const char* header, uint period_count);
129
130 // Rebuilds the remembered set by scanning from bottom to TARS for all regions
131 // using the given work gang.
132 void rebuild_rem_set(G1ConcurrentMark* cm, WorkGang* workers, uint worker_id_offset);
133 };
134
135 #endif // SHARE_GC_G1_G1REMSET_HPP