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. 22 * 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 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 G1CollectedHeap* _g1h; 64 size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator. 65 66 G1CardTable* _ct; 67 G1Policy* _g1p; 68 G1HotCardCache* _hot_card_cache; 69 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 remembered sets of the collection set for references into the collection 89 // set. 90 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code 91 // roots list for each region in the collection set. 92 void scan_rem_set(G1ParScanThreadState* pss, 93 uint worker_i, 94 G1GCPhaseTimes::GCParPhases scan_phase, 95 G1GCPhaseTimes::GCParPhases objcopy_phase, 96 G1GCPhaseTimes::GCParPhases coderoots_phase); 97 98 // Flush remaining refinement buffers for cross-region references to either evacuate references 99 // into the collection set or update the remembered set. 100 void update_rem_set(G1ParScanThreadState* pss, uint worker_i); 101 102 // Prepare for and cleanup after an oops_into_collection_set_do 103 // call. Must call each of these once before and after (in sequential 104 // code) any thread calls oops_into_collection_set_do. 105 void prepare_for_oops_into_collection_set_do(); 106 void cleanup_after_oops_into_collection_set_do(); 107 108 G1RemSetScanState* scan_state() const { return _scan_state; } 109 110 // Refine the card corresponding to "card_ptr". Safe to be called concurrently 111 // to the mutator. 112 void refine_card_concurrently(CardValue* card_ptr, 113 uint worker_i); 114 115 // Refine the card corresponding to "card_ptr", applying the given closure to 116 // all references found. Must only be called during gc. 117 // Returns whether the card has been scanned. 118 bool refine_card_during_gc(CardValue* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl); 119 120 // Print accumulated summary info from the start of the VM. 121 void print_summary_info(); 122 123 // Print accumulated summary info from the last time called. 124 void print_periodic_summary_info(const char* header, uint period_count); 125 126 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; } 127 128 // Rebuilds the remembered set by scanning from bottom to TARS for all regions 129 // using the given work gang. 130 void rebuild_rem_set(G1ConcurrentMark* cm, WorkGang* workers, uint worker_id_offset); 131 }; 132 133 class G1ScanRSForRegionClosure : public HeapRegionClosure { 134 G1CollectedHeap* _g1h; 135 G1CardTable *_ct; 136 137 G1ParScanThreadState* _pss; 138 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl; 139 140 G1RemSetScanState* _scan_state; 141 142 G1GCPhaseTimes::GCParPhases _phase; 143 144 uint _worker_i; 145 146 size_t _opt_refs_scanned; 147 size_t _opt_refs_memory_used; 148 149 size_t _cards_scanned; 150 size_t _cards_claimed; 151 size_t _cards_skipped; 152 153 Tickspan _rem_set_root_scan_time; 154 Tickspan _rem_set_trim_partially_time; 155 156 Tickspan _strong_code_root_scan_time; 157 Tickspan _strong_code_trim_partially_time; 158 159 void claim_card(size_t card_index, const uint region_idx_for_card); 160 void scan_card(MemRegion mr, uint region_idx_for_card); 161 162 void scan_opt_rem_set_roots(HeapRegion* r); 163 void scan_rem_set_roots(HeapRegion* r); 164 void scan_strong_code_roots(HeapRegion* r); 165 public: 166 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state, 167 G1ScanObjsDuringScanRSClosure* scan_obj_on_card, 168 G1ParScanThreadState* pss, 169 G1GCPhaseTimes::GCParPhases phase, 170 uint worker_i); 171 172 bool do_heap_region(HeapRegion* r); 173 174 Tickspan rem_set_root_scan_time() const { return _rem_set_root_scan_time; } 175 Tickspan rem_set_trim_partially_time() const { return _rem_set_trim_partially_time; } 176 177 Tickspan strong_code_root_scan_time() const { return _strong_code_root_scan_time; } 178 Tickspan strong_code_root_trim_partially_time() const { return _strong_code_trim_partially_time; } 179 180 size_t cards_scanned() const { return _cards_scanned; } 181 size_t cards_claimed() const { return _cards_claimed; } 182 size_t cards_skipped() const { return _cards_skipped; } 183 184 size_t opt_refs_scanned() const { return _opt_refs_scanned; } 185 size_t opt_refs_memory_used() const { return _opt_refs_memory_used; } 186 }; 187 188 #endif // SHARE_GC_G1_G1REMSET_HPP