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. 22 * 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 36 // A G1RemSet provides ways of iterating over pointers into a selected 37 // collection set. 38 39 class BitMap; 40 class CardTableBarrierSet; 41 class G1BlockOffsetTable; 42 class CodeBlobClosure; 43 class G1CollectedHeap; 44 class G1CMBitMap; 45 class G1HotCardCache; 46 class G1RemSetScanState; 47 class G1ParScanThreadState; 48 class G1Policy; 49 class G1ScanObjsDuringScanRSClosure; 50 class G1ScanObjsDuringUpdateRSClosure; 51 class HeapRegionClaimer; 52 53 // A G1RemSet in which each heap region has a rem set that records the 54 // external heap references into it. Uses a mod ref bs to track updates, 55 // so that they can be used to update the individual region remsets. 56 class G1RemSet: public CHeapObj<mtGC> { 57 private: 58 G1RemSetScanState* _scan_state; 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 G1CardTable* _ct; 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 G1CardTable* ct, 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 // Refine the card corresponding to "card_ptr". Safe to be called concurrently 118 // to the mutator. 119 void refine_card_concurrently(jbyte* card_ptr, 120 uint worker_i); 121 122 // Refine the card corresponding to "card_ptr", applying the given closure to 123 // all references found. Must only be called during gc. 124 // Returns whether the card has been scanned. 125 bool refine_card_during_gc(jbyte* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl); 126 127 // Print accumulated summary info from the start of the VM. 128 void print_summary_info(); 129 130 // Print accumulated summary info from the last time called. 131 void print_periodic_summary_info(const char* header, uint period_count); 132 133 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; } 134 135 // Rebuilds the remembered set by scanning from bottom to TARS for all regions 136 // using the given work gang. 137 void rebuild_rem_set(G1ConcurrentMark* cm, WorkGang* workers, uint worker_id_offset); 138 }; 139 140 class G1ScanRSForRegionClosure : public HeapRegionClosure { 141 G1RemSetScanState* _scan_state; 142 143 size_t _cards_scanned; 144 size_t _cards_claimed; 145 size_t _cards_skipped; 146 147 G1CollectedHeap* _g1h; 148 149 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl; 150 CodeBlobClosure* _code_root_cl; 151 152 G1BlockOffsetTable* _bot; 153 G1CardTable *_ct; 154 155 double _strong_code_root_scan_time_sec; 156 uint _worker_i; 157 158 void claim_card(size_t card_index, const uint region_idx_for_card); 159 void scan_card(MemRegion mr, uint region_idx_for_card); 160 void scan_strong_code_roots(HeapRegion* r); 161 public: 162 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state, 163 G1ScanObjsDuringScanRSClosure* scan_obj_on_card, 164 CodeBlobClosure* code_root_cl, 165 uint worker_i); 166 167 bool do_heap_region(HeapRegion* r); 168 169 double strong_code_root_scan_time_sec() { 170 return _strong_code_root_scan_time_sec; 171 } 172 173 size_t cards_scanned() const { return _cards_scanned; } 174 size_t cards_claimed() const { return _cards_claimed; } 175 size_t cards_skipped() const { return _cards_skipped; } 176 }; 177 178 #endif // SHARE_VM_GC_G1_G1REMSET_HPP