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. 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/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