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 // Record, if necessary, the fact that *p (where "p" is in region "from", 118 // which is required to be non-NULL) has changed to a new non-NULL value. 119 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 120 121 // Eliminates any remembered set entries that correspond to dead heap ranges. 122 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer); 123 124 // Refine the card corresponding to "card_ptr". Safe to be called concurrently 125 // to the mutator. 126 void refine_card_concurrently(jbyte* card_ptr, 127 uint worker_i); 128 129 // Refine the card corresponding to "card_ptr", applying the given closure to 130 // all references found. Must only be called during gc. 131 void refine_card_during_gc(jbyte* card_ptr, G1ScanObjsDuringUpdateRSClosure* update_rs_cl); 132 133 // Print accumulated summary info from the start of the VM. 134 void print_summary_info(); 135 136 // Print accumulated summary info from the last time called. 137 void print_periodic_summary_info(const char* header, uint period_count); 138 139 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; } 140 141 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 142 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 143 144 // Verify that the liveness count data created concurrently matches one created 145 // during this safepoint. 146 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap); 147 148 void clear_card_live_data(WorkGang* workers); 149 150 #ifdef ASSERT 151 void verify_card_live_data_is_clear(); 152 #endif 153 }; 154 155 class G1ScanRSForRegionClosure : public HeapRegionClosure { 156 G1RemSetScanState* _scan_state; 157 158 size_t _cards_scanned; 159 size_t _cards_claimed; 160 size_t _cards_skipped; 161 162 G1CollectedHeap* _g1h; 163 164 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl; 165 CodeBlobClosure* _code_root_cl; 166 167 G1BlockOffsetTable* _bot; 168 G1SATBCardTableModRefBS *_ct_bs; 169 170 double _strong_code_root_scan_time_sec; 171 uint _worker_i; 172 173 void claim_card(size_t card_index, const uint region_idx_for_card); 174 void scan_card(MemRegion mr, uint region_idx_for_card); 175 void scan_strong_code_roots(HeapRegion* r); 176 public: 177 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state, 178 G1ScanObjsDuringScanRSClosure* scan_obj_on_card, 179 CodeBlobClosure* code_root_cl, 180 uint worker_i); 181 182 bool doHeapRegion(HeapRegion* r); 183 184 double strong_code_root_scan_time_sec() { 185 return _strong_code_root_scan_time_sec; 186 } 187 188 size_t cards_scanned() const { return _cards_scanned; } 189 size_t cards_claimed() const { return _cards_claimed; } 190 size_t cards_skipped() const { return _cards_skipped; } 191 }; 192 193 class RebuildRSOopClosure: public ExtendedOopClosure { 194 HeapRegion* _from; 195 G1RemSet* _rs; 196 uint _worker_i; 197 198 template <class T> void do_oop_work(T* p); 199 200 public: 201 RebuildRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 202 _from(NULL), _rs(rs), _worker_i(worker_i) 203 {} 204 205 void set_from(HeapRegion* from) { 206 assert(from != NULL, "from region must be non-NULL"); 207 _from = from; 208 } 209 210 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 211 virtual void do_oop(oop* p) { do_oop_work(p); } 212 }; 213 214 #endif // SHARE_VM_GC_G1_G1REMSET_HPP