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 // A DirtyCardQueueSet that is used to hold cards that contain 63 // references into the current collection set. This is used to 64 // update the remembered sets of the regions in the collection 65 // set in the event of an evacuation failure. 66 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 67 68 // Scan all remembered sets of the collection set for references into the collection 69 // set. 70 void scan_rem_set(G1ParScanThreadState* pss, 71 CodeBlobClosure* heap_region_codeblobs, 72 uint worker_i); 73 74 // Flush remaining refinement buffers for cross-region references to either evacuate references 75 // into the collection set or update the remembered set. 76 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParScanThreadState* pss, uint worker_i); 77 78 protected: 79 G1CollectedHeap* _g1; 80 size_t _conc_refine_cards; 81 uint n_workers(); 82 83 protected: 84 CardTableModRefBS* _ct_bs; 85 G1Policy* _g1p; 86 G1HotCardCache* _hot_card_cache; 87 88 public: 89 // Gives an approximation on how many threads can be expected to add records to 90 // a remembered set in parallel. This can be used for sizing data structures to 91 // decrease performance losses due to data structure sharing. 92 // Examples for quantities that influence this value are the maximum number of 93 // mutator threads, maximum number of concurrent refinement or GC threads. 94 static uint num_par_rem_sets(); 95 96 // Initialize data that depends on the heap size being known. 97 void initialize(size_t capacity, uint max_regions); 98 99 // This is called to reset dual hash tables after the gc pause 100 // is finished and the initial hash table is no longer being 101 // scanned. 102 void cleanupHRRS(); 103 104 G1RemSet(G1CollectedHeap* g1, 105 CardTableModRefBS* ct_bs, 106 G1HotCardCache* hot_card_cache); 107 ~G1RemSet(); 108 109 // Process all oops in the collection set from the cards in the refinement buffers and 110 // remembered sets using pss. 111 // 112 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code 113 // roots list for each region in the collection set. 114 void oops_into_collection_set_do(G1ParScanThreadState* pss, 115 CodeBlobClosure* heap_region_codeblobs, 116 uint worker_i); 117 118 // Prepare for and cleanup after an oops_into_collection_set_do 119 // call. Must call each of these once before and after (in sequential 120 // code) any thread calls oops_into_collection_set_do. 121 void prepare_for_oops_into_collection_set_do(); 122 void cleanup_after_oops_into_collection_set_do(); 123 124 G1RemSetScanState* scan_state() const { return _scan_state; } 125 126 // Record, if necessary, the fact that *p (where "p" is in region "from", 127 // which is required to be non-NULL) has changed to a new non-NULL value. 128 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 129 130 // Eliminates any remembered set entries that correspond to dead heap ranges. 131 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer); 132 133 // Refine the card corresponding to "card_ptr". Safe to be called concurrently 134 // to the mutator. 135 void refine_card_concurrently(jbyte* card_ptr, 136 uint worker_i); 137 138 // Refine the card corresponding to "card_ptr", applying the given closure to 139 // all references found. Returns "true" if the given card contains 140 // oops that have references into the current collection set. Must only be 141 // called during gc. 142 bool refine_card_during_gc(jbyte* card_ptr, 143 G1ScanObjsDuringUpdateRSClosure* update_rs_cl); 144 145 // Print accumulated summary info from the start of the VM. 146 void print_summary_info(); 147 148 // Print accumulated summary info from the last time called. 149 void print_periodic_summary_info(const char* header, uint period_count); 150 151 // Prepare remembered set for verification. 152 void prepare_for_verify(); 153 154 size_t conc_refine_cards() const { return _conc_refine_cards; } 155 156 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 157 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 158 159 // Verify that the liveness count data created concurrently matches one created 160 // during this safepoint. 161 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap); 162 163 void clear_card_live_data(WorkGang* workers); 164 165 #ifdef ASSERT 166 void verify_card_live_data_is_clear(); 167 #endif 168 }; 169 170 class G1ScanRSForRegionClosure : public HeapRegionClosure { 171 G1RemSetScanState* _scan_state; 172 173 size_t _cards_scanned; 174 size_t _cards_claimed; 175 size_t _cards_skipped; 176 177 G1CollectedHeap* _g1h; 178 179 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl; 180 CodeBlobClosure* _code_root_cl; 181 182 G1BlockOffsetTable* _bot; 183 G1SATBCardTableModRefBS *_ct_bs; 184 185 double _strong_code_root_scan_time_sec; 186 uint _worker_i; 187 188 void scan_card(size_t index, HeapWord* card_start, HeapRegion *r); 189 void scan_strong_code_roots(HeapRegion* r); 190 public: 191 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state, 192 G1ScanObjsDuringScanRSClosure* scan_obj_on_card, 193 CodeBlobClosure* code_root_cl, 194 uint worker_i); 195 196 bool doHeapRegion(HeapRegion* r); 197 198 double strong_code_root_scan_time_sec() { 199 return _strong_code_root_scan_time_sec; 200 } 201 202 size_t cards_scanned() const { return _cards_scanned; } 203 size_t cards_claimed() const { return _cards_claimed; } 204 size_t cards_skipped() const { return _cards_skipped; } 205 }; 206 207 class RebuildRSOopClosure: public ExtendedOopClosure { 208 HeapRegion* _from; 209 G1RemSet* _rs; 210 uint _worker_i; 211 212 template <class T> void do_oop_work(T* p); 213 214 public: 215 RebuildRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 216 _from(NULL), _rs(rs), _worker_i(worker_i) 217 {} 218 219 void set_from(HeapRegion* from) { 220 assert(from != NULL, "from region must be non-NULL"); 221 _from = from; 222 } 223 224 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 225 virtual void do_oop(oop* p) { do_oop_work(p); } 226 }; 227 228 #endif // SHARE_VM_GC_G1_G1REMSET_HPP