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 G1ParPushHeapRSClosure; 45 class G1RemSetScanState; 46 class G1Policy; 47 class G1SATBCardTableModRefBS; 48 class HeapRegionClaimer; 49 50 // A G1RemSet in which each heap region has a rem set that records the 51 // external heap references into it. Uses a mod ref bs to track updates, 52 // so that they can be used to update the individual region remsets. 53 class G1RemSet: public CHeapObj<mtGC> { 54 private: 55 G1RemSetScanState* _scan_state; 56 G1CardLiveData _card_live_data; 57 58 G1RemSetSummary _prev_period_summary; 59 60 // A DirtyCardQueueSet that is used to hold cards that contain 61 // references into the current collection set. This is used to 62 // update the remembered sets of the regions in the collection 63 // set in the event of an evacuation failure. 64 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 65 66 protected: 67 G1CollectedHeap* _g1; 68 size_t _conc_refine_cards; 69 uint n_workers(); 70 71 protected: 72 CardTableModRefBS* _ct_bs; 73 G1Policy* _g1p; 74 G1HotCardCache* _hot_card_cache; 75 76 public: 77 // Gives an approximation on how many threads can be expected to add records to 78 // a remembered set in parallel. This can be used for sizing data structures to 79 // decrease performance losses due to data structure sharing. 80 // Examples for quantities that influence this value are the maximum number of 81 // mutator threads, maximum number of concurrent refinement or GC threads. 82 static uint num_par_rem_sets(); 83 84 // Initialize data that depends on the heap size being known. 85 void initialize(size_t capacity, uint max_regions); 86 87 // This is called to reset dual hash tables after the gc pause 88 // is finished and the initial hash table is no longer being 89 // scanned. 90 void cleanupHRRS(); 91 92 G1RemSet(G1CollectedHeap* g1, 93 CardTableModRefBS* ct_bs, 94 G1HotCardCache* hot_card_cache); 95 ~G1RemSet(); 96 97 // Invoke "cl->do_oop" on all pointers into the collection set 98 // from objects in regions outside the collection set (having 99 // invoked "cl->set_region" to set the "from" region correctly 100 // beforehand.) 101 // 102 // Apply non_heap_roots on the oops of the unmarked nmethods 103 // on the strong code roots list for each region in the 104 // collection set. 105 // 106 // The "worker_i" param is for the parallel case where the id 107 // of the worker thread calling this function can be helpful in 108 // partitioning the work to be done. It should be the same as 109 // the "i" passed to the calling thread's work(i) function. 110 // In the sequential case this param will be ignored. 111 // 112 // Returns the number of cards scanned while looking for pointers 113 // into the collection set. 114 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* cl, 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 threads call oops_into_collection_set_do. (This offers an 121 // opportunity to sequential setup and teardown of structures needed by a 122 // parallel iteration over the CS's RS.) 123 void prepare_for_oops_into_collection_set_do(); 124 void cleanup_after_oops_into_collection_set_do(); 125 126 size_t scan_rem_set(G1ParPushHeapRSClosure* oops_in_heap_closure, 127 CodeBlobClosure* heap_region_codeblobs, 128 uint worker_i); 129 130 G1RemSetScanState* scan_state() const { return _scan_state; } 131 132 // Flush remaining refinement buffers into the remembered set, 133 // applying oops_in_heap_closure on the references found. 134 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParPushHeapRSClosure* oops_in_heap_closure, uint worker_i); 135 136 // Record, if necessary, the fact that *p (where "p" is in region "from", 137 // which is required to be non-NULL) has changed to a new non-NULL value. 138 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 139 140 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 141 // or card, respectively, such that a region or card with a corresponding 142 // 0 bit contains no part of any live object. Eliminates any remembered 143 // set entries that correspond to dead heap ranges. "worker_num" is the 144 // parallel thread id of the current thread, and "hrclaimer" is the 145 // HeapRegionClaimer that should be used. 146 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer); 147 148 // Refine the card corresponding to "card_ptr". 149 // If oops_in_heap_closure is not NULL, a true result is returned 150 // if the given card contains oops that have references into the 151 // current collection set. 152 bool refine_card(jbyte* card_ptr, 153 uint worker_i, 154 G1ParPushHeapRSClosure* oops_in_heap_closure); 155 156 // Print accumulated summary info from the start of the VM. 157 void print_summary_info(); 158 159 // Print accumulated summary info from the last time called. 160 void print_periodic_summary_info(const char* header, uint period_count); 161 162 // Prepare remembered set for verification. 163 void prepare_for_verify(); 164 165 size_t conc_refine_cards() const { 166 return _conc_refine_cards; 167 } 168 169 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 170 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 171 172 // Verify that the liveness count data created concurrently matches one created 173 // during this safepoint. 174 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap); 175 176 void clear_card_live_data(WorkGang* workers); 177 178 #ifdef ASSERT 179 void verify_card_live_data_is_clear(); 180 #endif 181 }; 182 183 class G1ScanRSClosure : public HeapRegionClosure { 184 G1RemSetScanState* _scan_state; 185 186 size_t _cards_done; 187 size_t _cards; 188 G1CollectedHeap* _g1h; 189 190 G1ParPushHeapRSClosure* _push_heap_cl; 191 CodeBlobClosure* _code_root_cl; 192 193 G1BlockOffsetTable* _bot; 194 G1SATBCardTableModRefBS *_ct_bs; 195 196 double _strong_code_root_scan_time_sec; 197 uint _worker_i; 198 size_t _block_size; 199 200 void scan_card(size_t index, HeapRegion *r); 201 void scan_strong_code_roots(HeapRegion* r); 202 public: 203 G1ScanRSClosure(G1RemSetScanState* scan_state, 204 G1ParPushHeapRSClosure* push_heap_cl, 205 CodeBlobClosure* code_root_cl, 206 uint worker_i); 207 208 bool doHeapRegion(HeapRegion* r); 209 210 double strong_code_root_scan_time_sec() { 211 return _strong_code_root_scan_time_sec; 212 } 213 214 size_t cards_done() { return _cards_done;} 215 size_t cards_looked_up() { return _cards;} 216 }; 217 218 class UpdateRSOopClosure: public ExtendedOopClosure { 219 HeapRegion* _from; 220 G1RemSet* _rs; 221 uint _worker_i; 222 223 template <class T> void do_oop_work(T* p); 224 225 public: 226 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 227 _from(NULL), _rs(rs), _worker_i(worker_i) 228 {} 229 230 void set_from(HeapRegion* from) { 231 assert(from != NULL, "from region must be non-NULL"); 232 _from = from; 233 } 234 235 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 236 virtual void do_oop(oop* p) { do_oop_work(p); } 237 }; 238 239 #endif // SHARE_VM_GC_G1_G1REMSET_HPP