1 /* 2 * Copyright (c) 2001, 2015, 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 ConcurrentG1Refine; 42 class CodeBlobClosure; 43 class G1CollectedHeap; 44 class G1CollectorPolicy; 45 class G1ParPushHeapRSClosure; 46 class G1SATBCardTableModRefBS; 47 class HeapRegionClaimer; 48 49 // A G1RemSet in which each heap region has a rem set that records the 50 // external heap references into it. Uses a mod ref bs to track updates, 51 // so that they can be used to update the individual region remsets. 52 class G1RemSet: public CHeapObj<mtGC> { 53 private: 54 G1CardLiveData _card_live_data; 55 56 G1RemSetSummary _prev_period_summary; 57 58 // A DirtyCardQueueSet that is used to hold cards that contain 59 // references into the current collection set. This is used to 60 // update the remembered sets of the regions in the collection 61 // set in the event of an evacuation failure. 62 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 63 64 protected: 65 G1CollectedHeap* _g1; 66 size_t _conc_refine_cards; 67 uint n_workers(); 68 69 protected: 70 CardTableModRefBS* _ct_bs; 71 G1CollectorPolicy* _g1p; 72 73 ConcurrentG1Refine* _cg1r; 74 75 // Used for caching the closure that is responsible for scanning 76 // references into the collection set. 77 G1ParPushHeapRSClosure** _cset_rs_update_cl; 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, CardTableModRefBS* ct_bs); 96 ~G1RemSet(); 97 98 // Invoke "blk->do_oop" on all pointers into the collection set 99 // from objects in regions outside the collection set (having 100 // invoked "blk->set_region" to set the "from" region correctly 101 // beforehand.) 102 // 103 // Apply non_heap_roots on the oops of the unmarked nmethods 104 // on the strong code roots list for each region in the 105 // collection set. 106 // 107 // The "worker_i" param is for the parallel case where the id 108 // of the worker thread calling this function can be helpful in 109 // partitioning the work to be done. It should be the same as 110 // the "i" passed to the calling thread's work(i) function. 111 // In the sequential case this param will be ignored. 112 // 113 // Returns the number of cards scanned while looking for pointers 114 // into the collection set. 115 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk, 116 CodeBlobClosure* heap_region_codeblobs, 117 uint worker_i); 118 119 // Prepare for and cleanup after an oops_into_collection_set_do 120 // call. Must call each of these once before and after (in sequential 121 // code) any threads call oops_into_collection_set_do. (This offers an 122 // opportunity to sequential setup and teardown of structures needed by a 123 // parallel iteration over the CS's RS.) 124 void prepare_for_oops_into_collection_set_do(); 125 void cleanup_after_oops_into_collection_set_do(); 126 127 size_t scanRS(G1ParPushHeapRSClosure* oc, 128 CodeBlobClosure* heap_region_codeblobs, 129 uint worker_i); 130 131 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 132 133 CardTableModRefBS* ct_bs() { return _ct_bs; } 134 135 // Record, if necessary, the fact that *p (where "p" is in region "from", 136 // which is required to be non-NULL) has changed to a new non-NULL value. 137 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 138 139 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 140 // or card, respectively, such that a region or card with a corresponding 141 // 0 bit contains no part of any live object. Eliminates any remembered 142 // set entries that correspond to dead heap ranges. "worker_num" is the 143 // parallel thread id of the current thread, and "hrclaimer" is the 144 // HeapRegionClaimer that should be used. 145 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer); 146 147 // Refine the card corresponding to "card_ptr". 148 // If check_for_refs_into_cset is true, a true result is returned 149 // if the given card contains oops that have references into the 150 // current collection set. 151 virtual bool refine_card(jbyte* card_ptr, 152 uint worker_i, 153 bool check_for_refs_into_cset); 154 155 // Print accumulated summary info from the start of the VM. 156 virtual void print_summary_info(); 157 158 // Print accumulated summary info from the last time called. 159 virtual void print_periodic_summary_info(const char* header, uint period_count); 160 161 // Prepare remembered set for verification. 162 virtual void prepare_for_verify(); 163 164 size_t conc_refine_cards() const { 165 return _conc_refine_cards; 166 } 167 168 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 169 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap); 170 171 // Verify that the liveness count data created concurrently matches one created 172 // during this safepoint. 173 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap); 174 175 void clear_card_live_data(WorkGang* workers); 176 177 #ifdef ASSERT 178 void verify_card_live_data_is_clear(); 179 #endif 180 }; 181 182 class ScanRSClosure : public HeapRegionClosure { 183 size_t _cards_done, _cards; 184 G1CollectedHeap* _g1h; 185 186 G1ParPushHeapRSClosure* _oc; 187 CodeBlobClosure* _code_root_cl; 188 189 G1BlockOffsetTable* _bot; 190 G1SATBCardTableModRefBS *_ct_bs; 191 192 double _strong_code_root_scan_time_sec; 193 uint _worker_i; 194 size_t _block_size; 195 bool _try_claimed; 196 197 public: 198 ScanRSClosure(G1ParPushHeapRSClosure* oc, 199 CodeBlobClosure* code_root_cl, 200 uint worker_i); 201 202 bool doHeapRegion(HeapRegion* r); 203 204 double strong_code_root_scan_time_sec() { 205 return _strong_code_root_scan_time_sec; 206 } 207 size_t cards_done() { return _cards_done;} 208 size_t cards_looked_up() { return _cards;} 209 void set_try_claimed() { _try_claimed = true; } 210 private: 211 void scanCard(size_t index, HeapRegion *r); 212 void printCard(HeapRegion* card_region, size_t card_index, 213 HeapWord* card_start); 214 void scan_strong_code_roots(HeapRegion* r); 215 }; 216 217 class UpdateRSOopClosure: public ExtendedOopClosure { 218 HeapRegion* _from; 219 G1RemSet* _rs; 220 uint _worker_i; 221 222 template <class T> void do_oop_work(T* p); 223 224 public: 225 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 226 _from(NULL), _rs(rs), _worker_i(worker_i) 227 {} 228 229 void set_from(HeapRegion* from) { 230 assert(from != NULL, "from region must be non-NULL"); 231 _from = from; 232 } 233 234 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 235 virtual void do_oop(oop* p) { do_oop_work(p); } 236 }; 237 238 #endif // SHARE_VM_GC_G1_G1REMSET_HPP