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/g1RemSetSummary.hpp" 30 #include "gc/g1/heapRegion.hpp" 31 #include "memory/allocation.hpp" 32 #include "memory/iterator.hpp" 33 34 // A G1RemSet provides ways of iterating over pointers into a selected 35 // collection set. 36 37 class BitMap; 38 class CardTableModRefBS; 39 class G1BlockOffsetSharedArray; 40 class ConcurrentG1Refine; 41 class CodeBlobClosure; 42 class G1CollectedHeap; 43 class G1CollectorPolicy; 44 class G1ParPushHeapRSClosure; 45 class G1SATBCardTableModRefBS; 46 class HeapRegionClaimer; 47 48 // A G1RemSet in which each heap region has a rem set that records the 49 // external heap references into it. Uses a mod ref bs to track updates, 50 // so that they can be used to update the individual region remsets. 51 52 class G1RemSet: public CHeapObj<mtGC> { 53 private: 54 G1RemSetSummary _prev_period_summary; 55 56 // A DirtyCardQueueSet that is used to hold cards that contain 57 // references into the current collection set. This is used to 58 // update the remembered sets of the regions in the collection 59 // set in the event of an evacuation failure. 60 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 61 62 protected: 63 G1CollectedHeap* _g1; 64 size_t _conc_refine_cards; 65 uint n_workers(); 66 67 protected: 68 CardTableModRefBS* _ct_bs; 69 G1CollectorPolicy* _g1p; 70 71 ConcurrentG1Refine* _cg1r; 72 73 // Used for caching the closure that is responsible for scanning 74 // references into the collection set. 75 G1ParPushHeapRSClosure** _cset_rs_update_cl; 76 77 public: 78 // Gives an approximation on how many threads can be expected to add records to 79 // a remembered set in parallel. This can be used for sizing data structures to 80 // decrease performance losses due to data structure sharing. 81 // Examples for quantities that influence this value are the maximum number of 82 // mutator threads, maximum number of concurrent refinement or GC threads. 83 static uint num_par_rem_sets(); 84 85 // Initialize data that depends on that the heap size is known. 86 static void initialize(uint max_regions); 87 88 // This is called to reset dual hash tables after the gc pause 89 // is finished and the initial hash table is no longer being 90 // scanned. 91 void cleanupHRRS(); 92 93 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); 94 ~G1RemSet(); 95 96 // Invoke "blk->do_oop" on all pointers into the collection set 97 // from objects in regions outside the collection set (having 98 // invoked "blk->set_region" to set the "from" region correctly 99 // beforehand.) 100 // 101 // Apply non_heap_roots on the oops of the unmarked nmethods 102 // on the strong code roots list for each region in the 103 // collection set. 104 // 105 // The "worker_i" param is for the parallel case where the id 106 // of the worker thread calling this function can be helpful in 107 // partitioning the work to be done. It should be the same as 108 // the "i" passed to the calling thread's work(i) function. 109 // In the sequential case this param will be ignored. 110 // 111 // Returns the number of cards scanned while looking for pointers 112 // into the collection set. 113 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk, 114 CodeBlobClosure* heap_region_codeblobs, 115 uint worker_i); 116 117 // Prepare for and cleanup after an oops_into_collection_set_do 118 // call. Must call each of these once before and after (in sequential 119 // code) any threads call oops_into_collection_set_do. (This offers an 120 // opportunity to sequential setup and teardown of structures needed by a 121 // parallel iteration over the CS's RS.) 122 void prepare_for_oops_into_collection_set_do(); 123 void cleanup_after_oops_into_collection_set_do(); 124 125 size_t scanRS(G1ParPushHeapRSClosure* oc, 126 CodeBlobClosure* heap_region_codeblobs, 127 uint worker_i); 128 129 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 130 131 CardTableModRefBS* ct_bs() { return _ct_bs; } 132 133 // Record, if necessary, the fact that *p (where "p" is in region "from", 134 // which is required to be non-NULL) has changed to a new non-NULL value. 135 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 136 137 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 138 // or card, respectively, such that a region or card with a corresponding 139 // 0 bit contains no part of any live object. Eliminates any remembered 140 // set entries that correspond to dead heap ranges. "worker_num" is the 141 // parallel thread id of the current thread, and "hrclaimer" is the 142 // HeapRegionClaimer that should be used. 143 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 144 145 // Refine the card corresponding to "card_ptr". 146 // If check_for_refs_into_cset is true, a true result is returned 147 // if the given card contains oops that have references into the 148 // current collection set. 149 virtual bool refine_card(jbyte* card_ptr, 150 uint worker_i, 151 bool check_for_refs_into_cset); 152 153 // Print accumulated summary info from the start of the VM. 154 virtual void print_summary_info(); 155 156 // Print accumulated summary info from the last time called. 157 virtual void print_periodic_summary_info(const char* header, uint period_count); 158 159 // Prepare remembered set for verification. 160 virtual void prepare_for_verify(); 161 162 size_t conc_refine_cards() const { 163 return _conc_refine_cards; 164 } 165 }; 166 167 class ScanRSClosure : public HeapRegionClosure { 168 size_t _cards_done, _cards; 169 G1CollectedHeap* _g1h; 170 171 G1ParPushHeapRSClosure* _oc; 172 CodeBlobClosure* _code_root_cl; 173 174 G1BlockOffsetSharedArray* _bot_shared; 175 G1SATBCardTableModRefBS *_ct_bs; 176 177 double _strong_code_root_scan_time_sec; 178 uint _worker_i; 179 size_t _block_size; 180 bool _try_claimed; 181 182 public: 183 ScanRSClosure(G1ParPushHeapRSClosure* oc, 184 CodeBlobClosure* code_root_cl, 185 uint worker_i); 186 187 bool doHeapRegion(HeapRegion* r); 188 189 double strong_code_root_scan_time_sec() { 190 return _strong_code_root_scan_time_sec; 191 } 192 size_t cards_done() { return _cards_done;} 193 size_t cards_looked_up() { return _cards;} 194 void set_try_claimed() { _try_claimed = true; } 195 private: 196 void scanCard(size_t index, HeapRegion *r); 197 void printCard(HeapRegion* card_region, size_t card_index, 198 HeapWord* card_start); 199 void scan_strong_code_roots(HeapRegion* r); 200 }; 201 202 class UpdateRSOopClosure: public ExtendedOopClosure { 203 HeapRegion* _from; 204 G1RemSet* _rs; 205 uint _worker_i; 206 207 template <class T> void do_oop_work(T* p); 208 209 public: 210 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 211 _from(NULL), _rs(rs), _worker_i(worker_i) 212 {} 213 214 void set_from(HeapRegion* from) { 215 assert(from != NULL, "from region must be non-NULL"); 216 _from = from; 217 } 218 219 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 220 virtual void do_oop(oop* p) { do_oop_work(p); } 221 }; 222 223 #endif // SHARE_VM_GC_G1_G1REMSET_HPP