1 /* 2 * Copyright (c) 2001, 2010, 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_IMPLEMENTATION_G1_G1REMSET_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP 27 28 // A G1RemSet provides ways of iterating over pointers into a selected 29 // collection set. 30 31 class G1CollectedHeap; 32 class CardTableModRefBarrierSet; 33 class ConcurrentG1Refine; 34 35 // A G1RemSet in which each heap region has a rem set that records the 36 // external heap references into it. Uses a mod ref bs to track updates, 37 // so that they can be used to update the individual region remsets. 38 39 class G1RemSet: public CHeapObj { 40 protected: 41 G1CollectedHeap* _g1; 42 unsigned _conc_refine_cards; 43 size_t n_workers(); 44 45 protected: 46 enum SomePrivateConstants { 47 UpdateRStoMergeSync = 0, 48 MergeRStoDoDirtySync = 1, 49 DoDirtySync = 2, 50 LastSync = 3, 51 52 SeqTask = 0, 53 NumSeqTasks = 1 54 }; 55 56 CardTableModRefBS* _ct_bs; 57 SubTasksDone* _seq_task; 58 G1CollectorPolicy* _g1p; 59 60 ConcurrentG1Refine* _cg1r; 61 62 size_t* _cards_scanned; 63 size_t _total_cards_scanned; 64 65 // _traversal_in_progress is "true" iff a traversal is in progress. 66 67 bool _traversal_in_progress; 68 void set_traversal(bool b) { _traversal_in_progress = b; } 69 70 // Used for caching the closure that is responsible for scanning 71 // references into the collection set. 72 OopsInHeapRegionClosure** _cset_rs_update_cl; 73 74 // The routine that performs the actual work of refining a dirty 75 // card. 76 // If check_for_refs_into_refs is true then a true result is returned 77 // if the card contains oops that have references into the current 78 // collection set. 79 bool concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i, 80 bool check_for_refs_into_cset); 81 82 protected: 83 template <class T> void write_ref_nv(HeapRegion* from, T* p); 84 template <class T> void par_write_ref_nv(HeapRegion* from, T* p, int tid); 85 86 public: 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, CardTableModRefBS* ct_bs); 93 ~G1RemSet(); 94 95 // Invoke "blk->do_oop" on all pointers into the CS in objects in regions 96 // outside the CS (having invoked "blk->set_region" to set the "from" 97 // region correctly beforehand.) The "worker_i" param is for the 98 // parallel case where the number of the worker thread calling this 99 // function can be helpful in partitioning the work to be done. It 100 // should be the same as the "i" passed to the calling thread's 101 // work(i) function. In the sequential case this param will be ingored. 102 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, 103 int worker_i); 104 105 // Prepare for and cleanup after an oops_into_collection_set_do 106 // call. Must call each of these once before and after (in sequential 107 // code) any threads call oops_into_collection_set_do. (This offers an 108 // opportunity to sequential setup and teardown of structures needed by a 109 // parallel iteration over the CS's RS.) 110 void prepare_for_oops_into_collection_set_do(); 111 void cleanup_after_oops_into_collection_set_do(); 112 113 void scanRS(OopsInHeapRegionClosure* oc, int worker_i); 114 void updateRS(DirtyCardQueue* into_cset_dcq, int worker_i); 115 116 HeapRegion* calculateStartRegion(int i); 117 118 CardTableModRefBS* ct_bs() { return _ct_bs; } 119 size_t cardsScanned() { return _total_cards_scanned; } 120 121 // Record, if necessary, the fact that *p (where "p" is in region "from", 122 // which is required to be non-NULL) has changed to a new non-NULL value. 123 // [Below the virtual version calls a non-virtual protected 124 // workhorse that is templatified for narrow vs wide oop.] 125 inline void write_ref(HeapRegion* from, oop* p) { 126 write_ref_nv(from, p); 127 } 128 inline void write_ref(HeapRegion* from, narrowOop* p) { 129 write_ref_nv(from, p); 130 } 131 inline void par_write_ref(HeapRegion* from, oop* p, int tid) { 132 par_write_ref_nv(from, p, tid); 133 } 134 inline void par_write_ref(HeapRegion* from, narrowOop* p, int tid) { 135 par_write_ref_nv(from, p, tid); 136 } 137 138 bool self_forwarded(oop obj); 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. 144 void scrub(BitMap* region_bm, BitMap* card_bm); 145 146 // Like the above, but assumes is called in parallel: "worker_num" is the 147 // parallel thread id of the current thread, and "claim_val" is the 148 // value that should be used to claim heap regions. 149 void scrub_par(BitMap* region_bm, BitMap* card_bm, 150 int worker_num, int claim_val); 151 152 // Refine the card corresponding to "card_ptr". If "sts" is non-NULL, 153 // join and leave around parts that must be atomic wrt GC. (NULL means 154 // being done at a safepoint.) 155 // If check_for_refs_into_cset is true, a true result is returned 156 // if the given card contains oops that have references into the 157 // current collection set. 158 virtual bool concurrentRefineOneCard(jbyte* card_ptr, int worker_i, 159 bool check_for_refs_into_cset); 160 161 // Print any relevant summary info. 162 virtual void print_summary_info(); 163 164 // Prepare remembered set for verification. 165 virtual void prepare_for_verify(); 166 }; 167 168 #define G1_REM_SET_LOGGING 0 169 170 class CountNonCleanMemRegionClosure: public MemRegionClosure { 171 G1CollectedHeap* _g1; 172 int _n; 173 HeapWord* _start_first; 174 public: 175 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) : 176 _g1(g1), _n(0), _start_first(NULL) 177 {} 178 void do_MemRegion(MemRegion mr); 179 int n() { return _n; }; 180 HeapWord* start_first() { return _start_first; } 181 }; 182 183 class UpdateRSOopClosure: public OopClosure { 184 HeapRegion* _from; 185 G1RemSet* _rs; 186 int _worker_i; 187 188 template <class T> void do_oop_work(T* p); 189 190 public: 191 UpdateRSOopClosure(G1RemSet* rs, int worker_i = 0) : 192 _from(NULL), _rs(rs), _worker_i(worker_i) { 193 guarantee(_rs != NULL, "Requires an HRIntoG1RemSet"); 194 } 195 196 void set_from(HeapRegion* from) { 197 assert(from != NULL, "from region must be non-NULL"); 198 _from = from; 199 } 200 201 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 202 virtual void do_oop(oop* p) { do_oop_work(p); } 203 204 // Override: this closure is idempotent. 205 // bool idempotent() { return true; } 206 bool apply_to_weak_ref_discovered_field() { return true; } 207 }; 208 209 class UpdateRSetImmediate: public OopsInHeapRegionClosure { 210 private: 211 G1RemSet* _g1_rem_set; 212 213 template <class T> void do_oop_work(T* p); 214 public: 215 UpdateRSetImmediate(G1RemSet* rs) : 216 _g1_rem_set(rs) {} 217 218 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 219 virtual void do_oop( oop* p) { do_oop_work(p); } 220 }; 221 222 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP