1 /* 2 * Copyright (c) 2001, 2013, 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 #include "gc_implementation/g1/g1RemSetSummary.hpp" 29 30 // A G1RemSet provides ways of iterating over pointers into a selected 31 // collection set. 32 33 class G1CollectedHeap; 34 class CardTableModRefBarrierSet; 35 class ConcurrentG1Refine; 36 37 // A G1RemSet in which each heap region has a rem set that records the 38 // external heap references into it. Uses a mod ref bs to track updates, 39 // so that they can be used to update the individual region remsets. 40 41 class G1RemSet: public CHeapObj<mtGC> { 42 private: 43 G1RemSetSummary _prev_period_summary; 44 protected: 45 G1CollectedHeap* _g1; 46 size_t _conc_refine_cards; 47 uint n_workers(); 48 49 protected: 50 enum SomePrivateConstants { 51 UpdateRStoMergeSync = 0, 52 MergeRStoDoDirtySync = 1, 53 DoDirtySync = 2, 54 LastSync = 3, 55 56 SeqTask = 0, 57 NumSeqTasks = 1 58 }; 59 60 CardTableModRefBS* _ct_bs; 61 SubTasksDone* _seq_task; 62 G1CollectorPolicy* _g1p; 63 64 ConcurrentG1Refine* _cg1r; 65 66 size_t* _cards_scanned; 67 size_t _total_cards_scanned; 68 69 // Used for caching the closure that is responsible for scanning 70 // references into the collection set. 71 OopsInHeapRegionClosure** _cset_rs_update_cl; 72 73 // Print the given summary info 74 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL); 75 public: 76 // This is called to reset dual hash tables after the gc pause 77 // is finished and the initial hash table is no longer being 78 // scanned. 79 void cleanupHRRS(); 80 81 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); 82 ~G1RemSet(); 83 84 // Invoke "blk->do_oop" on all pointers into the CS in objects in regions 85 // outside the CS (having invoked "blk->set_region" to set the "from" 86 // region correctly beforehand.) The "worker_i" param is for the 87 // parallel case where the number of the worker thread calling this 88 // function can be helpful in partitioning the work to be done. It 89 // should be the same as the "i" passed to the calling thread's 90 // work(i) function. In the sequential case this param will be ingored. 91 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, int worker_i); 92 93 // Prepare for and cleanup after an oops_into_collection_set_do 94 // call. Must call each of these once before and after (in sequential 95 // code) any threads call oops_into_collection_set_do. (This offers an 96 // opportunity to sequential setup and teardown of structures needed by a 97 // parallel iteration over the CS's RS.) 98 void prepare_for_oops_into_collection_set_do(); 99 void cleanup_after_oops_into_collection_set_do(); 100 101 void scanRS(OopsInHeapRegionClosure* oc, int worker_i); 102 void updateRS(DirtyCardQueue* into_cset_dcq, int worker_i); 103 104 CardTableModRefBS* ct_bs() { return _ct_bs; } 105 size_t cardsScanned() { return _total_cards_scanned; } 106 107 // Record, if necessary, the fact that *p (where "p" is in region "from", 108 // which is required to be non-NULL) has changed to a new non-NULL value. 109 template <class T> void write_ref(HeapRegion* from, T* p); 110 template <class T> void par_write_ref(HeapRegion* from, T* p, int tid); 111 112 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 113 // or card, respectively, such that a region or card with a corresponding 114 // 0 bit contains no part of any live object. Eliminates any remembered 115 // set entries that correspond to dead heap ranges. 116 void scrub(BitMap* region_bm, BitMap* card_bm); 117 118 // Like the above, but assumes is called in parallel: "worker_num" is the 119 // parallel thread id of the current thread, and "claim_val" is the 120 // value that should be used to claim heap regions. 121 void scrub_par(BitMap* region_bm, BitMap* card_bm, 122 uint worker_num, int claim_val); 123 124 // Refine the card corresponding to "card_ptr". 125 // If check_for_refs_into_cset is true, a true result is returned 126 // if the given card contains oops that have references into the 127 // current collection set. 128 virtual bool refine_card(jbyte* card_ptr, 129 int worker_i, 130 bool check_for_refs_into_cset); 131 132 // Print accumulated summary info from the start of the VM. 133 virtual void print_summary_info(); 134 135 // Print accumulated summary info from the last time called. 136 virtual void print_periodic_summary_info(); 137 138 // Prepare remembered set for verification. 139 virtual void prepare_for_verify(); 140 141 size_t conc_refine_cards() const { 142 return _conc_refine_cards; 143 } 144 }; 145 146 class CountNonCleanMemRegionClosure: public MemRegionClosure { 147 G1CollectedHeap* _g1; 148 int _n; 149 HeapWord* _start_first; 150 public: 151 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) : 152 _g1(g1), _n(0), _start_first(NULL) 153 {} 154 void do_MemRegion(MemRegion mr); 155 int n() { return _n; }; 156 HeapWord* start_first() { return _start_first; } 157 }; 158 159 class UpdateRSOopClosure: public ExtendedOopClosure { 160 HeapRegion* _from; 161 G1RemSet* _rs; 162 int _worker_i; 163 164 template <class T> void do_oop_work(T* p); 165 166 public: 167 UpdateRSOopClosure(G1RemSet* rs, int worker_i = 0) : 168 _from(NULL), _rs(rs), _worker_i(worker_i) 169 {} 170 171 void set_from(HeapRegion* from) { 172 assert(from != NULL, "from region must be non-NULL"); 173 _from = from; 174 } 175 176 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 177 virtual void do_oop(oop* p) { do_oop_work(p); } 178 179 // Override: this closure is idempotent. 180 // bool idempotent() { return true; } 181 bool apply_to_weak_ref_discovered_field() { return true; } 182 }; 183 184 class UpdateRSetImmediate: public OopsInHeapRegionClosure { 185 private: 186 G1RemSet* _g1_rem_set; 187 188 template <class T> void do_oop_work(T* p); 189 public: 190 UpdateRSetImmediate(G1RemSet* rs) : 191 _g1_rem_set(rs) {} 192 193 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 194 virtual void do_oop( oop* p) { do_oop_work(p); } 195 }; 196 197 198 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP