1 /* 2 * Copyright (c) 2001, 2014, 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 collection set 85 // from objects in regions outside the collection set (having 86 // invoked "blk->set_region" to set the "from" region correctly 87 // beforehand.) 88 // 89 // Invoke code_root_cl->do_code_blob on the unmarked nmethods 90 // on the strong code roots list for each region in the 91 // collection set. 92 // 93 // The "worker_i" param is for the parallel case where the id 94 // of the worker thread calling this function can be helpful in 95 // partitioning the work to be done. It should be the same as 96 // the "i" passed to the calling thread's work(i) function. 97 // In the sequential case this param will be ignored. 98 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, 99 CodeBlobClosure* code_root_cl, 100 uint worker_i); 101 102 // Prepare for and cleanup after an oops_into_collection_set_do 103 // call. Must call each of these once before and after (in sequential 104 // code) any threads call oops_into_collection_set_do. (This offers an 105 // opportunity to sequential setup and teardown of structures needed by a 106 // parallel iteration over the CS's RS.) 107 void prepare_for_oops_into_collection_set_do(); 108 void cleanup_after_oops_into_collection_set_do(); 109 110 void scanRS(OopsInHeapRegionClosure* oc, 111 CodeBlobClosure* code_root_cl, 112 uint worker_i); 113 114 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 115 116 CardTableModRefBS* ct_bs() { return _ct_bs; } 117 size_t cardsScanned() { return _total_cards_scanned; } 118 119 // Record, if necessary, the fact that *p (where "p" is in region "from", 120 // which is required to be non-NULL) has changed to a new non-NULL value. 121 template <class T> void write_ref(HeapRegion* from, T* p); 122 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 123 124 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 125 // or card, respectively, such that a region or card with a corresponding 126 // 0 bit contains no part of any live object. Eliminates any remembered 127 // set entries that correspond to dead heap ranges. 128 void scrub(BitMap* region_bm, BitMap* card_bm); 129 130 // Like the above, but assumes is called in parallel: "worker_num" is the 131 // parallel thread id of the current thread, and "hrclaimer" is the shared 132 // HeapRegionClaimer that should be used to claim heap regions. 133 void scrub_par(BitMap* region_bm, BitMap* card_bm, 134 uint worker_num, HeapRegionClaimer* hrclaimer); 135 136 // Refine the card corresponding to "card_ptr". 137 // If check_for_refs_into_cset is true, a true result is returned 138 // if the given card contains oops that have references into the 139 // current collection set. 140 virtual bool refine_card(jbyte* card_ptr, 141 uint worker_i, 142 bool check_for_refs_into_cset); 143 144 // Print accumulated summary info from the start of the VM. 145 virtual void print_summary_info(); 146 147 // Print accumulated summary info from the last time called. 148 virtual void print_periodic_summary_info(const char* header); 149 150 // Prepare remembered set for verification. 151 virtual void prepare_for_verify(); 152 153 size_t conc_refine_cards() const { 154 return _conc_refine_cards; 155 } 156 }; 157 158 class CountNonCleanMemRegionClosure: public MemRegionClosure { 159 G1CollectedHeap* _g1; 160 int _n; 161 HeapWord* _start_first; 162 public: 163 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) : 164 _g1(g1), _n(0), _start_first(NULL) 165 {} 166 void do_MemRegion(MemRegion mr); 167 int n() { return _n; }; 168 HeapWord* start_first() { return _start_first; } 169 }; 170 171 class UpdateRSOopClosure: public ExtendedOopClosure { 172 HeapRegion* _from; 173 G1RemSet* _rs; 174 uint _worker_i; 175 176 template <class T> void do_oop_work(T* p); 177 178 public: 179 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 180 _from(NULL), _rs(rs), _worker_i(worker_i) 181 {} 182 183 void set_from(HeapRegion* from) { 184 assert(from != NULL, "from region must be non-NULL"); 185 _from = from; 186 } 187 188 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 189 virtual void do_oop(oop* p) { do_oop_work(p); } 190 191 // Override: this closure is idempotent. 192 // bool idempotent() { return true; } 193 bool apply_to_weak_ref_discovered_field() { return true; } 194 }; 195 196 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP