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