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 ConcurrentG1Refine; 35 class G1ParPushHeapRSClosure; 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 G1ParPushHeapRSClosure** _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(G1ParPushHeapRSClosure* 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(G1ParPushHeapRSClosure* 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. "worker_num" is the 128 // parallel thread id of the current thread, and "hrclaimer" is the 129 // HeapRegionClaimer that should be used. 130 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 131 132 // Refine the card corresponding to "card_ptr". 133 // If check_for_refs_into_cset is true, a true result is returned 134 // if the given card contains oops that have references into the 135 // current collection set. 136 virtual bool refine_card(jbyte* card_ptr, 137 uint worker_i, 138 bool check_for_refs_into_cset); 139 140 // Print accumulated summary info from the start of the VM. 141 virtual void print_summary_info(); 142 143 // Print accumulated summary info from the last time called. 144 virtual void print_periodic_summary_info(const char* header); 145 146 // Prepare remembered set for verification. 147 virtual void prepare_for_verify(); 148 149 size_t conc_refine_cards() const { 150 return _conc_refine_cards; 151 } 152 }; 153 154 class UpdateRSOopClosure: public ExtendedOopClosure { 155 HeapRegion* _from; 156 G1RemSet* _rs; 157 uint _worker_i; 158 159 template <class T> void do_oop_work(T* p); 160 161 public: 162 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 163 _from(NULL), _rs(rs), _worker_i(worker_i) 164 {} 165 166 void set_from(HeapRegion* from) { 167 assert(from != NULL, "from region must be non-NULL"); 168 _from = from; 169 } 170 171 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 172 virtual void do_oop(oop* p) { do_oop_work(p); } 173 174 // Override: this closure is idempotent. 175 // bool idempotent() { return true; } 176 bool apply_to_weak_ref_discovered_field() { return true; } 177 }; 178 179 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP