1 /* 2 * Copyright (c) 2001, 2015, 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_G1_G1REMSET_HPP 26 #define SHARE_VM_GC_G1_G1REMSET_HPP 27 28 #include "gc/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 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 G1ParPushHeapRSClosure** _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(G1ParPushHeapRSClosure* 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(G1ParPushHeapRSClosure* 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, uint 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. "worker_num" is the 127 // parallel thread id of the current thread, and "hrclaimer" is the 128 // HeapRegionClaimer that should be used. 129 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 130 131 // Refine the card corresponding to "card_ptr". 132 // If check_for_refs_into_cset is true, a true result is returned 133 // if the given card contains oops that have references into the 134 // current collection set. 135 virtual bool refine_card(jbyte* card_ptr, 136 uint worker_i, 137 bool check_for_refs_into_cset); 138 139 // Print accumulated summary info from the start of the VM. 140 virtual void print_summary_info(); 141 142 // Print accumulated summary info from the last time called. 143 virtual void print_periodic_summary_info(const char* header); 144 145 // Prepare remembered set for verification. 146 virtual void prepare_for_verify(); 147 148 size_t conc_refine_cards() const { 149 return _conc_refine_cards; 150 } 151 }; 152 153 class UpdateRSOopClosure: public ExtendedOopClosure { 154 HeapRegion* _from; 155 G1RemSet* _rs; 156 uint _worker_i; 157 158 template <class T> void do_oop_work(T* p); 159 160 public: 161 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 162 _from(NULL), _rs(rs), _worker_i(worker_i) 163 {} 164 165 void set_from(HeapRegion* from) { 166 assert(from != NULL, "from region must be non-NULL"); 167 _from = from; 168 } 169 170 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 171 virtual void do_oop(oop* p) { do_oop_work(p); } 172 173 // Override: this closure is idempotent. 174 // bool idempotent() { return true; } 175 bool apply_to_weak_ref_discovered_field() { return true; } 176 }; 177 178 #endif // SHARE_VM_GC_G1_G1REMSET_HPP