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 ConcurrentG1Refine; 34 class G1CollectedHeap; 35 class G1EvacuationRootClosures; 36 class G1ParPushHeapRSClosure; 37 38 // A G1RemSet in which each heap region has a rem set that records the 39 // external heap references into it. Uses a mod ref bs to track updates, 40 // so that they can be used to update the individual region remsets. 41 42 class G1RemSet: public CHeapObj<mtGC> { 43 private: 44 G1RemSetSummary _prev_period_summary; 45 protected: 46 G1CollectedHeap* _g1; 47 size_t _conc_refine_cards; 48 uint n_workers(); 49 50 protected: 51 enum SomePrivateConstants { 52 UpdateRStoMergeSync = 0, 53 MergeRStoDoDirtySync = 1, 54 DoDirtySync = 2, 55 LastSync = 3, 56 57 SeqTask = 0, 58 NumSeqTasks = 1 59 }; 60 61 CardTableModRefBS* _ct_bs; 62 G1CollectorPolicy* _g1p; 63 64 ConcurrentG1Refine* _cg1r; 65 66 // Used for caching the closure that is responsible for scanning 67 // references into the collection set. 68 G1ParPushHeapRSClosure** _cset_rs_update_cl; 69 70 // Print the given summary info 71 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL); 72 public: 73 // This is called to reset dual hash tables after the gc pause 74 // is finished and the initial hash table is no longer being 75 // scanned. 76 void cleanupHRRS(); 77 78 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); 79 ~G1RemSet(); 80 81 // Invoke "blk->do_oop" on all pointers into the collection set 82 // from objects in regions outside the collection set (having 83 // invoked "blk->set_region" to set the "from" region correctly 84 // beforehand.) 85 // 86 // Apply non_heap_roots on the oops of the unmarked nmethods 87 // on the strong code roots list for each region in the 88 // collection set. 89 // 90 // The "worker_i" param is for the parallel case where the id 91 // of the worker thread calling this function can be helpful in 92 // partitioning the work to be done. It should be the same as 93 // the "i" passed to the calling thread's work(i) function. 94 // In the sequential case this param will be ignored. 95 // 96 // Returns the number of cards scanned while looking for pointers 97 // into the collection set. 98 size_t oops_into_collection_set_do(G1EvacuationRootClosures* closures, 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 size_t scanRS(G1EvacuationRootClosures* closures, 110 uint worker_i); 111 112 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 113 114 CardTableModRefBS* ct_bs() { return _ct_bs; } 115 116 // Record, if necessary, the fact that *p (where "p" is in region "from", 117 // which is required to be non-NULL) has changed to a new non-NULL value. 118 template <class T> void write_ref(HeapRegion* from, T* p); 119 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 120 121 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 122 // or card, respectively, such that a region or card with a corresponding 123 // 0 bit contains no part of any live object. Eliminates any remembered 124 // set entries that correspond to dead heap ranges. "worker_num" is the 125 // parallel thread id of the current thread, and "hrclaimer" is the 126 // HeapRegionClaimer that should be used. 127 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 128 129 // Refine the card corresponding to "card_ptr". 130 // If check_for_refs_into_cset is true, a true result is returned 131 // if the given card contains oops that have references into the 132 // current collection set. 133 virtual bool refine_card(jbyte* card_ptr, 134 uint worker_i, 135 bool check_for_refs_into_cset); 136 137 // Print accumulated summary info from the start of the VM. 138 virtual void print_summary_info(); 139 140 // Print accumulated summary info from the last time called. 141 virtual void print_periodic_summary_info(const char* header); 142 143 // Prepare remembered set for verification. 144 virtual void prepare_for_verify(); 145 146 size_t conc_refine_cards() const { 147 return _conc_refine_cards; 148 } 149 }; 150 151 class UpdateRSOopClosure: public ExtendedOopClosure { 152 HeapRegion* _from; 153 G1RemSet* _rs; 154 uint _worker_i; 155 156 template <class T> void do_oop_work(T* p); 157 158 public: 159 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 160 _from(NULL), _rs(rs), _worker_i(worker_i) 161 {} 162 163 void set_from(HeapRegion* from) { 164 assert(from != NULL, "from region must be non-NULL"); 165 _from = from; 166 } 167 168 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 169 virtual void do_oop(oop* p) { do_oop_work(p); } 170 171 // Override: this closure is idempotent. 172 // bool idempotent() { return true; } 173 bool apply_to_weak_ref_discovered_field() { return true; } 174 }; 175 176 #endif // SHARE_VM_GC_G1_G1REMSET_HPP