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 45 // A DirtyCardQueueSet that is used to hold cards that contain 46 // references into the current collection set. This is used to 47 // update the remembered sets of the regions in the collection 48 // set in the event of an evacuation failure. 49 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 50 51 protected: 52 G1CollectedHeap* _g1; 53 size_t _conc_refine_cards; 54 uint n_workers(); 55 56 protected: 57 enum SomePrivateConstants { 58 UpdateRStoMergeSync = 0, 59 MergeRStoDoDirtySync = 1, 60 DoDirtySync = 2, 61 LastSync = 3, 62 63 SeqTask = 0, 64 NumSeqTasks = 1 65 }; 66 67 CardTableModRefBS* _ct_bs; 68 G1CollectorPolicy* _g1p; 69 70 ConcurrentG1Refine* _cg1r; 71 72 // Used for caching the closure that is responsible for scanning 73 // references into the collection set. 74 G1ParPushHeapRSClosure** _cset_rs_update_cl; 75 76 // Print the given summary info 77 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL); 78 public: 79 // This is called to reset dual hash tables after the gc pause 80 // is finished and the initial hash table is no longer being 81 // scanned. 82 void cleanupHRRS(); 83 84 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); 85 ~G1RemSet(); 86 87 // Invoke "blk->do_oop" on all pointers into the collection set 88 // from objects in regions outside the collection set (having 89 // invoked "blk->set_region" to set the "from" region correctly 90 // beforehand.) 91 // 92 // Apply non_heap_roots on the oops of the unmarked nmethods 93 // on the strong code roots list for each region in the 94 // collection set. 95 // 96 // The "worker_i" param is for the parallel case where the id 97 // of the worker thread calling this function can be helpful in 98 // partitioning the work to be done. It should be the same as 99 // the "i" passed to the calling thread's work(i) function. 100 // In the sequential case this param will be ignored. 101 // 102 // Returns the number of cards scanned while looking for pointers 103 // into the collection set. 104 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk, 105 CodeBlobClosure* heap_region_codeblobs, 106 uint worker_i); 107 108 // Prepare for and cleanup after an oops_into_collection_set_do 109 // call. Must call each of these once before and after (in sequential 110 // code) any threads call oops_into_collection_set_do. (This offers an 111 // opportunity to sequential setup and teardown of structures needed by a 112 // parallel iteration over the CS's RS.) 113 void prepare_for_oops_into_collection_set_do(); 114 void cleanup_after_oops_into_collection_set_do(); 115 116 size_t scanRS(G1ParPushHeapRSClosure* oc, 117 CodeBlobClosure* heap_region_codeblobs, 118 uint worker_i); 119 120 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 121 122 CardTableModRefBS* ct_bs() { return _ct_bs; } 123 124 // Record, if necessary, the fact that *p (where "p" is in region "from", 125 // which is required to be non-NULL) has changed to a new non-NULL value. 126 template <class T> void write_ref(HeapRegion* from, T* p); 127 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 128 129 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 130 // or card, respectively, such that a region or card with a corresponding 131 // 0 bit contains no part of any live object. Eliminates any remembered 132 // set entries that correspond to dead heap ranges. "worker_num" is the 133 // parallel thread id of the current thread, and "hrclaimer" is the 134 // HeapRegionClaimer that should be used. 135 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 136 137 // Refine the card corresponding to "card_ptr". 138 // If check_for_refs_into_cset is true, a true result is returned 139 // if the given card contains oops that have references into the 140 // current collection set. 141 virtual bool refine_card(jbyte* card_ptr, 142 uint worker_i, 143 bool check_for_refs_into_cset); 144 145 // Print accumulated summary info from the start of the VM. 146 virtual void print_summary_info(); 147 148 // Print accumulated summary info from the last time called. 149 virtual void print_periodic_summary_info(const char* header); 150 151 // Prepare remembered set for verification. 152 virtual void prepare_for_verify(); 153 154 size_t conc_refine_cards() const { 155 return _conc_refine_cards; 156 } 157 }; 158 159 class UpdateRSOopClosure: public ExtendedOopClosure { 160 HeapRegion* _from; 161 G1RemSet* _rs; 162 uint _worker_i; 163 164 template <class T> void do_oop_work(T* p); 165 166 public: 167 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 168 _from(NULL), _rs(rs), _worker_i(worker_i) 169 {} 170 171 void set_from(HeapRegion* from) { 172 assert(from != NULL, "from region must be non-NULL"); 173 _from = from; 174 } 175 176 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 177 virtual void do_oop(oop* p) { do_oop_work(p); } 178 179 // Override: this closure is idempotent. 180 // bool idempotent() { return true; } 181 bool apply_to_weak_ref_discovered_field() { return true; } 182 }; 183 184 #endif // SHARE_VM_GC_G1_G1REMSET_HPP