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 // Used for caching the closure that is responsible for scanning 66 // references into the collection set. 67 G1ParPushHeapRSClosure** _cset_rs_update_cl; 68 69 // Print the given summary info 70 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL); 71 public: 72 // This is called to reset dual hash tables after the gc pause 73 // is finished and the initial hash table is no longer being 74 // scanned. 75 void cleanupHRRS(); 76 77 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); 78 ~G1RemSet(); 79 80 // Invoke "blk->do_oop" on all pointers into the collection set 81 // from objects in regions outside the collection set (having 82 // invoked "blk->set_region" to set the "from" region correctly 83 // beforehand.) 84 // 85 // Apply non_heap_roots on the oops of the unmarked nmethods 86 // on the strong code roots list for each region in the 87 // collection set. 88 // 89 // The "worker_i" param is for the parallel case where the id 90 // of the worker thread calling this function can be helpful in 91 // partitioning the work to be done. It should be the same as 92 // the "i" passed to the calling thread's work(i) function. 93 // In the sequential case this param will be ignored. 94 // 95 // Returns the number of cards scanned while looking for pointers 96 // into the collection set. 97 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk, 98 CodeBlobClosure* heap_region_codeblobs, 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(G1ParPushHeapRSClosure* oc, 110 CodeBlobClosure* heap_region_codeblobs, 111 uint worker_i); 112 113 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i); 114 115 CardTableModRefBS* ct_bs() { return _ct_bs; } 116 117 // Record, if necessary, the fact that *p (where "p" is in region "from", 118 // which is required to be non-NULL) has changed to a new non-NULL value. 119 template <class T> void write_ref(HeapRegion* from, T* p); 120 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid); 121 122 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region 123 // or card, respectively, such that a region or card with a corresponding 124 // 0 bit contains no part of any live object. Eliminates any remembered 125 // set entries that correspond to dead heap ranges. "worker_num" is the 126 // parallel thread id of the current thread, and "hrclaimer" is the 127 // HeapRegionClaimer that should be used. 128 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer); 129 130 // Refine the card corresponding to "card_ptr". 131 // If check_for_refs_into_cset is true, a true result is returned 132 // if the given card contains oops that have references into the 133 // current collection set. 134 virtual bool refine_card(jbyte* card_ptr, 135 uint worker_i, 136 bool check_for_refs_into_cset); 137 138 // Print accumulated summary info from the start of the VM. 139 virtual void print_summary_info(); 140 141 // Print accumulated summary info from the last time called. 142 virtual void print_periodic_summary_info(const char* header); 143 144 // Prepare remembered set for verification. 145 virtual void prepare_for_verify(); 146 147 size_t conc_refine_cards() const { 148 return _conc_refine_cards; 149 } 150 }; 151 152 class UpdateRSOopClosure: public ExtendedOopClosure { 153 HeapRegion* _from; 154 G1RemSet* _rs; 155 uint _worker_i; 156 157 template <class T> void do_oop_work(T* p); 158 159 public: 160 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) : 161 _from(NULL), _rs(rs), _worker_i(worker_i) 162 {} 163 164 void set_from(HeapRegion* from) { 165 assert(from != NULL, "from region must be non-NULL"); 166 _from = from; 167 } 168 169 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 170 virtual void do_oop(oop* p) { do_oop_work(p); } 171 172 // Override: this closure is idempotent. 173 // bool idempotent() { return true; } 174 bool apply_to_weak_ref_discovered_field() { return true; } 175 }; 176 177 #endif // SHARE_VM_GC_G1_G1REMSET_HPP