1 /*
2 * Copyright (c) 2001, 2017, 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.
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1REMSET_HPP
26 #define SHARE_VM_GC_G1_G1REMSET_HPP
27
28 #include "gc/g1/dirtyCardQueue.hpp"
29 #include "gc/g1/g1CardLiveData.hpp"
30 #include "gc/g1/g1RemSetSummary.hpp"
31 #include "gc/g1/heapRegion.hpp"
32 #include "memory/allocation.hpp"
33 #include "memory/iterator.hpp"
34
35 // A G1RemSet provides ways of iterating over pointers into a selected
36 // collection set.
37
38 class BitMap;
39 class CardTableModRefBS;
40 class G1BlockOffsetTable;
41 class CodeBlobClosure;
42 class G1CollectedHeap;
43 class G1HotCardCache;
44 class G1RemSetScanState;
45 class G1ParScanThreadState;
46 class G1Policy;
47 class G1SATBCardTableModRefBS;
48 class G1ScanObjsDuringScanRSClosure;
49 class G1ScanObjsDuringUpdateRSClosure;
50 class HeapRegionClaimer;
51
52 // A G1RemSet in which each heap region has a rem set that records the
53 // external heap references into it. Uses a mod ref bs to track updates,
54 // so that they can be used to update the individual region remsets.
55 class G1RemSet: public CHeapObj<mtGC> {
56 private:
57 G1RemSetScanState* _scan_state;
58 G1CardLiveData _card_live_data;
59
60 G1RemSetSummary _prev_period_summary;
61
62 // A DirtyCardQueueSet that is used to hold cards that contain
63 // references into the current collection set. This is used to
64 // update the remembered sets of the regions in the collection
65 // set in the event of an evacuation failure.
66 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
67
68 // Scan all remembered sets of the collection set for references into the collection
69 // set.
70 void scan_rem_set(G1ParScanThreadState* pss,
71 CodeBlobClosure* heap_region_codeblobs,
72 uint worker_i);
73
74 // Flush remaining refinement buffers for cross-region references to either evacuate references
75 // into the collection set or update the remembered set.
76 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParScanThreadState* pss, uint worker_i);
77
78 G1CollectedHeap* _g1;
79 size_t _conc_refine_cards;
80
81 CardTableModRefBS* _ct_bs;
82 G1Policy* _g1p;
83 G1HotCardCache* _hot_card_cache;
84
85 public:
86 // Gives an approximation on how many threads can be expected to add records to
87 // a remembered set in parallel. This can be used for sizing data structures to
88 // decrease performance losses due to data structure sharing.
89 // Examples for quantities that influence this value are the maximum number of
90 // mutator threads, maximum number of concurrent refinement or GC threads.
91 static uint num_par_rem_sets();
92
93 // Initialize data that depends on the heap size being known.
94 void initialize(size_t capacity, uint max_regions);
95
96 // This is called to reset dual hash tables after the gc pause
97 // is finished and the initial hash table is no longer being
98 // scanned.
99 void cleanupHRRS();
100
101 G1RemSet(G1CollectedHeap* g1,
102 CardTableModRefBS* ct_bs,
103 G1HotCardCache* hot_card_cache);
104 ~G1RemSet();
105
106 // Process all oops in the collection set from the cards in the refinement buffers and
107 // remembered sets using pss.
108 //
109 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code
110 // roots list for each region in the collection set.
111 void oops_into_collection_set_do(G1ParScanThreadState* pss,
112 CodeBlobClosure* heap_region_codeblobs,
113 uint worker_i);
114
115 // Prepare for and cleanup after an oops_into_collection_set_do
116 // call. Must call each of these once before and after (in sequential
117 // code) any thread calls oops_into_collection_set_do.
118 void prepare_for_oops_into_collection_set_do();
119 void cleanup_after_oops_into_collection_set_do();
120
121 G1RemSetScanState* scan_state() const { return _scan_state; }
122
123 // Record, if necessary, the fact that *p (where "p" is in region "from",
124 // which is required to be non-NULL) has changed to a new non-NULL value.
125 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
126
127 // Eliminates any remembered set entries that correspond to dead heap ranges.
128 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer);
129
130 // Refine the card corresponding to "card_ptr". Safe to be called concurrently
131 // to the mutator.
132 void refine_card_concurrently(jbyte* card_ptr,
133 uint worker_i);
134
135 // Refine the card corresponding to "card_ptr", applying the given closure to
136 // all references found. Returns "true" if the given card contains
137 // oops that have references into the current collection set. Must only be
138 // called during gc.
139 bool refine_card_during_gc(jbyte* card_ptr,
140 G1ScanObjsDuringUpdateRSClosure* update_rs_cl);
141
142 // Print accumulated summary info from the start of the VM.
143 void print_summary_info();
144
145 // Print accumulated summary info from the last time called.
146 void print_periodic_summary_info(const char* header, uint period_count);
147
148 // Prepare remembered set for verification.
149 void prepare_for_verify();
150
151 size_t conc_refine_cards() const { return _conc_refine_cards; }
152
153 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
154 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
155
156 // Verify that the liveness count data created concurrently matches one created
157 // during this safepoint.
158 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap);
159
160 void clear_card_live_data(WorkGang* workers);
161
162 #ifdef ASSERT
163 void verify_card_live_data_is_clear();
164 #endif
165 };
166
167 class G1ScanRSForRegionClosure : public HeapRegionClosure {
168 G1RemSetScanState* _scan_state;
169
170 size_t _cards_scanned;
171 size_t _cards_claimed;
172 size_t _cards_skipped;
173
174 G1CollectedHeap* _g1h;
175
176 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl;
177 CodeBlobClosure* _code_root_cl;
178
179 G1BlockOffsetTable* _bot;
180 G1SATBCardTableModRefBS *_ct_bs;
181
182 double _strong_code_root_scan_time_sec;
183 uint _worker_i;
184
185 void scan_card(size_t index, HeapWord* card_start, HeapRegion *r);
186 void scan_strong_code_roots(HeapRegion* r);
187 public:
188 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state,
189 G1ScanObjsDuringScanRSClosure* scan_obj_on_card,
190 CodeBlobClosure* code_root_cl,
191 uint worker_i);
192
193 bool doHeapRegion(HeapRegion* r);
194
195 double strong_code_root_scan_time_sec() {
196 return _strong_code_root_scan_time_sec;
197 }
198
199 size_t cards_scanned() const { return _cards_scanned; }
200 size_t cards_claimed() const { return _cards_claimed; }
201 size_t cards_skipped() const { return _cards_skipped; }
202 };
203
204 class RebuildRSOopClosure: public ExtendedOopClosure {
205 HeapRegion* _from;
206 G1RemSet* _rs;
207 uint _worker_i;
208
209 template <class T> void do_oop_work(T* p);
210
211 public:
212 RebuildRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
213 _from(NULL), _rs(rs), _worker_i(worker_i)
214 {}
215
216 void set_from(HeapRegion* from) {
217 assert(from != NULL, "from region must be non-NULL");
218 _from = from;
219 }
220
221 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
222 virtual void do_oop(oop* p) { do_oop_work(p); }
223 };
224
225 #endif // SHARE_VM_GC_G1_G1REMSET_HPP