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.
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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
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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 G1ParPushHeapRSClosure;
45 class G1RemSetScanState;
46 class G1Policy;
47 class G1SATBCardTableModRefBS;
48 class HeapRegionClaimer;
49
50 // A G1RemSet in which each heap region has a rem set that records the
51 // external heap references into it. Uses a mod ref bs to track updates,
52 // so that they can be used to update the individual region remsets.
53 class G1RemSet: public CHeapObj<mtGC> {
54 friend class G1ParScrubRemSetTask;
55
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 protected:
69 G1CollectedHeap* _g1;
70 size_t _conc_refine_cards;
71 uint n_workers();
72
73 protected:
74 CardTableModRefBS* _ct_bs;
75 G1Policy* _g1p;
76 G1HotCardCache* _hot_card_cache;
77
78 public:
79 // Gives an approximation on how many threads can be expected to add records to
80 // a remembered set in parallel. This can be used for sizing data structures to
81 // decrease performance losses due to data structure sharing.
82 // Examples for quantities that influence this value are the maximum number of
83 // mutator threads, maximum number of concurrent refinement or GC threads.
84 static uint num_par_rem_sets();
85
86 // Initialize data that depends on the heap size being known.
87 void initialize(size_t capacity, uint max_regions);
88
89 // This is called to reset dual hash tables after the gc pause
90 // is finished and the initial hash table is no longer being
91 // scanned.
92 void cleanupHRRS();
93
94 G1RemSet(G1CollectedHeap* g1,
95 CardTableModRefBS* ct_bs,
96 G1HotCardCache* hot_card_cache);
97 ~G1RemSet();
98
99 // Invoke "cl->do_oop" on all pointers into the collection set
100 // from objects in regions outside the collection set (having
101 // invoked "cl->set_region" to set the "from" region correctly
102 // beforehand.)
103 //
104 // Apply non_heap_roots on the oops of the unmarked nmethods
105 // on the strong code roots list for each region in the
106 // collection set.
107 //
108 // The "worker_i" param is for the parallel case where the id
109 // of the worker thread calling this function can be helpful in
110 // partitioning the work to be done. It should be the same as
111 // the "i" passed to the calling thread's work(i) function.
112 // In the sequential case this param will be ignored.
113 //
114 // Returns the number of cards scanned while looking for pointers
115 // into the collection set.
116 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* cl,
117 CodeBlobClosure* heap_region_codeblobs,
118 uint worker_i);
119
120 // Prepare for and cleanup after an oops_into_collection_set_do
121 // call. Must call each of these once before and after (in sequential
122 // code) any threads call oops_into_collection_set_do. (This offers an
123 // opportunity to sequential setup and teardown of structures needed by a
124 // parallel iteration over the CS's RS.)
125 void prepare_for_oops_into_collection_set_do();
126 void cleanup_after_oops_into_collection_set_do();
127
128 size_t scan_rem_set(G1ParPushHeapRSClosure* oops_in_heap_closure,
129 CodeBlobClosure* heap_region_codeblobs,
130 uint worker_i);
131
132 G1RemSetScanState* scan_state() const { return _scan_state; }
133
134 // Flush remaining refinement buffers into the remembered set,
135 // applying oops_in_heap_closure on the references found.
136 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParPushHeapRSClosure* oops_in_heap_closure, uint worker_i);
137
138 // Record, if necessary, the fact that *p (where "p" is in region "from",
139 // which is required to be non-NULL) has changed to a new non-NULL value.
140 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
141
142 // Refine the card corresponding to "card_ptr".
143 // If oops_in_heap_closure is not NULL, a true result is returned
144 // if the given card contains oops that have references into the
145 // current collection set.
146 bool refine_card(jbyte* card_ptr,
147 uint worker_i,
148 G1ParPushHeapRSClosure* oops_in_heap_closure);
149
150 // Print accumulated summary info from the start of the VM.
151 void print_summary_info();
152
153 // Print accumulated summary info from the last time called.
154 void print_periodic_summary_info(const char* header, uint period_count);
155
156 // Prepare remembered set for verification.
157 void prepare_for_verify();
158
159 size_t conc_refine_cards() const {
160 return _conc_refine_cards;
161 }
162
163 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
164 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
165
166 // Verify that the liveness count data created concurrently matches one created
167 // during this safepoint.
168 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap);
169
170 void clear_card_live_data(WorkGang* workers);
171
172 #ifdef ASSERT
173 void verify_card_live_data_is_clear();
174 #endif
175 };
176
177 class G1ScanRSClosure : public HeapRegionClosure {
178 G1RemSetScanState* _scan_state;
179
180 size_t _cards_done;
181 size_t _cards;
182 G1CollectedHeap* _g1h;
183
184 G1ParPushHeapRSClosure* _push_heap_cl;
185 CodeBlobClosure* _code_root_cl;
186
187 G1BlockOffsetTable* _bot;
188 G1SATBCardTableModRefBS *_ct_bs;
189
190 double _strong_code_root_scan_time_sec;
191 uint _worker_i;
192 size_t _block_size;
193
194 void scan_card(size_t index, HeapRegion *r);
195 void scan_strong_code_roots(HeapRegion* r);
196 public:
197 G1ScanRSClosure(G1RemSetScanState* scan_state,
198 G1ParPushHeapRSClosure* push_heap_cl,
199 CodeBlobClosure* code_root_cl,
200 uint worker_i);
201
202 bool doHeapRegion(HeapRegion* r);
203
204 double strong_code_root_scan_time_sec() {
205 return _strong_code_root_scan_time_sec;
206 }
207
208 size_t cards_done() { return _cards_done;}
209 size_t cards_looked_up() { return _cards;}
210 };
211
212 class UpdateRSOopClosure: public ExtendedOopClosure {
213 HeapRegion* _from;
214 G1RemSet* _rs;
215 uint _worker_i;
216
217 template <class T> void do_oop_work(T* p);
218
219 public:
220 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
221 _from(NULL), _rs(rs), _worker_i(worker_i)
222 {}
223
224 void set_from(HeapRegion* from) {
225 assert(from != NULL, "from region must be non-NULL");
226 _from = from;
227 }
228
229 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
230 virtual void do_oop(oop* p) { do_oop_work(p); }
231 };
232
233 #endif // SHARE_VM_GC_G1_G1REMSET_HPP