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.
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5 * This code is free software; you can redistribute it and/or modify it
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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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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 // Closure used for updating remembered sets and recording references that
53 // point into the collection set while the mutator is running.
54 // Assumed to be only executed concurrently with the mutator. Yields via
55 // SuspendibleThreadSet after every card.
56 class G1RefineCardConcurrentlyClosure: public CardTableEntryClosure {
57 public:
58 bool do_card_ptr(jbyte* card_ptr, uint worker_i);
59 };
60
61 // A G1RemSet in which each heap region has a rem set that records the
62 // external heap references into it. Uses a mod ref bs to track updates,
63 // so that they can be used to update the individual region remsets.
64 class G1RemSet: public CHeapObj<mtGC> {
65 private:
66 G1RefineCardConcurrentlyClosure _refine_card_concurrently_cl;
67
68 G1RemSetScanState* _scan_state;
69 G1CardLiveData _card_live_data;
70
71 G1RemSetSummary _prev_period_summary;
72
73 // A DirtyCardQueueSet that is used to hold cards that contain
74 // references into the current collection set. This is used to
75 // update the remembered sets of the regions in the collection
76 // set in the event of an evacuation failure.
77 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
78
79 // Scan all remembered sets of the collection set for references into the collection
80 // set.
81 void scan_rem_set(G1ParScanThreadState* pss,
82 CodeBlobClosure* heap_region_codeblobs,
83 uint worker_i);
84
85 // Flush remaining refinement buffers for cross-region references to either evacuate references
86 // into the collection set or update the remembered set.
87 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParScanThreadState* pss, uint worker_i);
88
89 G1CollectedHeap* _g1;
90 size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.
91
92 CardTableModRefBS* _ct_bs;
93 G1Policy* _g1p;
94 G1HotCardCache* _hot_card_cache;
95
96 public:
97 // Gives an approximation on how many threads can be expected to add records to
98 // a remembered set in parallel. This can be used for sizing data structures to
99 // decrease performance losses due to data structure sharing.
100 // Examples for quantities that influence this value are the maximum number of
101 // mutator threads, maximum number of concurrent refinement or GC threads.
102 static uint num_par_rem_sets();
103
104 // Initialize data that depends on the heap size being known.
105 void initialize(size_t capacity, uint max_regions);
106
107 // This is called to reset dual hash tables after the gc pause
108 // is finished and the initial hash table is no longer being
109 // scanned.
110 void cleanupHRRS();
111
112 G1RemSet(G1CollectedHeap* g1,
113 CardTableModRefBS* ct_bs,
114 G1HotCardCache* hot_card_cache);
115 ~G1RemSet();
116
117 // Process all oops in the collection set from the cards in the refinement buffers and
118 // remembered sets using pss.
119 //
120 // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code
121 // roots list for each region in the collection set.
122 void oops_into_collection_set_do(G1ParScanThreadState* pss,
123 CodeBlobClosure* heap_region_codeblobs,
124 uint worker_i);
125
126 // Prepare for and cleanup after an oops_into_collection_set_do
127 // call. Must call each of these once before and after (in sequential
128 // code) any thread calls oops_into_collection_set_do.
129 void prepare_for_oops_into_collection_set_do();
130 void cleanup_after_oops_into_collection_set_do();
131
132 G1RemSetScanState* scan_state() const { return _scan_state; }
133
134 // Record, if necessary, the fact that *p (where "p" is in region "from",
135 // which is required to be non-NULL) has changed to a new non-NULL value.
136 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
137
138 // Eliminates any remembered set entries that correspond to dead heap ranges.
139 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer);
140
141 G1RefineCardConcurrentlyClosure* refine_card_concurrently_closure() { return &_refine_card_concurrently_cl; }
142
143 // Refine the card corresponding to "card_ptr". Safe to be called concurrently
144 // to the mutator.
145 void refine_card_concurrently(jbyte* card_ptr,
146 uint worker_i);
147
148 // Refine the card corresponding to "card_ptr", applying the given closure to
149 // all references found. Returns "true" if the given card contains
150 // oops that have references into the current collection set. Must only be
151 // called during gc.
152 bool refine_card_during_gc(jbyte* card_ptr,
153 G1ScanObjsDuringUpdateRSClosure* update_rs_cl);
154
155 // Print accumulated summary info from the start of the VM.
156 void print_summary_info();
157
158 // Print accumulated summary info from the last time called.
159 void print_periodic_summary_info(const char* header, uint period_count);
160
161 size_t num_conc_refined_cards() const { return _num_conc_refined_cards; }
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 G1ScanRSForRegionClosure : public HeapRegionClosure {
178 G1RemSetScanState* _scan_state;
179
180 size_t _cards_scanned;
181 size_t _cards_claimed;
182 size_t _cards_skipped;
183
184 G1CollectedHeap* _g1h;
185
186 G1ScanObjsDuringScanRSClosure* _scan_objs_on_card_cl;
187 CodeBlobClosure* _code_root_cl;
188
189 G1BlockOffsetTable* _bot;
190 G1SATBCardTableModRefBS *_ct_bs;
191
192 double _strong_code_root_scan_time_sec;
193 uint _worker_i;
194
195 void claim_card(size_t card_index, const uint region_idx_for_card);
196 void scan_card(MemRegion mr, uint region_idx_for_card);
197 void scan_strong_code_roots(HeapRegion* r);
198 public:
199 G1ScanRSForRegionClosure(G1RemSetScanState* scan_state,
200 G1ScanObjsDuringScanRSClosure* scan_obj_on_card,
201 CodeBlobClosure* code_root_cl,
202 uint worker_i);
203
204 bool doHeapRegion(HeapRegion* r);
205
206 double strong_code_root_scan_time_sec() {
207 return _strong_code_root_scan_time_sec;
208 }
209
210 size_t cards_scanned() const { return _cards_scanned; }
211 size_t cards_claimed() const { return _cards_claimed; }
212 size_t cards_skipped() const { return _cards_skipped; }
213 };
214
215 class RebuildRSOopClosure: public ExtendedOopClosure {
216 HeapRegion* _from;
217 G1RemSet* _rs;
218 uint _worker_i;
219
220 template <class T> void do_oop_work(T* p);
221
222 public:
223 RebuildRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
224 _from(NULL), _rs(rs), _worker_i(worker_i)
225 {}
226
227 void set_from(HeapRegion* from) {
228 assert(from != NULL, "from region must be non-NULL");
229 _from = from;
230 }
231
232 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
233 virtual void do_oop(oop* p) { do_oop_work(p); }
234 };
235
236 #endif // SHARE_VM_GC_G1_G1REMSET_HPP