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.
22 *
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 private:
55 G1RemSetScanState* _scan_state;
56 G1CardLiveData _card_live_data;
57
58 G1RemSetSummary _prev_period_summary;
59
60 // A DirtyCardQueueSet that is used to hold cards that contain
61 // references into the current collection set. This is used to
62 // update the remembered sets of the regions in the collection
63 // set in the event of an evacuation failure.
64 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
65
66 protected:
67 G1CollectedHeap* _g1;
68 size_t _conc_refine_cards;
69 uint n_workers();
70
71 protected:
72 CardTableModRefBS* _ct_bs;
73 G1Policy* _g1p;
74 G1HotCardCache* _hot_card_cache;
75
76 public:
77 // Gives an approximation on how many threads can be expected to add records to
78 // a remembered set in parallel. This can be used for sizing data structures to
79 // decrease performance losses due to data structure sharing.
80 // Examples for quantities that influence this value are the maximum number of
81 // mutator threads, maximum number of concurrent refinement or GC threads.
82 static uint num_par_rem_sets();
83
84 // Initialize data that depends on the heap size being known.
85 void initialize(size_t capacity, uint max_regions);
86
87 // This is called to reset dual hash tables after the gc pause
88 // is finished and the initial hash table is no longer being
89 // scanned.
90 void cleanupHRRS();
91
92 G1RemSet(G1CollectedHeap* g1,
93 CardTableModRefBS* ct_bs,
94 G1HotCardCache* hot_card_cache);
95 ~G1RemSet();
96
97 // Invoke "cl->do_oop" on all pointers into the collection set
98 // from objects in regions outside the collection set (having
99 // invoked "cl->set_region" to set the "from" region correctly
100 // beforehand.)
101 //
102 // Apply non_heap_roots on the oops of the unmarked nmethods
103 // on the strong code roots list for each region in the
104 // collection set.
105 //
106 // The "worker_i" param is for the parallel case where the id
107 // of the worker thread calling this function can be helpful in
108 // partitioning the work to be done. It should be the same as
109 // the "i" passed to the calling thread's work(i) function.
110 // In the sequential case this param will be ignored.
111 void oops_into_collection_set_do(G1ParPushHeapRSClosure* cl,
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 threads call oops_into_collection_set_do. (This offers an
118 // opportunity to sequential setup and teardown of structures needed by a
119 // parallel iteration over the CS's RS.)
120 void prepare_for_oops_into_collection_set_do();
121 void cleanup_after_oops_into_collection_set_do();
122
123 void scan_rem_set(G1ParPushHeapRSClosure* oops_in_heap_closure,
124 CodeBlobClosure* heap_region_codeblobs,
125 uint worker_i);
126
127 G1RemSetScanState* scan_state() const { return _scan_state; }
128
129 // Flush remaining refinement buffers into the remembered set,
130 // applying oops_in_heap_closure on the references found.
131 void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParPushHeapRSClosure* oops_in_heap_closure, uint worker_i);
132
133 // Record, if necessary, the fact that *p (where "p" is in region "from",
134 // which is required to be non-NULL) has changed to a new non-NULL value.
135 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
136
137 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
138 // or card, respectively, such that a region or card with a corresponding
139 // 0 bit contains no part of any live object. Eliminates any remembered
140 // set entries that correspond to dead heap ranges. "worker_num" is the
141 // parallel thread id of the current thread, and "hrclaimer" is the
142 // HeapRegionClaimer that should be used.
143 void scrub(uint worker_num, HeapRegionClaimer* hrclaimer);
144
145 // Refine the card corresponding to "card_ptr".
146 void refine_card_concurrently(jbyte* card_ptr,
147 uint worker_i);
148
149 // Refine the card corresponding to "card_ptr". Returns "true" if the given card contains
150 // oops that have references into the current collection set.
151 bool refine_card_during_gc(jbyte* card_ptr,
152 uint worker_i,
153 G1ParPushHeapRSClosure* oops_in_heap_closure);
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 // Prepare remembered set for verification.
162 void prepare_for_verify();
163
164 size_t conc_refine_cards() const {
165 return _conc_refine_cards;
166 }
167
168 void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
169 void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);
170
171 // Verify that the liveness count data created concurrently matches one created
172 // during this safepoint.
173 void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap);
174
175 void clear_card_live_data(WorkGang* workers);
176
177 #ifdef ASSERT
178 void verify_card_live_data_is_clear();
179 #endif
180 };
181
182 class G1ScanRSClosure : public HeapRegionClosure {
183 G1RemSetScanState* _scan_state;
184
185 size_t _cards_scanned;
186 size_t _cards_claimed;
187 size_t _cards_skipped;
188
189 G1CollectedHeap* _g1h;
190
191 G1ParPushHeapRSClosure* _push_heap_cl;
192 CodeBlobClosure* _code_root_cl;
193
194 G1BlockOffsetTable* _bot;
195 G1SATBCardTableModRefBS *_ct_bs;
196
197 double _strong_code_root_scan_time_sec;
198 uint _worker_i;
199 size_t _block_size;
200
201 void scan_card(size_t index, HeapWord* card_start, HeapRegion *r);
202 void scan_strong_code_roots(HeapRegion* r);
203 public:
204 G1ScanRSClosure(G1RemSetScanState* scan_state,
205 G1ParPushHeapRSClosure* push_heap_cl,
206 CodeBlobClosure* code_root_cl,
207 uint worker_i);
208
209 bool doHeapRegion(HeapRegion* r);
210
211 double strong_code_root_scan_time_sec() {
212 return _strong_code_root_scan_time_sec;
213 }
214
215 size_t cards_scanned() const { return _cards_scanned; }
216 size_t cards_claimed() const { return _cards_claimed; }
217 size_t cards_skipped() const { return _cards_skipped; }
218 };
219
220 class UpdateRSOopClosure: public ExtendedOopClosure {
221 HeapRegion* _from;
222 G1RemSet* _rs;
223 uint _worker_i;
224
225 template <class T> void do_oop_work(T* p);
226
227 public:
228 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
229 _from(NULL), _rs(rs), _worker_i(worker_i)
230 {}
231
232 void set_from(HeapRegion* from) {
233 assert(from != NULL, "from region must be non-NULL");
234 _from = from;
235 }
236
237 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
238 virtual void do_oop(oop* p) { do_oop_work(p); }
239 };
240
241 #endif // SHARE_VM_GC_G1_G1REMSET_HPP