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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 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/g1RemSetSummary.hpp"
30 #include "gc/g1/heapRegion.hpp"
31 #include "memory/allocation.hpp"
32 #include "memory/iterator.hpp"
33
34 // A G1RemSet provides ways of iterating over pointers into a selected
35 // collection set.
36
37 class BitMap;
38 class CardTableModRefBS;
39 class G1BlockOffsetSharedArray;
40 class ConcurrentG1Refine;
41 class CodeBlobClosure;
42 class G1CollectedHeap;
43 class G1CollectorPolicy;
44 class G1ParPushHeapRSClosure;
45 class G1SATBCardTableModRefBS;
46 class HeapRegionClaimer;
47
48 // A G1RemSet in which each heap region has a rem set that records the
49 // external heap references into it. Uses a mod ref bs to track updates,
50 // so that they can be used to update the individual region remsets.
51
52 class G1RemSet: public CHeapObj<mtGC> {
53 private:
54 G1RemSetSummary _prev_period_summary;
55
56 // A DirtyCardQueueSet that is used to hold cards that contain
57 // references into the current collection set. This is used to
58 // update the remembered sets of the regions in the collection
59 // set in the event of an evacuation failure.
60 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
61
62 protected:
63 G1CollectedHeap* _g1;
64 size_t _conc_refine_cards;
65 uint n_workers();
66
67 protected:
68 CardTableModRefBS* _ct_bs;
69 G1CollectorPolicy* _g1p;
70
71 ConcurrentG1Refine* _cg1r;
72
73 // Used for caching the closure that is responsible for scanning
74 // references into the collection set.
75 G1ParPushHeapRSClosure** _cset_rs_update_cl;
76
77 public:
78 // Gives an approximation on how many threads add records to a remembered set
79 // in parallel for sizing buffers to decrease performance losses due to sharing.
80 // Examples are mutator threads together with the concurrent refinement threads
81 // or GC threads.
82 static uint num_par_rem_sets();
83
84 // Initialize data that depends on a known heap size.
85 static void init_heap(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, CardTableModRefBS* ct_bs);
93 ~G1RemSet();
94
95 // Invoke "blk->do_oop" on all pointers into the collection set
96 // from objects in regions outside the collection set (having
97 // invoked "blk->set_region" to set the "from" region correctly
98 // beforehand.)
99 //
100 // Apply non_heap_roots on the oops of the unmarked nmethods
101 // on the strong code roots list for each region in the
102 // collection set.
103 //
104 // The "worker_i" param is for the parallel case where the id
105 // of the worker thread calling this function can be helpful in
106 // partitioning the work to be done. It should be the same as
107 // the "i" passed to the calling thread's work(i) function.
108 // In the sequential case this param will be ignored.
109 //
110 // Returns the number of cards scanned while looking for pointers
111 // into the collection set.
112 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
113 CodeBlobClosure* heap_region_codeblobs,
114 uint worker_i);
115
116 // Prepare for and cleanup after an oops_into_collection_set_do
117 // call. Must call each of these once before and after (in sequential
118 // code) any threads call oops_into_collection_set_do. (This offers an
119 // opportunity to sequential setup and teardown of structures needed by a
120 // parallel iteration over the CS's RS.)
121 void prepare_for_oops_into_collection_set_do();
122 void cleanup_after_oops_into_collection_set_do();
123
124 size_t scanRS(G1ParPushHeapRSClosure* oc,
125 CodeBlobClosure* heap_region_codeblobs,
126 uint worker_i);
127
128 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
129
130 CardTableModRefBS* ct_bs() { return _ct_bs; }
131
132 // Record, if necessary, the fact that *p (where "p" is in region "from",
133 // which is required to be non-NULL) has changed to a new non-NULL value.
134 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
135
136 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
137 // or card, respectively, such that a region or card with a corresponding
138 // 0 bit contains no part of any live object. Eliminates any remembered
139 // set entries that correspond to dead heap ranges. "worker_num" is the
140 // parallel thread id of the current thread, and "hrclaimer" is the
141 // HeapRegionClaimer that should be used.
142 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
143
144 // Refine the card corresponding to "card_ptr".
145 // If check_for_refs_into_cset is true, a true result is returned
146 // if the given card contains oops that have references into the
147 // current collection set.
148 virtual bool refine_card(jbyte* card_ptr,
149 uint worker_i,
150 bool check_for_refs_into_cset);
151
152 // Print accumulated summary info from the start of the VM.
153 virtual void print_summary_info();
154
155 // Print accumulated summary info from the last time called.
156 virtual void print_periodic_summary_info(const char* header, uint period_count);
157
158 // Prepare remembered set for verification.
159 virtual void prepare_for_verify();
160
161 size_t conc_refine_cards() const {
162 return _conc_refine_cards;
163 }
164 };
165
166 class ScanRSClosure : public HeapRegionClosure {
167 size_t _cards_done, _cards;
168 G1CollectedHeap* _g1h;
169
170 G1ParPushHeapRSClosure* _oc;
171 CodeBlobClosure* _code_root_cl;
172
173 G1BlockOffsetSharedArray* _bot_shared;
174 G1SATBCardTableModRefBS *_ct_bs;
175
176 double _strong_code_root_scan_time_sec;
177 uint _worker_i;
178 size_t _block_size;
179 bool _try_claimed;
180
181 public:
182 ScanRSClosure(G1ParPushHeapRSClosure* oc,
183 CodeBlobClosure* code_root_cl,
184 uint worker_i);
185
186 bool doHeapRegion(HeapRegion* r);
187
188 double strong_code_root_scan_time_sec() {
189 return _strong_code_root_scan_time_sec;
190 }
191 size_t cards_done() { return _cards_done;}
192 size_t cards_looked_up() { return _cards;}
193 void set_try_claimed() { _try_claimed = true; }
194 private:
195 void scanCard(size_t index, HeapRegion *r);
196 void printCard(HeapRegion* card_region, size_t card_index,
197 HeapWord* card_start);
198 void scan_strong_code_roots(HeapRegion* r);
199 };
200
201 class UpdateRSOopClosure: public ExtendedOopClosure {
202 HeapRegion* _from;
203 G1RemSet* _rs;
204 uint _worker_i;
205
206 template <class T> void do_oop_work(T* p);
207
208 public:
209 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
210 _from(NULL), _rs(rs), _worker_i(worker_i)
211 {}
212
213 void set_from(HeapRegion* from) {
214 assert(from != NULL, "from region must be non-NULL");
215 _from = from;
216 }
217
218 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
219 virtual void do_oop(oop* p) { do_oop_work(p); }
220 };
221
222 #endif // SHARE_VM_GC_G1_G1REMSET_HPP