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/g1RemSetSummary.hpp"
29
30 // A G1RemSet provides ways of iterating over pointers into a selected
31 // collection set.
32
33 class G1CollectedHeap;
34 class ConcurrentG1Refine;
35 class G1ParPushHeapRSClosure;
36 class outputStream;
37
38 // A G1RemSet in which each heap region has a rem set that records the
39 // external heap references into it. Uses a mod ref bs to track updates,
40 // so that they can be used to update the individual region remsets.
41
42 class G1RemSet: public CHeapObj<mtGC> {
43 private:
44 G1RemSetSummary _prev_period_summary;
45
46 // A DirtyCardQueueSet that is used to hold cards that contain
47 // references into the current collection set. This is used to
48 // update the remembered sets of the regions in the collection
49 // set in the event of an evacuation failure.
50 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
51
52 protected:
53 G1CollectedHeap* _g1;
54 size_t _conc_refine_cards;
55 uint n_workers();
56
57 protected:
58 CardTableModRefBS* _ct_bs;
59 G1CollectorPolicy* _g1p;
60
61 ConcurrentG1Refine* _cg1r;
62
63 // Used for caching the closure that is responsible for scanning
64 // references into the collection set.
65 G1ParPushHeapRSClosure** _cset_rs_update_cl;
66
67 public:
68 // This is called to reset dual hash tables after the gc pause
69 // is finished and the initial hash table is no longer being
70 // scanned.
71 void cleanupHRRS();
72
73 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
74 ~G1RemSet();
75
76 // Invoke "blk->do_oop" on all pointers into the collection set
77 // from objects in regions outside the collection set (having
78 // invoked "blk->set_region" to set the "from" region correctly
79 // beforehand.)
80 //
81 // Apply non_heap_roots on the oops of the unmarked nmethods
82 // on the strong code roots list for each region in the
83 // collection set.
84 //
85 // The "worker_i" param is for the parallel case where the id
86 // of the worker thread calling this function can be helpful in
87 // partitioning the work to be done. It should be the same as
88 // the "i" passed to the calling thread's work(i) function.
89 // In the sequential case this param will be ignored.
90 //
91 // Returns the number of cards scanned while looking for pointers
92 // into the collection set.
93 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
94 CodeBlobClosure* heap_region_codeblobs,
95 uint worker_i);
96
97 // Prepare for and cleanup after an oops_into_collection_set_do
98 // call. Must call each of these once before and after (in sequential
99 // code) any threads call oops_into_collection_set_do. (This offers an
100 // opportunity to sequential setup and teardown of structures needed by a
101 // parallel iteration over the CS's RS.)
102 void prepare_for_oops_into_collection_set_do();
103 void cleanup_after_oops_into_collection_set_do();
104
105 size_t scanRS(G1ParPushHeapRSClosure* oc,
106 CodeBlobClosure* heap_region_codeblobs,
107 uint worker_i);
108
109 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
110
111 CardTableModRefBS* ct_bs() { return _ct_bs; }
112
113 // Record, if necessary, the fact that *p (where "p" is in region "from",
114 // which is required to be non-NULL) has changed to a new non-NULL value.
115 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
116
117 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
118 // or card, respectively, such that a region or card with a corresponding
119 // 0 bit contains no part of any live object. Eliminates any remembered
120 // set entries that correspond to dead heap ranges. "worker_num" is the
121 // parallel thread id of the current thread, and "hrclaimer" is the
122 // HeapRegionClaimer that should be used.
123 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
124
125 // Refine the card corresponding to "card_ptr".
126 // If check_for_refs_into_cset is true, a true result is returned
127 // if the given card contains oops that have references into the
128 // current collection set.
129 virtual bool refine_card(jbyte* card_ptr,
130 uint worker_i,
131 bool check_for_refs_into_cset);
132
133 // Print accumulated summary info from the start of the VM.
134 virtual void print_summary_info();
135
136 // Print accumulated summary info from the last time called.
137 virtual void print_periodic_summary_info(const char* header, uint period_count);
138
139 // Prepare remembered set for verification.
140 virtual void prepare_for_verify();
141
142 size_t conc_refine_cards() const {
143 return _conc_refine_cards;
144 }
145 };
146
147 class ScanRSClosure : public HeapRegionClosure {
148 size_t _cards_done, _cards;
149 G1CollectedHeap* _g1h;
150
151 G1ParPushHeapRSClosure* _oc;
152 CodeBlobClosure* _code_root_cl;
153
154 G1BlockOffsetSharedArray* _bot_shared;
155 G1SATBCardTableModRefBS *_ct_bs;
156
157 double _strong_code_root_scan_time_sec;
158 uint _worker_i;
159 size_t _block_size;
160 bool _try_claimed;
161
162 public:
163 ScanRSClosure(G1ParPushHeapRSClosure* oc,
164 CodeBlobClosure* code_root_cl,
165 uint worker_i);
166
167 bool doHeapRegion(HeapRegion* r);
168
169 double strong_code_root_scan_time_sec() {
170 return _strong_code_root_scan_time_sec;
171 }
172 size_t cards_done() { return _cards_done;}
173 size_t cards_looked_up() { return _cards;}
174 void set_try_claimed() { _try_claimed = true; }
175 private:
176 void scanCard(size_t index, HeapRegion *r);
177 void printCard(HeapRegion* card_region, size_t card_index,
178 HeapWord* card_start);
179 void scan_strong_code_roots(HeapRegion* r);
180 };
181
182 class UpdateRSOopClosure: public ExtendedOopClosure {
183 HeapRegion* _from;
184 G1RemSet* _rs;
185 uint _worker_i;
186
187 template <class T> void do_oop_work(T* p);
188
189 public:
190 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
191 _from(NULL), _rs(rs), _worker_i(worker_i)
192 {}
193
194 void set_from(HeapRegion* from) {
195 assert(from != NULL, "from region must be non-NULL");
196 _from = from;
197 }
198
199 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
200 virtual void do_oop(oop* p) { do_oop_work(p); }
201
202 // Override: this closure is idempotent.
203 // bool idempotent() { return true; }
204 bool apply_to_weak_ref_discovered_field() { return true; }
205 };
206
207 #endif // SHARE_VM_GC_G1_G1REMSET_HPP