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.
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.
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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 enum SomePrivateConstants {
59 UpdateRStoMergeSync = 0,
60 MergeRStoDoDirtySync = 1,
61 DoDirtySync = 2,
62 LastSync = 3,
63
64 SeqTask = 0,
65 NumSeqTasks = 1
66 };
67
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 // This is called to reset dual hash tables after the gc pause
79 // is finished and the initial hash table is no longer being
80 // scanned.
81 void cleanupHRRS();
82
83 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
84 ~G1RemSet();
85
86 // Invoke "blk->do_oop" on all pointers into the collection set
87 // from objects in regions outside the collection set (having
88 // invoked "blk->set_region" to set the "from" region correctly
89 // beforehand.)
90 //
91 // Apply non_heap_roots on the oops of the unmarked nmethods
92 // on the strong code roots list for each region in the
93 // collection set.
94 //
95 // The "worker_i" param is for the parallel case where the id
96 // of the worker thread calling this function can be helpful in
97 // partitioning the work to be done. It should be the same as
98 // the "i" passed to the calling thread's work(i) function.
99 // In the sequential case this param will be ignored.
100 //
101 // Returns the number of cards scanned while looking for pointers
102 // into the collection set.
103 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
104 CodeBlobClosure* heap_region_codeblobs,
105 uint worker_i);
106
107 // Prepare for and cleanup after an oops_into_collection_set_do
108 // call. Must call each of these once before and after (in sequential
109 // code) any threads call oops_into_collection_set_do. (This offers an
110 // opportunity to sequential setup and teardown of structures needed by a
111 // parallel iteration over the CS's RS.)
112 void prepare_for_oops_into_collection_set_do();
113 void cleanup_after_oops_into_collection_set_do();
114
115 size_t scanRS(G1ParPushHeapRSClosure* oc,
116 CodeBlobClosure* heap_region_codeblobs,
117 uint worker_i);
118
119 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
120
121 CardTableModRefBS* ct_bs() { return _ct_bs; }
122
123 // Record, if necessary, the fact that *p (where "p" is in region "from",
124 // which is required to be non-NULL) has changed to a new non-NULL value.
125 template <class T> void write_ref(HeapRegion* from, T* p);
126 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
127
128 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
129 // or card, respectively, such that a region or card with a corresponding
130 // 0 bit contains no part of any live object. Eliminates any remembered
131 // set entries that correspond to dead heap ranges. "worker_num" is the
132 // parallel thread id of the current thread, and "hrclaimer" is the
133 // HeapRegionClaimer that should be used.
134 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
135
136 // Refine the card corresponding to "card_ptr".
137 // If check_for_refs_into_cset is true, a true result is returned
138 // if the given card contains oops that have references into the
139 // current collection set.
140 virtual bool refine_card(jbyte* card_ptr,
141 uint worker_i,
142 bool check_for_refs_into_cset);
143
144 // Print accumulated summary info from the start of the VM.
145 virtual void print_summary_info();
146
147 // Print accumulated summary info from the last time called.
148 virtual void print_periodic_summary_info(const char* header, uint period_count);
149
150 // Prepare remembered set for verification.
151 virtual void prepare_for_verify();
152
153 size_t conc_refine_cards() const {
154 return _conc_refine_cards;
155 }
156 };
157
158 class UpdateRSOopClosure: public ExtendedOopClosure {
159 HeapRegion* _from;
160 G1RemSet* _rs;
161 uint _worker_i;
162
163 template <class T> void do_oop_work(T* p);
164
165 public:
166 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
167 _from(NULL), _rs(rs), _worker_i(worker_i)
168 {}
169
170 void set_from(HeapRegion* from) {
171 assert(from != NULL, "from region must be non-NULL");
172 _from = from;
173 }
174
175 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
176 virtual void do_oop(oop* p) { do_oop_work(p); }
177
178 // Override: this closure is idempotent.
179 // bool idempotent() { return true; }
180 bool apply_to_weak_ref_discovered_field() { return true; }
181 };
182
183 #endif // SHARE_VM_GC_G1_G1REMSET_HPP