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
37 // A G1RemSet in which each heap region has a rem set that records the
38 // external heap references into it. Uses a mod ref bs to track updates,
39 // so that they can be used to update the individual region remsets.
40
41 class G1RemSet: public CHeapObj<mtGC> {
42 private:
43 G1RemSetSummary _prev_period_summary;
44
45 // A DirtyCardQueueSet that is used to hold cards that contain
46 // references into the current collection set. This is used to
47 // update the remembered sets of the regions in the collection
48 // set in the event of an evacuation failure.
49 DirtyCardQueueSet _into_cset_dirty_card_queue_set;
50
51 protected:
52 G1CollectedHeap* _g1;
53 size_t _conc_refine_cards;
54 uint n_workers();
55
56 protected:
57 enum SomePrivateConstants {
58 UpdateRStoMergeSync = 0,
59 MergeRStoDoDirtySync = 1,
60 DoDirtySync = 2,
61 LastSync = 3,
62
63 SeqTask = 0,
64 NumSeqTasks = 1
65 };
66
67 CardTableModRefBS* _ct_bs;
68 G1CollectorPolicy* _g1p;
69
70 ConcurrentG1Refine* _cg1r;
71
72 // Used for caching the closure that is responsible for scanning
73 // references into the collection set.
74 G1ParPushHeapRSClosure** _cset_rs_update_cl;
75
76 // Print the given summary info
77 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
78 public:
79 // This is called to reset dual hash tables after the gc pause
80 // is finished and the initial hash table is no longer being
81 // scanned.
82 void cleanupHRRS();
83
84 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
85 ~G1RemSet();
86
87 // Invoke "blk->do_oop" on all pointers into the collection set
88 // from objects in regions outside the collection set (having
89 // invoked "blk->set_region" to set the "from" region correctly
90 // beforehand.)
91 //
92 // Apply non_heap_roots on the oops of the unmarked nmethods
93 // on the strong code roots list for each region in the
94 // collection set.
95 //
96 // The "worker_i" param is for the parallel case where the id
97 // of the worker thread calling this function can be helpful in
98 // partitioning the work to be done. It should be the same as
99 // the "i" passed to the calling thread's work(i) function.
100 // In the sequential case this param will be ignored.
101 //
102 // Returns the number of cards scanned while looking for pointers
103 // into the collection set.
104 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
105 CodeBlobClosure* heap_region_codeblobs,
106 uint worker_i);
107
108 // Prepare for and cleanup after an oops_into_collection_set_do
109 // call. Must call each of these once before and after (in sequential
110 // code) any threads call oops_into_collection_set_do. (This offers an
111 // opportunity to sequential setup and teardown of structures needed by a
112 // parallel iteration over the CS's RS.)
113 void prepare_for_oops_into_collection_set_do();
114 void cleanup_after_oops_into_collection_set_do();
115
116 size_t scanRS(G1ParPushHeapRSClosure* oc,
117 CodeBlobClosure* heap_region_codeblobs,
118 uint worker_i);
119
120 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
121
122 CardTableModRefBS* ct_bs() { return _ct_bs; }
123
124 // Record, if necessary, the fact that *p (where "p" is in region "from",
125 // which is required to be non-NULL) has changed to a new non-NULL value.
126 template <class T> void write_ref(HeapRegion* from, T* p);
127 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
128
129 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
130 // or card, respectively, such that a region or card with a corresponding
131 // 0 bit contains no part of any live object. Eliminates any remembered
132 // set entries that correspond to dead heap ranges. "worker_num" is the
133 // parallel thread id of the current thread, and "hrclaimer" is the
134 // HeapRegionClaimer that should be used.
135 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
136
137 // Refine the card corresponding to "card_ptr".
138 // If check_for_refs_into_cset is true, a true result is returned
139 // if the given card contains oops that have references into the
140 // current collection set.
141 virtual bool refine_card(jbyte* card_ptr,
142 uint worker_i,
143 bool check_for_refs_into_cset);
144
145 // Print accumulated summary info from the start of the VM.
146 virtual void print_summary_info();
147
148 // Print accumulated summary info from the last time called.
149 virtual void print_periodic_summary_info(const char* header);
150
151 // Prepare remembered set for verification.
152 virtual void prepare_for_verify();
153
154 size_t conc_refine_cards() const {
155 return _conc_refine_cards;
156 }
157 };
158
159 class UpdateRSOopClosure: public ExtendedOopClosure {
160 HeapRegion* _from;
161 G1RemSet* _rs;
162 uint _worker_i;
163
164 template <class T> void do_oop_work(T* p);
165
166 public:
167 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
168 _from(NULL), _rs(rs), _worker_i(worker_i)
169 {}
170
171 void set_from(HeapRegion* from) {
172 assert(from != NULL, "from region must be non-NULL");
173 _from = from;
174 }
175
176 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
177 virtual void do_oop(oop* p) { do_oop_work(p); }
178
179 // Override: this closure is idempotent.
180 // bool idempotent() { return true; }
181 bool apply_to_weak_ref_discovered_field() { return true; }
182 };
183
184 #endif // SHARE_VM_GC_G1_G1REMSET_HPP