1 /*
2 * Copyright (c) 2001, 2013, 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_IMPLEMENTATION_G1_G1REMSET_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP
27
28 #include "gc_implementation/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 CardTableModRefBarrierSet;
35 class ConcurrentG1Refine;
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 _last_period_summary;
44 protected:
45 G1CollectedHeap* _g1;
46 size_t _conc_refine_cards;
47 uint n_workers();
48
49 protected:
50 enum SomePrivateConstants {
51 UpdateRStoMergeSync = 0,
52 MergeRStoDoDirtySync = 1,
53 DoDirtySync = 2,
54 LastSync = 3,
55
56 SeqTask = 0,
57 NumSeqTasks = 1
58 };
59
60 CardTableModRefBS* _ct_bs;
61 SubTasksDone* _seq_task;
62 G1CollectorPolicy* _g1p;
63
64 ConcurrentG1Refine* _cg1r;
65
66 size_t* _cards_scanned;
67 size_t _total_cards_scanned;
68
69 // Used for caching the closure that is responsible for scanning
70 // references into the collection set.
71 OopsInHeapRegionClosure** _cset_rs_update_cl;
72
73 // Print the given summary info
74 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
75 public:
76 // This is called to reset dual hash tables after the gc pause
77 // is finished and the initial hash table is no longer being
78 // scanned.
79 void cleanupHRRS();
80
81 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
82 ~G1RemSet();
83
84 // Invoke "blk->do_oop" on all pointers into the CS in objects in regions
85 // outside the CS (having invoked "blk->set_region" to set the "from"
86 // region correctly beforehand.) The "worker_i" param is for the
87 // parallel case where the number of the worker thread calling this
88 // function can be helpful in partitioning the work to be done. It
89 // should be the same as the "i" passed to the calling thread's
90 // work(i) function. In the sequential case this param will be ingored.
91 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, int worker_i);
92
93 // Prepare for and cleanup after an oops_into_collection_set_do
94 // call. Must call each of these once before and after (in sequential
95 // code) any threads call oops_into_collection_set_do. (This offers an
96 // opportunity to sequential setup and teardown of structures needed by a
97 // parallel iteration over the CS's RS.)
98 void prepare_for_oops_into_collection_set_do();
99 void cleanup_after_oops_into_collection_set_do();
100
101 void scanRS(OopsInHeapRegionClosure* oc, int worker_i);
102 void updateRS(DirtyCardQueue* into_cset_dcq, int worker_i);
103
104 CardTableModRefBS* ct_bs() { return _ct_bs; }
105 size_t cardsScanned() { return _total_cards_scanned; }
106
107 // Record, if necessary, the fact that *p (where "p" is in region "from",
108 // which is required to be non-NULL) has changed to a new non-NULL value.
109 template <class T> void write_ref(HeapRegion* from, T* p);
110 template <class T> void par_write_ref(HeapRegion* from, T* p, int tid);
111
112 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
113 // or card, respectively, such that a region or card with a corresponding
114 // 0 bit contains no part of any live object. Eliminates any remembered
115 // set entries that correspond to dead heap ranges.
116 void scrub(BitMap* region_bm, BitMap* card_bm);
117
118 // Like the above, but assumes is called in parallel: "worker_num" is the
119 // parallel thread id of the current thread, and "claim_val" is the
120 // value that should be used to claim heap regions.
121 void scrub_par(BitMap* region_bm, BitMap* card_bm,
122 uint worker_num, int claim_val);
123
124 // Refine the card corresponding to "card_ptr".
125 // If check_for_refs_into_cset is true, a true result is returned
126 // if the given card contains oops that have references into the
127 // current collection set.
128 virtual bool refine_card(jbyte* card_ptr,
129 int worker_i,
130 bool check_for_refs_into_cset);
131
132 // Print accumulated summary info from the start of the VM.
133 virtual void print_summary_info();
134
135 // Print accumulated summary info from the last time called.
136 virtual void print_periodic_summary_info();
137
138 // Prepare remembered set for verification.
139 virtual void prepare_for_verify();
140
141 size_t conc_refine_cards() const {
142 return _conc_refine_cards;
143 }
144 };
145
146 class CountNonCleanMemRegionClosure: public MemRegionClosure {
147 G1CollectedHeap* _g1;
148 int _n;
149 HeapWord* _start_first;
150 public:
151 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) :
152 _g1(g1), _n(0), _start_first(NULL)
153 {}
154 void do_MemRegion(MemRegion mr);
155 int n() { return _n; };
156 HeapWord* start_first() { return _start_first; }
157 };
158
159 class UpdateRSOopClosure: public ExtendedOopClosure {
160 HeapRegion* _from;
161 G1RemSet* _rs;
162 int _worker_i;
163
164 template <class T> void do_oop_work(T* p);
165
166 public:
167 UpdateRSOopClosure(G1RemSet* rs, int 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 class UpdateRSetImmediate: public OopsInHeapRegionClosure {
185 private:
186 G1RemSet* _g1_rem_set;
187
188 template <class T> void do_oop_work(T* p);
189 public:
190 UpdateRSetImmediate(G1RemSet* rs) :
191 _g1_rem_set(rs) {}
192
193 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
194 virtual void do_oop( oop* p) { do_oop_work(p); }
195 };
196
197
198 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP