1 /*
2 * Copyright (c) 2001, 2014, 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
20 * or visit www.oracle.com if you need additional information or have any
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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 class G1ParPushHeapRSClosure;
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 protected:
46 G1CollectedHeap* _g1;
47 size_t _conc_refine_cards;
48 uint n_workers();
49
50 protected:
51 enum SomePrivateConstants {
52 UpdateRStoMergeSync = 0,
53 MergeRStoDoDirtySync = 1,
54 DoDirtySync = 2,
55 LastSync = 3,
56
57 SeqTask = 0,
58 NumSeqTasks = 1
59 };
60
61 CardTableModRefBS* _ct_bs;
62 SubTasksDone* _seq_task;
63 G1CollectorPolicy* _g1p;
64
65 ConcurrentG1Refine* _cg1r;
66
67 size_t* _cards_scanned;
68 size_t _total_cards_scanned;
69
70 // Used for caching the closure that is responsible for scanning
71 // references into the collection set.
72 G1ParPushHeapRSClosure** _cset_rs_update_cl;
73
74 // Print the given summary info
75 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
76 public:
77 // This is called to reset dual hash tables after the gc pause
78 // is finished and the initial hash table is no longer being
79 // scanned.
80 void cleanupHRRS();
81
82 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
83 ~G1RemSet();
84
85 // Invoke "blk->do_oop" on all pointers into the collection set
86 // from objects in regions outside the collection set (having
87 // invoked "blk->set_region" to set the "from" region correctly
88 // beforehand.)
89 //
90 // Invoke code_root_cl->do_code_blob on the unmarked nmethods
91 // on the strong code roots list for each region in the
92 // collection set.
93 //
94 // The "worker_i" param is for the parallel case where the id
95 // of the worker thread calling this function can be helpful in
96 // partitioning the work to be done. It should be the same as
97 // the "i" passed to the calling thread's work(i) function.
98 // In the sequential case this param will be ignored.
99 void oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
100 CodeBlobClosure* code_root_cl,
101 uint worker_i);
102
103 // Prepare for and cleanup after an oops_into_collection_set_do
104 // call. Must call each of these once before and after (in sequential
105 // code) any threads call oops_into_collection_set_do. (This offers an
106 // opportunity to sequential setup and teardown of structures needed by a
107 // parallel iteration over the CS's RS.)
108 void prepare_for_oops_into_collection_set_do();
109 void cleanup_after_oops_into_collection_set_do();
110
111 void scanRS(G1ParPushHeapRSClosure* oc,
112 CodeBlobClosure* code_root_cl,
113 uint worker_i);
114
115 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
116
117 CardTableModRefBS* ct_bs() { return _ct_bs; }
118 size_t cardsScanned() { return _total_cards_scanned; }
119
120 // Record, if necessary, the fact that *p (where "p" is in region "from",
121 // which is required to be non-NULL) has changed to a new non-NULL value.
122 template <class T> void write_ref(HeapRegion* from, T* p);
123 template <class T> void par_write_ref(HeapRegion* from, T* p, int tid);
124
125 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
126 // or card, respectively, such that a region or card with a corresponding
127 // 0 bit contains no part of any live object. Eliminates any remembered
128 // set entries that correspond to dead heap ranges.
129 void scrub(BitMap* region_bm, BitMap* card_bm);
130
131 // Like the above, but assumes is called in parallel: "worker_num" is the
132 // parallel thread id of the current thread, and "claim_val" is the
133 // value that should be used to claim heap regions.
134 void scrub_par(BitMap* region_bm, BitMap* card_bm,
135 uint worker_num, int claim_val);
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 CountNonCleanMemRegionClosure: public MemRegionClosure {
160 G1CollectedHeap* _g1;
161 int _n;
162 HeapWord* _start_first;
163 public:
164 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) :
165 _g1(g1), _n(0), _start_first(NULL)
166 {}
167 void do_MemRegion(MemRegion mr);
168 int n() { return _n; };
169 HeapWord* start_first() { return _start_first; }
170 };
171
172 class UpdateRSOopClosure: public ExtendedOopClosure {
173 HeapRegion* _from;
174 G1RemSet* _rs;
175 uint _worker_i;
176
177 template <class T> void do_oop_work(T* p);
178
179 public:
180 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
181 _from(NULL), _rs(rs), _worker_i(worker_i)
182 {}
183
184 void set_from(HeapRegion* from) {
185 assert(from != NULL, "from region must be non-NULL");
186 _from = from;
187 }
188
189 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
190 virtual void do_oop(oop* p) { do_oop_work(p); }
191
192 // Override: this closure is idempotent.
193 // bool idempotent() { return true; }
194 bool apply_to_weak_ref_discovered_field() { return true; }
195 };
196
197 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP