1 /*
2 * Copyright (c) 2001, 2018, 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_G1_G1SATBCARDTABLEMODREFBS_HPP
26 #define SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP
27
28 #include "gc/g1/g1RegionToSpaceMapper.hpp"
29 #include "gc/shared/cardTableModRefBS.hpp"
30 #include "memory/memRegion.hpp"
31 #include "oops/oop.hpp"
32 #include "utilities/macros.hpp"
33
34 class DirtyCardQueueSet;
35 class G1SATBCardTableLoggingModRefBS;
36
37 // This barrier is specialized to use a logging barrier to support
38 // snapshot-at-the-beginning marking.
39
40 class G1SATBCardTableModRefBS: public CardTableModRefBS {
41 friend class VMStructs;
42 protected:
43 enum G1CardValues {
44 g1_young_gen = CT_MR_BS_last_reserved << 1
45 };
46
47 G1SATBCardTableModRefBS(MemRegion whole_heap, const BarrierSet::FakeRtti& fake_rtti);
48 ~G1SATBCardTableModRefBS() { }
49
50 public:
51 static int g1_young_card_val() { return g1_young_gen; }
52
53 // Add "pre_val" to a set of objects that may have been disconnected from the
54 // pre-marking object graph.
55 static void enqueue(oop pre_val);
56
57 static void enqueue_if_weak_or_archive(DecoratorSet decorators, oop value);
58
59 template <class T> void write_ref_array_pre_work(T* dst, int count);
60 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);
61 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);
62
63 template <DecoratorSet decorators, typename T>
64 void write_ref_field_pre(T* field);
65
66 /*
67 Claimed and deferred bits are used together in G1 during the evacuation
68 pause. These bits can have the following state transitions:
69 1. The claimed bit can be put over any other card state. Except that
70 the "dirty -> dirty and claimed" transition is checked for in
71 G1 code and is not used.
72 2. Deferred bit can be set only if the previous state of the card
73 was either clean or claimed. mark_card_deferred() is wait-free.
74 We do not care if the operation is be successful because if
75 it does not it will only result in duplicate entry in the update
76 buffer because of the "cache-miss". So it's not worth spinning.
77 */
78
79 bool is_card_claimed(size_t card_index) {
80 jbyte val = _byte_map[card_index];
81 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val();
82 }
83
84 inline void set_card_claimed(size_t card_index);
85
86 void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN;
87 void g1_mark_as_young(const MemRegion& mr);
88
89 bool mark_card_deferred(size_t card_index);
90
91 bool is_card_deferred(size_t card_index) {
92 jbyte val = _byte_map[card_index];
93 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
94 }
95
96 virtual bool is_in_young(oop obj) const;
97 };
98
99 template<>
100 struct BarrierSet::GetName<G1SATBCardTableModRefBS> {
101 static const BarrierSet::Name value = BarrierSet::G1SATBCT;
102 };
103
104 template<>
105 struct BarrierSet::GetType<BarrierSet::G1SATBCT> {
106 typedef G1SATBCardTableModRefBS type;
107 };
108
109 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener {
110 private:
111 G1SATBCardTableLoggingModRefBS* _card_table;
112 public:
113 G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { }
114
115 void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; }
116
117 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
118 };
119
120 // Adds card-table logging to the post-barrier.
121 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
122 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
123 friend class G1SATBCardTableLoggingModRefBSChangedListener;
124 private:
125 G1SATBCardTableLoggingModRefBSChangedListener _listener;
126 DirtyCardQueueSet& _dcqs;
127
128 public:
129 static size_t compute_size(size_t mem_region_size_in_words) {
130 size_t number_of_slots = (mem_region_size_in_words / card_size_in_words);
131 return ReservedSpace::allocation_align_size_up(number_of_slots);
132 }
133
134 // Returns how many bytes of the heap a single byte of the Card Table corresponds to.
135 static size_t heap_map_factor() {
136 return CardTableModRefBS::card_size;
137 }
138
139 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap);
140
141 virtual void initialize() { }
142 virtual void initialize(G1RegionToSpaceMapper* mapper);
143
144 virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); }
145
146 // NB: if you do a whole-heap invalidation, the "usual invariant" defined
147 // above no longer applies.
148 void invalidate(MemRegion mr);
149
150 void write_region(MemRegion mr) { invalidate(mr); }
151 void write_ref_array_work(MemRegion mr) { invalidate(mr); }
152
153 template <DecoratorSet decorators, typename T>
154 void write_ref_field_post(T* field, oop new_val);
155 void write_ref_field_post_slow(volatile jbyte* byte);
156
157 virtual void flush_deferred_barriers(JavaThread* thread);
158
159 virtual bool card_mark_must_follow_store() const {
160 return true;
161 }
162
163 // Callbacks for runtime accesses.
164 template <DecoratorSet decorators, typename BarrierSetT = G1SATBCardTableLoggingModRefBS>
165 class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {
166 typedef ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> ModRef;
167 typedef BarrierSet::AccessBarrier<decorators, BarrierSetT> Raw;
168
169 public:
170 // Needed for loads on non-heap weak references
171 template <typename T>
172 static oop oop_load_not_in_heap(T* addr);
173
174 // Needed for non-heap stores
175 template <typename T>
176 static void oop_store_not_in_heap(T* addr, oop new_value);
177
178 // Needed for weak references
179 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset);
180
181 // Defensive: will catch weak oops at addresses in heap
182 template <typename T>
183 static oop oop_load_in_heap(T* addr);
184 };
185 };
186
187 template<>
188 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> {
189 static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging;
190 };
191
192 template<>
193 struct BarrierSet::GetType<BarrierSet::G1SATBCTLogging> {
194 typedef G1SATBCardTableLoggingModRefBS type;
195 };
196
197 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP