1 /*
2 * Copyright (c) 2001, 2017, 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(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
97 template<>
98 struct BarrierSet::GetName<G1SATBCardTableModRefBS> {
99 static const BarrierSet::Name value = BarrierSet::G1SATBCT;
100 };
101
102 template<>
103 struct BarrierSet::GetType<BarrierSet::G1SATBCT> {
104 typedef G1SATBCardTableModRefBS type;
105 };
106
107 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener {
108 private:
109 G1SATBCardTableLoggingModRefBS* _card_table;
110 public:
111 G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { }
112
113 void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; }
114
115 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
116 };
117
118 // Adds card-table logging to the post-barrier.
119 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
120 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
121 friend class G1SATBCardTableLoggingModRefBSChangedListener;
122 private:
123 G1SATBCardTableLoggingModRefBSChangedListener _listener;
124 DirtyCardQueueSet& _dcqs;
125
126 public:
127 static size_t compute_size(size_t mem_region_size_in_words) {
128 size_t number_of_slots = (mem_region_size_in_words / card_size_in_words);
129 return ReservedSpace::allocation_align_size_up(number_of_slots);
130 }
131
132 // Returns how many bytes of the heap a single byte of the Card Table corresponds to.
133 static size_t heap_map_factor() {
134 return CardTableModRefBS::card_size;
135 }
136
137 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap);
138
139 virtual void initialize() { }
140 virtual void initialize(G1RegionToSpaceMapper* mapper);
141
142 virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); }
143
144 // NB: if you do a whole-heap invalidation, the "usual invariant" defined
145 // above no longer applies.
146 void invalidate(MemRegion mr);
147
148 void write_region_work(MemRegion mr) { invalidate(mr); }
149 void write_ref_array_work(MemRegion mr) { invalidate(mr); }
150
151 template <DecoratorSet decorators, typename T>
152 void write_ref_field_post(T* field, oop new_val);
153 void write_ref_field_post_slow(volatile jbyte* byte);
154
155 // Callbacks for runtime accesses.
156 template <DecoratorSet decorators, typename BarrierSetT = G1SATBCardTableLoggingModRefBS>
157 class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {
158 typedef ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> ModRef;
159 typedef BarrierSet::AccessBarrier<decorators, BarrierSetT> Raw;
160
161 public:
162 // Needed for loads on non-heap weak references
163 template <typename T>
164 static oop oop_load_not_in_heap(T* addr);
165
166 // Needed for non-heap stores
167 template <typename T>
168 static void oop_store_not_in_heap(T* addr, oop new_value);
169
170 // Needed for weak references
171 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset);
172
173 // Defensive: will catch weak oops at addresses in heap
174 template <typename T>
175 static oop oop_load_in_heap(T* addr);
176 };
177 };
178
179 template<>
180 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> {
181 static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging;
182 };
183
184 template<>
185 struct BarrierSet::GetType<BarrierSet::G1SATBCTLogging> {
186 typedef G1SATBCardTableLoggingModRefBS type;
187 };
188
189 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP