1 /*
2 * Copyright (c) 2001, 2011, 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_G1SATBCARDTABLEMODREFBS_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP
27
28 #include "memory/cardTableModRefBS.hpp"
29 #include "memory/memRegion.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "utilities/macros.hpp"
32
33 #if INCLUDE_ALL_GCS
34
35 class DirtyCardQueueSet;
36
37 // This barrier is specialized to use a logging barrier to support
38 // snapshot-at-the-beginning marking.
39
40 class G1SATBCardTableModRefBS: public CardTableModRefBSForCTRS {
41 protected:
42 enum G1CardValues {
43 g1_young_gen = CT_MR_BS_last_reserved << 1
44 };
45
46 public:
47 static int g1_young_card_val() { return g1_young_gen; }
48
49 // Add "pre_val" to a set of objects that may have been disconnected from the
50 // pre-marking object graph.
51 static void enqueue(oop pre_val);
52
53 G1SATBCardTableModRefBS(MemRegion whole_heap,
54 int max_covered_regions);
55
56 bool is_a(BarrierSet::Name bsn) {
57 return bsn == BarrierSet::G1SATBCT || CardTableModRefBS::is_a(bsn);
58 }
59
60 virtual bool has_write_ref_pre_barrier() { return true; }
61
62 // This notes that we don't need to access any BarrierSet data
63 // structures, so this can be called from a static context.
64 template <class T> static void write_ref_field_pre_static(T* field, oop newVal) {
65 T heap_oop = oopDesc::load_heap_oop(field);
66 if (!oopDesc::is_null(heap_oop)) {
67 enqueue(oopDesc::decode_heap_oop(heap_oop));
68 }
69 }
70
71 // We export this to make it available in cases where the static
72 // type of the barrier set is known. Note that it is non-virtual.
73 template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) {
74 write_ref_field_pre_static(field, newVal);
75 }
76
77 // These are the more general virtual versions.
78 virtual void write_ref_field_pre_work(oop* field, oop new_val) {
79 inline_write_ref_field_pre(field, new_val);
80 }
81 virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {
82 inline_write_ref_field_pre(field, new_val);
83 }
84 virtual void write_ref_field_pre_work(void* field, oop new_val) {
85 guarantee(false, "Not needed");
86 }
87
88 template <class T> void write_ref_array_pre_work(T* dst, int count);
89 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
90 if (!dest_uninitialized) {
91 write_ref_array_pre_work(dst, count);
92 }
93 }
94 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
95 if (!dest_uninitialized) {
96 write_ref_array_pre_work(dst, count);
97 }
98 }
99
100 /*
101 Claimed and deferred bits are used together in G1 during the evacuation
102 pause. These bits can have the following state transitions:
103 1. The claimed bit can be put over any other card state. Except that
104 the "dirty -> dirty and claimed" transition is checked for in
105 G1 code and is not used.
106 2. Deferred bit can be set only if the previous state of the card
107 was either clean or claimed. mark_card_deferred() is wait-free.
108 We do not care if the operation is be successful because if
109 it does not it will only result in duplicate entry in the update
110 buffer because of the "cache-miss". So it's not worth spinning.
111 */
112
113 bool is_card_claimed(size_t card_index) {
114 jbyte val = _byte_map[card_index];
115 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val();
116 }
117
118 void set_card_claimed(size_t card_index) {
119 jbyte val = _byte_map[card_index];
120 if (val == clean_card_val()) {
121 val = (jbyte)claimed_card_val();
122 } else {
123 val |= (jbyte)claimed_card_val();
124 }
125 _byte_map[card_index] = val;
126 }
127
128 void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN;
129 void g1_mark_as_young(const MemRegion& mr);
130
131 bool mark_card_deferred(size_t card_index);
132
133 bool is_card_deferred(size_t card_index) {
134 jbyte val = _byte_map[card_index];
135 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
136 }
137
138 };
139
140 // Adds card-table logging to the post-barrier.
141 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
142 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
143 private:
144 DirtyCardQueueSet& _dcqs;
145 public:
146 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap,
147 int max_covered_regions);
148
149 bool is_a(BarrierSet::Name bsn) {
150 return bsn == BarrierSet::G1SATBCTLogging ||
151 G1SATBCardTableModRefBS::is_a(bsn);
152 }
153
154 void write_ref_field_work(void* field, oop new_val);
155
156 // Can be called from static contexts.
157 static void write_ref_field_static(void* field, oop new_val);
158
159 // NB: if you do a whole-heap invalidation, the "usual invariant" defined
160 // above no longer applies.
161 void invalidate(MemRegion mr, bool whole_heap = false);
162
163 void write_region_work(MemRegion mr) { invalidate(mr); }
164 void write_ref_array_work(MemRegion mr) { invalidate(mr); }
165
166
167 };
168
169
170 #endif // INCLUDE_ALL_GCS
171
172 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP