1 /*
2 * Copyright (c) 2015, 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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_VM_GC_SHARED_CARDTABLEMODREFBSFORCTRS_HPP
26 #define SHARE_VM_GC_SHARED_CARDTABLEMODREFBSFORCTRS_HPP
27
28 #include "gc/shared/cardTableModRefBS.hpp"
29
30 class CardTableRS;
31 class DirtyCardToOopClosure;
32 class OopsInGenClosure;
33
34 // A specialization for the CardTableRS gen rem set.
35 class CardTableModRefBSForCTRS: public CardTableModRefBS {
36 friend class CardTableRS;
37
38 public:
39 CardTableModRefBSForCTRS(MemRegion whole_heap);
40 ~CardTableModRefBSForCTRS();
41
42 virtual void initialize();
43
44 void set_CTRS(CardTableRS* rs) { _rs = rs; }
45
46 virtual bool card_mark_must_follow_store() const {
47 return UseConcMarkSweepGC;
48 }
49
50 virtual bool is_in_young(oop obj) const;
51
52 private:
53 CardTableRS* _rs;
54
55 // *** Support for parallel card scanning.
56
57 // dirty and precleaned are equivalent wrt younger_refs_iter.
58 static bool card_is_dirty_wrt_gen_iter(jbyte cv) {
59 return cv == dirty_card || cv == precleaned_card;
60 }
61
62 // Returns "true" iff the value "cv" will cause the card containing it
63 // to be scanned in the current traversal. May be overridden by
64 // subtypes.
65 bool card_will_be_scanned(jbyte cv);
66
67 // Returns "true" iff the value "cv" may have represented a dirty card at
68 // some point.
69 bool card_may_have_been_dirty(jbyte cv);
70
71 // Iterate over the portion of the card-table which covers the given
72 // region mr in the given space and apply cl to any dirty sub-regions
73 // of mr. Clears the dirty cards as they are processed.
74 void non_clean_card_iterate_possibly_parallel(Space* sp, MemRegion mr,
75 OopsInGenClosure* cl, CardTableRS* ct,
76 uint n_threads);
77
78 // Work method used to implement non_clean_card_iterate_possibly_parallel()
79 // above in the parallel case.
80 void non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,
81 OopsInGenClosure* cl, CardTableRS* ct,
82 uint n_threads);
83
84 // This is an array, one element per covered region of the card table.
85 // Each entry is itself an array, with one element per chunk in the
86 // covered region. Each entry of these arrays is the lowest non-clean
87 // card of the corresponding chunk containing part of an object from the
88 // previous chunk, or else NULL.
89 typedef jbyte* CardPtr;
90 typedef CardPtr* CardArr;
91 CardArr* _lowest_non_clean;
92 size_t* _lowest_non_clean_chunk_size;
93 uintptr_t* _lowest_non_clean_base_chunk_index;
94 volatile int* _last_LNC_resizing_collection;
95
96 // Initializes "lowest_non_clean" to point to the array for the region
97 // covering "sp", and "lowest_non_clean_base_chunk_index" to the chunk
98 // index of the corresponding to the first element of that array.
99 // Ensures that these arrays are of sufficient size, allocating if necessary.
100 // May be called by several threads concurrently.
101 void get_LNC_array_for_space(Space* sp,
102 jbyte**& lowest_non_clean,
103 uintptr_t& lowest_non_clean_base_chunk_index,
104 size_t& lowest_non_clean_chunk_size);
105
106 // Returns the number of chunks necessary to cover "mr".
107 size_t chunks_to_cover(MemRegion mr) {
108 return (size_t)(addr_to_chunk_index(mr.last()) -
109 addr_to_chunk_index(mr.start()) + 1);
110 }
111
112 // Returns the index of the chunk in a stride which
113 // covers the given address.
114 uintptr_t addr_to_chunk_index(const void* addr) {
115 uintptr_t card = (uintptr_t) byte_for(addr);
116 return card / ParGCCardsPerStrideChunk;
117 }
118
119 // Apply cl, which must either itself apply dcto_cl or be dcto_cl,
120 // to the cards in the stride (of n_strides) within the given space.
121 void process_stride(Space* sp,
122 MemRegion used,
123 jint stride, int n_strides,
124 OopsInGenClosure* cl,
125 CardTableRS* ct,
126 jbyte** lowest_non_clean,
127 uintptr_t lowest_non_clean_base_chunk_index,
128 size_t lowest_non_clean_chunk_size);
129
130 // Makes sure that chunk boundaries are handled appropriately, by
131 // adjusting the min_done of dcto_cl, and by using a special card-table
132 // value to indicate how min_done should be set.
133 void process_chunk_boundaries(Space* sp,
134 DirtyCardToOopClosure* dcto_cl,
135 MemRegion chunk_mr,
136 MemRegion used,
137 jbyte** lowest_non_clean,
138 uintptr_t lowest_non_clean_base_chunk_index,
139 size_t lowest_non_clean_chunk_size);
140
141 };
142
143 template<>
144 struct BarrierSet::GetName<CardTableModRefBSForCTRS> {
145 static const BarrierSet::Name value = BarrierSet::CardTableForRS;
146 };
147
148 template<>
149 struct BarrierSet::GetType<BarrierSet::CardTableForRS> {
150 typedef CardTableModRefBSForCTRS type;
151 };
152
153 #endif // SHARE_VM_GC_SHARED_CARDTABLEMODREFBSFORCTRS_HPP