1 #ifdef USE_PRAGMA_IDENT_HDR
2 #pragma ident "@(#)cardTableRS.hpp 1.29 07/05/05 17:05:44 JVM"
3 #endif
4 /*
5 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 class Space;
29 class OopsInGenClosure;
30 class DirtyCardToOopClosure;
31
32 // This kind of "GenRemSet" uses a card table both as shared data structure
33 // for a mod ref barrier set and for the rem set information.
34
35 class CardTableRS: public GenRemSet {
36 friend class VMStructs;
37 // Below are private classes used in impl.
38 friend class VerifyCTSpaceClosure;
39 friend class ClearNoncleanCardWrapper;
40
41 static jbyte clean_card_val() {
42 return CardTableModRefBS::clean_card;
43 }
44
45 static bool
46 card_is_dirty_wrt_gen_iter(jbyte cv) {
47 return CardTableModRefBS::card_is_dirty_wrt_gen_iter(cv);
48 }
49
50 CardTableModRefBSForCTRS* _ct_bs;
51
52 virtual void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl);
53
54 void verify_space(Space* s, HeapWord* gen_start);
55
56 enum ExtendedCardValue {
57 youngergen_card = CardTableModRefBS::CT_MR_BS_last_reserved + 1,
58 // These are for parallel collection.
59 // There are three P (parallel) youngergen card values. In general, this
60 // needs to be more than the number of generations (including the perm
61 // gen) that might have younger_refs_do invoked on them separately. So
62 // if we add more gens, we have to add more values.
63 youngergenP1_card = CardTableModRefBS::CT_MR_BS_last_reserved + 2,
64 youngergenP2_card = CardTableModRefBS::CT_MR_BS_last_reserved + 3,
65 youngergenP3_card = CardTableModRefBS::CT_MR_BS_last_reserved + 4,
66 cur_youngergen_and_prev_nonclean_card =
67 CardTableModRefBS::CT_MR_BS_last_reserved + 5
68 };
69
70 // An array that contains, for each generation, the card table value last
71 // used as the current value for a younger_refs_do iteration of that
72 // portion of the table. (The perm gen is index 0; other gens are at
73 // their level plus 1. They youngest gen is in the table, but will
74 // always have the value "clean_card".)
75 jbyte* _last_cur_val_in_gen;
76
77 jbyte _cur_youngergen_card_val;
78
79 int _regions_to_iterate;
80
81 jbyte cur_youngergen_card_val() {
82 return _cur_youngergen_card_val;
83 }
84 void set_cur_youngergen_card_val(jbyte v) {
85 _cur_youngergen_card_val = v;
86 }
87 bool is_prev_youngergen_card_val(jbyte v) {
88 return
89 youngergen_card <= v &&
90 v < cur_youngergen_and_prev_nonclean_card &&
91 v != _cur_youngergen_card_val;
92 }
93 // Return a youngergen_card_value that is not currently in use.
94 jbyte find_unused_youngergenP_card_value();
95
96 public:
97 CardTableRS(MemRegion whole_heap, int max_covered_regions);
98
99 // *** GenRemSet functions.
100 GenRemSet::Name rs_kind() { return GenRemSet::CardTable; }
101
102 CardTableRS* as_CardTableRS() { return this; }
103
104 CardTableModRefBS* ct_bs() { return _ct_bs; }
105
106 // Override.
107 void prepare_for_younger_refs_iterate(bool parallel);
108
109 // Card table entries are cleared before application; "blk" is
110 // responsible for dirtying if the oop is still older-to-younger after
111 // closure application.
112 void younger_refs_iterate(Generation* g, OopsInGenClosure* blk);
113
114 void inline_write_ref_field_gc(void* field, oop new_val) {
115 jbyte* byte = _ct_bs->byte_for(field);
116 *byte = youngergen_card;
117 }
118 void write_ref_field_gc_work(void* field, oop new_val) {
119 inline_write_ref_field_gc(field, new_val);
120 }
121
122 // Override. Might want to devirtualize this in the same fashion as
123 // above. Ensures that the value of the card for field says that it's
124 // a younger card in the current collection.
125 virtual void write_ref_field_gc_par(void* field, oop new_val);
126
127 void resize_covered_region(MemRegion new_region);
128
129 bool is_aligned(HeapWord* addr) {
130 return _ct_bs->is_card_aligned(addr);
131 }
132
133 void verify();
134 void verify_aligned_region_empty(MemRegion mr);
135
136 void clear(MemRegion mr) { _ct_bs->clear(mr); }
137 void clear_into_younger(Generation* gen, bool clear_perm);
138
139 void invalidate(MemRegion mr, bool whole_heap = false) {
140 _ct_bs->invalidate(mr, whole_heap);
141 }
142 void invalidate_or_clear(Generation* gen, bool younger, bool perm);
143
144 static uintx ct_max_alignment_constraint() {
145 return CardTableModRefBS::ct_max_alignment_constraint();
146 }
147
148 jbyte* byte_for(void* p) { return _ct_bs->byte_for(p); }
149 jbyte* byte_after(void* p) { return _ct_bs->byte_after(p); }
150 HeapWord* addr_for(jbyte* p) { return _ct_bs->addr_for(p); }
151
152 bool is_prev_nonclean_card_val(jbyte v) {
153 return
154 youngergen_card <= v &&
155 v <= cur_youngergen_and_prev_nonclean_card &&
156 v != _cur_youngergen_card_val;
157 }
158
159 static bool youngergen_may_have_been_dirty(jbyte cv) {
160 return cv == CardTableRS::cur_youngergen_and_prev_nonclean_card;
161 }
162
163 };