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comparison src/share/vm/memory/genRemSet.hpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2001-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // A GenRemSet provides ways of iterating over pointers accross generations.
26 // (This is especially useful for older-to-younger.)
27
28 class Generation;
29 class BarrierSet;
30 class OopsInGenClosure;
31 class CardTableRS;
32
33 class GenRemSet: public CHeapObj {
34 friend class Generation;
35
36 BarrierSet* _bs;
37
38 public:
39 enum Name {
40 CardTable,
41 Other
42 };
43
44 GenRemSet(BarrierSet * bs) : _bs(bs) {}
45
46 virtual Name rs_kind() = 0;
47
48 // These are for dynamic downcasts. Unfortunately that it names the
49 // possible subtypes (but not that they are subtypes!) Return NULL if
50 // the cast is invalide.
51 virtual CardTableRS* as_CardTableRS() { return NULL; }
52
53 // Return the barrier set associated with "this."
54 BarrierSet* bs() { return _bs; }
55
56 // Do any (sequential) processing necessary to prepare for (possibly
57 // "parallel", if that arg is true) calls to younger_refs_iterate.
58 virtual void prepare_for_younger_refs_iterate(bool parallel) = 0;
59
60 // Apply the "do_oop" method of "blk" to (exactly) all oop locations
61 // 1) that are in objects allocated in "g" at the time of the last call
62 // to "save_Marks", and
63 // 2) that point to objects in younger generations.
64 virtual void younger_refs_iterate(Generation* g, OopsInGenClosure* blk) = 0;
65
66 virtual void younger_refs_in_space_iterate(Space* sp,
67 OopsInGenClosure* cl) = 0;
68
69 // This method is used to notify the remembered set that "new_val" has
70 // been written into "field" by the garbage collector.
71 void write_ref_field_gc(oop* field, oop new_val);
72 protected:
73 virtual void write_ref_field_gc_work(oop* field, oop new_val) = 0;
74 public:
75
76 // A version of the above suitable for use by parallel collectors.
77 virtual void write_ref_field_gc_par(oop* field, oop new_val) = 0;
78
79 // Resize one of the regions covered by the remembered set.
80 virtual void resize_covered_region(MemRegion new_region) = 0;
81
82 // If the rem set imposes any alignment restrictions on boundaries
83 // within the heap, this function tells whether they are met.
84 virtual bool is_aligned(HeapWord* addr) = 0;
85
86 // If the RS (or BS) imposes an aligment constraint on maximum heap size.
87 // (This must be static, and dispatch on "nm", because it is called
88 // before an RS is created.)
89 static uintx max_alignment_constraint(Name nm);
90
91 virtual void verify() = 0;
92
93 // Verify that the remembered set has no entries for
94 // the heap interval denoted by mr.
95 virtual void verify_empty(MemRegion mr) = 0;
96
97 // If appropriate, print some information about the remset on "tty".
98 virtual void print() {}
99
100 // Informs the RS that the given memregion contains no references to
101 // younger generations.
102 virtual void clear(MemRegion mr) = 0;
103
104 // Informs the RS that there are no references to generations
105 // younger than gen from generations gen and older.
106 // The parameter clear_perm indicates if the perm_gen's
107 // remembered set should also be processed/cleared.
108 virtual void clear_into_younger(Generation* gen, bool clear_perm) = 0;
109
110 // Informs the RS that refs in the given "mr" may have changed
111 // arbitrarily, and therefore may contain old-to-young pointers.
112 virtual void invalidate(MemRegion mr) = 0;
113
114 // Informs the RS that refs in this generation
115 // may have changed arbitrarily, and therefore may contain
116 // old-to-young pointers in arbitrary locations. The parameter
117 // younger indicates if the same should be done for younger generations
118 // as well. The parameter perm indicates if the same should be done for
119 // perm gen as well.
120 virtual void invalidate_or_clear(Generation* gen, bool younger, bool perm) = 0;
121 };