1 /*
2 * Copyright (c) 2011, 2023, 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
20 * or visit www.oracle.com if you need additional information or have any
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23 */
24 #ifndef SHARE_MEMORY_CLASSLOADERMETASPACE_HPP
25 #define SHARE_MEMORY_CLASSLOADERMETASPACE_HPP
26
27 #include "memory/allocation.hpp"
28 #include "memory/metaspace.hpp"
29 #include "utilities/debug.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 class outputStream;
33
34 namespace metaspace {
35 struct ClmsStats;
36 class MetaspaceArena;
37 }
38
39 // A ClassLoaderMetaspace manages MetaspaceArena(s) for a CLD.
40 //
41 // A CLD owns one MetaspaceArena if UseCompressedClassPointers is false. Otherwise
42 // it owns two - one for the Klass* objects from the class space, one for the other
43 // types of MetaspaceObjs from the non-class space.
44 //
45 // +------+ +----------------------+ +-------------------+
46 // | CLD | ---> | ClassLoaderMetaspace | ----> | (non class) Arena |
47 // +------+ +----------------------+ | +-------------------+ allocation top
48 // | | v
49 // | + chunk -- chunk ... -- chunk
50 // |
51 // | +-------------------+
52 // +--> | (class) Arena |
53 // +-------------------+
54 // |
55 // + chunk ... chunk
56 // ^
57 // alloc top
58 //
59 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
60
61 // A reference to an outside lock, held by the CLD.
62 Mutex* const _lock;
63
64 const Metaspace::MetaspaceType _space_type;
65
66 // Arena for allocations from non-class metaspace
67 // (resp. for all allocations if -XX:-UseCompressedClassPointers).
68 metaspace::MetaspaceArena* _non_class_space_arena;
69
70 // Arena for allocations from class space
71 // (null if -XX:-UseCompressedClassPointers).
72 metaspace::MetaspaceArena* _class_space_arena;
73
74 Mutex* lock() const { return _lock; }
75 metaspace::MetaspaceArena* non_class_space_arena() const { return _non_class_space_arena; }
76 metaspace::MetaspaceArena* class_space_arena() const { return _class_space_arena; }
77
78 public:
79
80 ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType space_type);
81
82 ~ClassLoaderMetaspace();
83
84 Metaspace::MetaspaceType space_type() const { return _space_type; }
85
86 // Allocate word_size words from Metaspace.
87 MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdType);
88
89 // Attempt to expand the GC threshold to be good for at least another word_size words
90 // and allocate. Returns null if failure. Used during Metaspace GC.
91 MetaWord* expand_and_allocate(size_t word_size, Metaspace::MetadataType mdType);
92
93 // Prematurely returns a metaspace allocation to the _block_freelists
94 // because it is not needed anymore.
95 void deallocate(MetaWord* ptr, size_t word_size, bool is_class);
96
97 // Update statistics. This walks all in-use chunks.
98 void add_to_statistics(metaspace::ClmsStats* out) const;
99
100 DEBUG_ONLY(void verify() const;)
101
102 // Convenience method to get the most important usage statistics for either class
103 // or non-class space. For more detailed statistics, use add_to_statistics().
104 void usage_numbers(Metaspace::MetadataType mdType, size_t* p_used_words,
105 size_t* p_committed_words, size_t* p_capacity_words) const;
106
107 // Convenience method to get the most important usage statistics (totals; both class- and non-class spaces)
108 // For more detailed statistics, use add_to_statistics().
109 void usage_numbers(size_t* p_used_words, size_t* p_committed_words,
110 size_t* p_capacity_words) const;
111
112 }; // end: ClassLoaderMetaspace
113
114
115 #endif // SHARE_MEMORY_CLASSLOADERMETASPACE_HPP