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.
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 #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 ClmsTester;
37 class MetaspaceArena;
38 class MetaspaceContext;
39 }
40
41 // A ClassLoaderMetaspace manages MetaspaceArena(s) for a CLD.
42 //
43 // A CLD owns one MetaspaceArena if UseCompressedClassPointers is false. Otherwise
44 // it owns two - one for the Klass* objects from the class space, one for the other
45 // types of MetaspaceObjs from the non-class space.
46 //
47 // +------+ +----------------------+ +-------------------+
48 // | CLD | ---> | ClassLoaderMetaspace | ----> | (non class) Arena |
49 // +------+ +----------------------+ | +-------------------+ allocation top
50 // | | v
51 // | + chunk -- chunk ... -- chunk
52 // |
53 // | +-------------------+
54 // +--> | (class) Arena |
55 // +-------------------+
56 // |
57 // + chunk ... chunk
58 // ^
59 // alloc top
60 //
61 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
62 friend class metaspace::ClmsTester; // for gtests
63
64 // A reference to an outside lock, held by the CLD.
65 Mutex* const _lock;
66
67 const Metaspace::MetaspaceType _space_type;
68
69 // Arena for allocations from non-class metaspace
70 // (resp. for all allocations if -XX:-UseCompressedClassPointers).
71 metaspace::MetaspaceArena* _non_class_space_arena;
72
73 // Arena for allocations from class space
74 // (null if -XX:-UseCompressedClassPointers).
75 metaspace::MetaspaceArena* _class_space_arena;
76
77 Mutex* lock() const { return _lock; }
78 metaspace::MetaspaceArena* non_class_space_arena() const { return _non_class_space_arena; }
79 metaspace::MetaspaceArena* class_space_arena() const { return _class_space_arena; }
80
81 bool have_class_space_arena() const { return _class_space_arena != nullptr; }
82
83 ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType space_type,
84 metaspace::MetaspaceContext* non_class_context,
85 metaspace::MetaspaceContext* class_context,
86 size_t klass_alignment_words);
87
88 public:
89 ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType space_type);
90
91 ~ClassLoaderMetaspace();
92
93 Metaspace::MetaspaceType space_type() const { return _space_type; }
94
95 // Allocate word_size words from Metaspace.
96 MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdType);
97
98 // Attempt to expand the GC threshold to be good for at least another word_size words
99 // and allocate. Returns null if failure. Used during Metaspace GC.
100 MetaWord* expand_and_allocate(size_t word_size, Metaspace::MetadataType mdType);
101
102 // Prematurely returns a metaspace allocation to the _block_freelists
103 // because it is not needed anymore.
104 void deallocate(MetaWord* ptr, size_t word_size, bool is_class);
105
106 // Update statistics. This walks all in-use chunks.
107 void add_to_statistics(metaspace::ClmsStats* out) const;
108
109 DEBUG_ONLY(void verify() const;)
110
111 // Convenience method to get the most important usage statistics for either class
112 // or non-class space. For more detailed statistics, use add_to_statistics().
113 void usage_numbers(Metaspace::MetadataType mdType, size_t* p_used_words,
114 size_t* p_committed_words, size_t* p_capacity_words) const;
115
116 // Convenience method to get the most important usage statistics (totals; both class- and non-class spaces)
117 // For more detailed statistics, use add_to_statistics().
118 void usage_numbers(size_t* p_used_words, size_t* p_committed_words,
119 size_t* p_capacity_words) const;
120
121 }; // end: ClassLoaderMetaspace
122
123
124 #endif // SHARE_MEMORY_CLASSLOADERMETASPACE_HPP