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comparison src/share/vm/memory/metaspace.hpp @ 6725:da91efe96a93

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6964458: Reimplement class meta-data storage to use native memory Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>
author coleenp
date Sat, 01 Sep 2012 13:25:18 -0400
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6724:36d1d483d5d6 6725:da91efe96a93
1 /*
2 * Copyright (c) 2011, 2012, 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_VM_MEMORY_METASPACE_HPP
25 #define SHARE_VM_MEMORY_METASPACE_HPP
26
27 #include "memory/allocation.hpp"
28 #include "memory/memRegion.hpp"
29 #include "runtime/virtualspace.hpp"
30 #include "utilities/exceptions.hpp"
31
32 // Metaspace
33 //
34 // Metaspaces are Arenas for the VM's metadata.
35 // They are allocated one per class loader object, and one for the null
36 // bootstrap class loader
37 // Eventually for bootstrap loader we'll have a read-only section and read-write
38 // to write for DumpSharedSpaces and read for UseSharedSpaces
39 //
40 // block X ---+ +-------------------+
41 // | | Virtualspace |
42 // | | |
43 // | | |
44 // | |-------------------|
45 // | || Chunk |
46 // | || |
47 // | ||---------- |
48 // +------>||| block 0 | |
49 // ||---------- |
50 // ||| block 1 | |
51 // ||---------- |
52 // || |
53 // |-------------------|
54 // | |
55 // | |
56 // +-------------------+
57 //
58
59 class ClassLoaderData;
60 class MetaWord;
61 class Mutex;
62 class outputStream;
63 class FreeChunk;
64 template <class Chunk_t> class FreeList;
65 template <class Chunk_t> class BinaryTreeDictionary;
66 class SpaceManager;
67
68 // Metaspaces each have a SpaceManager and allocations
69 // are done by the SpaceManager. Allocations are done
70 // out of the current Metachunk. When the current Metachunk
71 // is exhausted, the SpaceManager gets a new one from
72 // the current VirtualSpace. When the VirtualSpace is exhausted
73 // the SpaceManager gets a new one. The SpaceManager
74 // also manages freelists of available Chunks.
75 //
76 // Currently the space manager maintains the list of
77 // virtual spaces and the list of chunks in use. Its
78 // allocate() method returns a block for use as a
79 // quantum of metadata.
80
81 class VirtualSpaceList;
82
83 class Metaspace : public CHeapObj<mtClass> {
84 friend class VMStructs;
85 friend class SpaceManager;
86 friend class VM_CollectForMetadataAllocation;
87 friend class MetaspaceGC;
88 friend class MetaspaceAux;
89
90 public:
91 enum MetadataType {ClassType, NonClassType};
92
93 private:
94 void initialize(Mutex* lock, size_t initial_size = 0);
95
96 static size_t _first_chunk_word_size;
97
98 SpaceManager* _vsm;
99 SpaceManager* vsm() const { return _vsm; }
100
101 SpaceManager* _class_vsm;
102 SpaceManager* class_vsm() const { return _class_vsm; }
103
104 MetaWord* allocate(size_t word_size, MetadataType mdtype);
105
106 // Virtual Space lists for both classes and other metadata
107 static VirtualSpaceList* _space_list;
108 static VirtualSpaceList* _class_space_list;
109
110 static VirtualSpaceList* space_list() { return _space_list; }
111 static VirtualSpaceList* class_space_list() { return _class_space_list; }
112
113 public:
114
115 Metaspace(Mutex* lock, size_t initial_size);
116 Metaspace(Mutex* lock);
117 ~Metaspace();
118
119 // Initialize globals for Metaspace
120 static void global_initialize();
121 static void initialize_class_space(ReservedSpace rs);
122
123 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
124
125 char* bottom() const;
126 size_t used_words(MetadataType mdtype) const;
127 size_t free_words(MetadataType mdtype) const;
128 size_t capacity_words(MetadataType mdtype) const;
129 size_t waste_words(MetadataType mdtype) const;
130
131 static MetaWord* allocate(ClassLoaderData* loader_data, size_t size,
132 bool read_only, MetadataType mdtype, TRAPS);
133
134 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
135
136 #ifndef PRODUCT
137 bool contains(const void *ptr) const;
138 bool contains_class(const void *ptr) const;
139 #endif
140
141 void dump(outputStream* const out) const;
142
143 void print_on(outputStream* st) const;
144 // Debugging support
145 void verify();
146 };
147
148 class MetaspaceAux : AllStatic {
149
150 // Statistics for class space and data space in metaspace.
151 static size_t used_in_bytes(Metaspace::MetadataType mdtype);
152 static size_t free_in_bytes(Metaspace::MetadataType mdtype);
153 static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);
154 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);
155
156 static size_t free_chunks_total(Metaspace::MetadataType mdtype);
157 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);
158
159 public:
160 // Total of space allocated to metadata in all Metaspaces
161 static size_t used_in_bytes() {
162 return used_in_bytes(Metaspace::ClassType) +
163 used_in_bytes(Metaspace::NonClassType);
164 }
165
166 // Total of available space in all Metaspaces
167 // Total of capacity allocated to all Metaspaces. This includes
168 // space in Metachunks not yet allocated and in the Metachunk
169 // freelist.
170 static size_t capacity_in_bytes() {
171 return capacity_in_bytes(Metaspace::ClassType) +
172 capacity_in_bytes(Metaspace::NonClassType);
173 }
174
175 // Total space reserved in all Metaspaces
176 static size_t reserved_in_bytes() {
177 return reserved_in_bytes(Metaspace::ClassType) +
178 reserved_in_bytes(Metaspace::NonClassType);
179 }
180
181 static size_t min_chunk_size();
182
183 // Print change in used metadata.
184 static void print_metaspace_change(size_t prev_metadata_used);
185 static void print_on(outputStream * out);
186 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
187
188 static void print_waste(outputStream* out);
189 static void dump(outputStream* out);
190 };
191
192 // Metaspace are deallocated when their class loader are GC'ed.
193 // This class implements a policy for inducing GC's to recover
194 // Metaspaces.
195
196 class MetaspaceGC : AllStatic {
197
198 // The current high-water-mark for inducing a GC. When
199 // the capacity of all space in the virtual lists reaches this value,
200 // a GC is induced and the value is increased. This should be changed
201 // to the space actually used for allocations to avoid affects of
202 // fragmentation losses to partially used chunks. Size is in words.
203 static size_t _capacity_until_GC;
204
205 // After a GC is done any allocation that fails should try to expand
206 // the capacity of the Metaspaces. This flag is set during attempts
207 // to allocate in the VMGCOperation that does the GC.
208 static bool _expand_after_GC;
209
210 // For a CMS collection, signal that a concurrent collection should
211 // be started.
212 static bool _should_concurrent_collect;
213
214 static uint _shrink_factor;
215
216 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }
217
218 static size_t shrink_factor() { return _shrink_factor; }
219 void set_shrink_factor(uint v) { _shrink_factor = v; }
220
221 public:
222
223 static size_t capacity_until_GC() { return _capacity_until_GC; }
224 static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; }
225 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
226 static void dec_capacity_until_GC(size_t v) {
227 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
228 }
229 static bool expand_after_GC() { return _expand_after_GC; }
230 static void set_expand_after_GC(bool v) { _expand_after_GC = v; }
231
232 static bool should_concurrent_collect() { return _should_concurrent_collect; }
233 static void set_should_concurrent_collect(bool v) {
234 _should_concurrent_collect = v;
235 }
236
237 // The amount to increase the high-water-mark (_capacity_until_GC)
238 static size_t delta_capacity_until_GC(size_t word_size);
239
240 // It is expected that this will be called when the current capacity
241 // has been used and a GC should be considered.
242 static bool should_expand(VirtualSpaceList* vsl, size_t word_size);
243
244 // Calculate the new high-water mark at which to induce
245 // a GC.
246 static void compute_new_size();
247 };
248
249 #endif // SHARE_VM_MEMORY_METASPACE_HPP