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.
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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 Metablock;
61 class MetaWord;
62 class Mutex;
63 class outputStream;
64 class SpaceManager;
65
66 // Metaspaces each have a SpaceManager and allocations
67 // are done by the SpaceManager. Allocations are done
68 // out of the current Metachunk. When the current Metachunk
69 // is exhausted, the SpaceManager gets a new one from
70 // the current VirtualSpace. When the VirtualSpace is exhausted
71 // the SpaceManager gets a new one. The SpaceManager
72 // also manages freelists of available Chunks.
73 //
74 // Currently the space manager maintains the list of
75 // virtual spaces and the list of chunks in use. Its
76 // allocate() method returns a block for use as a
77 // quantum of metadata.
78
79 class VirtualSpaceList;
80
81 class Metaspace : public CHeapObj<mtClass> {
82 friend class VMStructs;
83 friend class SpaceManager;
84 friend class VM_CollectForMetadataAllocation;
85 friend class MetaspaceGC;
86 friend class MetaspaceAux;
87
88 public:
89 enum MetadataType {ClassType, NonClassType};
90 enum MetaspaceType {
91 StandardMetaspaceType,
92 BootMetaspaceType,
93 ROMetaspaceType,
94 ReadWriteMetaspaceType,
95 AnonymousMetaspaceType,
96 ReflectionMetaspaceType
97 };
98
99 private:
100 void initialize(Mutex* lock, MetaspaceType type);
101
102 // Align up the word size to the allocation word size
103 static size_t align_word_size_up(size_t);
104
105 static size_t _first_chunk_word_size;
106 static size_t _first_class_chunk_word_size;
107
108 SpaceManager* _vsm;
109 SpaceManager* vsm() const { return _vsm; }
110
111 SpaceManager* _class_vsm;
112 SpaceManager* class_vsm() const { return _class_vsm; }
113
114 MetaWord* allocate(size_t word_size, MetadataType mdtype);
115
116 // Virtual Space lists for both classes and other metadata
117 static VirtualSpaceList* _space_list;
118 static VirtualSpaceList* _class_space_list;
119
120 static VirtualSpaceList* space_list() { return _space_list; }
121 static VirtualSpaceList* class_space_list() { return _class_space_list; }
122
123 public:
124
125 Metaspace(Mutex* lock, MetaspaceType type);
126 ~Metaspace();
127
128 // Initialize globals for Metaspace
129 static void global_initialize();
130 static void initialize_class_space(ReservedSpace rs);
131
132 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
133 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
134
135 char* bottom() const;
136 size_t used_words(MetadataType mdtype) const;
137 size_t free_words(MetadataType mdtype) const;
138 size_t capacity_words(MetadataType mdtype) const;
139 size_t waste_words(MetadataType mdtype) const;
140
141 static Metablock* allocate(ClassLoaderData* loader_data, size_t size,
142 bool read_only, MetadataType mdtype, TRAPS);
143 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
144
145 MetaWord* expand_and_allocate(size_t size,
146 MetadataType mdtype);
147
148 static bool is_initialized() { return _class_space_list != NULL; }
149
150 static bool contains(const void *ptr);
151 void dump(outputStream* const out) const;
152
153 void print_on(outputStream* st) const;
154 // Debugging support
155 void verify();
156 };
157
158 class MetaspaceAux : AllStatic {
159
160 static size_t free_chunks_total(Metaspace::MetadataType mdtype);
161 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);
162
163 public:
164 // Statistics for class space and data space in metaspace.
165 static size_t used_in_bytes(Metaspace::MetadataType mdtype);
166 static size_t free_in_bytes(Metaspace::MetadataType mdtype);
167 static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);
168 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);
169
170 // Total of space allocated to metadata in all Metaspaces
171 static size_t used_in_bytes() {
172 return used_in_bytes(Metaspace::ClassType) +
173 used_in_bytes(Metaspace::NonClassType);
174 }
175
176 // Total of available space in all Metaspaces
177 // Total of capacity allocated to all Metaspaces. This includes
178 // space in Metachunks not yet allocated and in the Metachunk
179 // freelist.
180 static size_t capacity_in_bytes() {
181 return capacity_in_bytes(Metaspace::ClassType) +
182 capacity_in_bytes(Metaspace::NonClassType);
183 }
184
185 // Total space reserved in all Metaspaces
186 static size_t reserved_in_bytes() {
187 return reserved_in_bytes(Metaspace::ClassType) +
188 reserved_in_bytes(Metaspace::NonClassType);
189 }
190
191 static size_t min_chunk_size();
192
193 // Print change in used metadata.
194 static void print_metaspace_change(size_t prev_metadata_used);
195 static void print_on(outputStream * out);
196 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
197
198 static void print_waste(outputStream* out);
199 static void dump(outputStream* out);
200 static void verify_free_chunks();
201 };
202
203 // Metaspace are deallocated when their class loader are GC'ed.
204 // This class implements a policy for inducing GC's to recover
205 // Metaspaces.
206
207 class MetaspaceGC : AllStatic {
208
209 // The current high-water-mark for inducing a GC. When
210 // the capacity of all space in the virtual lists reaches this value,
211 // a GC is induced and the value is increased. This should be changed
212 // to the space actually used for allocations to avoid affects of
213 // fragmentation losses to partially used chunks. Size is in words.
214 static size_t _capacity_until_GC;
215
216 // After a GC is done any allocation that fails should try to expand
217 // the capacity of the Metaspaces. This flag is set during attempts
218 // to allocate in the VMGCOperation that does the GC.
219 static bool _expand_after_GC;
220
221 // For a CMS collection, signal that a concurrent collection should
222 // be started.
223 static bool _should_concurrent_collect;
224
225 static uint _shrink_factor;
226
227 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }
228
229 static size_t shrink_factor() { return _shrink_factor; }
230 void set_shrink_factor(uint v) { _shrink_factor = v; }
231
232 public:
233
234 static size_t capacity_until_GC() { return _capacity_until_GC; }
235 static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; }
236 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
237 static void dec_capacity_until_GC(size_t v) {
238 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
239 }
240 static bool expand_after_GC() { return _expand_after_GC; }
241 static void set_expand_after_GC(bool v) { _expand_after_GC = v; }
242
243 static bool should_concurrent_collect() { return _should_concurrent_collect; }
244 static void set_should_concurrent_collect(bool v) {
245 _should_concurrent_collect = v;
246 }
247
248 // The amount to increase the high-water-mark (_capacity_until_GC)
249 static size_t delta_capacity_until_GC(size_t word_size);
250
251 // It is expected that this will be called when the current capacity
252 // has been used and a GC should be considered.
253 static bool should_expand(VirtualSpaceList* vsl, size_t word_size);
254
255 // Calculate the new high-water mark at which to induce
256 // a GC.
257 static void compute_new_size();
258 };
259
260 #endif // SHARE_VM_MEMORY_METASPACE_HPP