1 /*
2 * Copyright (c) 2011, 2013, 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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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 = 0,
90 NonClassType = ClassType + 1,
91 MetadataTypeCount = ClassType + 2
92 };
93 enum MetaspaceType {
94 StandardMetaspaceType,
95 BootMetaspaceType,
96 ROMetaspaceType,
97 ReadWriteMetaspaceType,
98 AnonymousMetaspaceType,
99 ReflectionMetaspaceType
100 };
101
102 private:
103 void initialize(Mutex* lock, MetaspaceType type);
104
105 // Align up the word size to the allocation word size
106 static size_t align_word_size_up(size_t);
107
108 static size_t _first_chunk_word_size;
109 static size_t _first_class_chunk_word_size;
110
111 SpaceManager* _vsm;
112 SpaceManager* vsm() const { return _vsm; }
113
114 SpaceManager* _class_vsm;
115 SpaceManager* class_vsm() const { return _class_vsm; }
116
117 // Allocate space for metadata of type mdtype. This is space
118 // within a Metachunk and is used by
119 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
120 // which returns a Metablock.
121 MetaWord* allocate(size_t word_size, MetadataType mdtype);
122
123 // Virtual Space lists for both classes and other metadata
124 static VirtualSpaceList* _space_list;
125 static VirtualSpaceList* _class_space_list;
126
127 static VirtualSpaceList* space_list() { return _space_list; }
128 static VirtualSpaceList* class_space_list() { return _class_space_list; }
129
130 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
131 // maintain a single list for now.
132 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
133
134 class AllocRecord : public CHeapObj<mtClass> {
135 public:
136 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
137 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
138 AllocRecord *_next;
139 address _ptr;
140 MetaspaceObj::Type _type;
141 int _byte_size;
142 };
143
144 AllocRecord * _alloc_record_head;
145 AllocRecord * _alloc_record_tail;
146
147 public:
148
149 Metaspace(Mutex* lock, MetaspaceType type);
150 ~Metaspace();
151
152 // Initialize globals for Metaspace
153 static void global_initialize();
154 static void initialize_class_space(ReservedSpace rs);
155
156 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
157 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
158
159 char* bottom() const;
160 size_t used_words_slow(MetadataType mdtype) const;
161 size_t free_words(MetadataType mdtype) const;
162 size_t capacity_words_slow(MetadataType mdtype) const;
163 size_t waste_words(MetadataType mdtype) const;
164
165 size_t used_bytes_slow(MetadataType mdtype) const;
166 size_t capacity_bytes_slow(MetadataType mdtype) const;
167
168 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size,
169 bool read_only, MetaspaceObj::Type type, TRAPS);
170 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
171
172 MetaWord* expand_and_allocate(size_t size,
173 MetadataType mdtype);
174
175 static bool is_initialized() { return _class_space_list != NULL; }
176
177 static bool contains(const void *ptr);
178 void dump(outputStream* const out) const;
179
180 // Free empty virtualspaces
181 static void purge();
182
183 void print_on(outputStream* st) const;
184 // Debugging support
185 void verify();
186
187 class AllocRecordClosure : public StackObj {
188 public:
189 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
190 };
191
192 void iterate(AllocRecordClosure *closure);
193 };
194
195 class MetaspaceAux : AllStatic {
196 static size_t free_chunks_total(Metaspace::MetadataType mdtype);
197 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);
198
199 public:
200 // Statistics for class space and data space in metaspace.
201
202 // These methods iterate over the classloader data graph
203 // for the given Metaspace type. These are slow.
204 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
205 static size_t free_in_bytes(Metaspace::MetadataType mdtype);
206 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
207
208 // Iterates over the virtual space list.
209 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);
210
211 // Running sum of space in all Metachunks that has been
212 // allocated to a Metaspace. This is used instead of
213 // iterating over all the classloaders. One for each
214 // type of Metadata
215 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount];
216 // Running sum of space in all Metachunks that have
217 // are being used for metadata. One for each
218 // type of Metadata.
219 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount];
220
221 public:
222 // Decrement and increment _allocated_capacity_words
223 static void dec_capacity(Metaspace::MetadataType type, size_t words);
224 static void inc_capacity(Metaspace::MetadataType type, size_t words);
225
226 // Decrement and increment _allocated_used_words
227 static void dec_used(Metaspace::MetadataType type, size_t words);
228 static void inc_used(Metaspace::MetadataType type, size_t words);
229
230 // Total of space allocated to metadata in all Metaspaces.
231 // This sums the space used in each Metachunk by
232 // iterating over the classloader data graph
233 static size_t used_bytes_slow() {
234 return used_bytes_slow(Metaspace::ClassType) +
235 used_bytes_slow(Metaspace::NonClassType);
236 }
237
238 // Used by MetaspaceCounters
239 static size_t free_chunks_total();
240 static size_t free_chunks_total_in_bytes();
241
242 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) {
243 return _allocated_capacity_words[mdtype];
244 }
245 static size_t allocated_capacity_words() {
246 return _allocated_capacity_words[Metaspace::ClassType] +
247 _allocated_capacity_words[Metaspace::NonClassType];
248 }
249 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) {
250 return allocated_capacity_words(mdtype) * BytesPerWord;
251 }
252 static size_t allocated_capacity_bytes() {
253 return allocated_capacity_words() * BytesPerWord;
254 }
255
256 static size_t allocated_used_words(Metaspace::MetadataType mdtype) {
257 return _allocated_used_words[mdtype];
258 }
259 static size_t allocated_used_words() {
260 return _allocated_used_words[Metaspace::ClassType] +
261 _allocated_used_words[Metaspace::NonClassType];
262 }
263 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) {
264 return allocated_used_words(mdtype) * BytesPerWord;
265 }
266 static size_t allocated_used_bytes() {
267 return allocated_used_words() * BytesPerWord;
268 }
269
270 static size_t free_bytes();
271
272 // Total capacity in all Metaspaces
273 static size_t capacity_bytes_slow() {
274 #ifdef PRODUCT
275 // Use allocated_capacity_bytes() in PRODUCT instead of this function.
276 guarantee(false, "Should not call capacity_bytes_slow() in the PRODUCT");
277 #endif
278 size_t class_capacity = capacity_bytes_slow(Metaspace::ClassType);
279 size_t non_class_capacity = capacity_bytes_slow(Metaspace::NonClassType);
280 assert(allocated_capacity_bytes() == class_capacity + non_class_capacity,
281 err_msg("bad accounting: allocated_capacity_bytes() " SIZE_FORMAT
282 " class_capacity + non_class_capacity " SIZE_FORMAT
283 " class_capacity " SIZE_FORMAT " non_class_capacity " SIZE_FORMAT,
284 allocated_capacity_bytes(), class_capacity + non_class_capacity,
285 class_capacity, non_class_capacity));
286
287 return class_capacity + non_class_capacity;
288 }
289
290 // Total space reserved in all Metaspaces
291 static size_t reserved_in_bytes() {
292 return reserved_in_bytes(Metaspace::ClassType) +
293 reserved_in_bytes(Metaspace::NonClassType);
294 }
295
296 static size_t min_chunk_size();
297
298 // Print change in used metadata.
299 static void print_metaspace_change(size_t prev_metadata_used);
300 static void print_on(outputStream * out);
301 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
302
303 static void print_waste(outputStream* out);
304 static void dump(outputStream* out);
305 static void verify_free_chunks();
306 // Checks that the values returned by allocated_capacity_bytes() and
307 // capacity_bytes_slow() are the same.
308 static void verify_capacity();
309 static void verify_used();
310 static void verify_metrics();
311 };
312
313 // Metaspace are deallocated when their class loader are GC'ed.
314 // This class implements a policy for inducing GC's to recover
315 // Metaspaces.
316
317 class MetaspaceGC : AllStatic {
318
319 // The current high-water-mark for inducing a GC. When
320 // the capacity of all space in the virtual lists reaches this value,
321 // a GC is induced and the value is increased. This should be changed
322 // to the space actually used for allocations to avoid affects of
323 // fragmentation losses to partially used chunks. Size is in words.
324 static size_t _capacity_until_GC;
325
326 // After a GC is done any allocation that fails should try to expand
327 // the capacity of the Metaspaces. This flag is set during attempts
328 // to allocate in the VMGCOperation that does the GC.
329 static bool _expand_after_GC;
330
331 // For a CMS collection, signal that a concurrent collection should
332 // be started.
333 static bool _should_concurrent_collect;
334
335 static uint _shrink_factor;
336
337 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }
338
339 static size_t shrink_factor() { return _shrink_factor; }
340 void set_shrink_factor(uint v) { _shrink_factor = v; }
341
342 public:
343
344 static size_t capacity_until_GC() { return _capacity_until_GC; }
345 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
346 static void dec_capacity_until_GC(size_t v) {
347 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
348 }
349 static bool expand_after_GC() { return _expand_after_GC; }
350 static void set_expand_after_GC(bool v) { _expand_after_GC = v; }
351
352 static bool should_concurrent_collect() { return _should_concurrent_collect; }
353 static void set_should_concurrent_collect(bool v) {
354 _should_concurrent_collect = v;
355 }
356
357 // The amount to increase the high-water-mark (_capacity_until_GC)
358 static size_t delta_capacity_until_GC(size_t word_size);
359
360 // It is expected that this will be called when the current capacity
361 // has been used and a GC should be considered.
362 static bool should_expand(VirtualSpaceList* vsl, size_t word_size);
363
364 // Calculate the new high-water mark at which to induce
365 // a GC.
366 static void compute_new_size();
367 };
368
369 #endif // SHARE_VM_MEMORY_METASPACE_HPP