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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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 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 ChunkManager;
60 class ClassLoaderData;
61 class Metablock;
62 class Metachunk;
63 class MetaWord;
64 class Mutex;
65 class outputStream;
66 class SpaceManager;
67 class VirtualSpaceList;
68
69 // Metaspaces each have a SpaceManager and allocations
70 // are done by the SpaceManager. Allocations are done
71 // out of the current Metachunk. When the current Metachunk
72 // is exhausted, the SpaceManager gets a new one from
73 // the current VirtualSpace. When the VirtualSpace is exhausted
74 // the SpaceManager gets a new one. The SpaceManager
75 // also manages freelists of available Chunks.
76 //
77 // Currently the space manager maintains the list of
78 // virtual spaces and the list of chunks in use. Its
79 // allocate() method returns a block for use as a
80 // quantum of metadata.
81
82 class Metaspace : public CHeapObj<mtClass> {
83 friend class VMStructs;
84 friend class SpaceManager;
85 friend class VM_CollectForMetadataAllocation;
86 friend class MetaspaceGC;
87 friend class MetaspaceAux;
88
89 public:
90 enum MetadataType {
91 ClassType,
92 NonClassType,
93 MetadataTypeCount
94 };
95 enum MetaspaceType {
96 StandardMetaspaceType,
97 BootMetaspaceType,
98 ROMetaspaceType,
99 ReadWriteMetaspaceType,
100 AnonymousMetaspaceType,
101 ReflectionMetaspaceType
102 };
103
104 private:
105 void initialize(Mutex* lock, MetaspaceType type);
106
107 // Get the first chunk for a Metaspace. Used for
108 // special cases such as the boot class loader, reflection
109 // class loader and anonymous class loader.
110 Metachunk* get_initialization_chunk(MetadataType mdtype,
111 size_t chunk_word_size,
112 size_t chunk_bunch);
113
114 // Align up the word size to the allocation word size
115 static size_t align_word_size_up(size_t);
116
117 // Aligned size of the metaspace.
118 static size_t _class_metaspace_size;
119
120 static size_t class_metaspace_size() {
121 return _class_metaspace_size;
122 }
123 static void set_class_metaspace_size(size_t metaspace_size) {
124 _class_metaspace_size = metaspace_size;
125 }
126
127 static size_t _first_chunk_word_size;
128 static size_t _first_class_chunk_word_size;
129
130 static size_t _commit_alignment;
131 static size_t _reserve_alignment;
132
133 SpaceManager* _vsm;
134 SpaceManager* vsm() const { return _vsm; }
135
136 SpaceManager* _class_vsm;
137 SpaceManager* class_vsm() const { return _class_vsm; }
138
139 // Allocate space for metadata of type mdtype. This is space
140 // within a Metachunk and is used by
141 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
142 // which returns a Metablock.
143 MetaWord* allocate(size_t word_size, MetadataType mdtype);
144
145 // Virtual Space lists for both classes and other metadata
146 static VirtualSpaceList* _space_list;
147 static VirtualSpaceList* _class_space_list;
148
149 static ChunkManager* _chunk_manager_metadata;
150 static ChunkManager* _chunk_manager_class;
151
152 public:
153 static VirtualSpaceList* space_list() { return _space_list; }
154 static VirtualSpaceList* class_space_list() { return _class_space_list; }
155 static VirtualSpaceList* get_space_list(MetadataType mdtype) {
156 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
157 return mdtype == ClassType ? class_space_list() : space_list();
158 }
159
160 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
161 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
162 static ChunkManager* get_chunk_manager(MetadataType mdtype) {
163 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
164 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
165 }
166
167 private:
168 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
169 // maintain a single list for now.
170 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
171
172 #ifdef _LP64
173 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
174
175 // Returns true if can use CDS with metaspace allocated as specified address.
176 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
177
178 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
179
180 static void initialize_class_space(ReservedSpace rs);
181 #endif
182
183 class AllocRecord : public CHeapObj<mtClass> {
184 public:
185 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
186 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
187 AllocRecord *_next;
188 address _ptr;
189 MetaspaceObj::Type _type;
190 int _byte_size;
191 };
192
193 AllocRecord * _alloc_record_head;
194 AllocRecord * _alloc_record_tail;
195
196 public:
197
198 Metaspace(Mutex* lock, MetaspaceType type);
199 ~Metaspace();
200
201 static void ergo_initialize();
202 static void global_initialize();
203
204 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
205 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
206
207 static size_t reserve_alignment() { return _reserve_alignment; }
208 static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
209 static size_t commit_alignment() { return _commit_alignment; }
210 static size_t commit_alignment_words() { return _commit_alignment / BytesPerWord; }
211
212 char* bottom() const;
213 size_t used_words_slow(MetadataType mdtype) const;
214 size_t free_words_slow(MetadataType mdtype) const;
215 size_t capacity_words_slow(MetadataType mdtype) const;
216
217 size_t used_bytes_slow(MetadataType mdtype) const;
218 size_t capacity_bytes_slow(MetadataType mdtype) const;
219
220 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size,
221 bool read_only, MetaspaceObj::Type type, TRAPS);
222 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
223
224 MetaWord* expand_and_allocate(size_t size,
225 MetadataType mdtype);
226
227 static bool contains(const void *ptr);
228 void dump(outputStream* const out) const;
229
230 // Free empty virtualspaces
231 static void purge(MetadataType mdtype);
232 static void purge();
233
234 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
235 MetadataType mdtype, TRAPS);
236
237 void print_on(outputStream* st) const;
238 // Debugging support
239 void verify();
240
241 class AllocRecordClosure : public StackObj {
242 public:
243 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
244 };
245
246 void iterate(AllocRecordClosure *closure);
247
248 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
249 static bool using_class_space() {
250 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
251 }
252
253 static bool is_class_space_allocation(MetadataType mdType) {
254 return mdType == ClassType && using_class_space();
255 }
256 };
257
258 class MetaspaceAux : AllStatic {
259 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
260
261 // These methods iterate over the classloader data graph
262 // for the given Metaspace type. These are slow.
263 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
264 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
265 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
266 static size_t capacity_bytes_slow();
267
268 // Running sum of space in all Metachunks that has been
269 // allocated to a Metaspace. This is used instead of
270 // iterating over all the classloaders. One for each
271 // type of Metadata
272 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount];
273 // Running sum of space in all Metachunks that have
274 // are being used for metadata. One for each
275 // type of Metadata.
276 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount];
277
278 public:
279 // Decrement and increment _allocated_capacity_words
280 static void dec_capacity(Metaspace::MetadataType type, size_t words);
281 static void inc_capacity(Metaspace::MetadataType type, size_t words);
282
283 // Decrement and increment _allocated_used_words
284 static void dec_used(Metaspace::MetadataType type, size_t words);
285 static void inc_used(Metaspace::MetadataType type, size_t words);
286
287 // Total of space allocated to metadata in all Metaspaces.
288 // This sums the space used in each Metachunk by
289 // iterating over the classloader data graph
290 static size_t used_bytes_slow() {
291 return used_bytes_slow(Metaspace::ClassType) +
292 used_bytes_slow(Metaspace::NonClassType);
293 }
294
295 // Used by MetaspaceCounters
296 static size_t free_chunks_total_words();
297 static size_t free_chunks_total_bytes();
298 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
299
300 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) {
301 return _allocated_capacity_words[mdtype];
302 }
303 static size_t allocated_capacity_words() {
304 return allocated_capacity_words(Metaspace::NonClassType) +
305 allocated_capacity_words(Metaspace::ClassType);
306 }
307 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) {
308 return allocated_capacity_words(mdtype) * BytesPerWord;
309 }
310 static size_t allocated_capacity_bytes() {
311 return allocated_capacity_words() * BytesPerWord;
312 }
313
314 static size_t allocated_used_words(Metaspace::MetadataType mdtype) {
315 return _allocated_used_words[mdtype];
316 }
317 static size_t allocated_used_words() {
318 return allocated_used_words(Metaspace::NonClassType) +
319 allocated_used_words(Metaspace::ClassType);
320 }
321 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) {
322 return allocated_used_words(mdtype) * BytesPerWord;
323 }
324 static size_t allocated_used_bytes() {
325 return allocated_used_words() * BytesPerWord;
326 }
327
328 static size_t free_bytes();
329 static size_t free_bytes(Metaspace::MetadataType mdtype);
330
331 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
332 static size_t reserved_bytes() {
333 return reserved_bytes(Metaspace::ClassType) +
334 reserved_bytes(Metaspace::NonClassType);
335 }
336
337 static size_t committed_bytes(Metaspace::MetadataType mdtype);
338 static size_t committed_bytes() {
339 return committed_bytes(Metaspace::ClassType) +
340 committed_bytes(Metaspace::NonClassType);
341 }
342
343 static size_t min_chunk_size_words();
344 static size_t min_chunk_size_bytes() {
345 return min_chunk_size_words() * BytesPerWord;
346 }
347
348 // Print change in used metadata.
349 static void print_metaspace_change(size_t prev_metadata_used);
350 static void print_on(outputStream * out);
351 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
352
353 static void print_class_waste(outputStream* out);
354 static void print_waste(outputStream* out);
355 static void dump(outputStream* out);
356 static void verify_free_chunks();
357 // Checks that the values returned by allocated_capacity_bytes() and
358 // capacity_bytes_slow() are the same.
359 static void verify_capacity();
360 static void verify_used();
361 static void verify_metrics();
362 };
363
364 // Metaspace are deallocated when their class loader are GC'ed.
365 // This class implements a policy for inducing GC's to recover
366 // Metaspaces.
367
368 class MetaspaceGC : AllStatic {
369
370 // The current high-water-mark for inducing a GC.
371 // When committed memory of all metaspaces reaches this value,
372 // a GC is induced and the value is increased. Size is in bytes.
373 static volatile intptr_t _capacity_until_GC;
374
375 // For a CMS collection, signal that a concurrent collection should
376 // be started.
377 static bool _should_concurrent_collect;
378
379 static uint _shrink_factor;
380
381 static size_t shrink_factor() { return _shrink_factor; }
382 void set_shrink_factor(uint v) { _shrink_factor = v; }
383
384 public:
385
386 static void initialize() { _capacity_until_GC = MetaspaceSize; }
387
388 static size_t capacity_until_GC();
389 static size_t inc_capacity_until_GC(size_t v);
390 static size_t dec_capacity_until_GC(size_t v);
391
392 static bool should_concurrent_collect() { return _should_concurrent_collect; }
393 static void set_should_concurrent_collect(bool v) {
394 _should_concurrent_collect = v;
395 }
396
397 // The amount to increase the high-water-mark (_capacity_until_GC)
398 static size_t delta_capacity_until_GC(size_t bytes);
399
400 // Tells if we have can expand metaspace without hitting set limits.
401 static bool can_expand(size_t words, bool is_class);
402
403 // Returns amount that we can expand without hitting a GC,
404 // measured in words.
405 static size_t allowed_expansion();
406
407 // Calculate the new high-water mark at which to induce
408 // a GC.
409 static void compute_new_size();
410 };
411
412 #endif // SHARE_VM_MEMORY_METASPACE_HPP