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 {ClassType = 0,
91 NonClassType = ClassType + 1,
92 MetadataTypeCount = ClassType + 2
93 };
94 enum MetaspaceType {
95 StandardMetaspaceType,
96 BootMetaspaceType,
97 ROMetaspaceType,
98 ReadWriteMetaspaceType,
99 AnonymousMetaspaceType,
100 ReflectionMetaspaceType
101 };
102
103 private:
104 void initialize(Mutex* lock, MetaspaceType type);
105
106 Metachunk* get_initialization_chunk(MetadataType mdtype,
107 size_t chunk_word_size,
108 size_t chunk_bunch);
109
110 // Align up the word size to the allocation word size
111 static size_t align_word_size_up(size_t);
112
113 // Aligned size of the metaspace.
114 static size_t _class_metaspace_size;
115
116 static size_t class_metaspace_size() {
117 return _class_metaspace_size;
118 }
119 static void set_class_metaspace_size(size_t metaspace_size) {
120 _class_metaspace_size = metaspace_size;
121 }
122
123 static size_t _first_chunk_word_size;
124 static size_t _first_class_chunk_word_size;
125
126 SpaceManager* _vsm;
127 SpaceManager* vsm() const { return _vsm; }
128
129 SpaceManager* _class_vsm;
130 SpaceManager* class_vsm() const { return _class_vsm; }
131
132 // Allocate space for metadata of type mdtype. This is space
133 // within a Metachunk and is used by
134 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
135 // which returns a Metablock.
136 MetaWord* allocate(size_t word_size, MetadataType mdtype);
137
138 // Virtual Space lists for both classes and other metadata
139 static VirtualSpaceList* _space_list;
140 static VirtualSpaceList* _class_space_list;
141
142 static ChunkManager* _chunk_manager_metadata;
143 static ChunkManager* _chunk_manager_class;
144
145 public:
146 static VirtualSpaceList* space_list() { return _space_list; }
147 static VirtualSpaceList* class_space_list() { return _class_space_list; }
148 static VirtualSpaceList* get_space_list(MetadataType mdtype) {
149 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
150 return mdtype == ClassType ? class_space_list() : space_list();
151 }
152
153 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
154 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
155 static ChunkManager* get_chunk_manager(MetadataType mdtype) {
156 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
157 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
158 }
159
160 private:
161 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
162 // maintain a single list for now.
163 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
164
165 #ifdef _LP64
166 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
167
168 // Returns true if can use CDS with metaspace allocated as specified address.
169 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
170
171 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
172
173 static void initialize_class_space(ReservedSpace rs);
174 #endif
175
176 class AllocRecord : public CHeapObj<mtClass> {
177 public:
178 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
179 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
180 AllocRecord *_next;
181 address _ptr;
182 MetaspaceObj::Type _type;
183 int _byte_size;
184 };
185
186 AllocRecord * _alloc_record_head;
187 AllocRecord * _alloc_record_tail;
188
189 public:
190
191 Metaspace(Mutex* lock, MetaspaceType type);
192 ~Metaspace();
193
194 // Initialize globals for Metaspace
195 static void global_initialize();
196
197 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
198 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
199
200 char* bottom() const;
201 size_t used_words_slow(MetadataType mdtype) const;
202 size_t free_words_slow(MetadataType mdtype) const;
203 size_t capacity_words_slow(MetadataType mdtype) const;
204
205 size_t used_bytes_slow(MetadataType mdtype) const;
206 size_t capacity_bytes_slow(MetadataType mdtype) const;
207
208 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size,
209 bool read_only, MetaspaceObj::Type type, TRAPS);
210 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
211
212 MetaWord* expand_and_allocate(size_t size,
213 MetadataType mdtype);
214
215 static bool contains(const void *ptr);
216 void dump(outputStream* const out) const;
217
218 // Free empty virtualspaces
219 static void purge(MetadataType mdtype);
220 static void purge();
221
222 void print_on(outputStream* st) const;
223 // Debugging support
224 void verify();
225
226 class AllocRecordClosure : public StackObj {
227 public:
228 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
229 };
230
231 void iterate(AllocRecordClosure *closure);
232
233 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
234 static bool using_class_space() {
235 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
236 }
237
238 static bool is_class_space_allocation(MetadataType mdType) {
239 return mdType == ClassType && using_class_space();
240 }
241 };
242
243 class MetaspaceAux : AllStatic {
244 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
245
246 // These methods iterate over the classloader data graph
247 // for the given Metaspace type. These are slow.
248 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
249 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
250 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
251 static size_t capacity_bytes_slow();
252
253 // Running sum of space in all Metachunks that has been
254 // allocated to a Metaspace. This is used instead of
255 // iterating over all the classloaders. One for each
256 // type of Metadata
257 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount];
258 // Running sum of space in all Metachunks that have
259 // are being used for metadata. One for each
260 // type of Metadata.
261 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount];
262
263 public:
264 // Decrement and increment _allocated_capacity_words
265 static void dec_capacity(Metaspace::MetadataType type, size_t words);
266 static void inc_capacity(Metaspace::MetadataType type, size_t words);
267
268 // Decrement and increment _allocated_used_words
269 static void dec_used(Metaspace::MetadataType type, size_t words);
270 static void inc_used(Metaspace::MetadataType type, size_t words);
271
272 // Total of space allocated to metadata in all Metaspaces.
273 // This sums the space used in each Metachunk by
274 // iterating over the classloader data graph
275 static size_t used_bytes_slow() {
276 return used_bytes_slow(Metaspace::ClassType) +
277 used_bytes_slow(Metaspace::NonClassType);
278 }
279
280 // Used by MetaspaceCounters
281 static size_t free_chunks_total_words();
282 static size_t free_chunks_total_bytes();
283 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
284
285 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) {
286 return _allocated_capacity_words[mdtype];
287 }
288 static size_t allocated_capacity_words() {
289 return allocated_capacity_words(Metaspace::NonClassType) +
290 allocated_capacity_words(Metaspace::ClassType);
291 }
292 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) {
293 return allocated_capacity_words(mdtype) * BytesPerWord;
294 }
295 static size_t allocated_capacity_bytes() {
296 return allocated_capacity_words() * BytesPerWord;
297 }
298
299 static size_t allocated_used_words(Metaspace::MetadataType mdtype) {
300 return _allocated_used_words[mdtype];
301 }
302 static size_t allocated_used_words() {
303 return allocated_used_words(Metaspace::NonClassType) +
304 allocated_used_words(Metaspace::ClassType);
305 }
306 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) {
307 return allocated_used_words(mdtype) * BytesPerWord;
308 }
309 static size_t allocated_used_bytes() {
310 return allocated_used_words() * BytesPerWord;
311 }
312
313 static size_t free_bytes();
314 static size_t free_bytes(Metaspace::MetadataType mdtype);
315
316 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
317 static size_t reserved_bytes() {
318 return reserved_bytes(Metaspace::ClassType) +
319 reserved_bytes(Metaspace::NonClassType);
320 }
321
322 static size_t committed_bytes(Metaspace::MetadataType mdtype);
323 static size_t committed_bytes() {
324 return committed_bytes(Metaspace::ClassType) +
325 committed_bytes(Metaspace::NonClassType);
326 }
327
328 static size_t min_chunk_size_words();
329 static size_t min_chunk_size_bytes() {
330 return min_chunk_size_words() * BytesPerWord;
331 }
332
333 // Print change in used metadata.
334 static void print_metaspace_change(size_t prev_metadata_used);
335 static void print_on(outputStream * out);
336 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
337
338 static void print_class_waste(outputStream* out);
339 static void print_waste(outputStream* out);
340 static void dump(outputStream* out);
341 static void verify_free_chunks();
342 // Checks that the values returned by allocated_capacity_bytes() and
343 // capacity_bytes_slow() are the same.
344 static void verify_capacity();
345 static void verify_used();
346 static void verify_metrics();
347 };
348
349 // Metaspace are deallocated when their class loader are GC'ed.
350 // This class implements a policy for inducing GC's to recover
351 // Metaspaces.
352
353 class MetaspaceGC : AllStatic {
354
355 // The current high-water-mark for inducing a GC. When
356 // the capacity of all space in the virtual lists reaches this value,
357 // a GC is induced and the value is increased. This should be changed
358 // to the space actually used for allocations to avoid affects of
359 // fragmentation losses to partially used chunks. Size is in words.
360 static size_t _capacity_until_GC;
361
362 // After a GC is done any allocation that fails should try to expand
363 // the capacity of the Metaspaces. This flag is set during attempts
364 // to allocate in the VMGCOperation that does the GC.
365 static bool _expand_after_GC;
366
367 // For a CMS collection, signal that a concurrent collection should
368 // be started.
369 static bool _should_concurrent_collect;
370
371 static uint _shrink_factor;
372
373 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }
374
375 static size_t shrink_factor() { return _shrink_factor; }
376 void set_shrink_factor(uint v) { _shrink_factor = v; }
377
378 public:
379
380 static size_t capacity_until_GC() { return _capacity_until_GC; }
381 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
382 static void dec_capacity_until_GC(size_t v) {
383 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
384 }
385 static bool expand_after_GC() { return _expand_after_GC; }
386 static void set_expand_after_GC(bool v) { _expand_after_GC = v; }
387
388 static bool should_concurrent_collect() { return _should_concurrent_collect; }
389 static void set_should_concurrent_collect(bool v) {
390 _should_concurrent_collect = v;
391 }
392
393 // The amount to increase the high-water-mark (_capacity_until_GC)
394 static size_t delta_capacity_until_GC(size_t word_size);
395
396 // It is expected that this will be called when the current capacity
397 // has been used and a GC should be considered.
398 static bool should_expand(VirtualSpaceList* vsl, size_t word_size);
399
400 // Calculate the new high-water mark at which to induce
401 // a GC.
402 static void compute_new_size();
403 };
404
405 #endif // SHARE_VM_MEMORY_METASPACE_HPP