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