1 /*
2 * Copyright (c) 2011, 2014, 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 "memory/metaspaceChunkFreeListSummary.hpp"
30 #include "runtime/virtualspace.hpp"
31 #include "utilities/exceptions.hpp"
32
33 // Metaspace
34 //
35 // Metaspaces are Arenas for the VM's metadata.
36 // They are allocated one per class loader object, and one for the null
37 // bootstrap class loader
38 // Eventually for bootstrap loader we'll have a read-only section and read-write
39 // to write for DumpSharedSpaces and read for UseSharedSpaces
40 //
41 // block X ---+ +-------------------+
42 // | | Virtualspace |
43 // | | |
44 // | | |
45 // | |-------------------|
46 // | || Chunk |
47 // | || |
48 // | ||---------- |
49 // +------>||| block 0 | |
50 // ||---------- |
51 // ||| block 1 | |
52 // ||---------- |
53 // || |
54 // |-------------------|
55 // | |
56 // | |
57 // +-------------------+
58 //
59
60 class ChunkManager;
61 class ClassLoaderData;
62 class Metablock;
63 class Metachunk;
64 class MetaspaceTracer;
65 class MetaWord;
66 class Mutex;
67 class outputStream;
68 class SpaceManager;
69 class VirtualSpaceList;
70
71 // Metaspaces each have a SpaceManager and allocations
72 // are done by the SpaceManager. Allocations are done
73 // out of the current Metachunk. When the current Metachunk
74 // is exhausted, the SpaceManager gets a new one from
75 // the current VirtualSpace. When the VirtualSpace is exhausted
76 // the SpaceManager gets a new one. The SpaceManager
77 // also manages freelists of available Chunks.
78 //
79 // Currently the space manager maintains the list of
80 // virtual spaces and the list of chunks in use. Its
81 // allocate() method returns a block for use as a
82 // quantum of metadata.
83
84 class Metaspace : public CHeapObj<mtClass> {
85 friend class VMStructs;
86 friend class SpaceManager;
87 friend class VM_CollectForMetadataAllocation;
88 friend class MetaspaceGC;
89 friend class MetaspaceAux;
90
91 public:
92 enum MetadataType {
93 ClassType,
94 NonClassType,
95 MetadataTypeCount
96 };
97 enum MetaspaceType {
98 StandardMetaspaceType,
99 BootMetaspaceType,
100 ROMetaspaceType,
101 ReadWriteMetaspaceType,
102 AnonymousMetaspaceType,
103 ReflectionMetaspaceType
104 };
105
106 private:
107 void initialize(Mutex* lock, MetaspaceType type);
108
109 // Get the first chunk for a Metaspace. Used for
110 // special cases such as the boot class loader, reflection
111 // class loader and anonymous class loader.
112 Metachunk* get_initialization_chunk(MetadataType mdtype,
113 size_t chunk_word_size,
114 size_t chunk_bunch);
115
116 // Align up the word size to the allocation word size
117 static size_t align_word_size_up(size_t);
118
119 // Aligned size of the metaspace.
120 static size_t _compressed_class_space_size;
121
122 static size_t compressed_class_space_size() {
123 return _compressed_class_space_size;
124 }
125
126 static void set_compressed_class_space_size(size_t size) {
127 _compressed_class_space_size = size;
128 }
129
130 static size_t _first_chunk_word_size;
131 static size_t _first_class_chunk_word_size;
132
133 static size_t _commit_alignment;
134 static size_t _reserve_alignment;
135
136 SpaceManager* _vsm;
137 SpaceManager* vsm() const { return _vsm; }
138
139 SpaceManager* _class_vsm;
140 SpaceManager* class_vsm() const { return _class_vsm; }
141
142 // Allocate space for metadata of type mdtype. This is space
143 // within a Metachunk and is used by
144 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
145 MetaWord* allocate(size_t word_size, MetadataType mdtype);
146
147 // Virtual Space lists for both classes and other metadata
148 static VirtualSpaceList* _space_list;
149 static VirtualSpaceList* _class_space_list;
150
151 static ChunkManager* _chunk_manager_metadata;
152 static ChunkManager* _chunk_manager_class;
153
154 static const MetaspaceTracer* _tracer;
155
156 public:
157 static VirtualSpaceList* space_list() { return _space_list; }
158 static VirtualSpaceList* class_space_list() { return _class_space_list; }
159 static VirtualSpaceList* get_space_list(MetadataType mdtype) {
160 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
161 return mdtype == ClassType ? class_space_list() : space_list();
162 }
163
164 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
165 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
166 static ChunkManager* get_chunk_manager(MetadataType mdtype) {
167 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
168 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
169 }
170
171 static const MetaspaceTracer* tracer() { return _tracer; }
172
173 private:
174 // These 2 methods are used by DumpSharedSpaces only, where only _vsm is used. So we will
175 // maintain a single list for now.
176 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
177 void record_deallocation(void* ptr, size_t word_size);
178
179 #ifdef _LP64
180 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
181
182 // Returns true if can use CDS with metaspace allocated as specified address.
183 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
184
185 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
186
187 static void initialize_class_space(ReservedSpace rs);
188 #endif
189
190 class AllocRecord : public CHeapObj<mtClass> {
191 public:
192 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
193 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
194 AllocRecord *_next;
195 address _ptr;
196 MetaspaceObj::Type _type;
197 int _byte_size;
198 };
199
200 AllocRecord * _alloc_record_head;
201 AllocRecord * _alloc_record_tail;
202
203 size_t class_chunk_size(size_t word_size);
204
205 public:
206
207 Metaspace(Mutex* lock, MetaspaceType type);
208 ~Metaspace();
209
210 static void ergo_initialize();
211 static void global_initialize();
212 static void post_initialize();
213
214 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
215 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
216
217 static size_t reserve_alignment() { return _reserve_alignment; }
218 static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
219 static size_t commit_alignment() { return _commit_alignment; }
220 static size_t commit_alignment_words() { return _commit_alignment / BytesPerWord; }
221
222 char* bottom() const;
223 size_t used_words_slow(MetadataType mdtype) const;
224 size_t free_words_slow(MetadataType mdtype) const;
225 size_t capacity_words_slow(MetadataType mdtype) const;
226
227 size_t used_bytes_slow(MetadataType mdtype) const;
228 size_t capacity_bytes_slow(MetadataType mdtype) const;
229
230 size_t allocated_blocks_bytes() const;
231 size_t allocated_chunks_bytes() const;
232
233 static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
234 bool read_only, MetaspaceObj::Type type, TRAPS);
235 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
236
237 MetaWord* expand_and_allocate(size_t size,
238 MetadataType mdtype);
239
240 static bool contains(const void* ptr);
241
242 void dump(outputStream* const out) const;
243
244 // Free empty virtualspaces
245 static void purge(MetadataType mdtype);
246 static void purge();
247
248 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
249 MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
250
251 static const char* metadata_type_name(Metaspace::MetadataType mdtype);
252
253 void print_on(outputStream* st) const;
254 // Debugging support
255 void verify();
256
257 class AllocRecordClosure : public StackObj {
258 public:
259 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
260 };
261
262 void iterate(AllocRecordClosure *closure);
263
264 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
265 static bool using_class_space() {
266 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
267 }
268
269 static bool is_class_space_allocation(MetadataType mdType) {
270 return mdType == ClassType && using_class_space();
271 }
272
273 };
274
275 class MetaspaceAux : AllStatic {
276 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
277
278 // These methods iterate over the classloader data graph
279 // for the given Metaspace type. These are slow.
280 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
281 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
282 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
283 static size_t capacity_bytes_slow();
284
285 // Running sum of space in all Metachunks that has been
286 // allocated to a Metaspace. This is used instead of
287 // iterating over all the classloaders. One for each
288 // type of Metadata
289 static size_t _capacity_words[Metaspace:: MetadataTypeCount];
290 // Running sum of space in all Metachunks that
291 // are being used for metadata. One for each
292 // type of Metadata.
293 static size_t _used_words[Metaspace:: MetadataTypeCount];
294
295 public:
296 // Decrement and increment _allocated_capacity_words
297 static void dec_capacity(Metaspace::MetadataType type, size_t words);
298 static void inc_capacity(Metaspace::MetadataType type, size_t words);
299
300 // Decrement and increment _allocated_used_words
301 static void dec_used(Metaspace::MetadataType type, size_t words);
302 static void inc_used(Metaspace::MetadataType type, size_t words);
303
304 // Total of space allocated to metadata in all Metaspaces.
305 // This sums the space used in each Metachunk by
306 // iterating over the classloader data graph
307 static size_t used_bytes_slow() {
308 return used_bytes_slow(Metaspace::ClassType) +
309 used_bytes_slow(Metaspace::NonClassType);
310 }
311
312 // Used by MetaspaceCounters
313 static size_t free_chunks_total_words();
314 static size_t free_chunks_total_bytes();
315 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
316
317 static size_t capacity_words(Metaspace::MetadataType mdtype) {
318 return _capacity_words[mdtype];
319 }
320 static size_t capacity_words() {
321 return capacity_words(Metaspace::NonClassType) +
322 capacity_words(Metaspace::ClassType);
323 }
324 static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
325 return capacity_words(mdtype) * BytesPerWord;
326 }
327 static size_t capacity_bytes() {
328 return capacity_words() * BytesPerWord;
329 }
330
331 static size_t used_words(Metaspace::MetadataType mdtype) {
332 return _used_words[mdtype];
333 }
334 static size_t used_words() {
335 return used_words(Metaspace::NonClassType) +
336 used_words(Metaspace::ClassType);
337 }
338 static size_t used_bytes(Metaspace::MetadataType mdtype) {
339 return used_words(mdtype) * BytesPerWord;
340 }
341 static size_t used_bytes() {
342 return used_words() * BytesPerWord;
343 }
344
345 static size_t free_bytes();
346 static size_t free_bytes(Metaspace::MetadataType mdtype);
347
348 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
349 static size_t reserved_bytes() {
350 return reserved_bytes(Metaspace::ClassType) +
351 reserved_bytes(Metaspace::NonClassType);
352 }
353
354 static size_t committed_bytes(Metaspace::MetadataType mdtype);
355 static size_t committed_bytes() {
356 return committed_bytes(Metaspace::ClassType) +
357 committed_bytes(Metaspace::NonClassType);
358 }
359
360 static size_t min_chunk_size_words();
361 static size_t min_chunk_size_bytes() {
362 return min_chunk_size_words() * BytesPerWord;
363 }
364
365 static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
366 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
367
368 // Print change in used metadata.
369 static void print_metaspace_change(size_t prev_metadata_used);
370 static void print_on(outputStream * out);
371 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
372
373 static void print_class_waste(outputStream* out);
374 static void print_waste(outputStream* out);
375 static void dump(outputStream* out);
376 static void verify_free_chunks();
377 // Checks that the values returned by allocated_capacity_bytes() and
378 // capacity_bytes_slow() are the same.
379 static void verify_capacity();
380 static void verify_used();
381 static void verify_metrics();
382 };
383
384 // Metaspace are deallocated when their class loader are GC'ed.
385 // This class implements a policy for inducing GC's to recover
386 // Metaspaces.
387
388 class MetaspaceGC : AllStatic {
389
390 // The current high-water-mark for inducing a GC.
391 // When committed memory of all metaspaces reaches this value,
392 // a GC is induced and the value is increased. Size is in bytes.
393 static volatile intptr_t _capacity_until_GC;
394
395 // For a CMS collection, signal that a concurrent collection should
396 // be started.
397 static bool _should_concurrent_collect;
398
399 static uint _shrink_factor;
400
401 static size_t shrink_factor() { return _shrink_factor; }
402 void set_shrink_factor(uint v) { _shrink_factor = v; }
403
404 public:
405
406 static void initialize();
407 static void post_initialize();
408
409 static size_t capacity_until_GC();
410 static size_t inc_capacity_until_GC(size_t v);
411 static size_t dec_capacity_until_GC(size_t v);
412
413 static bool should_concurrent_collect() { return _should_concurrent_collect; }
414 static void set_should_concurrent_collect(bool v) {
415 _should_concurrent_collect = v;
416 }
417
418 // The amount to increase the high-water-mark (_capacity_until_GC)
419 static size_t delta_capacity_until_GC(size_t bytes);
420
421 // Tells if we have can expand metaspace without hitting set limits.
422 static bool can_expand(size_t words, bool is_class);
423
424 // Returns amount that we can expand without hitting a GC,
425 // measured in words.
426 static size_t allowed_expansion();
427
428 // Calculate the new high-water mark at which to induce
429 // a GC.
430 static void compute_new_size();
431 };
432
433 #endif // SHARE_VM_MEMORY_METASPACE_HPP