1 /*
2 * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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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 static void verify_global_initialization();
108
109 void initialize(Mutex* lock, MetaspaceType type);
110
111 // Initialize the first chunk for a Metaspace. Used for
112 // special cases such as the boot class loader, reflection
113 // class loader and anonymous class loader.
114 void initialize_first_chunk(MetaspaceType type, MetadataType mdtype);
115 Metachunk* get_initialization_chunk(MetaspaceType type, MetadataType mdtype);
116
117 // Align up the word size to the allocation word size
118 static size_t align_word_size_up(size_t);
119
120 // Aligned size of the metaspace.
121 static size_t _compressed_class_space_size;
122
123 static size_t compressed_class_space_size() {
124 return _compressed_class_space_size;
125 }
126
127 static void set_compressed_class_space_size(size_t size) {
128 _compressed_class_space_size = size;
129 }
130
131 static size_t _first_chunk_word_size;
132 static size_t _first_class_chunk_word_size;
133
134 static size_t _commit_alignment;
135 static size_t _reserve_alignment;
136
137 SpaceManager* _vsm;
138 SpaceManager* vsm() const { return _vsm; }
139
140 SpaceManager* _class_vsm;
141 SpaceManager* class_vsm() const { return _class_vsm; }
142 SpaceManager* get_space_manager(MetadataType mdtype) {
143 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
144 return mdtype == ClassType ? class_vsm() : vsm();
145 }
146
147 // Allocate space for metadata of type mdtype. This is space
148 // within a Metachunk and is used by
149 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
150 MetaWord* allocate(size_t word_size, MetadataType mdtype);
151
152 // Virtual Space lists for both classes and other metadata
153 static VirtualSpaceList* _space_list;
154 static VirtualSpaceList* _class_space_list;
155
156 static ChunkManager* _chunk_manager_metadata;
157 static ChunkManager* _chunk_manager_class;
158
159 static const MetaspaceTracer* _tracer;
160
161 public:
162 static VirtualSpaceList* space_list() { return _space_list; }
163 static VirtualSpaceList* class_space_list() { return _class_space_list; }
164 static VirtualSpaceList* get_space_list(MetadataType mdtype) {
165 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
166 return mdtype == ClassType ? class_space_list() : space_list();
167 }
168
169 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
170 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
171 static ChunkManager* get_chunk_manager(MetadataType mdtype) {
172 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
173 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
174 }
175
176 static const MetaspaceTracer* tracer() { return _tracer; }
177
178 private:
179 // These 2 methods are used by DumpSharedSpaces only, where only _vsm is used. So we will
180 // maintain a single list for now.
181 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
182 void record_deallocation(void* ptr, size_t word_size);
183
184 #ifdef _LP64
185 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
186
187 // Returns true if can use CDS with metaspace allocated as specified address.
188 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
189
190 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
191
192 static void initialize_class_space(ReservedSpace rs);
193 #endif
194
195 class AllocRecord : public CHeapObj<mtClass> {
196 public:
197 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
198 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
199 AllocRecord *_next;
200 address _ptr;
201 MetaspaceObj::Type _type;
202 int _byte_size;
203 };
204
205 AllocRecord * _alloc_record_head;
206 AllocRecord * _alloc_record_tail;
207
208 size_t class_chunk_size(size_t word_size);
209
210 public:
211
212 Metaspace(Mutex* lock, MetaspaceType type);
213 ~Metaspace();
214
215 static void ergo_initialize();
216 static void global_initialize();
217 static void post_initialize();
218
219 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
220 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
221
222 static size_t reserve_alignment() { return _reserve_alignment; }
223 static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
224 static size_t commit_alignment() { return _commit_alignment; }
225 static size_t commit_alignment_words() { return _commit_alignment / BytesPerWord; }
226
227 char* bottom() const;
228 size_t used_words_slow(MetadataType mdtype) const;
229 size_t free_words_slow(MetadataType mdtype) const;
230 size_t capacity_words_slow(MetadataType mdtype) const;
231
232 size_t used_bytes_slow(MetadataType mdtype) const;
233 size_t capacity_bytes_slow(MetadataType mdtype) const;
234
235 size_t allocated_blocks_bytes() const;
236 size_t allocated_chunks_bytes() const;
237
238 static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
239 bool read_only, MetaspaceObj::Type type, TRAPS);
240 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
241
242 MetaWord* expand_and_allocate(size_t size,
243 MetadataType mdtype);
244
245 static bool contains(const void* ptr);
246
247 void dump(outputStream* const out) const;
248
249 // Free empty virtualspaces
250 static void purge(MetadataType mdtype);
251 static void purge();
252
253 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
254 MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
255
256 static const char* metadata_type_name(Metaspace::MetadataType mdtype);
257
258 void print_on(outputStream* st) const;
259 // Debugging support
260 void verify();
261
262 class AllocRecordClosure : public StackObj {
263 public:
264 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
265 };
266
267 void iterate(AllocRecordClosure *closure);
268
269 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
270 static bool using_class_space() {
271 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
272 }
273
274 static bool is_class_space_allocation(MetadataType mdType) {
275 return mdType == ClassType && using_class_space();
276 }
277
278 };
279
280 class MetaspaceAux : AllStatic {
281 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
282
283 // These methods iterate over the classloader data graph
284 // for the given Metaspace type. These are slow.
285 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
286 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
287 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
288 static size_t capacity_bytes_slow();
289
290 // Running sum of space in all Metachunks that has been
291 // allocated to a Metaspace. This is used instead of
292 // iterating over all the classloaders. One for each
293 // type of Metadata
294 static size_t _capacity_words[Metaspace:: MetadataTypeCount];
295 // Running sum of space in all Metachunks that
296 // are being used for metadata. One for each
297 // type of Metadata.
298 static size_t _used_words[Metaspace:: MetadataTypeCount];
299
300 public:
301 // Decrement and increment _allocated_capacity_words
302 static void dec_capacity(Metaspace::MetadataType type, size_t words);
303 static void inc_capacity(Metaspace::MetadataType type, size_t words);
304
305 // Decrement and increment _allocated_used_words
306 static void dec_used(Metaspace::MetadataType type, size_t words);
307 static void inc_used(Metaspace::MetadataType type, size_t words);
308
309 // Total of space allocated to metadata in all Metaspaces.
310 // This sums the space used in each Metachunk by
311 // iterating over the classloader data graph
312 static size_t used_bytes_slow() {
313 return used_bytes_slow(Metaspace::ClassType) +
314 used_bytes_slow(Metaspace::NonClassType);
315 }
316
317 // Used by MetaspaceCounters
318 static size_t free_chunks_total_words();
319 static size_t free_chunks_total_bytes();
320 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
321
322 static size_t capacity_words(Metaspace::MetadataType mdtype) {
323 return _capacity_words[mdtype];
324 }
325 static size_t capacity_words() {
326 return capacity_words(Metaspace::NonClassType) +
327 capacity_words(Metaspace::ClassType);
328 }
329 static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
330 return capacity_words(mdtype) * BytesPerWord;
331 }
332 static size_t capacity_bytes() {
333 return capacity_words() * BytesPerWord;
334 }
335
336 static size_t used_words(Metaspace::MetadataType mdtype) {
337 return _used_words[mdtype];
338 }
339 static size_t used_words() {
340 return used_words(Metaspace::NonClassType) +
341 used_words(Metaspace::ClassType);
342 }
343 static size_t used_bytes(Metaspace::MetadataType mdtype) {
344 return used_words(mdtype) * BytesPerWord;
345 }
346 static size_t used_bytes() {
347 return used_words() * BytesPerWord;
348 }
349
350 static size_t free_bytes();
351 static size_t free_bytes(Metaspace::MetadataType mdtype);
352
353 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
354 static size_t reserved_bytes() {
355 return reserved_bytes(Metaspace::ClassType) +
356 reserved_bytes(Metaspace::NonClassType);
357 }
358
359 static size_t committed_bytes(Metaspace::MetadataType mdtype);
360 static size_t committed_bytes() {
361 return committed_bytes(Metaspace::ClassType) +
362 committed_bytes(Metaspace::NonClassType);
363 }
364
365 static size_t min_chunk_size_words();
366 static size_t min_chunk_size_bytes() {
367 return min_chunk_size_words() * BytesPerWord;
368 }
369
370 static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
371 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
372
373 // Print change in used metadata.
374 static void print_metaspace_change(size_t prev_metadata_used);
375 static void print_on(outputStream * out);
376 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
377
378 static void print_class_waste(outputStream* out);
379 static void print_waste(outputStream* out);
380 static void dump(outputStream* out);
381 static void verify_free_chunks();
382 // Checks that the values returned by allocated_capacity_bytes() and
383 // capacity_bytes_slow() are the same.
384 static void verify_capacity();
385 static void verify_used();
386 static void verify_metrics();
387 };
388
389 // Metaspace are deallocated when their class loader are GC'ed.
390 // This class implements a policy for inducing GC's to recover
391 // Metaspaces.
392
393 class MetaspaceGC : AllStatic {
394
395 // The current high-water-mark for inducing a GC.
396 // When committed memory of all metaspaces reaches this value,
397 // a GC is induced and the value is increased. Size is in bytes.
398 static volatile intptr_t _capacity_until_GC;
399
400 // For a CMS collection, signal that a concurrent collection should
401 // be started.
402 static bool _should_concurrent_collect;
403
404 static uint _shrink_factor;
405
406 static size_t shrink_factor() { return _shrink_factor; }
407 void set_shrink_factor(uint v) { _shrink_factor = v; }
408
409 public:
410
411 static void initialize();
412 static void post_initialize();
413
414 static size_t capacity_until_GC();
415 static bool inc_capacity_until_GC(size_t v,
416 size_t* new_cap_until_GC = NULL,
417 size_t* old_cap_until_GC = NULL);
418 static size_t dec_capacity_until_GC(size_t v);
419
420 static bool should_concurrent_collect() { return _should_concurrent_collect; }
421 static void set_should_concurrent_collect(bool v) {
422 _should_concurrent_collect = v;
423 }
424
425 // The amount to increase the high-water-mark (_capacity_until_GC)
426 static size_t delta_capacity_until_GC(size_t bytes);
427
428 // Tells if we have can expand metaspace without hitting set limits.
429 static bool can_expand(size_t words, bool is_class);
430
431 // Returns amount that we can expand without hitting a GC,
432 // measured in words.
433 static size_t allowed_expansion();
434
435 // Calculate the new high-water mark at which to induce
436 // a GC.
437 static void compute_new_size();
438 };
439
440 #endif // SHARE_VM_MEMORY_METASPACE_HPP