1 /*
2 * Copyright (c) 2011, 2015, 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
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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
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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 *
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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 "memory/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 friend class CollectorPolicy;
91
92 public:
93 enum MetadataType {
94 ClassType,
95 NonClassType,
96 MetadataTypeCount
97 };
98 enum MetaspaceType {
99 StandardMetaspaceType,
100 BootMetaspaceType,
101 ROMetaspaceType,
102 ReadWriteMetaspaceType,
103 AnonymousMetaspaceType,
104 ReflectionMetaspaceType
105 };
106
107 private:
108 void verify_initialized();
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 MetaWord* expand_and_allocate(size_t size, MetadataType mdtype);
153
154 // Virtual Space lists for both classes and other metadata
155 static VirtualSpaceList* _space_list;
156 static VirtualSpaceList* _class_space_list;
157
158 static ChunkManager* _chunk_manager_metadata;
159 static ChunkManager* _chunk_manager_class;
160
161 static const MetaspaceTracer* _tracer;
162
163 public:
164 static VirtualSpaceList* space_list() { return _space_list; }
165 static VirtualSpaceList* class_space_list() { return _class_space_list; }
166 static VirtualSpaceList* get_space_list(MetadataType mdtype) {
167 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
168 return mdtype == ClassType ? class_space_list() : space_list();
169 }
170
171 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
172 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; }
173 static ChunkManager* get_chunk_manager(MetadataType mdtype) {
174 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
175 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
176 }
177
178 static const MetaspaceTracer* tracer() { return _tracer; }
179
180 private:
181 // These 2 methods are used by DumpSharedSpaces only, where only _vsm is used. So we will
182 // maintain a single list for now.
183 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
184 void record_deallocation(void* ptr, size_t word_size);
185
186 #ifdef _LP64
187 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
188
189 // Returns true if can use CDS with metaspace allocated as specified address.
190 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
191
192 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
193
194 static void initialize_class_space(ReservedSpace rs);
195 #endif
196
197 class AllocRecord : public CHeapObj<mtClass> {
198 public:
199 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
200 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
201 AllocRecord *_next;
202 address _ptr;
203 MetaspaceObj::Type _type;
204 int _byte_size;
205 };
206
207 AllocRecord * _alloc_record_head;
208 AllocRecord * _alloc_record_tail;
209
210 size_t class_chunk_size(size_t word_size);
211
212 public:
213
214 Metaspace(Mutex* lock, MetaspaceType type);
215 ~Metaspace();
216
217 static void ergo_initialize();
218 static void global_initialize();
219 static void post_initialize();
220
221 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
222 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
223
224 static size_t reserve_alignment() { return _reserve_alignment; }
225 static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
226 static size_t commit_alignment() { return _commit_alignment; }
227 static size_t commit_alignment_words() { return _commit_alignment / BytesPerWord; }
228
229 char* bottom() const;
230 size_t used_words_slow(MetadataType mdtype) const;
231 size_t free_words_slow(MetadataType mdtype) const;
232 size_t capacity_words_slow(MetadataType mdtype) const;
233
234 size_t used_bytes_slow(MetadataType mdtype) const;
235 size_t capacity_bytes_slow(MetadataType mdtype) const;
236
237 size_t allocated_blocks_bytes() const;
238 size_t allocated_chunks_bytes() const;
239
240 static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
241 bool read_only, MetaspaceObj::Type type, TRAPS);
242 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
243
244 static bool contains(const void* ptr);
245
246 void dump(outputStream* const out) const;
247
248 // Free empty virtualspaces
249 static void purge(MetadataType mdtype);
250 static void purge();
251
252 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
253 MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
254
255 static const char* metadata_type_name(Metaspace::MetadataType mdtype);
256
257 void print_on(outputStream* st) const;
258 // Debugging support
259 void verify();
260
261 static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
262
263 class AllocRecordClosure : public StackObj {
264 public:
265 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
266 };
267
268 void iterate(AllocRecordClosure *closure);
269
270 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
271 static bool using_class_space() {
272 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
273 }
274
275 static bool is_class_space_allocation(MetadataType mdType) {
276 return mdType == ClassType && using_class_space();
277 }
278
279 };
280
281 class MetaspaceAux : AllStatic {
282 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
283
284 // These methods iterate over the classloader data graph
285 // for the given Metaspace type. These are slow.
286 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
287 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
288 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
289 static size_t capacity_bytes_slow();
290
291 // Running sum of space in all Metachunks that has been
292 // allocated to a Metaspace. This is used instead of
293 // iterating over all the classloaders. One for each
294 // type of Metadata
295 static size_t _capacity_words[Metaspace:: MetadataTypeCount];
296 // Running sum of space in all Metachunks that
297 // are being used for metadata. One for each
298 // type of Metadata.
299 static size_t _used_words[Metaspace:: MetadataTypeCount];
300
301 public:
302 // Decrement and increment _allocated_capacity_words
303 static void dec_capacity(Metaspace::MetadataType type, size_t words);
304 static void inc_capacity(Metaspace::MetadataType type, size_t words);
305
306 // Decrement and increment _allocated_used_words
307 static void dec_used(Metaspace::MetadataType type, size_t words);
308 static void inc_used(Metaspace::MetadataType type, size_t words);
309
310 // Total of space allocated to metadata in all Metaspaces.
311 // This sums the space used in each Metachunk by
312 // iterating over the classloader data graph
313 static size_t used_bytes_slow() {
314 return used_bytes_slow(Metaspace::ClassType) +
315 used_bytes_slow(Metaspace::NonClassType);
316 }
317
318 // Used by MetaspaceCounters
319 static size_t free_chunks_total_words();
320 static size_t free_chunks_total_bytes();
321 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
322
323 static size_t capacity_words(Metaspace::MetadataType mdtype) {
324 return _capacity_words[mdtype];
325 }
326 static size_t capacity_words() {
327 return capacity_words(Metaspace::NonClassType) +
328 capacity_words(Metaspace::ClassType);
329 }
330 static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
331 return capacity_words(mdtype) * BytesPerWord;
332 }
333 static size_t capacity_bytes() {
334 return capacity_words() * BytesPerWord;
335 }
336
337 static size_t used_words(Metaspace::MetadataType mdtype) {
338 return _used_words[mdtype];
339 }
340 static size_t used_words() {
341 return used_words(Metaspace::NonClassType) +
342 used_words(Metaspace::ClassType);
343 }
344 static size_t used_bytes(Metaspace::MetadataType mdtype) {
345 return used_words(mdtype) * BytesPerWord;
346 }
347 static size_t used_bytes() {
348 return used_words() * BytesPerWord;
349 }
350
351 static size_t free_bytes();
352 static size_t free_bytes(Metaspace::MetadataType mdtype);
353
354 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
355 static size_t reserved_bytes() {
356 return reserved_bytes(Metaspace::ClassType) +
357 reserved_bytes(Metaspace::NonClassType);
358 }
359
360 static size_t committed_bytes(Metaspace::MetadataType mdtype);
361 static size_t committed_bytes() {
362 return committed_bytes(Metaspace::ClassType) +
363 committed_bytes(Metaspace::NonClassType);
364 }
365
366 static size_t min_chunk_size_words();
367 static size_t min_chunk_size_bytes() {
368 return min_chunk_size_words() * BytesPerWord;
369 }
370
371 static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
372 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
373
374 // Print change in used metadata.
375 static void print_metaspace_change(size_t prev_metadata_used);
376 static void print_on(outputStream * out);
377 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
378
379 static void print_class_waste(outputStream* out);
380 static void print_waste(outputStream* out);
381 static void dump(outputStream* out);
382 static void verify_free_chunks();
383 // Checks that the values returned by allocated_capacity_bytes() and
384 // capacity_bytes_slow() are the same.
385 static void verify_capacity();
386 static void verify_used();
387 static void verify_metrics();
388 };
389
390 // Metaspace are deallocated when their class loader are GC'ed.
391 // This class implements a policy for inducing GC's to recover
392 // Metaspaces.
393
394 class MetaspaceGC : AllStatic {
395
396 // The current high-water-mark for inducing a GC.
397 // When committed memory of all metaspaces reaches this value,
398 // a GC is induced and the value is increased. Size is in bytes.
399 static volatile intptr_t _capacity_until_GC;
400
401 // For a CMS collection, signal that a concurrent collection should
402 // be started.
403 static bool _should_concurrent_collect;
404
405 static uint _shrink_factor;
406
407 static size_t shrink_factor() { return _shrink_factor; }
408 void set_shrink_factor(uint v) { _shrink_factor = v; }
409
410 public:
411
412 static void initialize();
413 static void post_initialize();
414
415 static size_t capacity_until_GC();
416 static bool inc_capacity_until_GC(size_t v,
417 size_t* new_cap_until_GC = NULL,
418 size_t* old_cap_until_GC = NULL);
419 static size_t dec_capacity_until_GC(size_t v);
420
421 static bool should_concurrent_collect() { return _should_concurrent_collect; }
422 static void set_should_concurrent_collect(bool v) {
423 _should_concurrent_collect = v;
424 }
425
426 // The amount to increase the high-water-mark (_capacity_until_GC)
427 static size_t delta_capacity_until_GC(size_t bytes);
428
429 // Tells if we have can expand metaspace without hitting set limits.
430 static bool can_expand(size_t words, bool is_class);
431
432 // Returns amount that we can expand without hitting a GC,
433 // measured in words.
434 static size_t allowed_expansion();
435
436 // Calculate the new high-water mark at which to induce
437 // a GC.
438 static void compute_new_size();
439 };
440
441 #endif // SHARE_VM_MEMORY_METASPACE_HPP