1 /*
2 * Copyright (c) 2011, 2019, 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 *
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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 "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 ShenandoahCollectorPolicy;
69 class SpaceManager;
70 class VirtualSpaceList;
71
72 // Metaspaces each have a SpaceManager and allocations
73 // are done by the SpaceManager. Allocations are done
74 // out of the current Metachunk. When the current Metachunk
75 // is exhausted, the SpaceManager gets a new one from
76 // the current VirtualSpace. When the VirtualSpace is exhausted
77 // the SpaceManager gets a new one. The SpaceManager
78 // also manages freelists of available Chunks.
79 //
80 // Currently the space manager maintains the list of
81 // virtual spaces and the list of chunks in use. Its
82 // allocate() method returns a block for use as a
83 // quantum of metadata.
84
85 class Metaspace : public CHeapObj<mtClass> {
86 friend class VMStructs;
87 friend class SpaceManager;
88 friend class VM_CollectForMetadataAllocation;
89 friend class MetaspaceGC;
90 friend class MetaspaceAux;
91 friend class ShenandoahCollectorPolicy;
92
93 public:
94 enum MetadataType {
95 ClassType,
96 NonClassType,
97 MetadataTypeCount
98 };
99 enum MetaspaceType {
100 StandardMetaspaceType,
101 BootMetaspaceType,
102 ROMetaspaceType,
103 ReadWriteMetaspaceType,
104 AnonymousMetaspaceType,
105 ReflectionMetaspaceType
106 };
107
108 private:
109 static void verify_global_initialization();
110
111 void initialize(Mutex* lock, MetaspaceType type);
112
113 // Initialize the first chunk for a Metaspace. Used for
114 // special cases such as the boot class loader, reflection
115 // class loader and anonymous class loader.
116 void initialize_first_chunk(MetaspaceType type, MetadataType mdtype);
117 Metachunk* get_initialization_chunk(MetaspaceType type, MetadataType mdtype);
118
119 // Align up the word size to the allocation word size
120 static size_t align_word_size_up(size_t);
121
122 // Aligned size of the metaspace.
123 static size_t _compressed_class_space_size;
124
125 static size_t compressed_class_space_size() {
126 return _compressed_class_space_size;
127 }
128
129 static void set_compressed_class_space_size(size_t size) {
130 _compressed_class_space_size = size;
131 }
132
133 static size_t _first_chunk_word_size;
134 static size_t _first_class_chunk_word_size;
135
136 static size_t _commit_alignment;
137 static size_t _reserve_alignment;
138
139 SpaceManager* _vsm;
140 SpaceManager* vsm() const { return _vsm; }
141
142 SpaceManager* _class_vsm;
143 SpaceManager* class_vsm() const { return _class_vsm; }
144 SpaceManager* get_space_manager(MetadataType mdtype) {
145 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
146 return mdtype == ClassType ? class_vsm() : vsm();
147 }
148
149 // Allocate space for metadata of type mdtype. This is space
150 // within a Metachunk and is used by
151 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
152 MetaWord* allocate(size_t word_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 MetaWord* expand_and_allocate(size_t size,
245 MetadataType mdtype);
246
247 static bool contains(const void* ptr);
248
249 void dump(outputStream* const out) const;
250
251 // Free empty virtualspaces
252 static void purge(MetadataType mdtype);
253 static void purge();
254
255 static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
256 MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
257
258 static const char* metadata_type_name(Metaspace::MetadataType mdtype);
259
260 void print_on(outputStream* st) const;
261 // Debugging support
262 void verify();
263
264 static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
265
266 class AllocRecordClosure : public StackObj {
267 public:
268 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
269 };
270
271 void iterate(AllocRecordClosure *closure);
272
273 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
274 static bool using_class_space() {
275 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
276 }
277
278 static bool is_class_space_allocation(MetadataType mdType) {
279 return mdType == ClassType && using_class_space();
280 }
281
282 };
283
284 class MetaspaceAux : AllStatic {
285 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
286
287 // These methods iterate over the classloader data graph
288 // for the given Metaspace type. These are slow.
289 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
290 static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
291 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
292 static size_t capacity_bytes_slow();
293
294 // Running sum of space in all Metachunks that has been
295 // allocated to a Metaspace. This is used instead of
296 // iterating over all the classloaders. One for each
297 // type of Metadata
298 static size_t _capacity_words[Metaspace:: MetadataTypeCount];
299 // Running sum of space in all Metachunks that
300 // are being used for metadata. One for each
301 // type of Metadata.
302 static size_t _used_words[Metaspace:: MetadataTypeCount];
303
304 public:
305 // Decrement and increment _allocated_capacity_words
306 static void dec_capacity(Metaspace::MetadataType type, size_t words);
307 static void inc_capacity(Metaspace::MetadataType type, size_t words);
308
309 // Decrement and increment _allocated_used_words
310 static void dec_used(Metaspace::MetadataType type, size_t words);
311 static void inc_used(Metaspace::MetadataType type, size_t words);
312
313 // Total of space allocated to metadata in all Metaspaces.
314 // This sums the space used in each Metachunk by
315 // iterating over the classloader data graph
316 static size_t used_bytes_slow() {
317 return used_bytes_slow(Metaspace::ClassType) +
318 used_bytes_slow(Metaspace::NonClassType);
319 }
320
321 // Used by MetaspaceCounters
322 static size_t free_chunks_total_words();
323 static size_t free_chunks_total_bytes();
324 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
325
326 static size_t capacity_words(Metaspace::MetadataType mdtype) {
327 return _capacity_words[mdtype];
328 }
329 static size_t capacity_words() {
330 return capacity_words(Metaspace::NonClassType) +
331 capacity_words(Metaspace::ClassType);
332 }
333 static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
334 return capacity_words(mdtype) * BytesPerWord;
335 }
336 static size_t capacity_bytes() {
337 return capacity_words() * BytesPerWord;
338 }
339
340 static size_t used_words(Metaspace::MetadataType mdtype) {
341 return _used_words[mdtype];
342 }
343 static size_t used_words() {
344 return used_words(Metaspace::NonClassType) +
345 used_words(Metaspace::ClassType);
346 }
347 static size_t used_bytes(Metaspace::MetadataType mdtype) {
348 return used_words(mdtype) * BytesPerWord;
349 }
350 static size_t used_bytes() {
351 return used_words() * BytesPerWord;
352 }
353
354 static size_t free_bytes();
355 static size_t free_bytes(Metaspace::MetadataType mdtype);
356
357 static size_t reserved_bytes(Metaspace::MetadataType mdtype);
358 static size_t reserved_bytes() {
359 return reserved_bytes(Metaspace::ClassType) +
360 reserved_bytes(Metaspace::NonClassType);
361 }
362
363 static size_t committed_bytes(Metaspace::MetadataType mdtype);
364 static size_t committed_bytes() {
365 return committed_bytes(Metaspace::ClassType) +
366 committed_bytes(Metaspace::NonClassType);
367 }
368
369 static size_t min_chunk_size_words();
370 static size_t min_chunk_size_bytes() {
371 return min_chunk_size_words() * BytesPerWord;
372 }
373
374 static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
375 static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
376
377 // Print change in used metadata.
378 static void print_metaspace_change(size_t prev_metadata_used);
379 static void print_on(outputStream * out);
380 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
381
382 static void print_class_waste(outputStream* out);
383 static void print_waste(outputStream* out);
384 static void dump(outputStream* out);
385 static void verify_free_chunks();
386 // Checks that the values returned by allocated_capacity_bytes() and
387 // capacity_bytes_slow() are the same.
388 static void verify_capacity();
389 static void verify_used();
390 static void verify_metrics();
391 };
392
393 // Metaspace are deallocated when their class loader are GC'ed.
394 // This class implements a policy for inducing GC's to recover
395 // Metaspaces.
396
397 class MetaspaceGC : AllStatic {
398
399 // The current high-water-mark for inducing a GC.
400 // When committed memory of all metaspaces reaches this value,
401 // a GC is induced and the value is increased. Size is in bytes.
402 static volatile intptr_t _capacity_until_GC;
403
404 // For a CMS collection, signal that a concurrent collection should
405 // be started.
406 static bool _should_concurrent_collect;
407
408 static uint _shrink_factor;
409
410 static size_t shrink_factor() { return _shrink_factor; }
411 void set_shrink_factor(uint v) { _shrink_factor = v; }
412
413 public:
414
415 static void initialize();
416 static void post_initialize();
417
418 static size_t capacity_until_GC();
419 static bool inc_capacity_until_GC(size_t v,
420 size_t* new_cap_until_GC = NULL,
421 size_t* old_cap_until_GC = NULL,
422 bool* can_retry = NULL);
423 static size_t dec_capacity_until_GC(size_t v);
424
425 static bool should_concurrent_collect() { return _should_concurrent_collect; }
426 static void set_should_concurrent_collect(bool v) {
427 _should_concurrent_collect = v;
428 }
429
430 // The amount to increase the high-water-mark (_capacity_until_GC)
431 static size_t delta_capacity_until_GC(size_t bytes);
432
433 // Tells if we have can expand metaspace without hitting set limits.
434 static bool can_expand(size_t words, bool is_class);
435
436 // Returns amount that we can expand without hitting a GC,
437 // measured in words.
438 static size_t allowed_expansion();
439
440 // Calculate the new high-water mark at which to induce
441 // a GC.
442 static void compute_new_size();
443 };
444
445 #endif // SHARE_VM_MEMORY_METASPACE_HPP