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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 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 "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 ClassLoaderData;
60 class Metablock;
61 class MetaWord;
62 class Mutex;
63 class outputStream;
64 class SpaceManager;
65
66 // Metaspaces each have a SpaceManager and allocations
67 // are done by the SpaceManager. Allocations are done
68 // out of the current Metachunk. When the current Metachunk
69 // is exhausted, the SpaceManager gets a new one from
70 // the current VirtualSpace. When the VirtualSpace is exhausted
71 // the SpaceManager gets a new one. The SpaceManager
72 // also manages freelists of available Chunks.
73 //
74 // Currently the space manager maintains the list of
75 // virtual spaces and the list of chunks in use. Its
76 // allocate() method returns a block for use as a
77 // quantum of metadata.
78
79 class VirtualSpaceList;
80
81 class Metaspace : public CHeapObj<mtClass> {
82 friend class VMStructs;
83 friend class SpaceManager;
84 friend class VM_CollectForMetadataAllocation;
85 friend class MetaspaceGC;
86 friend class MetaspaceAux;
87
88 public:
89 enum MetadataType {ClassType = 0,
90 NonClassType = ClassType + 1,
91 MetadataTypeCount = ClassType + 2
92 };
93 enum MetaspaceType {
94 StandardMetaspaceType,
95 BootMetaspaceType,
96 ROMetaspaceType,
97 ReadWriteMetaspaceType,
98 AnonymousMetaspaceType,
99 ReflectionMetaspaceType
100 };
101
102 private:
103 void initialize(Mutex* lock, MetaspaceType type);
104
105 // Align up the word size to the allocation word size
106 static size_t align_word_size_up(size_t);
107
108 // Aligned size of the metaspace.
109 static size_t _class_metaspace_size;
110
111 static size_t class_metaspace_size() {
112 return _class_metaspace_size;
113 }
114 static void set_class_metaspace_size(size_t metaspace_size) {
115 _class_metaspace_size = metaspace_size;
116 }
117
118 static size_t _first_chunk_word_size;
119 static size_t _first_class_chunk_word_size;
120
121 SpaceManager* _vsm;
122 SpaceManager* vsm() const { return _vsm; }
123
124 SpaceManager* _class_vsm;
125 SpaceManager* class_vsm() const { return _class_vsm; }
126
127 // Allocate space for metadata of type mdtype. This is space
128 // within a Metachunk and is used by
129 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
130 // which returns a Metablock.
131 MetaWord* allocate(size_t word_size, MetadataType mdtype);
132
133 // Virtual Space lists for both classes and other metadata
134 static VirtualSpaceList* _space_list;
135 static VirtualSpaceList* _class_space_list;
136
137 static VirtualSpaceList* space_list() { return _space_list; }
138 static VirtualSpaceList* class_space_list() { return _class_space_list; }
139
140 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
141 // maintain a single list for now.
142 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
143
144 #ifdef _LP64
145 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
146
147 // Returns true if can use CDS with metaspace allocated as specified address.
148 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
149
150 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
151
152 static void initialize_class_space(ReservedSpace rs);
153 #endif
154
155 class AllocRecord : public CHeapObj<mtClass> {
156 public:
157 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
158 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
159 AllocRecord *_next;
160 address _ptr;
161 MetaspaceObj::Type _type;
162 int _byte_size;
163 };
164
165 AllocRecord * _alloc_record_head;
166 AllocRecord * _alloc_record_tail;
167
168 public:
169
170 Metaspace(Mutex* lock, MetaspaceType type);
171 ~Metaspace();
172
173 // Initialize globals for Metaspace
174 static void global_initialize();
175
176 static size_t first_chunk_word_size() { return _first_chunk_word_size; }
177 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
178
179 char* bottom() const;
180 size_t used_words_slow(MetadataType mdtype) const;
181 size_t free_words(MetadataType mdtype) const;
182 size_t capacity_words_slow(MetadataType mdtype) const;
183 size_t waste_words(MetadataType mdtype) const;
184
185 size_t used_bytes_slow(MetadataType mdtype) const;
186 size_t capacity_bytes_slow(MetadataType mdtype) const;
187
188 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size,
189 bool read_only, MetaspaceObj::Type type, TRAPS);
190 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
191
192 MetaWord* expand_and_allocate(size_t size,
193 MetadataType mdtype);
194
195 static bool contains(const void *ptr);
196 void dump(outputStream* const out) const;
197
198 // Free empty virtualspaces
199 static void purge();
200
201 void print_on(outputStream* st) const;
202 // Debugging support
203 void verify();
204
205 class AllocRecordClosure : public StackObj {
206 public:
207 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
208 };
209
210 void iterate(AllocRecordClosure *closure);
211
212 // Return TRUE only if UseCompressedKlassPointers is True and DumpSharedSpaces is False.
213 static bool using_class_space() {
214 return NOT_LP64(false) LP64_ONLY(UseCompressedKlassPointers && !DumpSharedSpaces);
215 }
216
217 };
218
219 class MetaspaceAux : AllStatic {
220 static size_t free_chunks_total(Metaspace::MetadataType mdtype);
221 static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);
222
223 public:
224 // Statistics for class space and data space in metaspace.
225
226 // These methods iterate over the classloader data graph
227 // for the given Metaspace type. These are slow.
228 static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
229 static size_t free_in_bytes(Metaspace::MetadataType mdtype);
230 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
231
232 // Iterates over the virtual space list.
233 static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);
234
235 // Running sum of space in all Metachunks that has been
236 // allocated to a Metaspace. This is used instead of
237 // iterating over all the classloaders. One for each
238 // type of Metadata
239 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount];
240 // Running sum of space in all Metachunks that have
241 // are being used for metadata. One for each
242 // type of Metadata.
243 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount];
244
245 public:
246 // Decrement and increment _allocated_capacity_words
247 static void dec_capacity(Metaspace::MetadataType type, size_t words);
248 static void inc_capacity(Metaspace::MetadataType type, size_t words);
249
250 // Decrement and increment _allocated_used_words
251 static void dec_used(Metaspace::MetadataType type, size_t words);
252 static void inc_used(Metaspace::MetadataType type, size_t words);
253
254 // Total of space allocated to metadata in all Metaspaces.
255 // This sums the space used in each Metachunk by
256 // iterating over the classloader data graph
257 static size_t used_bytes_slow() {
258 return used_bytes_slow(Metaspace::ClassType) +
259 used_bytes_slow(Metaspace::NonClassType);
260 }
261
262 // Used by MetaspaceCounters
263 static size_t free_chunks_total();
264 static size_t free_chunks_total_in_bytes();
265
266 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) {
267 return _allocated_capacity_words[mdtype];
268 }
269 static size_t allocated_capacity_words() {
270 return _allocated_capacity_words[Metaspace::NonClassType] +
271 (Metaspace::using_class_space() ?
272 _allocated_capacity_words[Metaspace::ClassType] : 0);
273 }
274 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) {
275 return allocated_capacity_words(mdtype) * BytesPerWord;
276 }
277 static size_t allocated_capacity_bytes() {
278 return allocated_capacity_words() * BytesPerWord;
279 }
280
281 static size_t allocated_used_words(Metaspace::MetadataType mdtype) {
282 return _allocated_used_words[mdtype];
283 }
284 static size_t allocated_used_words() {
285 return _allocated_used_words[Metaspace::NonClassType] +
286 (Metaspace::using_class_space() ?
287 _allocated_used_words[Metaspace::ClassType] : 0);
288 }
289 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) {
290 return allocated_used_words(mdtype) * BytesPerWord;
291 }
292 static size_t allocated_used_bytes() {
293 return allocated_used_words() * BytesPerWord;
294 }
295
296 static size_t free_bytes();
297
298 // Total capacity in all Metaspaces
299 static size_t capacity_bytes_slow() {
300 #ifdef PRODUCT
301 // Use allocated_capacity_bytes() in PRODUCT instead of this function.
302 guarantee(false, "Should not call capacity_bytes_slow() in the PRODUCT");
303 #endif
304 size_t class_capacity = capacity_bytes_slow(Metaspace::ClassType);
305 size_t non_class_capacity = capacity_bytes_slow(Metaspace::NonClassType);
306 assert(allocated_capacity_bytes() == class_capacity + non_class_capacity,
307 err_msg("bad accounting: allocated_capacity_bytes() " SIZE_FORMAT
308 " class_capacity + non_class_capacity " SIZE_FORMAT
309 " class_capacity " SIZE_FORMAT " non_class_capacity " SIZE_FORMAT,
310 allocated_capacity_bytes(), class_capacity + non_class_capacity,
311 class_capacity, non_class_capacity));
312
313 return class_capacity + non_class_capacity;
314 }
315
316 // Total space reserved in all Metaspaces
317 static size_t reserved_in_bytes() {
318 return reserved_in_bytes(Metaspace::ClassType) +
319 reserved_in_bytes(Metaspace::NonClassType);
320 }
321
322 static size_t min_chunk_size();
323
324 // Print change in used metadata.
325 static void print_metaspace_change(size_t prev_metadata_used);
326 static void print_on(outputStream * out);
327 static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
328
329 static void print_class_waste(outputStream* out);
330 static void print_waste(outputStream* out);
331 static void dump(outputStream* out);
332 static void verify_free_chunks();
333 // Checks that the values returned by allocated_capacity_bytes() and
334 // capacity_bytes_slow() are the same.
335 static void verify_capacity();
336 static void verify_used();
337 static void verify_metrics();
338 };
339
340 // Metaspace are deallocated when their class loader are GC'ed.
341 // This class implements a policy for inducing GC's to recover
342 // Metaspaces.
343
344 class MetaspaceGC : AllStatic {
345
346 // The current high-water-mark for inducing a GC. When
347 // the capacity of all space in the virtual lists reaches this value,
348 // a GC is induced and the value is increased. This should be changed
349 // to the space actually used for allocations to avoid affects of
350 // fragmentation losses to partially used chunks. Size is in words.
351 static size_t _capacity_until_GC;
352
353 // After a GC is done any allocation that fails should try to expand
354 // the capacity of the Metaspaces. This flag is set during attempts
355 // to allocate in the VMGCOperation that does the GC.
356 static bool _expand_after_GC;
357
358 // For a CMS collection, signal that a concurrent collection should
359 // be started.
360 static bool _should_concurrent_collect;
361
362 static uint _shrink_factor;
363
364 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }
365
366 static size_t shrink_factor() { return _shrink_factor; }
367 void set_shrink_factor(uint v) { _shrink_factor = v; }
368
369 public:
370
371 static size_t capacity_until_GC() { return _capacity_until_GC; }
372 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
373 static void dec_capacity_until_GC(size_t v) {
374 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
375 }
376 static bool expand_after_GC() { return _expand_after_GC; }
377 static void set_expand_after_GC(bool v) { _expand_after_GC = v; }
378
379 static bool should_concurrent_collect() { return _should_concurrent_collect; }
380 static void set_should_concurrent_collect(bool v) {
381 _should_concurrent_collect = v;
382 }
383
384 // The amount to increase the high-water-mark (_capacity_until_GC)
385 static size_t delta_capacity_until_GC(size_t word_size);
386
387 // It is expected that this will be called when the current capacity
388 // has been used and a GC should be considered.
389 static bool should_expand(VirtualSpaceList* vsl, size_t word_size);
390
391 // Calculate the new high-water mark at which to induce
392 // a GC.
393 static void compute_new_size();
394 };
395
396 #endif // SHARE_VM_MEMORY_METASPACE_HPP