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. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 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 ChunkManager; 60 class ClassLoaderData; 61 class Metablock; 62 class Metachunk; 63 class MetaWord; 64 class Mutex; 65 class outputStream; 66 class SpaceManager; 67 class VirtualSpaceList; 68 69 // Metaspaces each have a SpaceManager and allocations 70 // are done by the SpaceManager. Allocations are done 71 // out of the current Metachunk. When the current Metachunk 72 // is exhausted, the SpaceManager gets a new one from 73 // the current VirtualSpace. When the VirtualSpace is exhausted 74 // the SpaceManager gets a new one. The SpaceManager 75 // also manages freelists of available Chunks. 76 // 77 // Currently the space manager maintains the list of 78 // virtual spaces and the list of chunks in use. Its 79 // allocate() method returns a block for use as a 80 // quantum of metadata. 81 82 class Metaspace : public CHeapObj<mtClass> { 83 friend class VMStructs; 84 friend class SpaceManager; 85 friend class VM_CollectForMetadataAllocation; 86 friend class MetaspaceGC; 87 friend class MetaspaceAux; 88 89 public: 90 enum MetadataType {ClassType = 0, 91 NonClassType = ClassType + 1, 92 MetadataTypeCount = ClassType + 2 93 }; 94 enum MetaspaceType { 95 StandardMetaspaceType, 96 BootMetaspaceType, 97 ROMetaspaceType, 98 ReadWriteMetaspaceType, 99 AnonymousMetaspaceType, 100 ReflectionMetaspaceType 101 }; 102 103 private: 104 void initialize(Mutex* lock, MetaspaceType type); 105 106 Metachunk* get_initialization_chunk(MetadataType mdtype, 107 size_t chunk_word_size, 108 size_t chunk_bunch); 109 110 // Align up the word size to the allocation word size 111 static size_t align_word_size_up(size_t); 112 113 // Aligned size of the metaspace. 114 static size_t _class_metaspace_size; 115 116 static size_t class_metaspace_size() { 117 return _class_metaspace_size; 118 } 119 static void set_class_metaspace_size(size_t metaspace_size) { 120 _class_metaspace_size = metaspace_size; 121 } 122 123 static size_t _first_chunk_word_size; 124 static size_t _first_class_chunk_word_size; 125 126 SpaceManager* _vsm; 127 SpaceManager* vsm() const { return _vsm; } 128 129 SpaceManager* _class_vsm; 130 SpaceManager* class_vsm() const { return _class_vsm; } 131 132 // Allocate space for metadata of type mdtype. This is space 133 // within a Metachunk and is used by 134 // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS) 135 // which returns a Metablock. 136 MetaWord* allocate(size_t word_size, MetadataType mdtype); 137 138 // Virtual Space lists for both classes and other metadata 139 static VirtualSpaceList* _space_list; 140 static VirtualSpaceList* _class_space_list; 141 142 static ChunkManager* _chunk_manager_metadata; 143 static ChunkManager* _chunk_manager_class; 144 145 static VirtualSpaceList* space_list() { return _space_list; } 146 static VirtualSpaceList* class_space_list() { return _class_space_list; } 147 static VirtualSpaceList* get_space_list(MetadataType mdtype) { 148 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype"); 149 return mdtype == ClassType ? class_space_list() : space_list(); 150 } 151 152 static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; } 153 static ChunkManager* chunk_manager_class() { return _chunk_manager_class; } 154 static ChunkManager* get_chunk_manager(MetadataType mdtype) { 155 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype"); 156 return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata(); 157 } 158 159 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will 160 // maintain a single list for now. 161 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size); 162 163 #ifdef _LP64 164 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base); 165 166 // Returns true if can use CDS with metaspace allocated as specified address. 167 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base); 168 169 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base); 170 171 static void initialize_class_space(ReservedSpace rs); 172 #endif 173 174 class AllocRecord : public CHeapObj<mtClass> { 175 public: 176 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size) 177 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {} 178 AllocRecord *_next; 179 address _ptr; 180 MetaspaceObj::Type _type; 181 int _byte_size; 182 }; 183 184 AllocRecord * _alloc_record_head; 185 AllocRecord * _alloc_record_tail; 186 187 public: 188 189 Metaspace(Mutex* lock, MetaspaceType type); 190 ~Metaspace(); 191 192 // Initialize globals for Metaspace 193 static void global_initialize(); 194 195 static size_t first_chunk_word_size() { return _first_chunk_word_size; } 196 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; } 197 198 char* bottom() const; 199 size_t used_words_slow(MetadataType mdtype) const; 200 size_t free_words_slow(MetadataType mdtype) const; 201 size_t capacity_words_slow(MetadataType mdtype) const; 202 203 size_t used_bytes_slow(MetadataType mdtype) const; 204 size_t capacity_bytes_slow(MetadataType mdtype) const; 205 206 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size, 207 bool read_only, MetaspaceObj::Type type, TRAPS); 208 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class); 209 210 MetaWord* expand_and_allocate(size_t size, 211 MetadataType mdtype); 212 213 static bool contains(const void *ptr); 214 void dump(outputStream* const out) const; 215 216 // Free empty virtualspaces 217 static void purge(MetadataType mdtype); 218 static void purge(); 219 220 void print_on(outputStream* st) const; 221 // Debugging support 222 void verify(); 223 224 class AllocRecordClosure : public StackObj { 225 public: 226 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0; 227 }; 228 229 void iterate(AllocRecordClosure *closure); 230 231 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False. 232 static bool using_class_space() { 233 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces); 234 } 235 236 }; 237 238 class MetaspaceAux : AllStatic { 239 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype); 240 241 // These methods iterate over the classloader data graph 242 // for the given Metaspace type. These are slow. 243 static size_t used_bytes_slow(Metaspace::MetadataType mdtype); 244 static size_t free_bytes_slow(Metaspace::MetadataType mdtype); 245 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype); 246 static size_t capacity_bytes_slow(); 247 248 // Running sum of space in all Metachunks that has been 249 // allocated to a Metaspace. This is used instead of 250 // iterating over all the classloaders. One for each 251 // type of Metadata 252 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount]; 253 // Running sum of space in all Metachunks that have 254 // are being used for metadata. One for each 255 // type of Metadata. 256 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount]; 257 258 public: 259 // Decrement and increment _allocated_capacity_words 260 static void dec_capacity(Metaspace::MetadataType type, size_t words); 261 static void inc_capacity(Metaspace::MetadataType type, size_t words); 262 263 // Decrement and increment _allocated_used_words 264 static void dec_used(Metaspace::MetadataType type, size_t words); 265 static void inc_used(Metaspace::MetadataType type, size_t words); 266 267 // Total of space allocated to metadata in all Metaspaces. 268 // This sums the space used in each Metachunk by 269 // iterating over the classloader data graph 270 static size_t used_bytes_slow() { 271 return used_bytes_slow(Metaspace::ClassType) + 272 used_bytes_slow(Metaspace::NonClassType); 273 } 274 275 // Used by MetaspaceCounters 276 static size_t free_chunks_total_words(); 277 static size_t free_chunks_total_bytes(); 278 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype); 279 280 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) { 281 return _allocated_capacity_words[mdtype]; 282 } 283 static size_t allocated_capacity_words() { 284 return allocated_capacity_words(Metaspace::NonClassType) + 285 allocated_capacity_words(Metaspace::ClassType); 286 } 287 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) { 288 return allocated_capacity_words(mdtype) * BytesPerWord; 289 } 290 static size_t allocated_capacity_bytes() { 291 return allocated_capacity_words() * BytesPerWord; 292 } 293 294 static size_t allocated_used_words(Metaspace::MetadataType mdtype) { 295 return _allocated_used_words[mdtype]; 296 } 297 static size_t allocated_used_words() { 298 return allocated_used_words(Metaspace::NonClassType) + 299 allocated_used_words(Metaspace::ClassType); 300 } 301 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) { 302 return allocated_used_words(mdtype) * BytesPerWord; 303 } 304 static size_t allocated_used_bytes() { 305 return allocated_used_words() * BytesPerWord; 306 } 307 308 static size_t free_bytes(); 309 static size_t free_bytes(Metaspace::MetadataType mdtype); 310 311 static size_t reserved_bytes(Metaspace::MetadataType mdtype); 312 static size_t reserved_bytes() { 313 return reserved_bytes(Metaspace::ClassType) + 314 reserved_bytes(Metaspace::NonClassType); 315 } 316 317 static size_t committed_bytes(Metaspace::MetadataType mdtype); 318 static size_t committed_bytes() { 319 return committed_bytes(Metaspace::ClassType) + 320 committed_bytes(Metaspace::NonClassType); 321 } 322 323 static size_t min_chunk_size_words(); 324 static size_t min_chunk_size_bytes() { 325 return min_chunk_size_words() * BytesPerWord; 326 } 327 328 // Print change in used metadata. 329 static void print_metaspace_change(size_t prev_metadata_used); 330 static void print_on(outputStream * out); 331 static void print_on(outputStream * out, Metaspace::MetadataType mdtype); 332 333 static void print_class_waste(outputStream* out); 334 static void print_waste(outputStream* out); 335 static void dump(outputStream* out); 336 static void verify_free_chunks(); 337 // Checks that the values returned by allocated_capacity_bytes() and 338 // capacity_bytes_slow() are the same. 339 static void verify_capacity(); 340 static void verify_used(); 341 static void verify_metrics(); 342 }; 343 344 // Metaspace are deallocated when their class loader are GC'ed. 345 // This class implements a policy for inducing GC's to recover 346 // Metaspaces. 347 348 class MetaspaceGC : AllStatic { 349 350 // The current high-water-mark for inducing a GC. When 351 // the capacity of all space in the virtual lists reaches this value, 352 // a GC is induced and the value is increased. This should be changed 353 // to the space actually used for allocations to avoid affects of 354 // fragmentation losses to partially used chunks. Size is in words. 355 static size_t _capacity_until_GC; 356 357 // After a GC is done any allocation that fails should try to expand 358 // the capacity of the Metaspaces. This flag is set during attempts 359 // to allocate in the VMGCOperation that does the GC. 360 static bool _expand_after_GC; 361 362 // For a CMS collection, signal that a concurrent collection should 363 // be started. 364 static bool _should_concurrent_collect; 365 366 static uint _shrink_factor; 367 368 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; } 369 370 static size_t shrink_factor() { return _shrink_factor; } 371 void set_shrink_factor(uint v) { _shrink_factor = v; } 372 373 public: 374 375 static size_t capacity_until_GC() { return _capacity_until_GC; } 376 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; } 377 static void dec_capacity_until_GC(size_t v) { 378 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0; 379 } 380 static bool expand_after_GC() { return _expand_after_GC; } 381 static void set_expand_after_GC(bool v) { _expand_after_GC = v; } 382 383 static bool should_concurrent_collect() { return _should_concurrent_collect; } 384 static void set_should_concurrent_collect(bool v) { 385 _should_concurrent_collect = v; 386 } 387 388 // The amount to increase the high-water-mark (_capacity_until_GC) 389 static size_t delta_capacity_until_GC(size_t word_size); 390 391 // It is expected that this will be called when the current capacity 392 // has been used and a GC should be considered. 393 static bool should_expand(VirtualSpaceList* vsl, size_t word_size); 394 395 // Calculate the new high-water mark at which to induce 396 // a GC. 397 static void compute_new_size(); 398 }; 399 400 #endif // SHARE_VM_MEMORY_METASPACE_HPP