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 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 static VirtualSpaceList* get_space_list(MetadataType mdtype) { 140 assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype"); 141 return mdtype == ClassType ? class_space_list() : space_list(); 142 } 143 144 // This is used by DumpSharedSpaces only, where only _vsm is used. So we will 145 // maintain a single list for now. 146 void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size); 147 148 #ifdef _LP64 149 static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base); 150 151 // Returns true if can use CDS with metaspace allocated as specified address. 152 static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base); 153 154 static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base); 155 156 static void initialize_class_space(ReservedSpace rs); 157 #endif 158 159 class AllocRecord : public CHeapObj<mtClass> { 160 public: 161 AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size) 162 : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {} 163 AllocRecord *_next; 164 address _ptr; 165 MetaspaceObj::Type _type; 166 int _byte_size; 167 }; 168 169 AllocRecord * _alloc_record_head; 170 AllocRecord * _alloc_record_tail; 171 172 public: 173 174 Metaspace(Mutex* lock, MetaspaceType type); 175 ~Metaspace(); 176 177 // Initialize globals for Metaspace 178 static void global_initialize(); 179 180 static size_t first_chunk_word_size() { return _first_chunk_word_size; } 181 static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; } 182 183 char* bottom() const; 184 size_t used_words_slow(MetadataType mdtype) const; 185 size_t free_words_slow(MetadataType mdtype) const; 186 size_t capacity_words_slow(MetadataType mdtype) const; 187 188 size_t used_bytes_slow(MetadataType mdtype) const; 189 size_t capacity_bytes_slow(MetadataType mdtype) const; 190 191 static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size, 192 bool read_only, MetaspaceObj::Type type, TRAPS); 193 void deallocate(MetaWord* ptr, size_t byte_size, bool is_class); 194 195 MetaWord* expand_and_allocate(size_t size, 196 MetadataType mdtype); 197 198 static bool contains(const void *ptr); 199 void dump(outputStream* const out) const; 200 201 // Free empty virtualspaces 202 static void purge(); 203 204 void print_on(outputStream* st) const; 205 // Debugging support 206 void verify(); 207 208 class AllocRecordClosure : public StackObj { 209 public: 210 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0; 211 }; 212 213 void iterate(AllocRecordClosure *closure); 214 215 // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False. 216 static bool using_class_space() { 217 return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces); 218 } 219 220 }; 221 222 class MetaspaceAux : AllStatic { 223 static size_t free_chunks_total_words(Metaspace::MetadataType mdtype); 224 225 // These methods iterate over the classloader data graph 226 // for the given Metaspace type. These are slow. 227 static size_t used_bytes_slow(Metaspace::MetadataType mdtype); 228 static size_t free_bytes_slow(Metaspace::MetadataType mdtype); 229 static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype); 230 static size_t capacity_bytes_slow(); 231 232 // Running sum of space in all Metachunks that has been 233 // allocated to a Metaspace. This is used instead of 234 // iterating over all the classloaders. One for each 235 // type of Metadata 236 static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount]; 237 // Running sum of space in all Metachunks that have 238 // are being used for metadata. One for each 239 // type of Metadata. 240 static size_t _allocated_used_words[Metaspace:: MetadataTypeCount]; 241 242 public: 243 // Decrement and increment _allocated_capacity_words 244 static void dec_capacity(Metaspace::MetadataType type, size_t words); 245 static void inc_capacity(Metaspace::MetadataType type, size_t words); 246 247 // Decrement and increment _allocated_used_words 248 static void dec_used(Metaspace::MetadataType type, size_t words); 249 static void inc_used(Metaspace::MetadataType type, size_t words); 250 251 // Total of space allocated to metadata in all Metaspaces. 252 // This sums the space used in each Metachunk by 253 // iterating over the classloader data graph 254 static size_t used_bytes_slow() { 255 return used_bytes_slow(Metaspace::ClassType) + 256 used_bytes_slow(Metaspace::NonClassType); 257 } 258 259 // Used by MetaspaceCounters 260 static size_t free_chunks_total_words(); 261 static size_t free_chunks_total_bytes(); 262 static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype); 263 264 static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) { 265 return _allocated_capacity_words[mdtype]; 266 } 267 static size_t allocated_capacity_words() { 268 return allocated_capacity_words(Metaspace::NonClassType) + 269 allocated_capacity_words(Metaspace::ClassType); 270 } 271 static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) { 272 return allocated_capacity_words(mdtype) * BytesPerWord; 273 } 274 static size_t allocated_capacity_bytes() { 275 return allocated_capacity_words() * BytesPerWord; 276 } 277 278 static size_t allocated_used_words(Metaspace::MetadataType mdtype) { 279 return _allocated_used_words[mdtype]; 280 } 281 static size_t allocated_used_words() { 282 return allocated_used_words(Metaspace::NonClassType) + 283 allocated_used_words(Metaspace::ClassType); 284 } 285 static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) { 286 return allocated_used_words(mdtype) * BytesPerWord; 287 } 288 static size_t allocated_used_bytes() { 289 return allocated_used_words() * BytesPerWord; 290 } 291 292 static size_t free_bytes(); 293 static size_t free_bytes(Metaspace::MetadataType mdtype); 294 295 static size_t reserved_bytes(Metaspace::MetadataType mdtype); 296 static size_t reserved_bytes() { 297 return reserved_bytes(Metaspace::ClassType) + 298 reserved_bytes(Metaspace::NonClassType); 299 } 300 301 static size_t committed_bytes(Metaspace::MetadataType mdtype); 302 static size_t committed_bytes() { 303 return committed_bytes(Metaspace::ClassType) + 304 committed_bytes(Metaspace::NonClassType); 305 } 306 307 static size_t min_chunk_size_words(); 308 static size_t min_chunk_size_bytes() { 309 return min_chunk_size_words() * BytesPerWord; 310 } 311 312 // Print change in used metadata. 313 static void print_metaspace_change(size_t prev_metadata_used); 314 static void print_on(outputStream * out); 315 static void print_on(outputStream * out, Metaspace::MetadataType mdtype); 316 317 static void print_class_waste(outputStream* out); 318 static void print_waste(outputStream* out); 319 static void dump(outputStream* out); 320 static void verify_free_chunks(); 321 // Checks that the values returned by allocated_capacity_bytes() and 322 // capacity_bytes_slow() are the same. 323 static void verify_capacity(); 324 static void verify_used(); 325 static void verify_metrics(); 326 }; 327 328 // Metaspace are deallocated when their class loader are GC'ed. 329 // This class implements a policy for inducing GC's to recover 330 // Metaspaces. 331 332 class MetaspaceGC : AllStatic { 333 334 // The current high-water-mark for inducing a GC. When 335 // the capacity of all space in the virtual lists reaches this value, 336 // a GC is induced and the value is increased. This should be changed 337 // to the space actually used for allocations to avoid affects of 338 // fragmentation losses to partially used chunks. Size is in words. 339 static size_t _capacity_until_GC; 340 341 // After a GC is done any allocation that fails should try to expand 342 // the capacity of the Metaspaces. This flag is set during attempts 343 // to allocate in the VMGCOperation that does the GC. 344 static bool _expand_after_GC; 345 346 // For a CMS collection, signal that a concurrent collection should 347 // be started. 348 static bool _should_concurrent_collect; 349 350 static uint _shrink_factor; 351 352 static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; } 353 354 static size_t shrink_factor() { return _shrink_factor; } 355 void set_shrink_factor(uint v) { _shrink_factor = v; } 356 357 public: 358 359 static size_t capacity_until_GC() { return _capacity_until_GC; } 360 static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; } 361 static void dec_capacity_until_GC(size_t v) { 362 _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0; 363 } 364 static bool expand_after_GC() { return _expand_after_GC; } 365 static void set_expand_after_GC(bool v) { _expand_after_GC = v; } 366 367 static bool should_concurrent_collect() { return _should_concurrent_collect; } 368 static void set_should_concurrent_collect(bool v) { 369 _should_concurrent_collect = v; 370 } 371 372 // The amount to increase the high-water-mark (_capacity_until_GC) 373 static size_t delta_capacity_until_GC(size_t word_size); 374 375 // It is expected that this will be called when the current capacity 376 // has been used and a GC should be considered. 377 static bool should_expand(VirtualSpaceList* vsl, size_t word_size); 378 379 // Calculate the new high-water mark at which to induce 380 // a GC. 381 static void compute_new_size(); 382 }; 383 384 #endif // SHARE_VM_MEMORY_METASPACE_HPP