1 /*
   2  * Copyright (c) 2011, 2017, 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
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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 //
  39 //    block X ---+       +-------------------+
  40 //               |       |  Virtualspace     |
  41 //               |       |                   |
  42 //               |       |                   |
  43 //               |       |-------------------|
  44 //               |       || Chunk            |
  45 //               |       ||                  |
  46 //               |       ||----------        |
  47 //               +------>||| block 0 |       |
  48 //                       ||----------        |
  49 //                       ||| block 1 |       |
  50 //                       ||----------        |
  51 //                       ||                  |
  52 //                       |-------------------|
  53 //                       |                   |
  54 //                       |                   |
  55 //                       +-------------------+
  56 //
  57 
  58 class ChunkManager;
  59 class ClassLoaderData;
  60 class Metablock;
  61 class Metachunk;
  62 class MetaspaceTracer;
  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   friend class MetaspaceShared;
  89   friend class CollectorPolicy;
  90 
  91  public:
  92   enum MetadataType {
  93     ClassType,
  94     NonClassType,
  95     MetadataTypeCount
  96   };
  97   enum MetaspaceType {
  98     StandardMetaspaceType,
  99     BootMetaspaceType,
 100     AnonymousMetaspaceType,
 101     ReflectionMetaspaceType
 102   };
 103 
 104  private:
 105   static void verify_global_initialization();
 106 
 107   void initialize(Mutex* lock, MetaspaceType type);
 108 
 109   // Initialize the first chunk for a Metaspace.  Used for
 110   // special cases such as the boot class loader, reflection
 111   // class loader and anonymous class loader.
 112   void initialize_first_chunk(MetaspaceType type, MetadataType mdtype);
 113   Metachunk* get_initialization_chunk(MetaspaceType type, MetadataType mdtype);
 114 
 115   // Align up the word size to the allocation word size
 116   static size_t align_word_size_up(size_t);
 117 
 118   // Aligned size of the metaspace.
 119   static size_t _compressed_class_space_size;
 120 
 121   static size_t compressed_class_space_size() {
 122     return _compressed_class_space_size;
 123   }
 124 
 125   static void set_compressed_class_space_size(size_t size) {
 126     _compressed_class_space_size = size;
 127   }
 128 
 129   static size_t _first_chunk_word_size;
 130   static size_t _first_class_chunk_word_size;
 131 
 132   static size_t _commit_alignment;
 133   static size_t _reserve_alignment;
 134   DEBUG_ONLY(static bool   _frozen;)
 135 
 136   SpaceManager* _vsm;
 137   SpaceManager* vsm() const { return _vsm; }
 138 
 139   SpaceManager* _class_vsm;
 140   SpaceManager* class_vsm() const { return _class_vsm; }
 141   SpaceManager* get_space_manager(MetadataType mdtype) {
 142     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 143     return mdtype == ClassType ? class_vsm() : vsm();
 144   }
 145 
 146   // Allocate space for metadata of type mdtype. This is space
 147   // within a Metachunk and is used by
 148   //   allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
 149   MetaWord* allocate(size_t word_size, MetadataType mdtype);
 150 
 151   MetaWord* expand_and_allocate(size_t size, MetadataType mdtype);
 152 
 153   // Virtual Space lists for both classes and other metadata
 154   static VirtualSpaceList* _space_list;
 155   static VirtualSpaceList* _class_space_list;
 156 
 157   static ChunkManager* _chunk_manager_metadata;
 158   static ChunkManager* _chunk_manager_class;
 159 
 160   static const MetaspaceTracer* _tracer;
 161 
 162  public:
 163   static VirtualSpaceList* space_list()       { return _space_list; }
 164   static VirtualSpaceList* class_space_list() { return _class_space_list; }
 165   static VirtualSpaceList* get_space_list(MetadataType mdtype) {
 166     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 167     return mdtype == ClassType ? class_space_list() : space_list();
 168   }
 169 
 170   static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 171   static ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 172   static ChunkManager* get_chunk_manager(MetadataType mdtype) {
 173     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 174     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 175   }
 176 
 177   static const MetaspaceTracer* tracer() { return _tracer; }
 178   static void freeze() {
 179     assert(DumpSharedSpaces, "sanity");
 180     DEBUG_ONLY(_frozen = true;)
 181   }
 182  private:
 183 
 184 #ifdef _LP64
 185   static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
 186 
 187   // Returns true if can use CDS with metaspace allocated as specified address.
 188   static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
 189 
 190   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 191 
 192   static void initialize_class_space(ReservedSpace rs);
 193 #endif
 194   size_t class_chunk_size(size_t word_size);
 195 
 196  public:
 197 
 198   Metaspace(Mutex* lock, MetaspaceType type);
 199   ~Metaspace();
 200 
 201   static void ergo_initialize();
 202   static void global_initialize();
 203   static void post_initialize();
 204 
 205   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 206   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 207 
 208   static size_t reserve_alignment()       { return _reserve_alignment; }
 209   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 210   static size_t commit_alignment()        { return _commit_alignment; }
 211   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 212 
 213   size_t used_words_slow(MetadataType mdtype) const;
 214   size_t free_words_slow(MetadataType mdtype) const;
 215   size_t capacity_words_slow(MetadataType mdtype) const;
 216 
 217   size_t used_bytes_slow(MetadataType mdtype) const;
 218   size_t capacity_bytes_slow(MetadataType mdtype) const;
 219 
 220   size_t allocated_blocks_bytes() const;
 221   size_t allocated_chunks_bytes() const;
 222 
 223   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 224                             MetaspaceObj::Type type, TRAPS);
 225   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 226 
 227   static bool contains(const void* ptr);
 228   static bool contains_non_shared(const void* ptr);
 229 
 230   void dump(outputStream* const out) const;
 231 
 232   // Free empty virtualspaces
 233   static void purge(MetadataType mdtype);
 234   static void purge();
 235 
 236   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 237                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 238 
 239   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 240 
 241   void print_on(outputStream* st) const;
 242   // Debugging support
 243   void verify();
 244 
 245   static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
 246 
 247   // Return TRUE only if UseCompressedClassPointers is True.
 248   static bool using_class_space() {
 249     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
 250   }
 251 
 252   static bool is_class_space_allocation(MetadataType mdType) {
 253     return mdType == ClassType && using_class_space();
 254   }
 255 
 256 };
 257 
 258 class MetaspaceAux : AllStatic {
 259   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 260 
 261   // These methods iterate over the classloader data graph
 262   // for the given Metaspace type.  These are slow.
 263   static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
 264   static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
 265   static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
 266   static size_t capacity_bytes_slow();
 267 
 268   // Running sum of space in all Metachunks that has been
 269   // allocated to a Metaspace.  This is used instead of
 270   // iterating over all the classloaders. One for each
 271   // type of Metadata
 272   static size_t _capacity_words[Metaspace:: MetadataTypeCount];
 273   // Running sum of space in all Metachunks that
 274   // are being used for metadata. One for each
 275   // type of Metadata.
 276   static size_t _used_words[Metaspace:: MetadataTypeCount];
 277 
 278  public:
 279   // Decrement and increment _allocated_capacity_words
 280   static void dec_capacity(Metaspace::MetadataType type, size_t words);
 281   static void inc_capacity(Metaspace::MetadataType type, size_t words);
 282 
 283   // Decrement and increment _allocated_used_words
 284   static void dec_used(Metaspace::MetadataType type, size_t words);
 285   static void inc_used(Metaspace::MetadataType type, size_t words);
 286 
 287   // Total of space allocated to metadata in all Metaspaces.
 288   // This sums the space used in each Metachunk by
 289   // iterating over the classloader data graph
 290   static size_t used_bytes_slow() {
 291     return used_bytes_slow(Metaspace::ClassType) +
 292            used_bytes_slow(Metaspace::NonClassType);
 293   }
 294 
 295   // Used by MetaspaceCounters
 296   static size_t free_chunks_total_words();
 297   static size_t free_chunks_total_bytes();
 298   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 299 
 300   static size_t capacity_words(Metaspace::MetadataType mdtype) {
 301     return _capacity_words[mdtype];
 302   }
 303   static size_t capacity_words() {
 304     return capacity_words(Metaspace::NonClassType) +
 305            capacity_words(Metaspace::ClassType);
 306   }
 307   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 308     return capacity_words(mdtype) * BytesPerWord;
 309   }
 310   static size_t capacity_bytes() {
 311     return capacity_words() * BytesPerWord;
 312   }
 313 
 314   static size_t used_words(Metaspace::MetadataType mdtype) {
 315     return _used_words[mdtype];
 316   }
 317   static size_t used_words() {
 318     return used_words(Metaspace::NonClassType) +
 319            used_words(Metaspace::ClassType);
 320   }
 321   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 322     return used_words(mdtype) * BytesPerWord;
 323   }
 324   static size_t used_bytes() {
 325     return used_words() * BytesPerWord;
 326   }
 327 
 328   static size_t free_bytes();
 329   static size_t free_bytes(Metaspace::MetadataType mdtype);
 330 
 331   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 332   static size_t reserved_bytes() {
 333     return reserved_bytes(Metaspace::ClassType) +
 334            reserved_bytes(Metaspace::NonClassType);
 335   }
 336 
 337   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 338   static size_t committed_bytes() {
 339     return committed_bytes(Metaspace::ClassType) +
 340            committed_bytes(Metaspace::NonClassType);
 341   }
 342 
 343   static size_t min_chunk_size_words();
 344   static size_t min_chunk_size_bytes() {
 345     return min_chunk_size_words() * BytesPerWord;
 346   }
 347 
 348   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 349   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 350 
 351   // Print change in used metadata.
 352   static void print_metaspace_change(size_t prev_metadata_used);
 353   static void print_on(outputStream * out);
 354   static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
 355 
 356   static void print_class_waste(outputStream* out);
 357   static void print_waste(outputStream* out);
 358   static void dump(outputStream* out);
 359   static void verify_free_chunks();
 360   // Checks that the values returned by allocated_capacity_bytes() and
 361   // capacity_bytes_slow() are the same.
 362   static void verify_capacity();
 363   static void verify_used();
 364   static void verify_metrics();
 365 };
 366 
 367 // Metaspace are deallocated when their class loader are GC'ed.
 368 // This class implements a policy for inducing GC's to recover
 369 // Metaspaces.
 370 
 371 class MetaspaceGC : AllStatic {
 372 
 373   // The current high-water-mark for inducing a GC.
 374   // When committed memory of all metaspaces reaches this value,
 375   // a GC is induced and the value is increased. Size is in bytes.
 376   static volatile intptr_t _capacity_until_GC;
 377 
 378   // For a CMS collection, signal that a concurrent collection should
 379   // be started.
 380   static bool _should_concurrent_collect;
 381 
 382   static uint _shrink_factor;
 383 
 384   static size_t shrink_factor() { return _shrink_factor; }
 385   void set_shrink_factor(uint v) { _shrink_factor = v; }
 386 
 387  public:
 388 
 389   static void initialize();
 390   static void post_initialize();
 391 
 392   static size_t capacity_until_GC();
 393   static bool inc_capacity_until_GC(size_t v,
 394                                     size_t* new_cap_until_GC = NULL,
 395                                     size_t* old_cap_until_GC = NULL);
 396   static size_t dec_capacity_until_GC(size_t v);
 397 
 398   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 399   static void set_should_concurrent_collect(bool v) {
 400     _should_concurrent_collect = v;
 401   }
 402 
 403   // The amount to increase the high-water-mark (_capacity_until_GC)
 404   static size_t delta_capacity_until_GC(size_t bytes);
 405 
 406   // Tells if we have can expand metaspace without hitting set limits.
 407   static bool can_expand(size_t words, bool is_class);
 408 
 409   // Returns amount that we can expand without hitting a GC,
 410   // measured in words.
 411   static size_t allowed_expansion();
 412 
 413   // Calculate the new high-water mark at which to induce
 414   // a GC.
 415   static void compute_new_size();
 416 };
 417 
 418 #endif // SHARE_VM_MEMORY_METASPACE_HPP