1 /*
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   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
   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
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  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
  20  * or visit www.oracle.com if you need additional information or have any
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  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 SpaceManager;
  69 class VirtualSpaceList;
  70 
  71 // Metaspaces each have a  SpaceManager and allocations
  72 // are done by the SpaceManager.  Allocations are done
  73 // out of the current Metachunk.  When the current Metachunk
  74 // is exhausted, the SpaceManager gets a new one from
  75 // the current VirtualSpace.  When the VirtualSpace is exhausted
  76 // the SpaceManager gets a new one.  The SpaceManager
  77 // also manages freelists of available Chunks.
  78 //
  79 // Currently the space manager maintains the list of
  80 // virtual spaces and the list of chunks in use.  Its
  81 // allocate() method returns a block for use as a
  82 // quantum of metadata.
  83 
  84 class Metaspace : public CHeapObj<mtClass> {
  85   friend class VMStructs;
  86   friend class SpaceManager;
  87   friend class VM_CollectForMetadataAllocation;
  88   friend class MetaspaceGC;
  89   friend class MetaspaceAux;
  90 
  91  public:
  92   enum MetadataType {
  93     ClassType,
  94     NonClassType,
  95     MetadataTypeCount
  96   };
  97   enum MetaspaceType {
  98     StandardMetaspaceType,
  99     BootMetaspaceType,
 100     ROMetaspaceType,
 101     ReadWriteMetaspaceType,
 102     AnonymousMetaspaceType,
 103     ReflectionMetaspaceType
 104   };
 105 
 106  private:
 107   static void verify_global_initialization();
 108 
 109   void initialize(Mutex* lock, MetaspaceType type);
 110 
 111   // Initialize the first chunk for a Metaspace.  Used for
 112   // special cases such as the boot class loader, reflection
 113   // class loader and anonymous class loader.
 114   void initialize_first_chunk(MetaspaceType type, MetadataType mdtype);
 115   Metachunk* get_initialization_chunk(MetaspaceType type, MetadataType mdtype);
 116 
 117   // Align up the word size to the allocation word size
 118   static size_t align_word_size_up(size_t);
 119 
 120   // Aligned size of the metaspace.
 121   static size_t _compressed_class_space_size;
 122 
 123   static size_t compressed_class_space_size() {
 124     return _compressed_class_space_size;
 125   }
 126 
 127   static void set_compressed_class_space_size(size_t size) {
 128     _compressed_class_space_size = size;
 129   }
 130 
 131   static size_t _first_chunk_word_size;
 132   static size_t _first_class_chunk_word_size;
 133 
 134   static size_t _commit_alignment;
 135   static size_t _reserve_alignment;
 136 
 137   SpaceManager* _vsm;
 138   SpaceManager* vsm() const { return _vsm; }
 139 
 140   SpaceManager* _class_vsm;
 141   SpaceManager* class_vsm() const { return _class_vsm; }
 142   SpaceManager* get_space_manager(MetadataType mdtype) {
 143     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 144     return mdtype == ClassType ? class_vsm() : vsm();
 145   }
 146 
 147   // Allocate space for metadata of type mdtype. This is space
 148   // within a Metachunk and is used by
 149   //   allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
 150   MetaWord* allocate(size_t word_size, MetadataType mdtype);
 151 
 152   // Virtual Space lists for both classes and other metadata
 153   static VirtualSpaceList* _space_list;
 154   static VirtualSpaceList* _class_space_list;
 155 
 156   static ChunkManager* _chunk_manager_metadata;
 157   static ChunkManager* _chunk_manager_class;
 158 
 159   static const MetaspaceTracer* _tracer;
 160 
 161  public:
 162   static VirtualSpaceList* space_list()       { return _space_list; }
 163   static VirtualSpaceList* class_space_list() { return _class_space_list; }
 164   static VirtualSpaceList* get_space_list(MetadataType mdtype) {
 165     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 166     return mdtype == ClassType ? class_space_list() : space_list();
 167   }
 168 
 169   static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 170   static ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 171   static ChunkManager* get_chunk_manager(MetadataType mdtype) {
 172     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 173     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 174   }
 175 
 176   static const MetaspaceTracer* tracer() { return _tracer; }
 177 
 178  private:
 179   // These 2 methods are used by DumpSharedSpaces only, where only _vsm is used. So we will
 180   // maintain a single list for now.
 181   void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
 182   void record_deallocation(void* ptr, size_t word_size);
 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 
 195   class AllocRecord : public CHeapObj<mtClass> {
 196   public:
 197     AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
 198       : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
 199     AllocRecord *_next;
 200     address _ptr;
 201     MetaspaceObj::Type _type;
 202     int _byte_size;
 203   };
 204 
 205   AllocRecord * _alloc_record_head;
 206   AllocRecord * _alloc_record_tail;
 207 
 208   size_t class_chunk_size(size_t word_size);
 209 
 210  public:
 211 
 212   Metaspace(Mutex* lock, MetaspaceType type);
 213   ~Metaspace();
 214 
 215   static void ergo_initialize();
 216   static void global_initialize();
 217   static void post_initialize();
 218 
 219   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 220   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 221 
 222   static size_t reserve_alignment()       { return _reserve_alignment; }
 223   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 224   static size_t commit_alignment()        { return _commit_alignment; }
 225   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 226 
 227   char*  bottom() const;
 228   size_t used_words_slow(MetadataType mdtype) const;
 229   size_t free_words_slow(MetadataType mdtype) const;
 230   size_t capacity_words_slow(MetadataType mdtype) const;
 231 
 232   size_t used_bytes_slow(MetadataType mdtype) const;
 233   size_t capacity_bytes_slow(MetadataType mdtype) const;
 234 
 235   size_t allocated_blocks_bytes() const;
 236   size_t allocated_chunks_bytes() const;
 237 
 238   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 239                             bool read_only, MetaspaceObj::Type type, TRAPS);
 240   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 241 
 242   MetaWord* expand_and_allocate(size_t size,
 243                                 MetadataType mdtype);
 244 
 245   static bool contains(const void* ptr);
 246 
 247   void dump(outputStream* const out) const;
 248 
 249   // Free empty virtualspaces
 250   static void purge(MetadataType mdtype);
 251   static void purge();
 252 
 253   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 254                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 255 
 256   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 257 
 258   void print_on(outputStream* st) const;
 259   // Debugging support
 260   void verify();
 261 
 262   class AllocRecordClosure :  public StackObj {
 263   public:
 264     virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
 265   };
 266 
 267   void iterate(AllocRecordClosure *closure);
 268 
 269   // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
 270   static bool using_class_space() {
 271     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
 272   }
 273 
 274   static bool is_class_space_allocation(MetadataType mdType) {
 275     return mdType == ClassType && using_class_space();
 276   }
 277 
 278 };
 279 
 280 class MetaspaceAux : AllStatic {
 281   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 282 
 283   // These methods iterate over the classloader data graph
 284   // for the given Metaspace type.  These are slow.
 285   static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
 286   static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
 287   static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
 288   static size_t capacity_bytes_slow();
 289 
 290   // Running sum of space in all Metachunks that has been
 291   // allocated to a Metaspace.  This is used instead of
 292   // iterating over all the classloaders. One for each
 293   // type of Metadata
 294   static size_t _capacity_words[Metaspace:: MetadataTypeCount];
 295   // Running sum of space in all Metachunks that
 296   // are being used for metadata. One for each
 297   // type of Metadata.
 298   static size_t _used_words[Metaspace:: MetadataTypeCount];
 299 
 300  public:
 301   // Decrement and increment _allocated_capacity_words
 302   static void dec_capacity(Metaspace::MetadataType type, size_t words);
 303   static void inc_capacity(Metaspace::MetadataType type, size_t words);
 304 
 305   // Decrement and increment _allocated_used_words
 306   static void dec_used(Metaspace::MetadataType type, size_t words);
 307   static void inc_used(Metaspace::MetadataType type, size_t words);
 308 
 309   // Total of space allocated to metadata in all Metaspaces.
 310   // This sums the space used in each Metachunk by
 311   // iterating over the classloader data graph
 312   static size_t used_bytes_slow() {
 313     return used_bytes_slow(Metaspace::ClassType) +
 314            used_bytes_slow(Metaspace::NonClassType);
 315   }
 316 
 317   // Used by MetaspaceCounters
 318   static size_t free_chunks_total_words();
 319   static size_t free_chunks_total_bytes();
 320   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 321 
 322   static size_t capacity_words(Metaspace::MetadataType mdtype) {
 323     return _capacity_words[mdtype];
 324   }
 325   static size_t capacity_words() {
 326     return capacity_words(Metaspace::NonClassType) +
 327            capacity_words(Metaspace::ClassType);
 328   }
 329   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 330     return capacity_words(mdtype) * BytesPerWord;
 331   }
 332   static size_t capacity_bytes() {
 333     return capacity_words() * BytesPerWord;
 334   }
 335 
 336   static size_t used_words(Metaspace::MetadataType mdtype) {
 337     return _used_words[mdtype];
 338   }
 339   static size_t used_words() {
 340     return used_words(Metaspace::NonClassType) +
 341            used_words(Metaspace::ClassType);
 342   }
 343   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 344     return used_words(mdtype) * BytesPerWord;
 345   }
 346   static size_t used_bytes() {
 347     return used_words() * BytesPerWord;
 348   }
 349 
 350   static size_t free_bytes();
 351   static size_t free_bytes(Metaspace::MetadataType mdtype);
 352 
 353   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 354   static size_t reserved_bytes() {
 355     return reserved_bytes(Metaspace::ClassType) +
 356            reserved_bytes(Metaspace::NonClassType);
 357   }
 358 
 359   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 360   static size_t committed_bytes() {
 361     return committed_bytes(Metaspace::ClassType) +
 362            committed_bytes(Metaspace::NonClassType);
 363   }
 364 
 365   static size_t min_chunk_size_words();
 366   static size_t min_chunk_size_bytes() {
 367     return min_chunk_size_words() * BytesPerWord;
 368   }
 369 
 370   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 371   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 372 
 373   // Print change in used metadata.
 374   static void print_metaspace_change(size_t prev_metadata_used);
 375   static void print_on(outputStream * out);
 376   static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
 377 
 378   static void print_class_waste(outputStream* out);
 379   static void print_waste(outputStream* out);
 380   static void dump(outputStream* out);
 381   static void verify_free_chunks();
 382   // Checks that the values returned by allocated_capacity_bytes() and
 383   // capacity_bytes_slow() are the same.
 384   static void verify_capacity();
 385   static void verify_used();
 386   static void verify_metrics();
 387 };
 388 
 389 // Metaspace are deallocated when their class loader are GC'ed.
 390 // This class implements a policy for inducing GC's to recover
 391 // Metaspaces.
 392 
 393 class MetaspaceGC : AllStatic {
 394 
 395   // The current high-water-mark for inducing a GC.
 396   // When committed memory of all metaspaces reaches this value,
 397   // a GC is induced and the value is increased. Size is in bytes.
 398   static volatile intptr_t _capacity_until_GC;
 399 
 400   // For a CMS collection, signal that a concurrent collection should
 401   // be started.
 402   static bool _should_concurrent_collect;
 403 
 404   static uint _shrink_factor;
 405 
 406   static size_t shrink_factor() { return _shrink_factor; }
 407   void set_shrink_factor(uint v) { _shrink_factor = v; }
 408 
 409  public:
 410 
 411   static void initialize();
 412   static void post_initialize();
 413 
 414   static size_t capacity_until_GC();
 415   static bool inc_capacity_until_GC(size_t v,
 416                                     size_t* new_cap_until_GC = NULL,
 417                                     size_t* old_cap_until_GC = NULL);
 418   static size_t dec_capacity_until_GC(size_t v);
 419 
 420   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 421   static void set_should_concurrent_collect(bool v) {
 422     _should_concurrent_collect = v;
 423   }
 424 
 425   // The amount to increase the high-water-mark (_capacity_until_GC)
 426   static size_t delta_capacity_until_GC(size_t bytes);
 427 
 428   // Tells if we have can expand metaspace without hitting set limits.
 429   static bool can_expand(size_t words, bool is_class);
 430 
 431   // Returns amount that we can expand without hitting a GC,
 432   // measured in words.
 433   static size_t allowed_expansion();
 434 
 435   // Calculate the new high-water mark at which to induce
 436   // a GC.
 437   static void compute_new_size();
 438 };
 439 
 440 #endif // SHARE_VM_MEMORY_METASPACE_HPP