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.
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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 ChunkManager;
  60 class ClassLoaderData;
  61 class Metablock;
  62 class Metachunk;
  63 class MetaspaceTracer;
  64 class MetaWord;
  65 class Mutex;
  66 class outputStream;
  67 class SpaceManager;
  68 class VirtualSpaceList;
  69 
  70 // Metaspaces each have a  SpaceManager and allocations
  71 // are done by the SpaceManager.  Allocations are done
  72 // out of the current Metachunk.  When the current Metachunk
  73 // is exhausted, the SpaceManager gets a new one from
  74 // the current VirtualSpace.  When the VirtualSpace is exhausted
  75 // the SpaceManager gets a new one.  The SpaceManager
  76 // also manages freelists of available Chunks.
  77 //
  78 // Currently the space manager maintains the list of
  79 // virtual spaces and the list of chunks in use.  Its
  80 // allocate() method returns a block for use as a
  81 // quantum of metadata.
  82 
  83 class Metaspace : public CHeapObj<mtClass> {
  84   friend class VMStructs;
  85   friend class SpaceManager;
  86   friend class VM_CollectForMetadataAllocation;
  87   friend class MetaspaceGC;
  88   friend class MetaspaceAux;
  89 
  90  public:
  91   enum MetadataType {
  92     ClassType,
  93     NonClassType,
  94     MetadataTypeCount
  95   };
  96   enum MetaspaceType {
  97     StandardMetaspaceType,
  98     BootMetaspaceType,
  99     ROMetaspaceType,
 100     ReadWriteMetaspaceType,
 101     AnonymousMetaspaceType,
 102     ReflectionMetaspaceType
 103   };
 104 
 105  private:
 106   void initialize(Mutex* lock, MetaspaceType type);
 107 
 108   // Get the first chunk for a Metaspace.  Used for
 109   // special cases such as the boot class loader, reflection
 110   // class loader and anonymous class loader.
 111   Metachunk* get_initialization_chunk(MetadataType mdtype,
 112                                       size_t chunk_word_size,
 113                                       size_t chunk_bunch);
 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 
 135   SpaceManager* _vsm;
 136   SpaceManager* vsm() const { return _vsm; }
 137 
 138   SpaceManager* _class_vsm;
 139   SpaceManager* class_vsm() const { return _class_vsm; }
 140 
 141   // Allocate space for metadata of type mdtype. This is space
 142   // within a Metachunk and is used by
 143   //   allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
 144   MetaWord* allocate(size_t word_size, MetadataType mdtype);
 145 
 146   // Virtual Space lists for both classes and other metadata
 147   static VirtualSpaceList* _space_list;
 148   static VirtualSpaceList* _class_space_list;
 149 
 150   static ChunkManager* _chunk_manager_metadata;
 151   static ChunkManager* _chunk_manager_class;
 152 
 153   static const MetaspaceTracer* const _tracer;
 154 
 155  public:
 156   static VirtualSpaceList* space_list()       { return _space_list; }
 157   static VirtualSpaceList* class_space_list() { return _class_space_list; }
 158   static VirtualSpaceList* get_space_list(MetadataType mdtype) {
 159     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 160     return mdtype == ClassType ? class_space_list() : space_list();
 161   }
 162 
 163   static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 164   static ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 165   static ChunkManager* get_chunk_manager(MetadataType mdtype) {
 166     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 167     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 168   }
 169 
 170   static const MetaspaceTracer* tracer() { return _tracer; }
 171 
 172  private:
 173   // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
 174   // maintain a single list for now.
 175   void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
 176 
 177 #ifdef _LP64
 178   static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
 179 
 180   // Returns true if can use CDS with metaspace allocated as specified address.
 181   static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
 182 
 183   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 184 
 185   static void initialize_class_space(ReservedSpace rs);
 186 #endif
 187 
 188   class AllocRecord : public CHeapObj<mtClass> {
 189   public:
 190     AllocRecord(address ptr, MetaspaceObj::Type type, int byte_size)
 191       : _next(NULL), _ptr(ptr), _type(type), _byte_size(byte_size) {}
 192     AllocRecord *_next;
 193     address _ptr;
 194     MetaspaceObj::Type _type;
 195     int _byte_size;
 196   };
 197 
 198   AllocRecord * _alloc_record_head;
 199   AllocRecord * _alloc_record_tail;
 200 
 201   size_t class_chunk_size(size_t word_size);
 202 
 203  public:
 204 
 205   Metaspace(Mutex* lock, MetaspaceType type);
 206   ~Metaspace();
 207 
 208   static void ergo_initialize();
 209   static void global_initialize();
 210 
 211   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 212   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 213 
 214   static size_t reserve_alignment()       { return _reserve_alignment; }
 215   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 216   static size_t commit_alignment()        { return _commit_alignment; }
 217   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 218 
 219   char*  bottom() const;
 220   size_t used_words_slow(MetadataType mdtype) const;
 221   size_t free_words_slow(MetadataType mdtype) const;
 222   size_t capacity_words_slow(MetadataType mdtype) const;
 223 
 224   size_t used_bytes_slow(MetadataType mdtype) const;
 225   size_t capacity_bytes_slow(MetadataType mdtype) const;
 226 
 227   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 228                             bool read_only, MetaspaceObj::Type type, TRAPS);
 229   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 230 
 231   MetaWord* expand_and_allocate(size_t size,
 232                                 MetadataType mdtype);
 233 
 234   bool contains(const void* ptr);
 235   void dump(outputStream* const out) const;
 236 
 237   // Free empty virtualspaces
 238   static void purge(MetadataType mdtype);
 239   static void purge();
 240 
 241   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 242                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 243 
 244   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 245 
 246   void print_on(outputStream* st) const;
 247   // Debugging support
 248   void verify();
 249 
 250   class AllocRecordClosure :  public StackObj {
 251   public:
 252     virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) = 0;
 253   };
 254 
 255   void iterate(AllocRecordClosure *closure);
 256 
 257   // Return TRUE only if UseCompressedClassPointers is True and DumpSharedSpaces is False.
 258   static bool using_class_space() {
 259     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers && !DumpSharedSpaces);
 260   }
 261 
 262   static bool is_class_space_allocation(MetadataType mdType) {
 263     return mdType == ClassType && using_class_space();
 264   }
 265 
 266 };
 267 
 268 class MetaspaceAux : AllStatic {
 269   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 270 
 271   // These methods iterate over the classloader data graph
 272   // for the given Metaspace type.  These are slow.
 273   static size_t used_bytes_slow(Metaspace::MetadataType mdtype);
 274   static size_t free_bytes_slow(Metaspace::MetadataType mdtype);
 275   static size_t capacity_bytes_slow(Metaspace::MetadataType mdtype);
 276   static size_t capacity_bytes_slow();
 277 
 278   // Running sum of space in all Metachunks that has been
 279   // allocated to a Metaspace.  This is used instead of
 280   // iterating over all the classloaders. One for each
 281   // type of Metadata
 282   static size_t _allocated_capacity_words[Metaspace:: MetadataTypeCount];
 283   // Running sum of space in all Metachunks that have
 284   // are being used for metadata. One for each
 285   // type of Metadata.
 286   static size_t _allocated_used_words[Metaspace:: MetadataTypeCount];
 287 
 288  public:
 289   // Decrement and increment _allocated_capacity_words
 290   static void dec_capacity(Metaspace::MetadataType type, size_t words);
 291   static void inc_capacity(Metaspace::MetadataType type, size_t words);
 292 
 293   // Decrement and increment _allocated_used_words
 294   static void dec_used(Metaspace::MetadataType type, size_t words);
 295   static void inc_used(Metaspace::MetadataType type, size_t words);
 296 
 297   // Total of space allocated to metadata in all Metaspaces.
 298   // This sums the space used in each Metachunk by
 299   // iterating over the classloader data graph
 300   static size_t used_bytes_slow() {
 301     return used_bytes_slow(Metaspace::ClassType) +
 302            used_bytes_slow(Metaspace::NonClassType);
 303   }
 304 
 305   // Used by MetaspaceCounters
 306   static size_t free_chunks_total_words();
 307   static size_t free_chunks_total_bytes();
 308   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 309 
 310   static size_t allocated_capacity_words(Metaspace::MetadataType mdtype) {
 311     return _allocated_capacity_words[mdtype];
 312   }
 313   static size_t allocated_capacity_words() {
 314     return allocated_capacity_words(Metaspace::NonClassType) +
 315            allocated_capacity_words(Metaspace::ClassType);
 316   }
 317   static size_t allocated_capacity_bytes(Metaspace::MetadataType mdtype) {
 318     return allocated_capacity_words(mdtype) * BytesPerWord;
 319   }
 320   static size_t allocated_capacity_bytes() {
 321     return allocated_capacity_words() * BytesPerWord;
 322   }
 323 
 324   static size_t allocated_used_words(Metaspace::MetadataType mdtype) {
 325     return _allocated_used_words[mdtype];
 326   }
 327   static size_t allocated_used_words() {
 328     return allocated_used_words(Metaspace::NonClassType) +
 329            allocated_used_words(Metaspace::ClassType);
 330   }
 331   static size_t allocated_used_bytes(Metaspace::MetadataType mdtype) {
 332     return allocated_used_words(mdtype) * BytesPerWord;
 333   }
 334   static size_t allocated_used_bytes() {
 335     return allocated_used_words() * BytesPerWord;
 336   }
 337 
 338   static size_t free_bytes();
 339   static size_t free_bytes(Metaspace::MetadataType mdtype);
 340 
 341   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 342   static size_t reserved_bytes() {
 343     return reserved_bytes(Metaspace::ClassType) +
 344            reserved_bytes(Metaspace::NonClassType);
 345   }
 346 
 347   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 348   static size_t committed_bytes() {
 349     return committed_bytes(Metaspace::ClassType) +
 350            committed_bytes(Metaspace::NonClassType);
 351   }
 352 
 353   static size_t min_chunk_size_words();
 354   static size_t min_chunk_size_bytes() {
 355     return min_chunk_size_words() * BytesPerWord;
 356   }
 357 
 358   // Print change in used metadata.
 359   static void print_metaspace_change(size_t prev_metadata_used);
 360   static void print_on(outputStream * out);
 361   static void print_on(outputStream * out, Metaspace::MetadataType mdtype);
 362 
 363   static void print_class_waste(outputStream* out);
 364   static void print_waste(outputStream* out);
 365   static void dump(outputStream* out);
 366   static void verify_free_chunks();
 367   // Checks that the values returned by allocated_capacity_bytes() and
 368   // capacity_bytes_slow() are the same.
 369   static void verify_capacity();
 370   static void verify_used();
 371   static void verify_metrics();
 372 };
 373 
 374 // Metaspace are deallocated when their class loader are GC'ed.
 375 // This class implements a policy for inducing GC's to recover
 376 // Metaspaces.
 377 
 378 class MetaspaceGC : AllStatic {
 379 
 380   // The current high-water-mark for inducing a GC.
 381   // When committed memory of all metaspaces reaches this value,
 382   // a GC is induced and the value is increased. Size is in bytes.
 383   static volatile intptr_t _capacity_until_GC;
 384 
 385   // For a CMS collection, signal that a concurrent collection should
 386   // be started.
 387   static bool _should_concurrent_collect;
 388 
 389   static uint _shrink_factor;
 390 
 391   static size_t shrink_factor() { return _shrink_factor; }
 392   void set_shrink_factor(uint v) { _shrink_factor = v; }
 393 
 394  public:
 395 
 396   static void initialize() { _capacity_until_GC = MetaspaceSize; }
 397 
 398   static size_t capacity_until_GC();
 399   static size_t inc_capacity_until_GC(size_t v);
 400   static size_t dec_capacity_until_GC(size_t v);
 401 
 402   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 403   static void set_should_concurrent_collect(bool v) {
 404     _should_concurrent_collect = v;
 405   }
 406 
 407   // The amount to increase the high-water-mark (_capacity_until_GC)
 408   static size_t delta_capacity_until_GC(size_t bytes);
 409 
 410   // Tells if we have can expand metaspace without hitting set limits.
 411   static bool can_expand(size_t words, bool is_class);
 412 
 413   // Returns amount that we can expand without hitting a GC,
 414   // measured in words.
 415   static size_t allowed_expansion();
 416 
 417   // Calculate the new high-water mark at which to induce
 418   // a GC.
 419   static void compute_new_size();
 420 };
 421 
 422 #endif // SHARE_VM_MEMORY_METASPACE_HPP