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
--- EOF ---