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.
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   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).
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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_MEMORY_METASPACE_HPP
  25 #define SHARE_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 "memory/metaspace/metaspaceSizesSnapshot.hpp"
  32 #include "runtime/globals.hpp"
  33 #include "utilities/exceptions.hpp"
  34 
  35 // Metaspace
  36 //
  37 // Metaspaces are Arenas for the VM's metadata.
  38 // They are allocated one per class loader object, and one for the null
  39 // bootstrap class loader
  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 ClassLoaderData;
  61 class MetaspaceTracer;
  62 class Mutex;
  63 class outputStream;
  64 
  65 class CollectedHeap;
  66 
  67 namespace metaspace {
  68   class ChunkManager;
  69   class ClassLoaderMetaspaceStatistics;
  70   class Metablock;
  71   class Metachunk;
  72   class PrintCLDMetaspaceInfoClosure;
  73   class SpaceManager;
  74   class VirtualSpaceList;
  75   class VirtualSpaceNode;
  76 }
  77 
  78 // Metaspaces each have a  SpaceManager and allocations
  79 // are done by the SpaceManager.  Allocations are done
  80 // out of the current Metachunk.  When the current Metachunk
  81 // is exhausted, the SpaceManager gets a new one from
  82 // the current VirtualSpace.  When the VirtualSpace is exhausted
  83 // the SpaceManager gets a new one.  The SpaceManager
  84 // also manages freelists of available Chunks.
  85 //
  86 // Currently the space manager maintains the list of
  87 // virtual spaces and the list of chunks in use.  Its
  88 // allocate() method returns a block for use as a
  89 // quantum of metadata.
  90 
  91 // Namespace for important central static functions
  92 // (auxiliary stuff goes into MetaspaceUtils)
  93 class Metaspace : public AllStatic {
  94 
  95   friend class MetaspaceShared;
  96 
  97  public:
  98   enum MetadataType {
  99     ClassType,
 100     NonClassType,
 101     MetadataTypeCount
 102   };
 103   enum MetaspaceType {
 104     ZeroMetaspaceType = 0,
 105     StandardMetaspaceType = ZeroMetaspaceType,
 106     BootMetaspaceType = StandardMetaspaceType + 1,
 107     ClassMirrorHolderMetaspaceType = BootMetaspaceType + 1,
 108     ReflectionMetaspaceType = ClassMirrorHolderMetaspaceType + 1,
 109     MetaspaceTypeCount
 110   };
 111 
 112  private:
 113 
 114   // Align up the word size to the allocation word size
 115   static size_t align_word_size_up(size_t);
 116 
 117   // Aligned size of the metaspace.
 118   static size_t _compressed_class_space_size;
 119 
 120   static size_t compressed_class_space_size() {
 121     return _compressed_class_space_size;
 122   }
 123 
 124   static void set_compressed_class_space_size(size_t size) {
 125     _compressed_class_space_size = size;
 126   }
 127 
 128   static size_t _first_chunk_word_size;
 129   static size_t _first_class_chunk_word_size;
 130 
 131   static size_t _commit_alignment;
 132   static size_t _reserve_alignment;
 133   DEBUG_ONLY(static bool   _frozen;)
 134 
 135   // Virtual Space lists for both classes and other metadata
 136   static metaspace::VirtualSpaceList* _space_list;
 137   static metaspace::VirtualSpaceList* _class_space_list;
 138 
 139   static metaspace::ChunkManager* _chunk_manager_metadata;
 140   static metaspace::ChunkManager* _chunk_manager_class;
 141 
 142   static const MetaspaceTracer* _tracer;
 143 
 144   static bool _initialized;
 145 
 146  public:
 147   static metaspace::VirtualSpaceList* space_list()       { return _space_list; }
 148   static metaspace::VirtualSpaceList* class_space_list() { return _class_space_list; }
 149   static metaspace::VirtualSpaceList* get_space_list(MetadataType mdtype) {
 150     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 151     return mdtype == ClassType ? class_space_list() : space_list();
 152   }
 153 
 154   static metaspace::ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 155   static metaspace::ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 156   static metaspace::ChunkManager* get_chunk_manager(MetadataType mdtype) {
 157     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 158     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 159   }
 160 
 161   // convenience function
 162   static metaspace::ChunkManager* get_chunk_manager(bool is_class) {
 163     return is_class ? chunk_manager_class() : chunk_manager_metadata();
 164   }
 165 
 166   static const MetaspaceTracer* tracer() { return _tracer; }
 167   static void freeze() {
 168     assert(DumpSharedSpaces, "sanity");
 169     DEBUG_ONLY(_frozen = true;)
 170   }
 171   static void assert_not_frozen() {
 172     assert(!_frozen, "sanity");
 173   }
 174 
 175  private:
 176 
 177 #ifdef _LP64
 178 
 179   // Reserve a range of memory at an address suitable for en/decoding narrow
 180   // Klass pointers (see: CompressedClassPointers::is_valid_base()).
 181   // The returned address shall both be suitable as a compressed class pointers
 182   //  base, and aligned to Metaspace::reserve_alignment (which is equal to or a
 183   //  multiple of allocation granularity).
 184   // On error, returns an unreserved space.
 185   static ReservedSpace reserve_address_space_for_compressed_classes(size_t size);
 186 
 187   // Given a prereserved space, use that to set up the compressed class space list.
 188   static void initialize_class_space(ReservedSpace rs);
 189 
 190   // Returns true if class space has been setup (initialize_class_space).
 191   static bool class_space_is_initialized() { return _class_space_list != NULL; }
 192 
 193 #endif
 194 
 195  public:
 196 
 197   static void ergo_initialize();
 198   static void global_initialize();
 199   static void post_initialize();
 200 
 201   static void verify_global_initialization();
 202 
 203   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 204   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 205 
 206   static size_t reserve_alignment()       { return _reserve_alignment; }
 207   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 208   static size_t commit_alignment()        { return _commit_alignment; }
 209   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 210 
 211   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 212                             MetaspaceObj::Type type, TRAPS);
 213 
 214   static bool contains(const void* ptr);
 215   static bool contains_non_shared(const void* ptr);
 216 
 217   // Free empty virtualspaces
 218   static void purge(MetadataType mdtype);
 219   static void purge();
 220 
 221   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 222                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 223 
 224   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 225 
 226   static void print_compressed_class_space(outputStream* st) NOT_LP64({});
 227 
 228   // Return TRUE only if UseCompressedClassPointers is True.
 229   static bool using_class_space() {
 230     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
 231   }
 232 
 233   static bool is_class_space_allocation(MetadataType mdType) {
 234     return mdType == ClassType && using_class_space();
 235   }
 236 
 237   static bool initialized() { return _initialized; }
 238 
 239 };
 240 
 241 // Manages the metaspace portion belonging to a class loader
 242 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
 243   friend class CollectedHeap; // For expand_and_allocate()
 244   friend class ZCollectedHeap; // For expand_and_allocate()
 245   friend class ShenandoahHeap; // For expand_and_allocate()
 246   friend class Metaspace;
 247   friend class MetaspaceUtils;
 248   friend class metaspace::PrintCLDMetaspaceInfoClosure;
 249   friend class VM_CollectForMetadataAllocation; // For expand_and_allocate()
 250 
 251  private:
 252 
 253   void initialize(Mutex* lock, Metaspace::MetaspaceType type);
 254 
 255   // Initialize the first chunk for a Metaspace.  Used for
 256   // special cases such as the boot class loader, reflection
 257   // class loader and hidden class loader.
 258   void initialize_first_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
 259   metaspace::Metachunk* get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
 260 
 261   const Metaspace::MetaspaceType _space_type;
 262   Mutex* const  _lock;
 263   metaspace::SpaceManager* _vsm;
 264   metaspace::SpaceManager* _class_vsm;
 265 
 266   metaspace::SpaceManager* vsm() const { return _vsm; }
 267   metaspace::SpaceManager* class_vsm() const { return _class_vsm; }
 268   metaspace::SpaceManager* get_space_manager(Metaspace::MetadataType mdtype) {
 269     assert(mdtype != Metaspace::MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 270     return mdtype == Metaspace::ClassType ? class_vsm() : vsm();
 271   }
 272 
 273   Mutex* lock() const { return _lock; }
 274 
 275   MetaWord* expand_and_allocate(size_t size, Metaspace::MetadataType mdtype);
 276 
 277   size_t class_chunk_size(size_t word_size);
 278 
 279   // Adds to the given statistic object. Must be locked with CLD metaspace lock.
 280   void add_to_statistics_locked(metaspace::ClassLoaderMetaspaceStatistics* out) const;
 281 
 282   Metaspace::MetaspaceType space_type() const { return _space_type; }
 283 
 284  public:
 285 
 286   ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type);
 287   ~ClassLoaderMetaspace();
 288 
 289   // Allocate space for metadata of type mdtype. This is space
 290   // within a Metachunk and is used by
 291   //   allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
 292   MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdtype);
 293 
 294   size_t allocated_blocks_bytes() const;
 295   size_t allocated_chunks_bytes() const;
 296 
 297   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 298 
 299   void print_on(outputStream* st) const;
 300   // Debugging support
 301   void verify();
 302 
 303   // Adds to the given statistic object. Will lock with CLD metaspace lock.
 304   void add_to_statistics(metaspace::ClassLoaderMetaspaceStatistics* out) const;
 305 
 306 }; // ClassLoaderMetaspace
 307 
 308 class MetaspaceUtils : AllStatic {
 309 
 310   // Spacemanager updates running counters.
 311   friend class metaspace::SpaceManager;
 312 
 313   // Special access for error reporting (checks without locks).
 314   friend class oopDesc;
 315   friend class Klass;
 316 
 317   // Running counters for statistics concerning in-use chunks.
 318   // Note: capacity = used + free + waste + overhead. Note that we do not
 319   // count free and waste. Their sum can be deduces from the three other values.
 320   // For more details, one should call print_report() from within a safe point.
 321   static size_t _capacity_words [Metaspace:: MetadataTypeCount];
 322   static size_t _overhead_words [Metaspace:: MetadataTypeCount];
 323   static volatile size_t _used_words [Metaspace:: MetadataTypeCount];
 324 
 325   // Atomically decrement or increment in-use statistic counters
 326   static void dec_capacity(Metaspace::MetadataType mdtype, size_t words);
 327   static void inc_capacity(Metaspace::MetadataType mdtype, size_t words);
 328   static void dec_used(Metaspace::MetadataType mdtype, size_t words);
 329   static void inc_used(Metaspace::MetadataType mdtype, size_t words);
 330   static void dec_overhead(Metaspace::MetadataType mdtype, size_t words);
 331   static void inc_overhead(Metaspace::MetadataType mdtype, size_t words);
 332 
 333 
 334   // Getters for the in-use counters.
 335   static size_t capacity_words(Metaspace::MetadataType mdtype)        { return _capacity_words[mdtype]; }
 336   static size_t used_words(Metaspace::MetadataType mdtype)            { return _used_words[mdtype]; }
 337   static size_t overhead_words(Metaspace::MetadataType mdtype)        { return _overhead_words[mdtype]; }
 338 
 339   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 340 
 341   // Helper for print_xx_report.
 342   static void print_vs(outputStream* out, size_t scale);
 343 
 344 public:
 345 
 346   // Collect used metaspace statistics. This involves walking the CLDG. The resulting
 347   // output will be the accumulated values for all live metaspaces.
 348   // Note: method does not do any locking.
 349   static void collect_statistics(metaspace::ClassLoaderMetaspaceStatistics* out);
 350 
 351   // Used by MetaspaceCounters
 352   static size_t free_chunks_total_words();
 353   static size_t free_chunks_total_bytes();
 354   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 355 
 356   static size_t capacity_words() {
 357     return capacity_words(Metaspace::NonClassType) +
 358            capacity_words(Metaspace::ClassType);
 359   }
 360   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 361     return capacity_words(mdtype) * BytesPerWord;
 362   }
 363   static size_t capacity_bytes() {
 364     return capacity_words() * BytesPerWord;
 365   }
 366 
 367   static size_t used_words() {
 368     return used_words(Metaspace::NonClassType) +
 369            used_words(Metaspace::ClassType);
 370   }
 371   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 372     return used_words(mdtype) * BytesPerWord;
 373   }
 374   static size_t used_bytes() {
 375     return used_words() * BytesPerWord;
 376   }
 377 
 378   // Space committed but yet unclaimed by any class loader.
 379   static size_t free_in_vs_bytes();
 380   static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
 381 
 382   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 383   static size_t reserved_bytes() {
 384     return reserved_bytes(Metaspace::ClassType) +
 385            reserved_bytes(Metaspace::NonClassType);
 386   }
 387 
 388   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 389   static size_t committed_bytes() {
 390     return committed_bytes(Metaspace::ClassType) +
 391            committed_bytes(Metaspace::NonClassType);
 392   }
 393 
 394   static size_t min_chunk_size_words();
 395 
 396   // Flags for print_report().
 397   enum ReportFlag {
 398     // Show usage by class loader.
 399     rf_show_loaders                 = (1 << 0),
 400     // Breaks report down by chunk type (small, medium, ...).
 401     rf_break_down_by_chunktype      = (1 << 1),
 402     // Breaks report down by space type (hidden, reflection, ...).
 403     rf_break_down_by_spacetype      = (1 << 2),
 404     // Print details about the underlying virtual spaces.
 405     rf_show_vslist                  = (1 << 3),
 406     // Print metaspace map.
 407     rf_show_vsmap                   = (1 << 4),
 408     // If show_loaders: show loaded classes for each loader.
 409     rf_show_classes                 = (1 << 5)
 410   };
 411 
 412   // This will print out a basic metaspace usage report but
 413   // unlike print_report() is guaranteed not to lock or to walk the CLDG.
 414   static void print_basic_report(outputStream* st, size_t scale);
 415 
 416   // Prints a report about the current metaspace state.
 417   // Optional parts can be enabled via flags.
 418   // Function will walk the CLDG and will lock the expand lock; if that is not
 419   // convenient, use print_basic_report() instead.
 420   static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
 421 
 422   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 423   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 424 
 425   // Log change in used metadata.
 426   static void print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values);
 427   static void print_on(outputStream * out);
 428 
 429   // Prints an ASCII representation of the given space.
 430   static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
 431 
 432   static void dump(outputStream* out);
 433   static void verify_free_chunks();
 434   // Check internal counters (capacity, used).
 435   static void verify_metrics();
 436 };
 437 
 438 // Metaspace are deallocated when their class loader are GC'ed.
 439 // This class implements a policy for inducing GC's to recover
 440 // Metaspaces.
 441 
 442 class MetaspaceGC : AllStatic {
 443 
 444   // The current high-water-mark for inducing a GC.
 445   // When committed memory of all metaspaces reaches this value,
 446   // a GC is induced and the value is increased. Size is in bytes.
 447   static volatile size_t _capacity_until_GC;
 448   static uint _shrink_factor;
 449 
 450   static size_t shrink_factor() { return _shrink_factor; }
 451   void set_shrink_factor(uint v) { _shrink_factor = v; }
 452 
 453  public:
 454 
 455   static void initialize();
 456   static void post_initialize();
 457 
 458   static size_t capacity_until_GC();
 459   static bool inc_capacity_until_GC(size_t v,
 460                                     size_t* new_cap_until_GC = NULL,
 461                                     size_t* old_cap_until_GC = NULL,
 462                                     bool* can_retry = NULL);
 463   static size_t dec_capacity_until_GC(size_t v);
 464 
 465   // The amount to increase the high-water-mark (_capacity_until_GC)
 466   static size_t delta_capacity_until_GC(size_t bytes);
 467 
 468   // Tells if we have can expand metaspace without hitting set limits.
 469   static bool can_expand(size_t words, bool is_class);
 470 
 471   // Returns amount that we can expand without hitting a GC,
 472   // measured in words.
 473   static size_t allowed_expansion();
 474 
 475   // Calculate the new high-water mark at which to induce
 476   // a GC.
 477   static void compute_new_size();
 478 };
 479 
 480 #endif // SHARE_MEMORY_METASPACE_HPP