1 /*
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   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
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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 "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 ClassLoaderData;
  59 class MetaspaceTracer;
  60 class MetaWord;
  61 class Mutex;
  62 class outputStream;
  63 
  64 class CollectedHeap;
  65 
  66 namespace metaspace {
  67   class ChunkManager;
  68   class ClassLoaderMetaspaceStatistics;
  69   class Metablock;
  70   class Metachunk;
  71   class PrintCLDMetaspaceInfoClosure;
  72   class SpaceManager;
  73   class VirtualSpaceList;
  74   class VirtualSpaceNode;
  75 }
  76 
  77 // Metaspaces each have a  SpaceManager and allocations
  78 // are done by the SpaceManager.  Allocations are done
  79 // out of the current Metachunk.  When the current Metachunk
  80 // is exhausted, the SpaceManager gets a new one from
  81 // the current VirtualSpace.  When the VirtualSpace is exhausted
  82 // the SpaceManager gets a new one.  The SpaceManager
  83 // also manages freelists of available Chunks.
  84 //
  85 // Currently the space manager maintains the list of
  86 // virtual spaces and the list of chunks in use.  Its
  87 // allocate() method returns a block for use as a
  88 // quantum of metadata.
  89 
  90 // Namespace for important central static functions
  91 // (auxiliary stuff goes into MetaspaceUtils)
  92 class Metaspace : public AllStatic {
  93 
  94   friend class MetaspaceShared;
  95 
  96  public:
  97   enum MetadataType {
  98     ClassType,
  99     NonClassType,
 100     MetadataTypeCount
 101   };
 102   enum MetaspaceType {
 103     ZeroMetaspaceType = 0,
 104     StandardMetaspaceType = ZeroMetaspaceType,
 105     BootMetaspaceType = StandardMetaspaceType + 1,
 106     AnonymousMetaspaceType = BootMetaspaceType + 1,
 107     ReflectionMetaspaceType = AnonymousMetaspaceType + 1,
 108     MetaspaceTypeCount
 109   };
 110 
 111  private:
 112 
 113   // Align up the word size to the allocation word size
 114   static size_t align_word_size_up(size_t);
 115 
 116   // Aligned size of the metaspace.
 117   static size_t _compressed_class_space_size;
 118 
 119   static size_t compressed_class_space_size() {
 120     return _compressed_class_space_size;
 121   }
 122 
 123   static void set_compressed_class_space_size(size_t size) {
 124     _compressed_class_space_size = size;
 125   }
 126 
 127   static size_t _first_chunk_word_size;
 128   static size_t _first_class_chunk_word_size;
 129 
 130   static size_t _commit_alignment;
 131   static size_t _reserve_alignment;
 132   DEBUG_ONLY(static bool   _frozen;)
 133 
 134   // Virtual Space lists for both classes and other metadata
 135   static metaspace::VirtualSpaceList* _space_list;
 136   static metaspace::VirtualSpaceList* _class_space_list;
 137 
 138   static metaspace::ChunkManager* _chunk_manager_metadata;
 139   static metaspace::ChunkManager* _chunk_manager_class;
 140 
 141   static const MetaspaceTracer* _tracer;
 142 
 143  public:
 144   static metaspace::VirtualSpaceList* space_list()       { return _space_list; }
 145   static metaspace::VirtualSpaceList* class_space_list() { return _class_space_list; }
 146   static metaspace::VirtualSpaceList* get_space_list(MetadataType mdtype) {
 147     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 148     return mdtype == ClassType ? class_space_list() : space_list();
 149   }
 150 
 151   static metaspace::ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 152   static metaspace::ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 153   static metaspace::ChunkManager* get_chunk_manager(MetadataType mdtype) {
 154     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 155     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 156   }
 157 
 158   // convenience function
 159   static metaspace::ChunkManager* get_chunk_manager(bool is_class) {
 160     return is_class ? chunk_manager_class() : chunk_manager_metadata();
 161   }
 162 
 163   static const MetaspaceTracer* tracer() { return _tracer; }
 164   static void freeze() {
 165     assert(DumpSharedSpaces, "sanity");
 166     DEBUG_ONLY(_frozen = true;)
 167   }
 168   static void assert_not_frozen() {
 169     assert(!_frozen, "sanity");
 170   }
 171 #ifdef _LP64
 172   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 173 #endif
 174 
 175  private:
 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 initialize_class_space(ReservedSpace rs);
 184 #endif
 185 
 186  public:
 187 
 188   static void ergo_initialize();
 189   static void global_initialize();
 190   static void post_initialize();
 191 
 192   static void verify_global_initialization();
 193 
 194   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 195   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 196 
 197   static size_t reserve_alignment()       { return _reserve_alignment; }
 198   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 199   static size_t commit_alignment()        { return _commit_alignment; }
 200   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 201 
 202   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 203                             MetaspaceObj::Type type, TRAPS);
 204 
 205   static bool contains(const void* ptr);
 206   static bool contains_non_shared(const void* ptr);
 207 
 208   // Free empty virtualspaces
 209   static void purge(MetadataType mdtype);
 210   static void purge();
 211 
 212   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 213                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 214 
 215   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 216 
 217   static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
 218 
 219   // Return TRUE only if UseCompressedClassPointers is True.
 220   static bool using_class_space() {
 221     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
 222   }
 223 
 224   static bool is_class_space_allocation(MetadataType mdType) {
 225     return mdType == ClassType && using_class_space();
 226   }
 227 
 228 };
 229 
 230 // Manages the metaspace portion belonging to a class loader
 231 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
 232   friend class CollectedHeap; // For expand_and_allocate()
 233   friend class ZCollectedHeap; // For expand_and_allocate()
 234   friend class Metaspace;
 235   friend class MetaspaceUtils;
 236   friend class metaspace::PrintCLDMetaspaceInfoClosure;
 237   friend class VM_CollectForMetadataAllocation; // For expand_and_allocate()
 238 
 239  private:
 240 
 241   void initialize(Mutex* lock, Metaspace::MetaspaceType type);
 242 
 243   // Initialize the first chunk for a Metaspace.  Used for
 244   // special cases such as the boot class loader, reflection
 245   // class loader and anonymous class loader.
 246   void initialize_first_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
 247   metaspace::Metachunk* get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
 248 
 249   const Metaspace::MetaspaceType _space_type;
 250   Mutex* const  _lock;
 251   metaspace::SpaceManager* _vsm;
 252   metaspace::SpaceManager* _class_vsm;
 253 
 254   metaspace::SpaceManager* vsm() const { return _vsm; }
 255   metaspace::SpaceManager* class_vsm() const { return _class_vsm; }
 256   metaspace::SpaceManager* get_space_manager(Metaspace::MetadataType mdtype) {
 257     assert(mdtype != Metaspace::MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 258     return mdtype == Metaspace::ClassType ? class_vsm() : vsm();
 259   }
 260 
 261   Mutex* lock() const { return _lock; }
 262 
 263   MetaWord* expand_and_allocate(size_t size, Metaspace::MetadataType mdtype);
 264 
 265   size_t class_chunk_size(size_t word_size);
 266 
 267   // Adds to the given statistic object. Must be locked with CLD metaspace lock.
 268   void add_to_statistics_locked(metaspace::ClassLoaderMetaspaceStatistics* out) const;
 269 
 270   Metaspace::MetaspaceType space_type() const { return _space_type; }
 271 
 272  public:
 273 
 274   ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type);
 275   ~ClassLoaderMetaspace();
 276 
 277   // Allocate space for metadata of type mdtype. This is space
 278   // within a Metachunk and is used by
 279   //   allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS)
 280   MetaWord* allocate(size_t word_size, Metaspace::MetadataType mdtype);
 281 
 282   size_t allocated_blocks_bytes() const;
 283   size_t allocated_chunks_bytes() const;
 284 
 285   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 286 
 287   void print_on(outputStream* st) const;
 288   // Debugging support
 289   void verify();
 290 
 291   // Adds to the given statistic object. Will lock with CLD metaspace lock.
 292   void add_to_statistics(metaspace::ClassLoaderMetaspaceStatistics* out) const;
 293 
 294 }; // ClassLoaderMetaspace
 295 
 296 class MetaspaceUtils : AllStatic {
 297 
 298   // Spacemanager updates running counters.
 299   friend class metaspace::SpaceManager;
 300 
 301   // Special access for error reporting (checks without locks).
 302   friend class oopDesc;
 303   friend class Klass;
 304 
 305   // Running counters for statistics concerning in-use chunks.
 306   // Note: capacity = used + free + waste + overhead. Note that we do not
 307   // count free and waste. Their sum can be deduces from the three other values.
 308   // For more details, one should call print_report() from within a safe point.
 309   static size_t _capacity_words [Metaspace:: MetadataTypeCount];
 310   static size_t _overhead_words [Metaspace:: MetadataTypeCount];
 311   static volatile size_t _used_words [Metaspace:: MetadataTypeCount];
 312 
 313   // Atomically decrement or increment in-use statistic counters
 314   static void dec_capacity(Metaspace::MetadataType mdtype, size_t words);
 315   static void inc_capacity(Metaspace::MetadataType mdtype, size_t words);
 316   static void dec_used(Metaspace::MetadataType mdtype, size_t words);
 317   static void inc_used(Metaspace::MetadataType mdtype, size_t words);
 318   static void dec_overhead(Metaspace::MetadataType mdtype, size_t words);
 319   static void inc_overhead(Metaspace::MetadataType mdtype, size_t words);
 320 
 321 
 322   // Getters for the in-use counters.
 323   static size_t capacity_words(Metaspace::MetadataType mdtype)        { return _capacity_words[mdtype]; }
 324   static size_t used_words(Metaspace::MetadataType mdtype)            { return _used_words[mdtype]; }
 325   static size_t overhead_words(Metaspace::MetadataType mdtype)        { return _overhead_words[mdtype]; }
 326 
 327   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 328 
 329   // Helper for print_xx_report.
 330   static void print_vs(outputStream* out, size_t scale);
 331 
 332   // Utils to check if a pointer or range is part of a committed metaspace region
 333   // without acquiring any locks.
 334   static metaspace::VirtualSpaceNode* find_enclosing_virtual_space(const void* p);
 335   static bool is_in_committed(const void* p);
 336   static bool is_range_in_committed(const void* from, const void* to);
 337 
 338 public:
 339 
 340   // Collect used metaspace statistics. This involves walking the CLDG. The resulting
 341   // output will be the accumulated values for all live metaspaces.
 342   // Note: method does not do any locking.
 343   static void collect_statistics(metaspace::ClassLoaderMetaspaceStatistics* out);
 344 
 345   // Used by MetaspaceCounters
 346   static size_t free_chunks_total_words();
 347   static size_t free_chunks_total_bytes();
 348   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 349 
 350   static size_t capacity_words() {
 351     return capacity_words(Metaspace::NonClassType) +
 352            capacity_words(Metaspace::ClassType);
 353   }
 354   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 355     return capacity_words(mdtype) * BytesPerWord;
 356   }
 357   static size_t capacity_bytes() {
 358     return capacity_words() * BytesPerWord;
 359   }
 360 
 361   static size_t used_words() {
 362     return used_words(Metaspace::NonClassType) +
 363            used_words(Metaspace::ClassType);
 364   }
 365   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 366     return used_words(mdtype) * BytesPerWord;
 367   }
 368   static size_t used_bytes() {
 369     return used_words() * BytesPerWord;
 370   }
 371 
 372   // Space committed but yet unclaimed by any class loader.
 373   static size_t free_in_vs_bytes();
 374   static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
 375 
 376   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 377   static size_t reserved_bytes() {
 378     return reserved_bytes(Metaspace::ClassType) +
 379            reserved_bytes(Metaspace::NonClassType);
 380   }
 381 
 382   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 383   static size_t committed_bytes() {
 384     return committed_bytes(Metaspace::ClassType) +
 385            committed_bytes(Metaspace::NonClassType);
 386   }
 387 
 388   static size_t min_chunk_size_words();
 389   static size_t min_chunk_size_bytes() {
 390     return min_chunk_size_words() * BytesPerWord;
 391   }
 392 
 393   // Flags for print_report().
 394   enum ReportFlag {
 395     // Show usage by class loader.
 396     rf_show_loaders                 = (1 << 0),
 397     // Breaks report down by chunk type (small, medium, ...).
 398     rf_break_down_by_chunktype      = (1 << 1),
 399     // Breaks report down by space type (anonymous, reflection, ...).
 400     rf_break_down_by_spacetype      = (1 << 2),
 401     // Print details about the underlying virtual spaces.
 402     rf_show_vslist                  = (1 << 3),
 403     // Print metaspace map.
 404     rf_show_vsmap                   = (1 << 4),
 405     // If show_loaders: show loaded classes for each loader.
 406     rf_show_classes                 = (1 << 5)
 407   };
 408 
 409   // This will print out a basic metaspace usage report but
 410   // unlike print_report() is guaranteed not to lock or to walk the CLDG.
 411   static void print_basic_report(outputStream* st, size_t scale);
 412 
 413   // Prints a report about the current metaspace state.
 414   // Optional parts can be enabled via flags.
 415   // Function will walk the CLDG and will lock the expand lock; if that is not
 416   // convenient, use print_basic_report() instead.
 417   static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
 418 
 419   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 420   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 421 
 422   // Print change in used metadata.
 423   static void print_metaspace_change(size_t prev_metadata_used);
 424   static void print_on(outputStream * out);
 425 
 426   // Prints an ASCII representation of the given space.
 427   static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
 428 
 429   static void dump(outputStream* out);
 430   static void verify_free_chunks();
 431   // Check internal counters (capacity, used).
 432   static void verify_metrics();
 433 };
 434 
 435 // Metaspace are deallocated when their class loader are GC'ed.
 436 // This class implements a policy for inducing GC's to recover
 437 // Metaspaces.
 438 
 439 class MetaspaceGC : AllStatic {
 440 
 441   // The current high-water-mark for inducing a GC.
 442   // When committed memory of all metaspaces reaches this value,
 443   // a GC is induced and the value is increased. Size is in bytes.
 444   static volatile size_t _capacity_until_GC;
 445 
 446   // For a CMS collection, signal that a concurrent collection should
 447   // be started.
 448   static bool _should_concurrent_collect;
 449 
 450   static uint _shrink_factor;
 451 
 452   static size_t shrink_factor() { return _shrink_factor; }
 453   void set_shrink_factor(uint v) { _shrink_factor = v; }
 454 
 455  public:
 456 
 457   static void initialize();
 458   static void post_initialize();
 459 
 460   static size_t capacity_until_GC();
 461   static bool inc_capacity_until_GC(size_t v,
 462                                     size_t* new_cap_until_GC = NULL,
 463                                     size_t* old_cap_until_GC = NULL,
 464                                     bool* can_retry = NULL);
 465   static size_t dec_capacity_until_GC(size_t v);
 466 
 467   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 468   static void set_should_concurrent_collect(bool v) {
 469     _should_concurrent_collect = v;
 470   }
 471 
 472   // The amount to increase the high-water-mark (_capacity_until_GC)
 473   static size_t delta_capacity_until_GC(size_t bytes);
 474 
 475   // Tells if we have can expand metaspace without hitting set limits.
 476   static bool can_expand(size_t words, bool is_class);
 477 
 478   // Returns amount that we can expand without hitting a GC,
 479   // measured in words.
 480   static size_t allowed_expansion();
 481 
 482   // Calculate the new high-water mark at which to induce
 483   // a GC.
 484   static void compute_new_size();
 485 };
 486 
 487 #endif // SHARE_VM_MEMORY_METASPACE_HPP