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
  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
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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 "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 Mutex;
  61 class outputStream;
  62 
  63 class CollectedHeap;
  64 
  65 namespace metaspace {
  66   class ChunkManager;
  67   class ClassLoaderMetaspaceStatistics;
  68   class Metablock;
  69   class Metachunk;
  70   class PrintCLDMetaspaceInfoClosure;
  71   class SpaceManager;
  72   class VirtualSpaceList;
  73   class VirtualSpaceNode;
  74 }
  75 
  76 // Metaspaces each have a  SpaceManager and allocations
  77 // are done by the SpaceManager.  Allocations are done
  78 // out of the current Metachunk.  When the current Metachunk
  79 // is exhausted, the SpaceManager gets a new one from
  80 // the current VirtualSpace.  When the VirtualSpace is exhausted
  81 // the SpaceManager gets a new one.  The SpaceManager
  82 // also manages freelists of available Chunks.
  83 //
  84 // Currently the space manager maintains the list of
  85 // virtual spaces and the list of chunks in use.  Its
  86 // allocate() method returns a block for use as a
  87 // quantum of metadata.
  88 
  89 // Namespace for important central static functions
  90 // (auxiliary stuff goes into MetaspaceUtils)
  91 class Metaspace : public AllStatic {
  92 
  93   friend class MetaspaceShared;
  94 
  95  public:
  96   enum MetadataType {
  97     ClassType,
  98     NonClassType,
  99     MetadataTypeCount
 100   };
 101   enum MetaspaceType {
 102     ZeroMetaspaceType = 0,
 103     StandardMetaspaceType = ZeroMetaspaceType,
 104     BootMetaspaceType = StandardMetaspaceType + 1,
 105     UnsafeAnonymousMetaspaceType = BootMetaspaceType + 1,
 106     ReflectionMetaspaceType = UnsafeAnonymousMetaspaceType + 1,
 107     MetaspaceTypeCount
 108   };
 109 
 110  private:
 111 
 112   // Align up the word size to the allocation word size
 113   static size_t align_word_size_up(size_t);
 114 
 115   // Aligned size of the metaspace.
 116   static size_t _compressed_class_space_size;
 117 
 118   static size_t compressed_class_space_size() {
 119     return _compressed_class_space_size;
 120   }
 121 
 122   static void set_compressed_class_space_size(size_t size) {
 123     _compressed_class_space_size = size;
 124   }
 125 
 126   static size_t _first_chunk_word_size;
 127   static size_t _first_class_chunk_word_size;
 128 
 129   static size_t _commit_alignment;
 130   static size_t _reserve_alignment;
 131   DEBUG_ONLY(static bool   _frozen;)
 132 
 133   // Virtual Space lists for both classes and other metadata
 134   static metaspace::VirtualSpaceList* _space_list;
 135   static metaspace::VirtualSpaceList* _class_space_list;
 136 
 137   static metaspace::ChunkManager* _chunk_manager_metadata;
 138   static metaspace::ChunkManager* _chunk_manager_class;
 139 
 140   static const MetaspaceTracer* _tracer;
 141 
 142  public:
 143   static metaspace::VirtualSpaceList* space_list()       { return _space_list; }
 144   static metaspace::VirtualSpaceList* class_space_list() { return _class_space_list; }
 145   static metaspace::VirtualSpaceList* get_space_list(MetadataType mdtype) {
 146     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 147     return mdtype == ClassType ? class_space_list() : space_list();
 148   }
 149 
 150   static metaspace::ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 151   static metaspace::ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 152   static metaspace::ChunkManager* get_chunk_manager(MetadataType mdtype) {
 153     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 154     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 155   }
 156 
 157   // convenience function
 158   static metaspace::ChunkManager* get_chunk_manager(bool is_class) {
 159     return is_class ? chunk_manager_class() : chunk_manager_metadata();
 160   }
 161 
 162   static const MetaspaceTracer* tracer() { return _tracer; }
 163   static void freeze() {
 164     assert(DumpSharedSpaces, "sanity");
 165     DEBUG_ONLY(_frozen = true;)
 166   }
 167   static void assert_not_frozen() {
 168     assert(!_frozen, "sanity");
 169   }
 170 #ifdef _LP64
 171   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 172 #endif
 173 
 174  private:
 175 
 176 #ifdef _LP64
 177   static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
 178 
 179   // Returns true if can use CDS with metaspace allocated as specified address.
 180   static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
 181 
 182   static void initialize_class_space(ReservedSpace rs);
 183 #endif
 184 
 185  public:
 186 
 187   static void ergo_initialize();
 188   static void global_initialize();
 189   static void post_initialize();
 190 
 191   static void verify_global_initialization();
 192 
 193   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
 194   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }
 195 
 196   static size_t reserve_alignment()       { return _reserve_alignment; }
 197   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 198   static size_t commit_alignment()        { return _commit_alignment; }
 199   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 200 
 201   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 202                             MetaspaceObj::Type type, TRAPS);
 203 
 204   static bool contains(const void* ptr);
 205   static bool contains_non_shared(const void* ptr);
 206 
 207   // Free empty virtualspaces
 208   static void purge(MetadataType mdtype);
 209   static void purge();
 210 
 211   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 212                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 213 
 214   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 215 
 216   static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
 217 
 218   // Return TRUE only if UseCompressedClassPointers is True.
 219   static bool using_class_space() {
 220     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
 221   }
 222 
 223   static bool is_class_space_allocation(MetadataType mdType) {
 224     return mdType == ClassType && using_class_space();
 225   }
 226 
 227 };
 228 
 229 // Manages the metaspace portion belonging to a class loader
 230 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
 231   friend class CollectedHeap; // For expand_and_allocate()
 232   friend class ZCollectedHeap; // For expand_and_allocate()
 233   friend class ShenandoahHeap; // 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_range_in_committed(const void* from, const void* to);
 336 
 337 public:
 338 
 339   // Collect used metaspace statistics. This involves walking the CLDG. The resulting
 340   // output will be the accumulated values for all live metaspaces.
 341   // Note: method does not do any locking.
 342   static void collect_statistics(metaspace::ClassLoaderMetaspaceStatistics* out);
 343 
 344   // Used by MetaspaceCounters
 345   static size_t free_chunks_total_words();
 346   static size_t free_chunks_total_bytes();
 347   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 348 
 349   static size_t capacity_words() {
 350     return capacity_words(Metaspace::NonClassType) +
 351            capacity_words(Metaspace::ClassType);
 352   }
 353   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 354     return capacity_words(mdtype) * BytesPerWord;
 355   }
 356   static size_t capacity_bytes() {
 357     return capacity_words() * BytesPerWord;
 358   }
 359 
 360   static size_t used_words() {
 361     return used_words(Metaspace::NonClassType) +
 362            used_words(Metaspace::ClassType);
 363   }
 364   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 365     return used_words(mdtype) * BytesPerWord;
 366   }
 367   static size_t used_bytes() {
 368     return used_words() * BytesPerWord;
 369   }
 370 
 371   // Space committed but yet unclaimed by any class loader.
 372   static size_t free_in_vs_bytes();
 373   static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
 374 
 375   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 376   static size_t reserved_bytes() {
 377     return reserved_bytes(Metaspace::ClassType) +
 378            reserved_bytes(Metaspace::NonClassType);
 379   }
 380 
 381   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 382   static size_t committed_bytes() {
 383     return committed_bytes(Metaspace::ClassType) +
 384            committed_bytes(Metaspace::NonClassType);
 385   }
 386 
 387   static size_t min_chunk_size_words();
 388 
 389   // Flags for print_report().
 390   enum ReportFlag {
 391     // Show usage by class loader.
 392     rf_show_loaders                 = (1 << 0),
 393     // Breaks report down by chunk type (small, medium, ...).
 394     rf_break_down_by_chunktype      = (1 << 1),
 395     // Breaks report down by space type (anonymous, reflection, ...).
 396     rf_break_down_by_spacetype      = (1 << 2),
 397     // Print details about the underlying virtual spaces.
 398     rf_show_vslist                  = (1 << 3),
 399     // Print metaspace map.
 400     rf_show_vsmap                   = (1 << 4),
 401     // If show_loaders: show loaded classes for each loader.
 402     rf_show_classes                 = (1 << 5)
 403   };
 404 
 405   // This will print out a basic metaspace usage report but
 406   // unlike print_report() is guaranteed not to lock or to walk the CLDG.
 407   static void print_basic_report(outputStream* st, size_t scale);
 408 
 409   // Prints a report about the current metaspace state.
 410   // Optional parts can be enabled via flags.
 411   // Function will walk the CLDG and will lock the expand lock; if that is not
 412   // convenient, use print_basic_report() instead.
 413   static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
 414 
 415   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 416   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 417 
 418   // Print change in used metadata.
 419   static void print_metaspace_change(size_t prev_metadata_used);
 420   static void print_on(outputStream * out);
 421 
 422   // Prints an ASCII representation of the given space.
 423   static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
 424 
 425   static void dump(outputStream* out);
 426   static void verify_free_chunks();
 427   // Check internal counters (capacity, used).
 428   static void verify_metrics();
 429 };
 430 
 431 // Metaspace are deallocated when their class loader are GC'ed.
 432 // This class implements a policy for inducing GC's to recover
 433 // Metaspaces.
 434 
 435 class MetaspaceGC : AllStatic {
 436 
 437   // The current high-water-mark for inducing a GC.
 438   // When committed memory of all metaspaces reaches this value,
 439   // a GC is induced and the value is increased. Size is in bytes.
 440   static volatile size_t _capacity_until_GC;
 441 
 442   // For a CMS collection, signal that a concurrent collection should
 443   // be started.
 444   static bool _should_concurrent_collect;
 445 
 446   static uint _shrink_factor;
 447 
 448   static size_t shrink_factor() { return _shrink_factor; }
 449   void set_shrink_factor(uint v) { _shrink_factor = v; }
 450 
 451  public:
 452 
 453   static void initialize();
 454   static void post_initialize();
 455 
 456   static size_t capacity_until_GC();
 457   static bool inc_capacity_until_GC(size_t v,
 458                                     size_t* new_cap_until_GC = NULL,
 459                                     size_t* old_cap_until_GC = NULL,
 460                                     bool* can_retry = NULL);
 461   static size_t dec_capacity_until_GC(size_t v);
 462 
 463   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 464   static void set_should_concurrent_collect(bool v) {
 465     _should_concurrent_collect = v;
 466   }
 467 
 468   // The amount to increase the high-water-mark (_capacity_until_GC)
 469   static size_t delta_capacity_until_GC(size_t bytes);
 470 
 471   // Tells if we have can expand metaspace without hitting set limits.
 472   static bool can_expand(size_t words, bool is_class);
 473 
 474   // Returns amount that we can expand without hitting a GC,
 475   // measured in words.
 476   static size_t allowed_expansion();
 477 
 478   // Calculate the new high-water mark at which to induce
 479   // a GC.
 480   static void compute_new_size();
 481 };
 482 
 483 #endif // SHARE_MEMORY_METASPACE_HPP