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.
  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_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 ChunkManager;
  59 class ClassLoaderData;
  60 class Metablock;
  61 class Metachunk;
  62 class MetaspaceTracer;
  63 class MetaWord;
  64 class Mutex;
  65 class outputStream;
  66 class PrintCLDMetaspaceInfoClosure;
  67 class SpaceManager;
  68 class VirtualSpaceList;
  69 class CollectedHeap;
  70 
  71 namespace metaspace {
  72 namespace internals {
  73   class ClassLoaderMetaspaceStatistics;
  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     //...
 104     StandardMetaspaceType = ZeroMetaspaceType,
 105     BootMetaspaceType = StandardMetaspaceType + 1,
 106     AnonymousMetaspaceType = BootMetaspaceType + 1,
 107     ReflectionMetaspaceType = AnonymousMetaspaceType + 1,
 108     //..
 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 VirtualSpaceList* _space_list;
 137   static VirtualSpaceList* _class_space_list;
 138 
 139   static ChunkManager* _chunk_manager_metadata;
 140   static ChunkManager* _chunk_manager_class;
 141 
 142   static const MetaspaceTracer* _tracer;
 143 
 144  public:
 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   // convenience function
 160   static ChunkManager* get_chunk_manager(bool is_class) {
 161     return is_class ? chunk_manager_class() : chunk_manager_metadata();
 162   }
 163 
 164   static const MetaspaceTracer* tracer() { return _tracer; }
 165   static void freeze() {
 166     assert(DumpSharedSpaces, "sanity");
 167     DEBUG_ONLY(_frozen = true;)
 168   }
 169   static void assert_not_frozen() {
 170     assert(!_frozen, "sanity");
 171   }
 172 #ifdef _LP64
 173   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 174 #endif
 175 
 176  private:
 177 
 178 #ifdef _LP64
 179   static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
 180 
 181   // Returns true if can use CDS with metaspace allocated as specified address.
 182   static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
 183 
 184   static void initialize_class_space(ReservedSpace rs);
 185 #endif
 186 
 187  public:
 188 
 189   static void ergo_initialize();
 190   static void global_initialize();
 191   static void post_initialize();
 192 
 193   static void verify_global_initialization();
 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   static size_t reserve_alignment()       { return _reserve_alignment; }
 199   static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }
 200   static size_t commit_alignment()        { return _commit_alignment; }
 201   static size_t commit_alignment_words()  { return _commit_alignment / BytesPerWord; }
 202 
 203   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
 204                             MetaspaceObj::Type type, TRAPS);
 205 
 206   static bool contains(const void* ptr);
 207   static bool contains_non_shared(const void* ptr);
 208 
 209   // Free empty virtualspaces
 210   static void purge(MetadataType mdtype);
 211   static void purge();
 212 
 213   static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,
 214                                    MetaspaceObj::Type type, MetadataType mdtype, TRAPS);
 215 
 216   static const char* metadata_type_name(Metaspace::MetadataType mdtype);
 217 
 218   static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});
 219 
 220   // Return TRUE only if UseCompressedClassPointers is True.
 221   static bool using_class_space() {
 222     return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);
 223   }
 224 
 225   static bool is_class_space_allocation(MetadataType mdType) {
 226     return mdType == ClassType && using_class_space();
 227   }
 228 
 229 };
 230 
 231 // Manages the metaspace portion belonging to a class loader
 232 class ClassLoaderMetaspace : public CHeapObj<mtClass> {
 233   friend class CollectedHeap; // For expand_and_allocate()
 234   friend class Metaspace;
 235   friend class MetaspaceUtils;
 236   friend class 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   Metachunk* get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype);
 248 
 249   const Metaspace::MetaspaceType _space_type;
 250   Mutex* const  _lock;
 251   SpaceManager* _vsm;
 252   SpaceManager* _class_vsm;
 253 
 254   SpaceManager* vsm() const { return _vsm; }
 255   SpaceManager* class_vsm() const { return _class_vsm; }
 256   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::internals::ClassLoaderMetaspaceStatistics* out) const;
 269 
 270  public:
 271 
 272   ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type);
 273   ~ClassLoaderMetaspace();
 274 
 275   Metaspace::MetaspaceType space_type() const { return _space_type; }
 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::internals::ClassLoaderMetaspaceStatistics* out) const;
 293 
 294 }; // ClassLoaderMetaspace
 295 
 296 class MetaspaceUtils : AllStatic {
 297 
 298   // Spacemanager updates running counters.
 299   friend class SpaceManager;
 300 
 301   // Running counters for statistics concerning in-use chunks.
 302   // Note: capacity = used + free + waste + overhead. Note that we do not
 303   // count free and waste. Their sum can be deduces from the three other values.
 304   // For more details, one should call print_report() from within a safe point.
 305   static size_t _capacity_words [Metaspace:: MetadataTypeCount];
 306   static size_t _overhead_words [Metaspace:: MetadataTypeCount];
 307   static volatile size_t _used_words [Metaspace:: MetadataTypeCount];
 308 
 309   // Atomically decrement or increment in-use statistic counters
 310   static void dec_capacity(Metaspace::MetadataType mdtype, size_t words);
 311   static void inc_capacity(Metaspace::MetadataType mdtype, size_t words);
 312   static void dec_used(Metaspace::MetadataType mdtype, size_t words);
 313   static void inc_used(Metaspace::MetadataType mdtype, size_t words);
 314   static void dec_overhead(Metaspace::MetadataType mdtype, size_t words);
 315   static void inc_overhead(Metaspace::MetadataType mdtype, size_t words);
 316 
 317 
 318   // Getters for the in-use counters.
 319   static size_t capacity_words(Metaspace::MetadataType mdtype)        { return _capacity_words[mdtype]; }
 320   static size_t used_words(Metaspace::MetadataType mdtype)            { return _used_words[mdtype]; }
 321   static size_t overhead_words(Metaspace::MetadataType mdtype)        { return _overhead_words[mdtype]; }
 322 
 323   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 324 
 325   // Helper for print_xx_report.
 326   static void print_vs(outputStream* out, size_t scale);
 327 
 328 public:
 329 
 330   // Collect used metaspace statistics. This involves walking the CLDG. The resulting
 331   // output will be the accumulated values for all live metaspaces.
 332   // Note: method does not do any locking.
 333   static void collect_statistics(metaspace::internals::ClassLoaderMetaspaceStatistics* out);
 334 
 335   // Used by MetaspaceCounters
 336   static size_t free_chunks_total_words();
 337   static size_t free_chunks_total_bytes();
 338   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 339 
 340   static size_t capacity_words() {
 341     return capacity_words(Metaspace::NonClassType) +
 342            capacity_words(Metaspace::ClassType);
 343   }
 344   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 345     return capacity_words(mdtype) * BytesPerWord;
 346   }
 347   static size_t capacity_bytes() {
 348     return capacity_words() * BytesPerWord;
 349   }
 350 
 351   static size_t used_words() {
 352     return used_words(Metaspace::NonClassType) +
 353            used_words(Metaspace::ClassType);
 354   }
 355   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 356     return used_words(mdtype) * BytesPerWord;
 357   }
 358   static size_t used_bytes() {
 359     return used_words() * BytesPerWord;
 360   }
 361 
 362   // Space committed but yet unclaimed by any class loader.
 363   static size_t free_in_vs_bytes();
 364   static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
 365 
 366   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 367   static size_t reserved_bytes() {
 368     return reserved_bytes(Metaspace::ClassType) +
 369            reserved_bytes(Metaspace::NonClassType);
 370   }
 371 
 372   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 373   static size_t committed_bytes() {
 374     return committed_bytes(Metaspace::ClassType) +
 375            committed_bytes(Metaspace::NonClassType);
 376   }
 377 
 378   static size_t min_chunk_size_words();
 379   static size_t min_chunk_size_bytes() {
 380     return min_chunk_size_words() * BytesPerWord;
 381   }
 382 
 383   // Flags for print_report().
 384   enum ReportFlag {
 385     // Show usage by class loader.
 386     rf_show_loaders                 = (1 << 0),
 387     // Breaks report down by chunk type (small, medium, ...).
 388     rf_break_down_by_chunktype      = (1 << 1),
 389     // Breaks report down by space type (anonymous, reflection, ...).
 390     rf_break_down_by_spacetype      = (1 << 2),
 391     // Print details about the underlying virtual spaces.
 392     rf_show_vslist                  = (1 << 3),
 393     // Print metaspace map.
 394     rf_show_vsmap                   = (1 << 4)
 395   };
 396 
 397   // This will print out a basic metaspace usage report but
 398   // unlike print_report() is guaranteed not to lock or to walk the CLDG.
 399   static void print_basic_report(outputStream* st, size_t scale);
 400 
 401   // Prints a report about the current metaspace state.
 402   // Optional parts can be enabled via flags.
 403   // Function will walk the CLDG and will lock the expand lock; if that is not
 404   // convenient, use print_basic_report() instead.
 405   static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
 406 
 407   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 408   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 409 
 410   // Print change in used metadata.
 411   static void print_metaspace_change(size_t prev_metadata_used);
 412   static void print_on(outputStream * out);
 413 
 414   // Prints an ASCII representation of the given space.
 415   static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
 416 
 417   static void dump(outputStream* out);
 418   static void verify_free_chunks();
 419   // Check internal counters (capacity, used).
 420   static void verify_metrics();
 421 };
 422 
 423 // Metaspace are deallocated when their class loader are GC'ed.
 424 // This class implements a policy for inducing GC's to recover
 425 // Metaspaces.
 426 
 427 class MetaspaceGC : AllStatic {
 428 
 429   // The current high-water-mark for inducing a GC.
 430   // When committed memory of all metaspaces reaches this value,
 431   // a GC is induced and the value is increased. Size is in bytes.
 432   static volatile intptr_t _capacity_until_GC;
 433 
 434   // For a CMS collection, signal that a concurrent collection should
 435   // be started.
 436   static bool _should_concurrent_collect;
 437 
 438   static uint _shrink_factor;
 439 
 440   static size_t shrink_factor() { return _shrink_factor; }
 441   void set_shrink_factor(uint v) { _shrink_factor = v; }
 442 
 443  public:
 444 
 445   static void initialize();
 446   static void post_initialize();
 447 
 448   static size_t capacity_until_GC();
 449   static bool inc_capacity_until_GC(size_t v,
 450                                     size_t* new_cap_until_GC = NULL,
 451                                     size_t* old_cap_until_GC = NULL);
 452   static size_t dec_capacity_until_GC(size_t v);
 453 
 454   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 455   static void set_should_concurrent_collect(bool v) {
 456     _should_concurrent_collect = v;
 457   }
 458 
 459   // The amount to increase the high-water-mark (_capacity_until_GC)
 460   static size_t delta_capacity_until_GC(size_t bytes);
 461 
 462   // Tells if we have can expand metaspace without hitting set limits.
 463   static bool can_expand(size_t words, bool is_class);
 464 
 465   // Returns amount that we can expand without hitting a GC,
 466   // measured in words.
 467   static size_t allowed_expansion();
 468 
 469   // Calculate the new high-water mark at which to induce
 470   // a GC.
 471   static void compute_new_size();
 472 };
 473 
 474 #endif // SHARE_VM_MEMORY_METASPACE_HPP