1 /*
   2  * Copyright (c) 2011, 2019, 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.
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  23  */
  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 "utilities/exceptions.hpp"
  33 
  34 // Metaspace
  35 //
  36 // Metaspaces are Arenas for the VM's metadata.
  37 // They are allocated one per class loader object, and one for the null
  38 // bootstrap class loader
  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 ClassLoaderData;
  60 class MetaspaceTracer;
  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     UnsafeAnonymousMetaspaceType = BootMetaspaceType + 1,
 107     ReflectionMetaspaceType = UnsafeAnonymousMetaspaceType + 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   static bool _initialized;
 144 
 145  public:
 146   static metaspace::VirtualSpaceList* space_list()       { return _space_list; }
 147   static metaspace::VirtualSpaceList* class_space_list() { return _class_space_list; }
 148   static metaspace::VirtualSpaceList* get_space_list(MetadataType mdtype) {
 149     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 150     return mdtype == ClassType ? class_space_list() : space_list();
 151   }
 152 
 153   static metaspace::ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
 154   static metaspace::ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
 155   static metaspace::ChunkManager* get_chunk_manager(MetadataType mdtype) {
 156     assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
 157     return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
 158   }
 159 
 160   // convenience function
 161   static metaspace::ChunkManager* get_chunk_manager(bool is_class) {
 162     return is_class ? chunk_manager_class() : chunk_manager_metadata();
 163   }
 164 
 165   static const MetaspaceTracer* tracer() { return _tracer; }
 166   static void freeze() {
 167     assert(DumpSharedSpaces, "sanity");
 168     DEBUG_ONLY(_frozen = true;)
 169   }
 170   static void assert_not_frozen() {
 171     assert(!_frozen, "sanity");
 172   }
 173 #ifdef _LP64
 174   static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);
 175 #endif
 176 
 177  private:
 178 
 179 #ifdef _LP64
 180   static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);
 181 
 182   // Returns true if can use CDS with metaspace allocated as specified address.
 183   static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);
 184 
 185   static void initialize_class_space(ReservedSpace rs);
 186 #endif
 187 
 188  public:
 189 
 190   static void ergo_initialize();
 191   static void global_initialize();
 192   static void post_initialize();
 193 
 194   static void verify_global_initialization();
 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   static bool initialized() { return _initialized; }
 228 
 229 };
 230 
 231 class MetaspaceUtils : AllStatic {
 232 
 233   // Spacemanager updates running counters.
 234   friend class metaspace::SpaceManager;
 235 
 236   // Special access for error reporting (checks without locks).
 237   friend class oopDesc;
 238   friend class Klass;
 239 
 240   // Running counters for statistics concerning in-use chunks.
 241   // Note: capacity = used + free + waste + overhead. Note that we do not
 242   // count free and waste. Their sum can be deduces from the three other values.
 243   // For more details, one should call print_report() from within a safe point.
 244   static size_t _capacity_words [Metaspace:: MetadataTypeCount];
 245   static size_t _overhead_words [Metaspace:: MetadataTypeCount];
 246   static volatile size_t _used_words [Metaspace:: MetadataTypeCount];
 247 
 248   // Atomically decrement or increment in-use statistic counters
 249   static void dec_capacity(Metaspace::MetadataType mdtype, size_t words);
 250   static void inc_capacity(Metaspace::MetadataType mdtype, size_t words);
 251   static void dec_used(Metaspace::MetadataType mdtype, size_t words);
 252   static void inc_used(Metaspace::MetadataType mdtype, size_t words);
 253   static void dec_overhead(Metaspace::MetadataType mdtype, size_t words);
 254   static void inc_overhead(Metaspace::MetadataType mdtype, size_t words);
 255 
 256 
 257   // Getters for the in-use counters.
 258   static size_t capacity_words(Metaspace::MetadataType mdtype)        { return _capacity_words[mdtype]; }
 259   static size_t used_words(Metaspace::MetadataType mdtype)            { return _used_words[mdtype]; }
 260   static size_t overhead_words(Metaspace::MetadataType mdtype)        { return _overhead_words[mdtype]; }
 261 
 262   static size_t free_chunks_total_words(Metaspace::MetadataType mdtype);
 263 
 264   // Helper for print_xx_report.
 265   static void print_vs(outputStream* out, size_t scale);
 266 
 267 public:
 268 
 269   // Collect used metaspace statistics. This involves walking the CLDG. The resulting
 270   // output will be the accumulated values for all live metaspaces.
 271   // Note: method does not do any locking.
 272   static void collect_statistics(metaspace::ClassLoaderMetaspaceStatistics* out);
 273 
 274   // Used by MetaspaceCounters
 275   static size_t free_chunks_total_words();
 276   static size_t free_chunks_total_bytes();
 277   static size_t free_chunks_total_bytes(Metaspace::MetadataType mdtype);
 278 
 279   static size_t capacity_words() {
 280     return capacity_words(Metaspace::NonClassType) +
 281            capacity_words(Metaspace::ClassType);
 282   }
 283   static size_t capacity_bytes(Metaspace::MetadataType mdtype) {
 284     return capacity_words(mdtype) * BytesPerWord;
 285   }
 286   static size_t capacity_bytes() {
 287     return capacity_words() * BytesPerWord;
 288   }
 289 
 290   static size_t used_words() {
 291     return used_words(Metaspace::NonClassType) +
 292            used_words(Metaspace::ClassType);
 293   }
 294   static size_t used_bytes(Metaspace::MetadataType mdtype) {
 295     return used_words(mdtype) * BytesPerWord;
 296   }
 297   static size_t used_bytes() {
 298     return used_words() * BytesPerWord;
 299   }
 300 
 301   // Space committed but yet unclaimed by any class loader.
 302   static size_t free_in_vs_bytes();
 303   static size_t free_in_vs_bytes(Metaspace::MetadataType mdtype);
 304 
 305   static size_t reserved_bytes(Metaspace::MetadataType mdtype);
 306   static size_t reserved_bytes() {
 307     return reserved_bytes(Metaspace::ClassType) +
 308            reserved_bytes(Metaspace::NonClassType);
 309   }
 310 
 311   static size_t committed_bytes(Metaspace::MetadataType mdtype);
 312   static size_t committed_bytes() {
 313     return committed_bytes(Metaspace::ClassType) +
 314            committed_bytes(Metaspace::NonClassType);
 315   }
 316 
 317   static size_t min_chunk_size_words();
 318 
 319   // Flags for print_report().
 320   enum ReportFlag {
 321     // Show usage by class loader.
 322     rf_show_loaders                 = (1 << 0),
 323     // Breaks report down by chunk type (small, medium, ...).
 324     rf_break_down_by_chunktype      = (1 << 1),
 325     // Breaks report down by space type (anonymous, reflection, ...).
 326     rf_break_down_by_spacetype      = (1 << 2),
 327     // Print details about the underlying virtual spaces.
 328     rf_show_vslist                  = (1 << 3),
 329     // Print metaspace map.
 330     rf_show_vsmap                   = (1 << 4),
 331     // If show_loaders: show loaded classes for each loader.
 332     rf_show_classes                 = (1 << 5)
 333   };
 334 
 335   // This will print out a basic metaspace usage report but
 336   // unlike print_report() is guaranteed not to lock or to walk the CLDG.
 337   static void print_basic_report(outputStream* st, size_t scale);
 338 
 339   // Prints a report about the current metaspace state.
 340   // Optional parts can be enabled via flags.
 341   // Function will walk the CLDG and will lock the expand lock; if that is not
 342   // convenient, use print_basic_report() instead.
 343   static void print_report(outputStream* out, size_t scale = 0, int flags = 0);
 344 
 345   static bool has_chunk_free_list(Metaspace::MetadataType mdtype);
 346   static MetaspaceChunkFreeListSummary chunk_free_list_summary(Metaspace::MetadataType mdtype);
 347 
 348   // Log change in used metadata.
 349   static void print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values);
 350   static void print_on(outputStream * out);
 351 
 352   // Prints an ASCII representation of the given space.
 353   static void print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype);
 354 
 355   static void dump(outputStream* out);
 356   static void verify_free_chunks();
 357   // Check internal counters (capacity, used).
 358   static void verify_metrics();
 359 };
 360 
 361 // Metaspace are deallocated when their class loader are GC'ed.
 362 // This class implements a policy for inducing GC's to recover
 363 // Metaspaces.
 364 
 365 class MetaspaceGC : AllStatic {
 366 
 367   // The current high-water-mark for inducing a GC.
 368   // When committed memory of all metaspaces reaches this value,
 369   // a GC is induced and the value is increased. Size is in bytes.
 370   static volatile size_t _capacity_until_GC;
 371 
 372   // For a CMS collection, signal that a concurrent collection should
 373   // be started.
 374   static bool _should_concurrent_collect;
 375 
 376   static uint _shrink_factor;
 377 
 378   static size_t shrink_factor() { return _shrink_factor; }
 379   void set_shrink_factor(uint v) { _shrink_factor = v; }
 380 
 381  public:
 382 
 383   static void initialize();
 384   static void post_initialize();
 385 
 386   static size_t capacity_until_GC();
 387   static bool inc_capacity_until_GC(size_t v,
 388                                     size_t* new_cap_until_GC = NULL,
 389                                     size_t* old_cap_until_GC = NULL,
 390                                     bool* can_retry = NULL);
 391   static size_t dec_capacity_until_GC(size_t v);
 392 
 393   static bool should_concurrent_collect() { return _should_concurrent_collect; }
 394   static void set_should_concurrent_collect(bool v) {
 395     _should_concurrent_collect = v;
 396   }
 397 
 398   // The amount to increase the high-water-mark (_capacity_until_GC)
 399   static size_t delta_capacity_until_GC(size_t bytes);
 400 
 401   // Tells if we have can expand metaspace without hitting set limits.
 402   static bool can_expand(size_t words, bool is_class);
 403 
 404   // Returns amount that we can expand without hitting a GC,
 405   // measured in words.
 406   static size_t allowed_expansion();
 407 
 408   // Calculate the new high-water mark at which to induce
 409   // a GC.
 410   static void compute_new_size();
 411 };
 412 
 413 #endif // SHARE_MEMORY_METASPACE_HPP