1 /*

     2  * Copyright (c) 2011, 2012, 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.

    22  *

    23  */

    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 "runtime/virtualspace.hpp"

    30 #include "utilities/exceptions.hpp"

    31 

    32 // Metaspace

    33 //

    34 // Metaspaces are Arenas for the VM's metadata.

    35 // They are allocated one per class loader object, and one for the null

    36 // bootstrap class loader

    37 // Eventually for bootstrap loader we'll have a read-only section and read-write

    38 // to write for DumpSharedSpaces and read for UseSharedSpaces

    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 MetaWord;

    61 class Mutex;

    62 class outputStream;

    63 class FreeChunk;

    64 template <class Chunk_t> class FreeList;

    65 template <class Chunk_t> class BinaryTreeDictionary;

    66 class SpaceManager;

    67 

    68 // Metaspaces each have a  SpaceManager and allocations

    69 // are done by the SpaceManager.  Allocations are done

    70 // out of the current Metachunk.  When the current Metachunk

    71 // is exhausted, the SpaceManager gets a new one from

    72 // the current VirtualSpace.  When the VirtualSpace is exhausted

    73 // the SpaceManager gets a new one.  The SpaceManager

    74 // also manages freelists of available Chunks.

    75 //

    76 // Currently the space manager maintains the list of

    77 // virtual spaces and the list of chunks in use.  Its

    78 // allocate() method returns a block for use as a

    79 // quantum of metadata.

    80 

    81 class VirtualSpaceList;

    82 

    83 class Metaspace : public CHeapObj<mtClass> {

    84   friend class VMStructs;

    85   friend class SpaceManager;

    86   friend class VM_CollectForMetadataAllocation;

    87   friend class MetaspaceGC;

    88   friend class MetaspaceAux;

    89 

    90  public:

    91   enum MetadataType {ClassType, NonClassType};

    92 

    93  private:

    94   void initialize(Mutex* lock, size_t initial_size = 0);

    95 

    96   static size_t _first_chunk_word_size;

    97 

    98   SpaceManager* _vsm;

    99   SpaceManager* vsm() const { return _vsm; }

   100 

   101   SpaceManager* _class_vsm;

   102   SpaceManager* class_vsm() const { return _class_vsm; }

   103 

   104   MetaWord* allocate(size_t word_size, MetadataType mdtype);

   105 

   106   // Virtual Space lists for both classes and other metadata

   107   static VirtualSpaceList* _space_list;

   108   static VirtualSpaceList* _class_space_list;

   109 

   110   static VirtualSpaceList* space_list()       { return _space_list; }

   111   static VirtualSpaceList* class_space_list() { return _class_space_list; }

   112 

   113  public:

   114 

   115   Metaspace(Mutex* lock, size_t initial_size);

   116   Metaspace(Mutex* lock);

   117   ~Metaspace();

   118 

   119   // Initialize globals for Metaspace

   120   static void global_initialize();

   121   static void initialize_class_space(ReservedSpace rs);

   122 

   123   static size_t first_chunk_word_size() { return _first_chunk_word_size; }

   124 

   125   char*  bottom() const;

   126   size_t used_words(MetadataType mdtype) const;

   127   size_t free_words(MetadataType mdtype) const;

   128   size_t capacity_words(MetadataType mdtype) const;

   129   size_t waste_words(MetadataType mdtype) const;

   130 

   131   static MetaWord* allocate(ClassLoaderData* loader_data, size_t size,

   132                             bool read_only, MetadataType mdtype, TRAPS);

   133 

   134   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);

   135 

   136 #ifndef PRODUCT

   137   bool contains(const void *ptr) const;

   138   bool contains_class(const void *ptr) const;

   139 #endif

   140 

   141   void dump(outputStream* const out) const;

   142 

   143   void print_on(outputStream* st) const;

   144   // Debugging support

   145   void verify();

   146 };

   147 

   148 class MetaspaceAux : AllStatic {

   149 

   150   // Statistics for class space and data space in metaspace.

   151   static size_t used_in_bytes(Metaspace::MetadataType mdtype);

   152   static size_t free_in_bytes(Metaspace::MetadataType mdtype);

   153   static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);

   154   static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);

   155 

   156   static size_t free_chunks_total(Metaspace::MetadataType mdtype);

   157   static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);

   158 

   159  public:

   160   // Total of space allocated to metadata in all Metaspaces

   161   static size_t used_in_bytes() {

   162     return used_in_bytes(Metaspace::ClassType) +

   163            used_in_bytes(Metaspace::NonClassType);

   164   }

   165 

   166   // Total of available space in all Metaspaces

   167   // Total of capacity allocated to all Metaspaces.  This includes

   168   // space in Metachunks not yet allocated and in the Metachunk

   169   // freelist.

   170   static size_t capacity_in_bytes() {

   171     return capacity_in_bytes(Metaspace::ClassType) +

   172            capacity_in_bytes(Metaspace::NonClassType);

   173   }

   174 

   175   // Total space reserved in all Metaspaces

   176   static size_t reserved_in_bytes() {

   177     return reserved_in_bytes(Metaspace::ClassType) +

   178            reserved_in_bytes(Metaspace::NonClassType);

   179   }

   180 

   181   static size_t min_chunk_size();

   182 

   183   // Print change in used metadata.

   184   static void print_metaspace_change(size_t prev_metadata_used);

   185   static void print_on(outputStream * out);

   186   static void print_on(outputStream * out, Metaspace::MetadataType mdtype);

   187 

   188   static void print_waste(outputStream* out);

   189   static void dump(outputStream* out);

   190 };

   191 

   192 // Metaspace are deallocated when their class loader are GC'ed.

   193 // This class implements a policy for inducing GC's to recover

   194 // Metaspaces.

   195 

   196 class MetaspaceGC : AllStatic {

   197 

   198   // The current high-water-mark for inducing a GC.  When

   199   // the capacity of all space in the virtual lists reaches this value,

   200   // a GC is induced and the value is increased.  This should be changed

   201   // to the space actually used for allocations to avoid affects of

   202   // fragmentation losses to partially used chunks.  Size is in words.

   203   static size_t _capacity_until_GC;

   204 

   205   // After a GC is done any allocation that fails should try to expand

   206   // the capacity of the Metaspaces.  This flag is set during attempts

   207   // to allocate in the VMGCOperation that does the GC.

   208   static bool _expand_after_GC;

   209 

   210   // For a CMS collection, signal that a concurrent collection should

   211   // be started.

   212   static bool _should_concurrent_collect;

   213 

   214   static uint _shrink_factor;

   215 

   216   static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }

   217 

   218   static size_t shrink_factor() { return _shrink_factor; }

   219   void set_shrink_factor(uint v) { _shrink_factor = v; }

   220 

   221  public:

   222 

   223   static size_t capacity_until_GC() { return _capacity_until_GC; }

   224   static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; }

   225   static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }

   226   static void dec_capacity_until_GC(size_t v) {

   227     _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;

   228   }

   229   static bool expand_after_GC()           { return _expand_after_GC; }

   230   static void set_expand_after_GC(bool v) { _expand_after_GC = v; }

   231 

   232   static bool should_concurrent_collect() { return _should_concurrent_collect; }

   233   static void set_should_concurrent_collect(bool v) {

   234     _should_concurrent_collect = v;

   235   }

   236 

   237   // The amount to increase the high-water-mark (_capacity_until_GC)

   238   static size_t delta_capacity_until_GC(size_t word_size);

   239 

   240   // It is expected that this will be called when the current capacity

   241   // has been used and a GC should be considered.

   242   static bool should_expand(VirtualSpaceList* vsl, size_t word_size);

   243 

   244   // Calculate the new high-water mark at which to induce

   245   // a GC.

   246   static void compute_new_size();

   247 };

   248 

   249 #endif // SHARE_VM_MEMORY_METASPACE_HPP