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 /*

  * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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  */

 #ifndef SHARE_VM_MEMORY_METASPACE_HPP

 #define SHARE_VM_MEMORY_METASPACE_HPP

 #include "memory/allocation.hpp"

 #include "memory/memRegion.hpp"

 #include "runtime/virtualspace.hpp"

 #include "utilities/exceptions.hpp"

 // Metaspace

 //

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

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

 // bootstrap class loader

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

 // to write for DumpSharedSpaces and read for UseSharedSpaces

 //

 //    block X ---+       +-------------------+

 //               |       |  Virtualspace     |

 //               |       |                   |

 //               |       |                   |

 //               |       |-------------------|

 //               |       || Chunk            |

 //               |       ||                  |

 //               |       ||----------        |

 //               +------>||| block 0 |       |

 //                       ||----------        |

 //                       ||| block 1 |       |

 //                       ||----------        |

 //                       ||                  |

 //                       |-------------------|

 //                       |                   |

 //                       |                   |

 //                       +-------------------+

 //

 class ClassLoaderData;

 class Metablock;

 class MetaWord;

 class Mutex;

 class outputStream;

 class SpaceManager;

 // Metaspaces each have a  SpaceManager and allocations

 // are done by the SpaceManager.  Allocations are done

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

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

 // the current VirtualSpace.  When the VirtualSpace is exhausted

 // the SpaceManager gets a new one.  The SpaceManager

 // also manages freelists of available Chunks.

 //

 // Currently the space manager maintains the list of

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

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

 // quantum of metadata.

 class VirtualSpaceList;

 class Metaspace : public CHeapObj<mtClass> {

   friend class VMStructs;

   friend class SpaceManager;

   friend class VM_CollectForMetadataAllocation;

   friend class MetaspaceGC;

   friend class MetaspaceAux;

  public:

   enum MetadataType {ClassType, NonClassType};

  private:

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

   static size_t _first_chunk_word_size;

   SpaceManager* _vsm;

   SpaceManager* vsm() const { return _vsm; }

   SpaceManager* _class_vsm;

   SpaceManager* class_vsm() const { return _class_vsm; }

   MetaWord* allocate(size_t word_size, MetadataType mdtype);

   // Virtual Space lists for both classes and other metadata

   static VirtualSpaceList* _space_list;

   static VirtualSpaceList* _class_space_list;

   static VirtualSpaceList* space_list()       { return _space_list; }

   static VirtualSpaceList* class_space_list() { return _class_space_list; }

  public:

   Metaspace(Mutex* lock, size_t initial_size);

   Metaspace(Mutex* lock);

   ~Metaspace();

   // Initialize globals for Metaspace

   static void global_initialize();

   static void initialize_class_space(ReservedSpace rs);

   static size_t first_chunk_word_size() { return _first_chunk_word_size; }

   char*  bottom() const;

   size_t used_words(MetadataType mdtype) const;

   size_t free_words(MetadataType mdtype) const;

   size_t capacity_words(MetadataType mdtype) const;

   size_t waste_words(MetadataType mdtype) const;

   static Metablock* allocate(ClassLoaderData* loader_data, size_t size,

                             bool read_only, MetadataType mdtype, TRAPS);

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

   MetaWord* expand_and_allocate(size_t size,

                                 MetadataType mdtype);

   static bool is_initialized() { return _class_space_list != NULL; }

 #ifndef PRODUCT

   bool contains(const void *ptr) const;

   bool contains_class(const void *ptr) const;

 #endif

   void dump(outputStream* const out) const;

   void print_on(outputStream* st) const;

   // Debugging support

   void verify();

 };

 class MetaspaceAux : AllStatic {

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

   static size_t used_in_bytes(Metaspace::MetadataType mdtype);

   static size_t free_in_bytes(Metaspace::MetadataType mdtype);

   static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);

   static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);

   static size_t free_chunks_total(Metaspace::MetadataType mdtype);

   static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);

  public:

   // Total of space allocated to metadata in all Metaspaces

   static size_t used_in_bytes() {

     return used_in_bytes(Metaspace::ClassType) +

            used_in_bytes(Metaspace::NonClassType);

   }

   // Total of available space in all Metaspaces

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

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

   // freelist.

   static size_t capacity_in_bytes() {

     return capacity_in_bytes(Metaspace::ClassType) +

            capacity_in_bytes(Metaspace::NonClassType);

   }

   // Total space reserved in all Metaspaces

   static size_t reserved_in_bytes() {

     return reserved_in_bytes(Metaspace::ClassType) +

            reserved_in_bytes(Metaspace::NonClassType);

   }

   static size_t min_chunk_size();

   // Print change in used metadata.

   static void print_metaspace_change(size_t prev_metadata_used);

   static void print_on(outputStream * out);

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

   static void print_waste(outputStream* out);

   static void dump(outputStream* out);

 };

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

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

 // Metaspaces.

 class MetaspaceGC : AllStatic {

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

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

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

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

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

   static size_t _capacity_until_GC;

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

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

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

   static bool _expand_after_GC;

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

   // be started.

   static bool _should_concurrent_collect;

   static uint _shrink_factor;

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

   static size_t shrink_factor() { return _shrink_factor; }

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

  public:

   static size_t capacity_until_GC() { return _capacity_until_GC; }

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

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

   static void dec_capacity_until_GC(size_t v) {

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

   }

   static bool expand_after_GC()           { return _expand_after_GC; }

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

   static bool should_concurrent_collect() { return _should_concurrent_collect; }

   static void set_should_concurrent_collect(bool v) {

     _should_concurrent_collect = v;

   }

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

   static size_t delta_capacity_until_GC(size_t word_size);

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

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

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

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

   // a GC.

   static void compute_new_size();

 };

 #endif // SHARE_VM_MEMORY_METASPACE_HPP