/*

 * 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

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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:

  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();

  // 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; }

  static bool contains(const void *ptr);

  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);

  static void verify_free_chunks();

};

// 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