/*

 * Copyright (c) 2011, 2019, 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_MEMORY_METASPACE_HPP

#define SHARE_MEMORY_METASPACE_HPP

#include "memory/allocation.hpp"

#include "memory/memRegion.hpp"

#include "memory/metaspaceChunkFreeListSummary.hpp"

#include "memory/virtualspace.hpp"

#include "runtime/globals.hpp"

#include "utilities/exceptions.hpp"

#include "utilities/globalDefinitions.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

//

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

//               |       |  Virtualspace     |

//               |       |                   |

//               |       |                   |

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

//               |       || Chunk            |

//               |       ||                  |

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

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

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

//                       ||| block 1 |       |

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

//                       ||                  |

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

//                       |                   |

//                       |                   |

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

//

class ClassLoaderData;

class MetaspaceShared;

class MetaspaceTracer;

class outputStream;

namespace metaspace {

class MetaspaceSizesSnapshot;

}

////////////////// Metaspace ///////////////////////

// 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.

// Namespace for important central static functions

// (auxiliary stuff goes into MetaspaceUtils)

class Metaspace : public AllStatic {

  friend class MetaspaceShared;

  // Base and size of the compressed class space.

  static MetaWord* _compressed_class_space_base;

  static size_t _compressed_class_space_size;

  static size_t _commit_alignment;

  static size_t _reserve_alignment;

  DEBUG_ONLY(static bool   _frozen;)

  static const MetaspaceTracer* _tracer;

  static bool _initialized;

  static MetaWord* compressed_class_space_base()              { return _compressed_class_space_base; }

  static size_t compressed_class_space_size()                 { return _compressed_class_space_size; }

public:

  static const MetaspaceTracer* tracer() { return _tracer; }

  static void freeze() {

    assert(DumpSharedSpaces, "sanity");

    DEBUG_ONLY(_frozen = true;)

  }

  static void assert_not_frozen() {

    assert(!_frozen, "sanity");

  }

#ifdef _LP64

  static void allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base);

#endif

 private:

#ifdef _LP64

  static void set_narrow_klass_base_and_shift(address metaspace_base, address cds_base);

  // Returns true if can use CDS with metaspace allocated as specified address.

  static bool can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base);

  static void initialize_class_space(ReservedSpace rs);

#endif

 public:

  static void ergo_initialize();

  static void global_initialize();

  static void post_initialize();

  // The alignment at which Metaspace mappings are reserved.

  static size_t reserve_alignment()       { return _reserve_alignment; }

  static size_t reserve_alignment_words() { return _reserve_alignment / BytesPerWord; }

  // The granularity at which Metaspace is committed and uncommitted.

  static size_t commit_alignment()        { return _commit_alignment; }

  static size_t commit_words()            { return _commit_alignment / BytesPerWord; }

  static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,

                            MetaspaceObj::Type type, TRAPS);

  static bool contains(const void* ptr);

  static bool contains_non_shared(const void* ptr);

  // Free empty virtualspaces

  static void purge();

  static void report_metadata_oome(ClassLoaderData* loader_data, size_t word_size,

  static void print_compressed_class_space(outputStream* st, const char* requested_addr = 0) NOT_LP64({});

  // Return TRUE only if UseCompressedClassPointers is True.

  static bool using_class_space() {

    return NOT_LP64(false) LP64_ONLY(UseCompressedClassPointers);

  }

  static bool initialized() { return _initialized; }

};

////////////////// MetaspaceGC ///////////////////////

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

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

// Metaspaces.

class MetaspaceGCThresholdUpdater : public AllStatic {

 public:

  enum Type {

    ComputeNewSize,

    ExpandAndAllocate,

    Last

  };

  static const char* to_string(MetaspaceGCThresholdUpdater::Type updater) {

    switch (updater) {

      case ComputeNewSize:

        return "compute_new_size";

      case ExpandAndAllocate:

        return "expand_and_allocate";

      default:

        assert(false, "Got bad updater: %d", (int) updater);

        return NULL;

    };

  }

};

class MetaspaceGC : public AllStatic {

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

  // When committed memory of all metaspaces reaches this value,

  // a GC is induced and the value is increased. Size is in bytes.

  static volatile size_t _capacity_until_GC;

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

  // be started.

  static bool _should_concurrent_collect;

  static uint _shrink_factor;

  static size_t shrink_factor() { return _shrink_factor; }

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

 public:

  static void initialize();

  static void post_initialize();

  static size_t capacity_until_GC();

  static bool inc_capacity_until_GC(size_t v,

                                    size_t* new_cap_until_GC = NULL,

                                    size_t* old_cap_until_GC = NULL,

                                    bool* can_retry = NULL);

  static size_t dec_capacity_until_GC(size_t 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 bytes);

  // Tells if we have can expand metaspace without hitting set limits.

  static bool can_expand(size_t words, bool is_class);

  // Returns amount that we can expand without hitting a GC,

  // measured in words.

  static size_t allowed_expansion();

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

  // a GC.

  static void compute_new_size();

};

class MetaspaceUtils : AllStatic {

public:

  // Committed space actually in use by Metadata

  static size_t used_words();

  // Space committed for Metaspace

  static size_t committed_words();

  // Space reserved for Metaspace

  static size_t reserved_words();

  // _bytes() variants for convenience...

  static size_t used_bytes()                                    { return used_words() * BytesPerWord; }

  static size_t committed_bytes()                               { return committed_words() * BytesPerWord; }

  static size_t reserved_bytes()                                { return reserved_words() * BytesPerWord; }

  // TODO. Do we need this really? This number is kind of uninformative.

  static size_t capacity_bytes()                                { return 0; }

  // Todo. Consolidate.

  // Committed space in freelists

  // Todo. Implement or Consolidate.

    return MetaspaceChunkFreeListSummary(0,0,0,0,0,0,0,0);

  }

  // Log change in used metadata.

  static void print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values);

  // Prints an ASCII representation of the given space.

  // This will print out a basic metaspace usage report but

  // unlike print_report() is guaranteed not to lock or to walk the CLDG.

  static void print_basic_report(outputStream* st, size_t scale = 0);

  // Prints a report about the current metaspace state.

  // Function will walk the CLDG and will lock the expand lock; if that is not

  // convenient, use print_basic_report() instead.

  static void print_full_report(outputStream* out, size_t scale = 0);

  static void print_on(outputStream * out);

  DEBUG_ONLY(static void verify(bool slow);)

};

#endif // SHARE_MEMORY_METASPACE_HPP