Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * 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

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "gc_interface/collectedHeap.hpp"

 #include "memory/binaryTreeDictionary.hpp"

 #include "memory/collectorPolicy.hpp"

 #include "memory/filemap.hpp"

 #include "memory/freeList.hpp"

 #include "memory/metaspace.hpp"

 #include "memory/metaspaceShared.hpp"

 #include "memory/resourceArea.hpp"

 #include "memory/universe.hpp"

 #include "runtime/globals.hpp"

 #include "runtime/mutex.hpp"

 #include "services/memTracker.hpp"

 #include "utilities/copy.hpp"

 #include "utilities/debug.hpp"

 // Define this macro to deallocate Metablock.  If not defined,

 // blocks are not yet deallocated and are only mangled.

 #undef DEALLOCATE_BLOCKS

 // Easily recognizable patterns

 // These patterns can be the same in 32bit or 64bit since

 // they only have to be easily recognizable.

 const void* metaspace_allocation_leader = (void*) 0X11111111;

 const void* metaspace_allocation_trailer = (void*) 0X77777777;

 // Parameters for stress mode testing

 const uint metadata_deallocate_a_lot_block = 10;

 const uint metadata_deallocate_a_lock_chunk = 3;

 size_t const allocation_from_dictionary_limit = 64 * K;

 const size_t metadata_chunk_initialize = 0xf7f7f7f7;

 const size_t metadata_deallocate = 0xf5f5f5f5;

 const size_t metadata_space_manager_allocate = 0xf3f3f3f3;

 MetaWord* last_allocated = 0;

 // Used in declarations in SpaceManager and ChunkManager

 enum ChunkIndex {

   SmallIndex = 0,

   MediumIndex = 1,

   HumongousIndex = 2,

   NumberOfFreeLists = 3

 };

 static ChunkIndex next_chunk_index(ChunkIndex i) {

   assert(i < NumberOfFreeLists, "Out of bound");

   return (ChunkIndex) (i+1);

 }

 // Originally _capacity_until_GC was set to MetaspaceSize here but

 // the default MetaspaceSize before argument processing was being

 // used which was not the desired value.  See the code

 // in should_expand() to see how the initialization is handled

 // now.

 size_t MetaspaceGC::_capacity_until_GC = 0;

 bool MetaspaceGC::_expand_after_GC = false;

 uint MetaspaceGC::_shrink_factor = 0;

 bool MetaspaceGC::_should_concurrent_collect = false;

 // Blocks of space for metadata are allocated out of Metachunks.

 //

 // Metachunk are allocated out of MetadataVirtualspaces and once

 // allocated there is no explicit link between a Metachunk and

 // the MetadataVirtualspaces from which it was allocated.

 //

 // Each SpaceManager maintains a

 // list of the chunks it is using and the current chunk.  The current

 // chunk is the chunk from which allocations are done.  Space freed in

 // a chunk is placed on the free list of blocks (BlockFreelist) and

 // reused from there.

 //

 // Future modification

 //

 // The Metachunk can conceivable be replaced by the Chunk in

 // allocation.hpp.  Note that the latter Chunk is the space for

 // allocation (allocations from the chunk are out of the space in

 // the Chunk after the header for the Chunk) where as Metachunks

 // point to space in a VirtualSpace.  To replace Metachunks with

 // Chunks, change Chunks so that they can be allocated out of a VirtualSpace.

 //

 // Metablock are the unit of allocation from a Chunk.  It contains

 // the size of the requested allocation in a debug build.

 // Also in a debug build it has a marker before and after the

 // body of the block. The address of the body is the address returned

 // by the allocation.

 //

 // Layout in a debug build.  In a product build only the body is present.

 //

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

 //     | word size | leader    | body       | ... | trailer   |

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

 //

 // A Metablock may be reused by its SpaceManager but are never moved between

 // SpaceManagers.  There is no explicit link to the Metachunk

 // from which it was allocated.  Metablock are not deallocated, rather

 // the Metachunk it is a part of will be deallocated when it's

 // associated class loader is collected.

 //

 // When the word size of a block is passed in to the deallocation

 // call the word size no longer needs to be part of a Metablock.

 class Metablock {

   friend class VMStructs;

  private:

   // Used to align the allocation (see below) and for debugging.

 #ifdef ASSERT

   struct {

     size_t _word_size;

     void*  _leader;

   } _header;

   void* _data[1];

 #endif

   static size_t _overhead;

 #ifdef ASSERT

   void set_word_size(size_t v) { _header._word_size = v; }

   void* leader() { return _header._leader; }

   void* trailer() {

     jlong index = (jlong) _header._word_size - sizeof(_header)/BytesPerWord - 1;

     assert(index > 0, err_msg("Bad indexling of trailer %d", index));

     void** ptr = &_data[index];

     return *ptr;

   }

   void set_leader(void* v) { _header._leader = v; }

   void set_trailer(void* v) {

     void** ptr = &_data[_header._word_size - sizeof(_header)/BytesPerWord - 1];

     *ptr = v;

   }

  public:

   size_t word_size() { return _header._word_size; }

 #endif

  public:

   static Metablock* initialize(MetaWord* p, size_t word_size);

   // This places the body of the block at a 2 word boundary

   // because every block starts on a 2 word boundary.  Work out

   // how to make the body on a 2 word boundary if the block

   // starts on a arbitrary boundary.  JJJ

 #ifdef ASSERT

   MetaWord* data() { return (MetaWord*) &_data[0]; }

 #else

   MetaWord* data() { return (MetaWord*) this; }

 #endif

   static Metablock* metablock_from_data(MetaWord* p) {

 #ifdef ASSERT

     size_t word_offset = offset_of(Metablock, _data)/BytesPerWord;

     Metablock* result = (Metablock*) (p - word_offset);

     return result;

 #else

     return (Metablock*) p;

 #endif

   }

   static size_t overhead() { return _overhead; }

   void verify();

 };

 //  Metachunk - Quantum of allocation from a Virtualspace

 //    Metachunks are reused (when freed are put on a global freelist) and

 //    have no permanent association to a SpaceManager.

 //            +--------------+ <- end

 //            |              |          --+       ---+

 //            |              |            | free     |

 //            |              |            |          |

 //            |              |            |          | capacity

 //            |              |            |          |

 //            |              | <- top   --+          |

 //            |              |           ---+        |

 //            |              |              | used   |

 //            |              |              |        |

 //            |              |              |        |

 //            +--------------+ <- bottom ---+     ---+

 class Metachunk VALUE_OBJ_CLASS_SPEC {

   // link to support lists of chunks

   Metachunk* _next;

   MetaWord* _bottom;

   MetaWord* _end;

   MetaWord* _top;

   size_t _word_size;

   // Metachunks are allocated out of a MetadataVirtualSpace and

   // and use some of its space to describe itself (plus alignment

   // considerations).  Metadata is allocated in the rest of the chunk.

   // This size is the overhead of maintaining the Metachunk within

   // the space.

   static size_t _overhead;

   void set_bottom(MetaWord* v) { _bottom = v; }

   void set_end(MetaWord* v) { _end = v; }

   void set_top(MetaWord* v) { _top = v; }

   void set_word_size(size_t v) { _word_size = v; }

  public:

   // Used to add a Metachunk to a list of Metachunks

   void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");}

   Metablock* allocate(size_t word_size);

   static Metachunk* initialize(MetaWord* ptr, size_t word_size);

   // Accessors

   Metachunk* next() const { return _next; }

   MetaWord* bottom() const { return _bottom; }

   MetaWord* end() const { return _end; }

   MetaWord* top() const { return _top; }

   size_t word_size() const { return _word_size; }

   static size_t overhead() { return _overhead; }

   // Reset top to bottom so chunk can be reused.

   void reset_empty() { _top = (_bottom + _overhead); }

   bool is_empty() { return _top == (_bottom + _overhead); }

   // used (has been allocated)

   // free (available for future allocations)

   // capacity (total size of chunk)

   size_t used_word_size();

   size_t free_word_size();

   size_t capacity_word_size();

 #ifdef ASSERT

   void mangle() {

     // Mangle the payload of the chunk and not the links that

     // maintain list of chunks.

     HeapWord* start = (HeapWord*)(bottom() + overhead());

     size_t word_size = capacity_word_size() - overhead();

     Copy::fill_to_words(start, word_size, metadata_chunk_initialize);

   }

 #endif // ASSERT

   void print_on(outputStream* st) const;

   void verify();

 };

 // Pointer to list of Metachunks.

 class ChunkList VALUE_OBJ_CLASS_SPEC {

   // List of free chunks

   Metachunk* _head;

  public:

   // Constructor

   ChunkList() : _head(NULL) {}

   // Accessors

   Metachunk* head() { return _head; }

   void set_head(Metachunk* v) { _head = v; }

   // Link at head of the list

   void add_at_head(Metachunk* head, Metachunk* tail);

   void add_at_head(Metachunk* head);

   size_t sum_list_size();

   size_t sum_list_count();

   size_t sum_list_capacity();

 };

 // Manages the global free lists of chunks.

 // Has three lists of free chunks, and a total size and

 // count that includes all three

 class ChunkManager VALUE_OBJ_CLASS_SPEC {

   // Free list of chunks of different sizes.

   //   SmallChunk

   //   MediumChunk

   //   HumongousChunk

   ChunkList _free_chunks[3];

   // ChunkManager in all lists of this type

   size_t _free_chunks_total;

   size_t _free_chunks_count;

   void dec_free_chunks_total(size_t v) {

     assert(_free_chunks_count > 0 &&

              _free_chunks_total > 0,

              "About to go negative");

     Atomic::add_ptr(-1, &_free_chunks_count);

     jlong minus_v = (jlong) - (jlong) v;

     Atomic::add_ptr(minus_v, &_free_chunks_total);

   }

   // Debug support

   size_t sum_free_chunks();

   size_t sum_free_chunks_count();

   void locked_verify_free_chunks_total();

   void locked_verify_free_chunks_count();

   void verify_free_chunks_count();

  public:

   ChunkManager() : _free_chunks_total(0), _free_chunks_count(0) {}

   // add or delete (return) a chunk to the global freelist.

   Metachunk* chunk_freelist_allocate(size_t word_size);

   void chunk_freelist_deallocate(Metachunk* chunk);

   // Total of the space in the free chunks list

   size_t free_chunks_total();

   size_t free_chunks_total_in_bytes();

   // Number of chunks in the free chunks list

   size_t free_chunks_count();

   void inc_free_chunks_total(size_t v, size_t count = 1) {

     Atomic::add_ptr(count, &_free_chunks_count);

     Atomic::add_ptr(v, &_free_chunks_total);

   }

   ChunkList* free_medium_chunks() { return &_free_chunks[1]; }

   ChunkList* free_small_chunks() { return &_free_chunks[0]; }

   ChunkList* free_humongous_chunks() { return &_free_chunks[2]; }

   ChunkList* free_chunks(ChunkIndex index);

   // Returns the list for the given chunk word size.

   ChunkList* find_free_chunks_list(size_t word_size);

   // Add and remove from a list by size.  Selects

   // list based on size of chunk.

   void free_chunks_put(Metachunk* chuck);

   Metachunk* free_chunks_get(size_t chunk_word_size);

   // Debug support

   void verify();

   void locked_verify();

   void verify_free_chunks_total();

   void locked_print_free_chunks(outputStream* st);

   void locked_print_sum_free_chunks(outputStream* st);

 };

 // Used to manage the free list of Metablocks (a block corresponds

 // to the allocation of a quantum of metadata).

 class BlockFreelist VALUE_OBJ_CLASS_SPEC {

 #ifdef DEALLOCATE_BLOCKS

   BinaryTreeDictionary<Metablock>* _dictionary;

 #endif

   static Metablock* initialize_free_chunk(Metablock* block, size_t word_size);

 #ifdef DEALLOCATE_BLOCKS

   // Accessors

   BinaryTreeDictionary<Metablock>* dictionary() const { return _dictionary; }

 #endif

  public:

   BlockFreelist();

   ~BlockFreelist();

   // Get and return a block to the free list

   Metablock* get_block(size_t word_size);

   void return_block(Metablock* block, size_t word_size);

   size_t totalSize() {

 #ifdef DEALLOCATE_BLOCKS

     if (dictionary() == NULL) {

       return 0;

     } else {

       return dictionary()->totalSize();

     }

 #else

     return 0;

 #endif

   }

   void print_on(outputStream* st) const;

 };

 class VirtualSpaceNode : public CHeapObj<mtClass> {

   friend class VirtualSpaceList;

   // Link to next VirtualSpaceNode

   VirtualSpaceNode* _next;

   // total in the VirtualSpace

   MemRegion _reserved;

   ReservedSpace _rs;

   VirtualSpace _virtual_space;

   MetaWord* _top;

   // Convenience functions for logical bottom and end

   MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }

   MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }

   // Convenience functions to access the _virtual_space

   char* low()  const { return virtual_space()->low(); }

   char* high() const { return virtual_space()->high(); }

  public:

   VirtualSpaceNode(size_t byte_size);

   VirtualSpaceNode(ReservedSpace rs) : _top(NULL), _next(NULL), _rs(rs) {}

   ~VirtualSpaceNode();

   // address of next available space in _virtual_space;

   // Accessors

   VirtualSpaceNode* next() { return _next; }

   void set_next(VirtualSpaceNode* v) { _next = v; }

   void set_reserved(MemRegion const v) { _reserved = v; }

   void set_top(MetaWord* v) { _top = v; }

   // Accessors

   MemRegion* reserved() { return &_reserved; }

   VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }

   // Returns true if "word_size" is available in the virtual space

   bool is_available(size_t word_size) { return _top + word_size <= end(); }

   MetaWord* top() const { return _top; }

   void inc_top(size_t word_size) { _top += word_size; }

   // used and capacity in this single entry in the list

   size_t used_words_in_vs() const;

   size_t capacity_words_in_vs() const;

   bool initialize();

   // get space from the virtual space

   Metachunk* take_from_committed(size_t chunk_word_size);

   // Allocate a chunk from the virtual space and return it.

   Metachunk* get_chunk_vs(size_t chunk_word_size);

   Metachunk* get_chunk_vs_with_expand(size_t chunk_word_size);

   // Expands/shrinks the committed space in a virtual space.  Delegates

   // to Virtualspace

   bool expand_by(size_t words, bool pre_touch = false);

   bool shrink_by(size_t words);

   // Debug support

   static void verify_virtual_space_total();

   static void verify_virtual_space_count();

   void mangle();

   void print_on(outputStream* st) const;

 };

   // byte_size is the size of the associated virtualspace.

 VirtualSpaceNode::VirtualSpaceNode(size_t byte_size) : _top(NULL), _next(NULL), _rs(0) {

   // This allocates memory with mmap.  For DumpSharedspaces, allocate the

   // space at low memory so that other shared images don't conflict.

   // This is the same address as memory needed for UseCompressedOops but

   // compressed oops don't work with CDS (offsets in metadata are wrong), so

   // borrow the same address.

   if (DumpSharedSpaces) {

     char* shared_base = (char*)HeapBaseMinAddress;

     _rs = ReservedSpace(byte_size, 0, false, shared_base, 0);

     if (_rs.is_reserved()) {

       assert(_rs.base() == shared_base, "should match");

     } else {

       // If we are dumping the heap, then allocate a wasted block of address

       // space in order to push the heap to a lower address.  This extra

       // address range allows for other (or larger) libraries to be loaded

       // without them occupying the space required for the shared spaces.

       uintx reserved = 0;

       uintx block_size = 64*1024*1024;

       while (reserved < SharedDummyBlockSize) {

         char* dummy = os::reserve_memory(block_size);

         reserved += block_size;

       }

       _rs = ReservedSpace(byte_size);

     }

     MetaspaceShared::set_shared_rs(&_rs);

   } else {

     _rs = ReservedSpace(byte_size);

   }

   MemTracker::record_virtual_memory_type((address)_rs.base(), mtClass);

 }

 // List of VirtualSpaces for metadata allocation.

 // It has a  _next link for singly linked list and a MemRegion

 // for total space in the VirtualSpace.

 class VirtualSpaceList : public CHeapObj<mtClass> {

   friend class VirtualSpaceNode;

   enum VirtualSpaceSizes {

     VirtualSpaceSize = 256 * K

   };

   // Global list of virtual spaces

   // Head of the list

   VirtualSpaceNode* _virtual_space_list;

   // virtual space currently being used for allocations

   VirtualSpaceNode* _current_virtual_space;

   // Free chunk list for all other metadata

   ChunkManager      _chunk_manager;

   // Can this virtual list allocate >1 spaces?  Also, used to determine

   // whether to allocate unlimited small chunks in this virtual space

   bool _is_class;

   bool can_grow() const { return !is_class() || !UseCompressedKlassPointers; }

   // Sum of space in all virtual spaces and number of virtual spaces

   size_t _virtual_space_total;

   size_t _virtual_space_count;

   ~VirtualSpaceList();

   VirtualSpaceNode* virtual_space_list() const { return _virtual_space_list; }

   void set_virtual_space_list(VirtualSpaceNode* v) {

     _virtual_space_list = v;

   }

   void set_current_virtual_space(VirtualSpaceNode* v) {

     _current_virtual_space = v;

   }

   void link_vs(VirtualSpaceNode* new_entry, size_t vs_word_size);

   // Get another virtual space and add it to the list.  This

   // is typically prompted by a failed attempt to allocate a chunk

   // and is typically followed by the allocation of a chunk.

   bool grow_vs(size_t vs_word_size);

  public:

   VirtualSpaceList(size_t word_size);

   VirtualSpaceList(ReservedSpace rs);

   Metachunk* get_new_chunk(size_t word_size, size_t grow_chunks_by_words);

   VirtualSpaceNode* current_virtual_space() {

     return _current_virtual_space;

   }

   ChunkManager* chunk_manager() { return &_chunk_manager; }

   bool is_class() const { return _is_class; }

   // Allocate the first virtualspace.

   void initialize(size_t word_size);

   size_t virtual_space_total() { return _virtual_space_total; }

   void inc_virtual_space_total(size_t v) {

     Atomic::add_ptr(v, &_virtual_space_total);

   }

   size_t virtual_space_count() { return _virtual_space_count; }

   void inc_virtual_space_count() {

     Atomic::inc_ptr(&_virtual_space_count);

   }

   // Used and capacity in the entire list of virtual spaces.

   // These are global values shared by all Metaspaces

   size_t capacity_words_sum();

   size_t capacity_bytes_sum() { return capacity_words_sum() * BytesPerWord; }

   size_t used_words_sum();

   size_t used_bytes_sum() { return used_words_sum() * BytesPerWord; }

   bool contains(const void *ptr);

   void print_on(outputStream* st) const;

   class VirtualSpaceListIterator : public StackObj {

     VirtualSpaceNode* _virtual_spaces;

    public:

     VirtualSpaceListIterator(VirtualSpaceNode* virtual_spaces) :

       _virtual_spaces(virtual_spaces) {}

     bool repeat() {

       return _virtual_spaces != NULL;

     }

     VirtualSpaceNode* get_next() {

       VirtualSpaceNode* result = _virtual_spaces;

       if (_virtual_spaces != NULL) {

         _virtual_spaces = _virtual_spaces->next();

       }

       return result;

     }

   };

 };

 class Metadebug : AllStatic {

   // Debugging support for Metaspaces

   static int _deallocate_block_a_lot_count;

   static int _deallocate_chunk_a_lot_count;

   static int _allocation_fail_alot_count;

  public:

   static int deallocate_block_a_lot_count() {

     return _deallocate_block_a_lot_count;

   }

   static void set_deallocate_block_a_lot_count(int v) {

     _deallocate_block_a_lot_count = v;

   }

   static void inc_deallocate_block_a_lot_count() {

     _deallocate_block_a_lot_count++;

   }

   static int deallocate_chunk_a_lot_count() {

     return _deallocate_chunk_a_lot_count;

   }

   static void reset_deallocate_chunk_a_lot_count() {

     _deallocate_chunk_a_lot_count = 1;

   }

   static void inc_deallocate_chunk_a_lot_count() {

     _deallocate_chunk_a_lot_count++;

   }

   static void init_allocation_fail_alot_count();

 #ifdef ASSERT

   static bool test_metadata_failure();

 #endif

   static void deallocate_chunk_a_lot(SpaceManager* sm,

                                      size_t chunk_word_size);

   static void deallocate_block_a_lot(SpaceManager* sm,

                                      size_t chunk_word_size);

 };

 int Metadebug::_deallocate_block_a_lot_count = 0;

 int Metadebug::_deallocate_chunk_a_lot_count = 0;

 int Metadebug::_allocation_fail_alot_count = 0;

 //  SpaceManager - used by Metaspace to handle allocations

 class SpaceManager : public CHeapObj<mtClass> {

   friend class Metaspace;

   friend class Metadebug;

  private:

   // protects allocations and contains.

   Mutex* const _lock;

   // List of chunks in use by this SpaceManager.  Allocations

   // are done from the current chunk.  The list is used for deallocating

   // chunks when the SpaceManager is freed.

   Metachunk* _chunks_in_use[NumberOfFreeLists];

   Metachunk* _current_chunk;

   // Virtual space where allocation comes from.

   VirtualSpaceList* _vs_list;

   // Number of small chunks to allocate to a manager

   // If class space manager, small chunks are unlimited

   static uint const _small_chunk_limit;

   bool has_small_chunk_limit() { return !vs_list()->is_class(); }

   // Sum of all space in allocated chunks

   size_t _allocation_total;

   // Free lists of blocks are per SpaceManager since they

   // are assumed to be in chunks in use by the SpaceManager

   // and all chunks in use by a SpaceManager are freed when

   // the class loader using the SpaceManager is collected.

   BlockFreelist _block_freelists;

   // protects virtualspace and chunk expansions

   static const char*  _expand_lock_name;

   static const int    _expand_lock_rank;

   static Mutex* const _expand_lock;

   // Accessors

   Metachunk* chunks_in_use(ChunkIndex index) const { return _chunks_in_use[index]; }

   void set_chunks_in_use(ChunkIndex index, Metachunk* v) { _chunks_in_use[index] = v; }

   BlockFreelist* block_freelists() const {

     return (BlockFreelist*) &_block_freelists;

   }

   VirtualSpaceList* vs_list() const    { return _vs_list; }

   Metachunk* current_chunk() const { return _current_chunk; }

   void set_current_chunk(Metachunk* v) {

     _current_chunk = v;

   }

   Metachunk* find_current_chunk(size_t word_size);

   // Add chunk to the list of chunks in use

   void add_chunk(Metachunk* v, bool make_current);

   // Debugging support

   void verify_chunks_in_use_index(ChunkIndex index, Metachunk* v) {

     switch (index) {

     case 0:

       assert(v->word_size() == SmallChunk, "Not a SmallChunk");

       break;

     case 1:

       assert(v->word_size() == MediumChunk, "Not a MediumChunk");

       break;

     case 2:

       assert(v->word_size() > MediumChunk, "Not a HumongousChunk");

       break;

     default:

       assert(false, "Wrong list.");

     }

   }

  protected:

   Mutex* lock() const { return _lock; }

  public:

   SpaceManager(Mutex* lock, VirtualSpaceList* vs_list);

   ~SpaceManager();

   enum ChunkSizes {    // in words.

     SmallChunk = 512,

     MediumChunk = 8 * K,

     MediumChunkBunch = 4 * MediumChunk

   };

   // Accessors

   size_t allocation_total() const { return _allocation_total; }

   void inc_allocation_total(size_t v) { Atomic::add_ptr(v, &_allocation_total); }

   static bool is_humongous(size_t word_size) { return word_size > MediumChunk; }

   static Mutex* expand_lock() { return _expand_lock; }

   size_t sum_capacity_in_chunks_in_use() const;

   size_t sum_used_in_chunks_in_use() const;

   size_t sum_free_in_chunks_in_use() const;

   size_t sum_waste_in_chunks_in_use() const;

   size_t sum_waste_in_chunks_in_use(ChunkIndex index ) const;

   size_t sum_count_in_chunks_in_use();

   size_t sum_count_in_chunks_in_use(ChunkIndex i);

   // Block allocation and deallocation.

   // Allocates a block from the current chunk

   MetaWord* allocate(size_t word_size);

   // Helper for allocations

   Metablock* allocate_work(size_t word_size);

   // Returns a block to the per manager freelist

   void deallocate(MetaWord* p);

   // Based on the allocation size and a minimum chunk size,

   // returned chunk size (for expanding space for chunk allocation).

   size_t calc_chunk_size(size_t allocation_word_size);

   // Called when an allocation from the current chunk fails.

   // Gets a new chunk (may require getting a new virtual space),

   // and allocates from that chunk.

   Metablock* grow_and_allocate(size_t word_size);

   // debugging support.

   void dump(outputStream* const out) const;

   void print_on(outputStream* st) const;

   void locked_print_chunks_in_use_on(outputStream* st) const;

   void verify();

 #ifdef ASSERT

   void mangle_freed_chunks();

   void verify_allocation_total();

 #endif

 };

 uint const SpaceManager::_small_chunk_limit = 4;

 const char* SpaceManager::_expand_lock_name =

   "SpaceManager chunk allocation lock";

 const int SpaceManager::_expand_lock_rank = Monitor::leaf - 1;

 Mutex* const SpaceManager::_expand_lock =

   new Mutex(SpaceManager::_expand_lock_rank,

             SpaceManager::_expand_lock_name,

             Mutex::_allow_vm_block_flag);

 #ifdef ASSERT

 size_t Metablock::_overhead =

   Chunk::aligned_overhead_size(sizeof(Metablock)) / BytesPerWord;

 #else

 size_t Metablock::_overhead = 0;

 #endif

 size_t Metachunk::_overhead =

   Chunk::aligned_overhead_size(sizeof(Metachunk)) / BytesPerWord;

 // New blocks returned by the Metaspace are zero initialized.

 // We should fix the constructors to not assume this instead.

 Metablock* Metablock::initialize(MetaWord* p, size_t word_size) {

   Metablock* result = (Metablock*) p;

   // Clear the memory

   Copy::fill_to_aligned_words((HeapWord*)result, word_size);

 #ifdef ASSERT

   result->set_word_size(word_size);

   // Check after work size is set.

   result->set_leader((void*) metaspace_allocation_leader);

   result->set_trailer((void*) metaspace_allocation_trailer);

 #endif

   return result;

 }

 void Metablock::verify() {

 #ifdef ASSERT

   assert(leader() == metaspace_allocation_leader &&

          trailer() == metaspace_allocation_trailer,

          "block has been corrupted");

 #endif

 }

 // Metachunk methods

 Metachunk* Metachunk::initialize(MetaWord* ptr, size_t word_size) {

   // Set bottom, top, and end.  Allow space for the Metachunk itself

   Metachunk* chunk = (Metachunk*) ptr;

   MetaWord* chunk_bottom = ptr + _overhead;

   chunk->set_bottom(ptr);

   chunk->set_top(chunk_bottom);

   MetaWord* chunk_end = ptr + word_size;

   assert(chunk_end > chunk_bottom, "Chunk must be too small");

   chunk->set_end(chunk_end);

   chunk->set_next(NULL);

   chunk->set_word_size(word_size);

 #ifdef ASSERT

   size_t data_word_size = pointer_delta(chunk_end, chunk_bottom, sizeof(MetaWord));

   Copy::fill_to_words((HeapWord*) chunk_bottom, data_word_size, metadata_chunk_initialize);

 #endif

   return chunk;

 }

 Metablock* Metachunk::allocate(size_t word_size) {

   Metablock* result = NULL;

   // If available, bump the pointer to allocate.

   if (free_word_size() >= word_size) {

     result = Metablock::initialize(_top, word_size);

     _top = _top + word_size;

   }

 #ifdef ASSERT

   assert(result == NULL ||

          result->word_size() == word_size,

          "Block size is not set correctly");

 #endif

   return result;

 }

 // _bottom points to the start of the chunk including the overhead.

 size_t Metachunk::used_word_size() {

   return pointer_delta(_top, _bottom, sizeof(MetaWord));

 }

 size_t Metachunk::free_word_size() {

   return pointer_delta(_end, _top, sizeof(MetaWord));

 }

 size_t Metachunk::capacity_word_size() {

   return pointer_delta(_end, _bottom, sizeof(MetaWord));

 }

 void Metachunk::print_on(outputStream* st) const {

   st->print_cr("Metachunk:"

                " bottom " PTR_FORMAT " top " PTR_FORMAT

                " end " PTR_FORMAT " size " SIZE_FORMAT,

                bottom(), top(), end(), word_size());

 }

 void Metachunk::verify() {

 #ifdef ASSERT

   // Cannot walk through the blocks unless the blocks have

   // headers with sizes.

   MetaWord* curr = bottom() + overhead();

   while (curr < top()) {

     Metablock* block = (Metablock*) curr;

     size_t word_size = block->word_size();

     block->verify();

     curr = curr + word_size;

   }

 #endif

   return;

 }

 // BlockFreelist methods

 #ifdef DEALLOCATE_BLOCKS

 BlockFreelist::BlockFreelist() : _dictionary(NULL) {}

 #else

 BlockFreelist::BlockFreelist() {}

 #endif

 BlockFreelist::~BlockFreelist() {

 #ifdef DEALLOCATE_BLOCKS

   if (_dictionary != NULL) {

     if (Verbose && TraceMetadataChunkAllocation) {

       _dictionary->print_free_lists(gclog_or_tty);

     }

     delete _dictionary;

   }

 #endif

 }

 Metablock* BlockFreelist::initialize_free_chunk(Metablock* block, size_t word_size) {

 #ifdef DEALLOCATE_BLOCKS

 #ifdef ASSERT

   assert(word_size = block->word_size(), "Wrong chunk size");

 #endif

   Metablock* result = block;

   result->setSize(word_size);

   result->linkPrev(NULL);

   result->linkNext(NULL);

   return result;

 #else

   ShouldNotReachHere();

   return block;

 #endif

 }

 void BlockFreelist::return_block(Metablock* block, size_t word_size) {

 #ifdef ASSERT

   assert(word_size = block->word_size(), "Block size is wrong");;

 #endif

   Metablock* free_chunk = initialize_free_chunk(block, word_size);

 #ifdef DEALLOCATE_BLOCKS

   if (dictionary() == NULL) {

    _dictionary = new BinaryTreeDictionary<Metablock>(false /* adaptive_freelists */);

   }

   dictionary()->returnChunk(free_chunk);

 #endif

 }

 Metablock* BlockFreelist::get_block(size_t word_size) {

 #ifdef DEALLOCATE_BLOCKS

   if (dictionary() == NULL) {

     return NULL;

   }

   Metablock* free_chunk =

     dictionary()->getChunk(word_size, FreeBlockDictionary<Metablock>::exactly);

 #else

   Metablock* free_chunk = NULL;

 #endif

   if (free_chunk == NULL) {

     return NULL;

   }

   assert(free_chunk->word_size() == word_size, "Size of chunk is incorrect");

   Metablock* block = Metablock::initialize((MetaWord*) free_chunk, word_size);

 #ifdef ASSERT

   assert(block->word_size() == word_size, "Block size is not set correctly");

 #endif

   return block;

 }

 void BlockFreelist::print_on(outputStream* st) const {

 #ifdef DEALLOCATE_BLOCKS

   if (dictionary() == NULL) {

     return;

   }

   dictionary()->print_free_lists(st);

 #else

   return;

 #endif

 }

 // VirtualSpaceNode methods

 VirtualSpaceNode::~VirtualSpaceNode() {

   _rs.release();

 }

 size_t VirtualSpaceNode::used_words_in_vs() const {

   return pointer_delta(top(), bottom(), sizeof(MetaWord));

 }

 // Space committed in the VirtualSpace

 size_t VirtualSpaceNode::capacity_words_in_vs() const {

   return pointer_delta(end(), bottom(), sizeof(MetaWord));

 }

 // Allocates the chunk from the virtual space only.

 // This interface is also used internally for debugging.  Not all

 // chunks removed here are necessarily used for allocation.

 Metachunk* VirtualSpaceNode::take_from_committed(size_t chunk_word_size) {

   // Bottom of the new chunk

   MetaWord* chunk_limit = top();

   assert(chunk_limit != NULL, "Not safe to call this method");

   if (!is_available(chunk_word_size)) {

     if (TraceMetadataChunkAllocation) {

       tty->print("VirtualSpaceNode::take_from_committed() not available %d words ", chunk_word_size);

       // Dump some information about the virtual space that is nearly full

       print_on(tty);

     }

     return NULL;

   }

   // Take the space  (bump top on the current virtual space).

   inc_top(chunk_word_size);

   // Point the chunk at the space

   Metachunk* result = Metachunk::initialize(chunk_limit, chunk_word_size);

   return result;

 }

 // Expand the virtual space (commit more of the reserved space)

 bool VirtualSpaceNode::expand_by(size_t words, bool pre_touch) {

   size_t bytes = words * BytesPerWord;

   bool result =  virtual_space()->expand_by(bytes, pre_touch);

   if (TraceMetavirtualspaceAllocation && !result) {

     gclog_or_tty->print_cr("VirtualSpaceNode::expand_by() failed "

                            "for byte size " SIZE_FORMAT, bytes);

     virtual_space()->print();

   }

   return result;

 }

 // Shrink the virtual space (commit more of the reserved space)

 bool VirtualSpaceNode::shrink_by(size_t words) {

   size_t bytes = words * BytesPerWord;

   virtual_space()->shrink_by(bytes);

   return true;

 }

 // Add another chunk to the chunk list.

 Metachunk* VirtualSpaceNode::get_chunk_vs(size_t chunk_word_size) {

   assert_lock_strong(SpaceManager::expand_lock());

   Metachunk* result = NULL;

   return take_from_committed(chunk_word_size);

 }

 Metachunk* VirtualSpaceNode::get_chunk_vs_with_expand(size_t chunk_word_size) {

   assert_lock_strong(SpaceManager::expand_lock());

   Metachunk* new_chunk = get_chunk_vs(chunk_word_size);

   if (new_chunk == NULL) {

     // Only a small part of the virtualspace is committed when first

     // allocated so committing more here can be expected.

     size_t page_size_words = os::vm_page_size() / BytesPerWord;

     size_t aligned_expand_vs_by_words = align_size_up(chunk_word_size,

                                                     page_size_words);

     expand_by(aligned_expand_vs_by_words, false);

     new_chunk = get_chunk_vs(chunk_word_size);

   }

   return new_chunk;

 }

 bool VirtualSpaceNode::initialize() {

   if (!_rs.is_reserved()) {

     return false;

   }

   // Commit only 1 page instead of the whole reserved space _rs.size()

   size_t committed_byte_size = os::vm_page_size();

   bool result = virtual_space()->initialize(_rs, committed_byte_size);

   if (result) {

     set_top((MetaWord*)virtual_space()->low());

     set_reserved(MemRegion((HeapWord*)_rs.base(),

                  (HeapWord*)(_rs.base() + _rs.size())));

     assert(reserved()->start() == (HeapWord*) _rs.base(),

       err_msg("Reserved start was not set properly " PTR_FORMAT

         " != " PTR_FORMAT, reserved()->start(), _rs.base()));

     assert(reserved()->word_size() == _rs.size() / BytesPerWord,

       err_msg("Reserved size was not set properly " SIZE_FORMAT

         " != " SIZE_FORMAT, reserved()->word_size(),

         _rs.size() / BytesPerWord));

   }

   return result;

 }

 void VirtualSpaceNode::print_on(outputStream* st) const {

   size_t used = used_words_in_vs();

   size_t capacity = capacity_words_in_vs();

   VirtualSpace* vs = virtual_space();

   st->print_cr("   space @ " PTR_FORMAT " " SIZE_FORMAT "K, %3d%% used "

            "[" PTR_FORMAT ", " PTR_FORMAT ", "

            PTR_FORMAT ", " PTR_FORMAT ")",

            vs, capacity / K, used * 100 / capacity,

            bottom(), top(), end(),

            vs->high_boundary());

 }

 void VirtualSpaceNode::mangle() {

   size_t word_size = capacity_words_in_vs();

   Copy::fill_to_words((HeapWord*) low(), word_size, 0xf1f1f1f1);

 }

 // VirtualSpaceList methods

 // Space allocated from the VirtualSpace

 VirtualSpaceList::~VirtualSpaceList() {

   VirtualSpaceListIterator iter(virtual_space_list());

   while (iter.repeat()) {

     VirtualSpaceNode* vsl = iter.get_next();

     delete vsl;

   }

 }

 size_t VirtualSpaceList::used_words_sum() {

   size_t allocated_by_vs = 0;

   VirtualSpaceListIterator iter(virtual_space_list());

   while (iter.repeat()) {

     VirtualSpaceNode* vsl = iter.get_next();

     // Sum used region [bottom, top) in each virtualspace

     allocated_by_vs += vsl->used_words_in_vs();

   }

   assert(allocated_by_vs >= chunk_manager()->free_chunks_total(),

     err_msg("Total in free chunks " SIZE_FORMAT

             " greater than total from virtual_spaces " SIZE_FORMAT,

             allocated_by_vs, chunk_manager()->free_chunks_total()));

   size_t used =

     allocated_by_vs - chunk_manager()->free_chunks_total();

   return used;

 }

 // Space available in all MetadataVirtualspaces allocated

 // for metadata.  This is the upper limit on the capacity

 // of chunks allocated out of all the MetadataVirtualspaces.

 size_t VirtualSpaceList::capacity_words_sum() {

   size_t capacity = 0;

   VirtualSpaceListIterator iter(virtual_space_list());

   while (iter.repeat()) {

     VirtualSpaceNode* vsl = iter.get_next();

     capacity += vsl->capacity_words_in_vs();

   }

   return capacity;

 }

 VirtualSpaceList::VirtualSpaceList(size_t word_size ) :

                                    _is_class(false),

                                    _virtual_space_list(NULL),

                                    _current_virtual_space(NULL),

                                    _virtual_space_total(0),

                                    _virtual_space_count(0) {

   MutexLockerEx cl(SpaceManager::expand_lock(),

                    Mutex::_no_safepoint_check_flag);

   bool initialization_succeeded = grow_vs(word_size);

   assert(initialization_succeeded,

     " VirtualSpaceList initialization should not fail");

 }

 VirtualSpaceList::VirtualSpaceList(ReservedSpace rs) :

                                    _is_class(true),

                                    _virtual_space_list(NULL),

                                    _current_virtual_space(NULL),

                                    _virtual_space_total(0),

                                    _virtual_space_count(0) {

   MutexLockerEx cl(SpaceManager::expand_lock(),

                    Mutex::_no_safepoint_check_flag);

   VirtualSpaceNode* class_entry = new VirtualSpaceNode(rs);

   bool succeeded = class_entry->initialize();

   assert(succeeded, " VirtualSpaceList initialization should not fail");

   link_vs(class_entry, rs.size()/BytesPerWord);

 }

 // Allocate another meta virtual space and add it to the list.

 bool VirtualSpaceList::grow_vs(size_t vs_word_size) {

   assert_lock_strong(SpaceManager::expand_lock());

   if (vs_word_size == 0) {

     return false;

   }

   // Reserve the space

   size_t vs_byte_size = vs_word_size * BytesPerWord;

   assert(vs_byte_size % os::vm_page_size() == 0, "Not aligned");

   // Allocate the meta virtual space and initialize it.

   VirtualSpaceNode* new_entry = new VirtualSpaceNode(vs_byte_size);

   if (!new_entry->initialize()) {

     delete new_entry;

     return false;

   } else {

     link_vs(new_entry, vs_word_size);

     return true;

   }

 }

 void VirtualSpaceList::link_vs(VirtualSpaceNode* new_entry, size_t vs_word_size) {

   if (virtual_space_list() == NULL) {

       set_virtual_space_list(new_entry);

   } else {

     current_virtual_space()->set_next(new_entry);

   }

   set_current_virtual_space(new_entry);

   inc_virtual_space_total(vs_word_size);

   inc_virtual_space_count();

 #ifdef ASSERT

   new_entry->mangle();

 #endif

   if (TraceMetavirtualspaceAllocation && Verbose) {

     VirtualSpaceNode* vsl = current_virtual_space();

     vsl->print_on(tty);

   }

 }

 Metachunk* VirtualSpaceList::get_new_chunk(size_t word_size,

                                            size_t grow_chunks_by_words) {

   // Get a chunk from the chunk freelist

   Metachunk* next = chunk_manager()->chunk_freelist_allocate(grow_chunks_by_words);

   // Allocate a chunk out of the current virtual space.

   if (next == NULL) {

     next = current_virtual_space()->get_chunk_vs(grow_chunks_by_words);

   }

   if (next == NULL) {

     // Not enough room in current virtual space.  Try to commit

     // more space.

     size_t expand_vs_by_words = MAX2((size_t)SpaceManager::MediumChunkBunch,

                                        grow_chunks_by_words);

     size_t page_size_words = os::vm_page_size() / BytesPerWord;

     size_t aligned_expand_vs_by_words = align_size_up(expand_vs_by_words,

                                                         page_size_words);

     bool vs_expanded =

       current_virtual_space()->expand_by(aligned_expand_vs_by_words, false);

     if (!vs_expanded) {

       // Should the capacity of the metaspaces be expanded for

       // this allocation?  If it's the virtual space for classes and is

       // being used for CompressedHeaders, don't allocate a new virtualspace.

       if (can_grow() && MetaspaceGC::should_expand(this, word_size)) {

         // Get another virtual space.

           size_t grow_vs_words =

             MAX2((size_t)VirtualSpaceSize, aligned_expand_vs_by_words);

         if (grow_vs(grow_vs_words)) {

           // Got it.  It's on the list now.  Get a chunk from it.

           next = current_virtual_space()->get_chunk_vs_with_expand(grow_chunks_by_words);

         }

         if (TraceMetadataHumongousAllocation && SpaceManager::is_humongous(word_size)) {

           gclog_or_tty->print_cr("  aligned_expand_vs_by_words " PTR_FORMAT,

                                  aligned_expand_vs_by_words);

           gclog_or_tty->print_cr("  grow_vs_words " PTR_FORMAT,

                                  grow_vs_words);

         }

       } else {

         // Allocation will fail and induce a GC

         if (TraceMetadataChunkAllocation && Verbose) {

           gclog_or_tty->print_cr("VirtualSpaceList::get_new_chunk():"

             " Fail instead of expand the metaspace");

         }

       }

     } else {

       // The virtual space expanded, get a new chunk

       next = current_virtual_space()->get_chunk_vs(grow_chunks_by_words);

       assert(next != NULL, "Just expanded, should succeed");

     }

   }

   return next;

 }

 void VirtualSpaceList::print_on(outputStream* st) const {

   if (TraceMetadataChunkAllocation && Verbose) {

     VirtualSpaceListIterator iter(virtual_space_list());

     while (iter.repeat()) {

       VirtualSpaceNode* node = iter.get_next();

       node->print_on(st);

     }

   }

 }

 #ifndef PRODUCT

 bool VirtualSpaceList::contains(const void *ptr) {

   VirtualSpaceNode* list = virtual_space_list();

   VirtualSpaceListIterator iter(list);

   while (iter.repeat()) {

     VirtualSpaceNode* node = iter.get_next();

     if (node->reserved()->contains(ptr)) {

       return true;

     }

   }

   return false;

 }

 #endif // PRODUCT

 // MetaspaceGC methods

 // VM_CollectForMetadataAllocation is the vm operation used to GC.

 // Within the VM operation after the GC the attempt to allocate the metadata

 // should succeed.  If the GC did not free enough space for the metaspace

 // allocation, the HWM is increased so that another virtualspace will be

 // allocated for the metadata.  With perm gen the increase in the perm

 // gen had bounds, MinMetaspaceExpansion and MaxMetaspaceExpansion.  The

 // metaspace policy uses those as the small and large steps for the HWM.

 //

 // After the GC the compute_new_size() for MetaspaceGC is called to

 // resize the capacity of the metaspaces.  The current implementation

 // is based on the flags MinHeapFreeRatio and MaxHeapFreeRatio used

 // to resize the Java heap by some GC's.  New flags can be implemented

 // if really needed.  MinHeapFreeRatio is used to calculate how much

 // free space is desirable in the metaspace capacity to decide how much

 // to increase the HWM.  MaxHeapFreeRatio is used to decide how much

 // free space is desirable in the metaspace capacity before decreasing

 // the HWM.

 // Calculate the amount to increase the high water mark (HWM).

 // Increase by a minimum amount (MinMetaspaceExpansion) so that

 // another expansion is not requested too soon.  If that is not

 // enough to satisfy the allocation (i.e. big enough for a word_size

 // allocation), increase by MaxMetaspaceExpansion.  If that is still

 // not enough, expand by the size of the allocation (word_size) plus

 // some.

 size_t MetaspaceGC::delta_capacity_until_GC(size_t word_size) {

   size_t before_inc = MetaspaceGC::capacity_until_GC();

   size_t min_delta_words = MinMetaspaceExpansion / BytesPerWord;

   size_t max_delta_words = MaxMetaspaceExpansion / BytesPerWord;

   size_t page_size_words = os::vm_page_size() / BytesPerWord;

   size_t size_delta_words = align_size_up(word_size, page_size_words);

   size_t delta_words = MAX2(size_delta_words, min_delta_words);

   if (delta_words > min_delta_words) {

     // Don't want to hit the high water mark on the next

     // allocation so make the delta greater than just enough

     // for this allocation.

     delta_words = MAX2(delta_words, max_delta_words);

     if (delta_words > max_delta_words) {

       // This allocation is large but the next ones are probably not

       // so increase by the minimum.

       delta_words = delta_words + min_delta_words;

     }

   }

   return delta_words;

 }

 bool MetaspaceGC::should_expand(VirtualSpaceList* vsl, size_t word_size) {

   // Class virtual space should always be expanded.  Call GC for the other

   // metadata virtual space.

   if (vsl == Metaspace::class_space_list()) return true;

   // If the user wants a limit, impose one.

   size_t max_metaspace_size_words = MaxMetaspaceSize / BytesPerWord;

   size_t metaspace_size_words = MetaspaceSize / BytesPerWord;

   if (!FLAG_IS_DEFAULT(MaxMetaspaceSize) &&

       vsl->capacity_words_sum() >= max_metaspace_size_words) {

     return false;

   }

   // If this is part of an allocation after a GC, expand

   // unconditionally.

   if(MetaspaceGC::expand_after_GC()) {

     return true;

   }

   // If the capacity is below the minimum capacity, allow the

   // expansion.  Also set the high-water-mark (capacity_until_GC)

   // to that minimum capacity so that a GC will not be induced

   // until that minimum capacity is exceeded.

   if (vsl->capacity_words_sum() < metaspace_size_words ||

       capacity_until_GC() == 0) {

     set_capacity_until_GC(metaspace_size_words);

     return true;

   } else {

     if (vsl->capacity_words_sum() < capacity_until_GC()) {

       return true;

     } else {

       if (TraceMetadataChunkAllocation && Verbose) {

         gclog_or_tty->print_cr("  allocation request size " SIZE_FORMAT

                         "  capacity_until_GC " SIZE_FORMAT

                         "  capacity_words_sum " SIZE_FORMAT

                         "  used_words_sum " SIZE_FORMAT

                         "  free chunks " SIZE_FORMAT

                         "  free chunks count %d",

                         word_size,

                         capacity_until_GC(),

                         vsl->capacity_words_sum(),

                         vsl->used_words_sum(),

                         vsl->chunk_manager()->free_chunks_total(),

                         vsl->chunk_manager()->free_chunks_count());

       }

       return false;

     }

   }

 }

 // Variables are in bytes

 void MetaspaceGC::compute_new_size() {

   assert(_shrink_factor <= 100, "invalid shrink factor");

   uint current_shrink_factor = _shrink_factor;

   _shrink_factor = 0;

   VirtualSpaceList *vsl = Metaspace::space_list();

   size_t capacity_after_gc = vsl->capacity_bytes_sum();

   // Check to see if these two can be calculated without walking the CLDG

   size_t used_after_gc = vsl->used_bytes_sum();

   size_t capacity_until_GC = vsl->capacity_bytes_sum();

   size_t free_after_gc = capacity_until_GC - used_after_gc;

   const double minimum_free_percentage = MinHeapFreeRatio / 100.0;

   const double maximum_used_percentage = 1.0 - minimum_free_percentage;

   const double min_tmp = used_after_gc / maximum_used_percentage;

   size_t minimum_desired_capacity =

     (size_t)MIN2(min_tmp, double(max_uintx));

   // Don't shrink less than the initial generation size

   minimum_desired_capacity = MAX2(minimum_desired_capacity,

                                   MetaspaceSize);

   if (PrintGCDetails && Verbose) {

     const double free_percentage = ((double)free_after_gc) / capacity_until_GC;

     gclog_or_tty->print_cr("\nMetaspaceGC::compute_new_size: ");

     gclog_or_tty->print_cr("  "

                   "  minimum_free_percentage: %6.2f"

                   "  maximum_used_percentage: %6.2f",

                   minimum_free_percentage,

                   maximum_used_percentage);

     double d_free_after_gc = free_after_gc / (double) K;

     gclog_or_tty->print_cr("  "

                   "   free_after_gc       : %6.1fK"

                   "   used_after_gc       : %6.1fK"

                   "   capacity_after_gc   : %6.1fK"

                   "   metaspace HWM     : %6.1fK",

                   free_after_gc / (double) K,

                   used_after_gc / (double) K,

                   capacity_after_gc / (double) K,

                   capacity_until_GC / (double) K);

     gclog_or_tty->print_cr("  "

                   "   free_percentage: %6.2f",

                   free_percentage);

   }

   if (capacity_until_GC < minimum_desired_capacity) {

     // If we have less capacity below the metaspace HWM, then

     // increment the HWM.

     size_t expand_bytes = minimum_desired_capacity - capacity_until_GC;

     // Don't expand unless it's significant

     if (expand_bytes >= MinMetaspaceExpansion) {

       size_t expand_words = expand_bytes / BytesPerWord;

       MetaspaceGC::inc_capacity_until_GC(expand_words);

     }

     if (PrintGCDetails && Verbose) {

       size_t new_capacity_until_GC = MetaspaceGC::capacity_until_GC_in_bytes();

       gclog_or_tty->print_cr("    expanding:"

                     "  minimum_desired_capacity: %6.1fK"

                     "  expand_words: %6.1fK"

                     "  MinMetaspaceExpansion: %6.1fK"

                     "  new metaspace HWM:  %6.1fK",

                     minimum_desired_capacity / (double) K,

                     expand_bytes / (double) K,

                     MinMetaspaceExpansion / (double) K,

                     new_capacity_until_GC / (double) K);

     }

     return;

   }

   // No expansion, now see if we want to shrink

   size_t shrink_words = 0;

   // We would never want to shrink more than this

   size_t max_shrink_words = capacity_until_GC - minimum_desired_capacity;

   assert(max_shrink_words >= 0, err_msg("max_shrink_words " SIZE_FORMAT,

     max_shrink_words));

   // Should shrinking be considered?

   if (MaxHeapFreeRatio < 100) {

     const double maximum_free_percentage = MaxHeapFreeRatio / 100.0;

     const double minimum_used_percentage = 1.0 - maximum_free_percentage;

     const double max_tmp = used_after_gc / minimum_used_percentage;

     size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));

     maximum_desired_capacity = MAX2(maximum_desired_capacity,

                                     MetaspaceSize);

     if (PrintGC && Verbose) {

       gclog_or_tty->print_cr("  "

                              "  maximum_free_percentage: %6.2f"

                              "  minimum_used_percentage: %6.2f",

                              maximum_free_percentage,

                              minimum_used_percentage);

       gclog_or_tty->print_cr("  "

                              "  capacity_until_GC: %6.1fK"

                              "  minimum_desired_capacity: %6.1fK"

                              "  maximum_desired_capacity: %6.1fK",

                              capacity_until_GC / (double) K,

                              minimum_desired_capacity / (double) K,

                              maximum_desired_capacity / (double) K);

     }

     assert(minimum_desired_capacity <= maximum_desired_capacity,

            "sanity check");

     if (capacity_until_GC > maximum_desired_capacity) {

       // Capacity too large, compute shrinking size

       shrink_words = capacity_until_GC - maximum_desired_capacity;

       // We don't want shrink all the way back to initSize if people call

       // System.gc(), because some programs do that between "phases" and then

       // we'd just have to grow the heap up again for the next phase.  So we

       // damp the shrinking: 0% on the first call, 10% on the second call, 40%

       // on the third call, and 100% by the fourth call.  But if we recompute

       // size without shrinking, it goes back to 0%.

       shrink_words = shrink_words / 100 * current_shrink_factor;

       assert(shrink_words <= max_shrink_words,

         err_msg("invalid shrink size " SIZE_FORMAT " not <= " SIZE_FORMAT,

           shrink_words, max_shrink_words));

       if (current_shrink_factor == 0) {

         _shrink_factor = 10;

       } else {

         _shrink_factor = MIN2(current_shrink_factor * 4, (uint) 100);

       }

       if (PrintGCDetails && Verbose) {

         gclog_or_tty->print_cr("  "

                       "  shrinking:"

                       "  initSize: %.1fK"

                       "  maximum_desired_capacity: %.1fK",

                       MetaspaceSize / (double) K,

                       maximum_desired_capacity / (double) K);

         gclog_or_tty->print_cr("  "

                       "  shrink_words: %.1fK"

                       "  current_shrink_factor: %d"

                       "  new shrink factor: %d"

                       "  MinMetaspaceExpansion: %.1fK",

                       shrink_words / (double) K,

                       current_shrink_factor,

                       _shrink_factor,

                       MinMetaspaceExpansion / (double) K);

       }

     }

   }

   // Don't shrink unless it's significant

   if (shrink_words >= MinMetaspaceExpansion) {

     VirtualSpaceNode* csp = vsl->current_virtual_space();

     size_t available_to_shrink = csp->capacity_words_in_vs() -

       csp->used_words_in_vs();

     shrink_words = MIN2(shrink_words, available_to_shrink);

     csp->shrink_by(shrink_words);

     MetaspaceGC::dec_capacity_until_GC(shrink_words);

     if (PrintGCDetails && Verbose) {

       size_t new_capacity_until_GC = MetaspaceGC::capacity_until_GC_in_bytes();

       gclog_or_tty->print_cr("  metaspace HWM: %.1fK", new_capacity_until_GC / (double) K);

     }

   }

   assert(vsl->used_bytes_sum() == used_after_gc &&

          used_after_gc <= vsl->capacity_bytes_sum(),

          "sanity check");

 }

 // Metadebug methods

 void Metadebug::deallocate_chunk_a_lot(SpaceManager* sm,

                                        size_t chunk_word_size){

 #ifdef ASSERT

   VirtualSpaceList* vsl = sm->vs_list();

   if (MetaDataDeallocateALot &&

       Metadebug::deallocate_chunk_a_lot_count() % MetaDataDeallocateALotInterval == 0 ) {

     Metadebug::reset_deallocate_chunk_a_lot_count();

     for (uint i = 0; i < metadata_deallocate_a_lock_chunk; i++) {

       Metachunk* dummy_chunk = vsl->current_virtual_space()->take_from_committed(chunk_word_size);

       if (dummy_chunk == NULL) {

         break;

       }

       vsl->chunk_manager()->chunk_freelist_deallocate(dummy_chunk);

       if (TraceMetadataChunkAllocation && Verbose) {

         gclog_or_tty->print("Metadebug::deallocate_chunk_a_lot: %d) ",

                                sm->sum_count_in_chunks_in_use());

         dummy_chunk->print_on(gclog_or_tty);

         gclog_or_tty->print_cr("  Free chunks total %d  count %d",

                                vsl->chunk_manager()->free_chunks_total(),

                                vsl->chunk_manager()->free_chunks_count());

       }

     }

   } else {

     Metadebug::inc_deallocate_chunk_a_lot_count();

   }

 #endif

 }

 void Metadebug::deallocate_block_a_lot(SpaceManager* sm,

                                        size_t raw_word_size){

 #ifdef ASSERT

   if (MetaDataDeallocateALot &&

         Metadebug::deallocate_block_a_lot_count() % MetaDataDeallocateALotInterval == 0 ) {

     Metadebug::set_deallocate_block_a_lot_count(0);

     for (uint i = 0; i < metadata_deallocate_a_lot_block; i++) {

       Metablock* dummy_block = sm->allocate_work(raw_word_size);

       if (dummy_block == 0) {

         break;

       }

 #ifdef ASSERT

       assert(dummy_block->word_size() == raw_word_size, "Block size is not set correctly");

 #endif

       sm->deallocate(dummy_block->data());

     }

   } else {

     Metadebug::inc_deallocate_block_a_lot_count();

   }

 #endif

 }

 void Metadebug::init_allocation_fail_alot_count() {

   if (MetadataAllocationFailALot) {

     _allocation_fail_alot_count =

       1+(long)((double)MetadataAllocationFailALotInterval*os::random()/(max_jint+1.0));

   }

 }

 #ifdef ASSERT

 bool Metadebug::test_metadata_failure() {

   if (MetadataAllocationFailALot &&

       Threads::is_vm_complete()) {

     if (_allocation_fail_alot_count > 0) {

       _allocation_fail_alot_count--;

     } else {

       if (TraceMetadataChunkAllocation && Verbose) {

         gclog_or_tty->print_cr("Metadata allocation failing for "

                                "MetadataAllocationFailALot");

       }

       init_allocation_fail_alot_count();

       return true;

     }

   }

   return false;

 }

 #endif

 // ChunkList methods

 size_t ChunkList::sum_list_size() {

   size_t result = 0;

   Metachunk* cur = head();

   while (cur != NULL) {

     result += cur->word_size();

     cur = cur->next();

   }

   return result;

 }

 size_t ChunkList::sum_list_count() {

   size_t result = 0;

   Metachunk* cur = head();

   while (cur != NULL) {

     result++;

     cur = cur->next();

   }

   return result;

 }

 size_t ChunkList::sum_list_capacity() {

   size_t result = 0;

   Metachunk* cur = head();

   while (cur != NULL) {

     result += cur->capacity_word_size();

     cur = cur->next();

   }

   return result;

 }

 void ChunkList::add_at_head(Metachunk* head, Metachunk* tail) {

   assert_lock_strong(SpaceManager::expand_lock());

   assert(tail->next() == NULL, "Not the tail");

   if (TraceMetadataChunkAllocation && Verbose) {

     tty->print("ChunkList::add_at_head: ");

     Metachunk* cur = head;

     while (cur != NULL) {

     tty->print(PTR_FORMAT " (" SIZE_FORMAT ") ", cur, cur->word_size());

       cur = cur->next();

     }

     tty->print_cr("");

   }

   if (tail != NULL) {

     tail->set_next(_head);

   }

   set_head(head);

 }

 void ChunkList::add_at_head(Metachunk* list) {

   if (list == NULL) {

     // Nothing to add

     return;

   }

   assert_lock_strong(SpaceManager::expand_lock());

   Metachunk* head = list;

   Metachunk* tail = list;

   Metachunk* cur = head->next();

   // Search for the tail since it is not passed.

   while (cur != NULL) {

     tail = cur;

     cur = cur->next();

   }

   add_at_head(head, tail);

 }

 // ChunkManager methods

 // Verification of _free_chunks_total and _free_chunks_count does not

 // work with the CMS collector because its use of additional locks

 // complicate the mutex deadlock detection but it can still be useful

 // for detecting errors in the chunk accounting with other collectors.

 size_t ChunkManager::free_chunks_total() {

 #ifdef ASSERT

   if (!UseConcMarkSweepGC && !SpaceManager::expand_lock()->is_locked()) {

     MutexLockerEx cl(SpaceManager::expand_lock(),

                      Mutex::_no_safepoint_check_flag);

     locked_verify_free_chunks_total();

   }

 #endif

   return _free_chunks_total;

 }

 size_t ChunkManager::free_chunks_total_in_bytes() {

   return free_chunks_total() * BytesPerWord;

 }

 size_t ChunkManager::free_chunks_count() {

 #ifdef ASSERT

   if (!UseConcMarkSweepGC && !SpaceManager::expand_lock()->is_locked()) {

     MutexLockerEx cl(SpaceManager::expand_lock(),

                      Mutex::_no_safepoint_check_flag);

     // This lock is only needed in debug because the verification

     // of the _free_chunks_totals walks the list of free chunks

     locked_verify_free_chunks_count();

   }

 #endif

     return _free_chunks_count;

 }

 void ChunkManager::locked_verify_free_chunks_total() {

   assert_lock_strong(SpaceManager::expand_lock());

   assert(sum_free_chunks() == _free_chunks_total,

     err_msg("_free_chunks_total " SIZE_FORMAT " is not the"

            " same as sum " SIZE_FORMAT, _free_chunks_total,

            sum_free_chunks()));

 }

 void ChunkManager::verify_free_chunks_total() {

   MutexLockerEx cl(SpaceManager::expand_lock(),

                      Mutex::_no_safepoint_check_flag);

   locked_verify_free_chunks_total();

 }

 void ChunkManager::locked_verify_free_chunks_count() {

   assert_lock_strong(SpaceManager::expand_lock());

   assert(sum_free_chunks_count() == _free_chunks_count,

     err_msg("_free_chunks_count " SIZE_FORMAT " is not the"

            " same as sum " SIZE_FORMAT, _free_chunks_count,

            sum_free_chunks_count()));

 }

 void ChunkManager::verify_free_chunks_count() {

 #ifdef ASSERT

   MutexLockerEx cl(SpaceManager::expand_lock(),

                      Mutex::_no_safepoint_check_flag);

   locked_verify_free_chunks_count();

 #endif

 }

 void ChunkManager::verify() {

 #ifdef ASSERT

   if (!UseConcMarkSweepGC) {

     MutexLockerEx cl(SpaceManager::expand_lock(),

                        Mutex::_no_safepoint_check_flag);

     locked_verify_free_chunks_total();

     locked_verify_free_chunks_count();

   }

 #endif

 }

 void ChunkManager::locked_verify() {

   locked_verify_free_chunks_total();

   locked_verify_free_chunks_count();

 }

 void ChunkManager::locked_print_free_chunks(outputStream* st) {

   assert_lock_strong(SpaceManager::expand_lock());

   st->print_cr("Free chunk total 0x%x  count 0x%x",

                 _free_chunks_total, _free_chunks_count);

 }

 void ChunkManager::locked_print_sum_free_chunks(outputStream* st) {

   assert_lock_strong(SpaceManager::expand_lock());

   st->print_cr("Sum free chunk total 0x%x  count 0x%x",

                 sum_free_chunks(), sum_free_chunks_count());

 }

 ChunkList* ChunkManager::free_chunks(ChunkIndex index) {

   return &_free_chunks[index];

 }

 // These methods that sum the free chunk lists are used in printing

 // methods that are used in product builds.

 size_t ChunkManager::sum_free_chunks() {

   assert_lock_strong(SpaceManager::expand_lock());

   size_t result = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     ChunkList* list = free_chunks(i);

     if (list == NULL) {

       continue;

     }

     result = result + list->sum_list_capacity();

   }

   return result;

 }

 size_t ChunkManager::sum_free_chunks_count() {

   assert_lock_strong(SpaceManager::expand_lock());

   size_t count = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     ChunkList* list = free_chunks(i);

     if (list == NULL) {

       continue;

     }

     count = count + list->sum_list_count();

   }

   return count;

 }

 ChunkList* ChunkManager::find_free_chunks_list(size_t word_size) {

   switch (word_size) {

   case SpaceManager::SmallChunk :

       return &_free_chunks[0];

   case SpaceManager::MediumChunk :

       return &_free_chunks[1];

   default:

     assert(word_size > SpaceManager::MediumChunk, "List inconsistency");

     return &_free_chunks[2];

   }

 }

 void ChunkManager::free_chunks_put(Metachunk* chunk) {

   assert_lock_strong(SpaceManager::expand_lock());

   ChunkList* free_list = find_free_chunks_list(chunk->word_size());

   chunk->set_next(free_list->head());

   free_list->set_head(chunk);

   // chunk is being returned to the chunk free list

   inc_free_chunks_total(chunk->capacity_word_size());

   locked_verify();

 }

 void ChunkManager::chunk_freelist_deallocate(Metachunk* chunk) {

   // The deallocation of a chunk originates in the freelist

   // manangement code for a Metaspace and does not hold the

   // lock.

   assert(chunk != NULL, "Deallocating NULL");

   // MutexLockerEx fcl(SpaceManager::expand_lock(), Mutex::_no_safepoint_check_flag);

   locked_verify();

   if (TraceMetadataChunkAllocation) {

     tty->print_cr("ChunkManager::chunk_freelist_deallocate: chunk "

                   PTR_FORMAT "  size " SIZE_FORMAT,

                   chunk, chunk->word_size());

   }

   free_chunks_put(chunk);

 }

 Metachunk* ChunkManager::free_chunks_get(size_t word_size) {

   assert_lock_strong(SpaceManager::expand_lock());

   locked_verify();

   ChunkList* free_list = find_free_chunks_list(word_size);

   assert(free_list != NULL, "Sanity check");

   Metachunk* chunk = free_list->head();

   debug_only(Metachunk* debug_head = chunk;)

   if (chunk == NULL) {

     return NULL;

   }

   Metachunk* prev_chunk = chunk;

   if (chunk->word_size() == word_size) {

     // Chunk is being removed from the chunks free list.

     dec_free_chunks_total(chunk->capacity_word_size());

     // Remove the chunk as the head of the list.

     free_list->set_head(chunk->next());

     chunk->set_next(NULL);

     if (TraceMetadataChunkAllocation && Verbose) {

       tty->print_cr("ChunkManager::free_chunks_get: free_list "

                     PTR_FORMAT " head " PTR_FORMAT " size " SIZE_FORMAT,

                     free_list, chunk, chunk->word_size());

     }

   } else {

     assert(SpaceManager::is_humongous(word_size),

       "Should only need to check humongous");

     // This code to find the best fit is just for purposes of

     // investigating the loss due to fragmentation on a humongous

     // chunk.  It will be replace by a binaryTreeDictionary for

     // the humongous chunks.

     uint count = 0;

     Metachunk* best_fit = NULL;

     Metachunk* best_fit_prev = NULL;

     while (chunk != NULL) {

       count++;

       if (chunk->word_size() < word_size) {

         prev_chunk = chunk;

         chunk = chunk->next();

       } else if (chunk->word_size() == word_size) {

         break;

       } else {

         if (best_fit == NULL ||

             best_fit->word_size() > chunk->word_size()) {

           best_fit_prev = prev_chunk;

           best_fit = chunk;

         }

         prev_chunk = chunk;

         chunk = chunk->next();

       }

     }

       if (chunk == NULL) {

         prev_chunk = best_fit_prev;

         chunk = best_fit;

       }

       if (chunk != NULL) {

         if (TraceMetadataHumongousAllocation) {

           size_t waste = chunk->word_size() - word_size;

           tty->print_cr("Free list allocate humongous chunk size " SIZE_FORMAT

                         " for requested size " SIZE_FORMAT

                         " waste " SIZE_FORMAT

                         " found at " SIZE_FORMAT " of " SIZE_FORMAT,

                         chunk->word_size(), word_size, waste,

                         count, free_list->sum_list_count());

         }

         // Chunk is being removed from the chunks free list.

         dec_free_chunks_total(chunk->capacity_word_size());

         // Remove the chunk if it is at the head of the list.

         if (chunk == free_list->head()) {

           free_list->set_head(chunk->next());

           if (TraceMetadataHumongousAllocation) {

             tty->print_cr("ChunkManager::free_chunks_get: humongous free_list "

                           PTR_FORMAT " chunk " PTR_FORMAT " size " SIZE_FORMAT

                           " new head " PTR_FORMAT,

                           free_list, chunk, chunk->word_size(),

                           free_list->head());

           }

         } else {

           // Remove a chunk in the interior of the list

           prev_chunk->set_next(chunk->next());

           if (TraceMetadataHumongousAllocation) {

             tty->print_cr("ChunkManager::free_chunks_get: humongous free_list "

                           PTR_FORMAT " chunk " PTR_FORMAT " size " SIZE_FORMAT

                           PTR_FORMAT "  prev " PTR_FORMAT " next " PTR_FORMAT,

                           free_list, chunk, chunk->word_size(),

                           prev_chunk, chunk->next());

           }

         }

         chunk->set_next(NULL);

       } else {

         if (TraceMetadataHumongousAllocation) {

           tty->print_cr("ChunkManager::free_chunks_get: New humongous chunk of size "

                         SIZE_FORMAT,

                         word_size);

         }

       }

   }

   locked_verify();

   return chunk;

 }

 Metachunk* ChunkManager::chunk_freelist_allocate(size_t word_size) {

   assert_lock_strong(SpaceManager::expand_lock());

   locked_verify();

   // Take from the beginning of the list

   Metachunk* chunk = free_chunks_get(word_size);

   if (chunk == NULL) {

     return NULL;

   }

   assert(word_size <= chunk->word_size() ||

            SpaceManager::is_humongous(chunk->word_size()),

            "Non-humongous variable sized chunk");

   if (TraceMetadataChunkAllocation) {

     tty->print("ChunkManager::chunk_freelist_allocate: chunk "

                PTR_FORMAT "  size " SIZE_FORMAT " ",

                chunk, chunk->word_size());

     locked_print_free_chunks(tty);

   }

   return chunk;

 }

 // SpaceManager methods

 size_t SpaceManager::sum_free_in_chunks_in_use() const {

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   size_t free = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     Metachunk* chunk = chunks_in_use(i);

     while (chunk != NULL) {

       free += chunk->free_word_size();

       chunk = chunk->next();

     }

   }

   return free;

 }

 size_t SpaceManager::sum_waste_in_chunks_in_use() const {

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   size_t result = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

    // Count the free space in all the chunk but not the

    // current chunk from which allocations are still being done.

    result += sum_waste_in_chunks_in_use(i);

   }

   return result;

 }

 size_t SpaceManager::sum_waste_in_chunks_in_use(ChunkIndex index) const {

   size_t result = 0;

   size_t count = 0;

   Metachunk* chunk = chunks_in_use(index);

   // Count the free space in all the chunk but not the

   // current chunk from which allocations are still being done.

   if (chunk != NULL) {

     while (chunk != NULL) {

       if (chunk != current_chunk()) {

         result += chunk->free_word_size();

       }

       chunk = chunk->next();

       count++;

     }

   }

   return result;

 }

 size_t SpaceManager::sum_capacity_in_chunks_in_use() const {

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   size_t sum = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     Metachunk* chunk = chunks_in_use(i);

     while (chunk != NULL) {

       // Just changed this sum += chunk->capacity_word_size();

       // sum += chunk->word_size() - Metachunk::overhead();

       sum += chunk->capacity_word_size();

       chunk = chunk->next();

     }

   }

   return sum;

 }

 size_t SpaceManager::sum_count_in_chunks_in_use() {

   size_t count = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     count = count + sum_count_in_chunks_in_use(i);

   }

   return count;

 }

 size_t SpaceManager::sum_count_in_chunks_in_use(ChunkIndex i) {

   size_t count = 0;

   Metachunk* chunk = chunks_in_use(i);

   while (chunk != NULL) {

     count++;

     chunk = chunk->next();

   }

   return count;

 }

 size_t SpaceManager::sum_used_in_chunks_in_use() const {

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   size_t used = 0;

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     Metachunk* chunk = chunks_in_use(i);

     while (chunk != NULL) {

       used += chunk->used_word_size();

       chunk = chunk->next();

     }

   }

   return used;

 }

 void SpaceManager::locked_print_chunks_in_use_on(outputStream* st) const {

   Metachunk* small_chunk = chunks_in_use(SmallIndex);

   st->print_cr("SpaceManager: small chunk " PTR_FORMAT

                " free " SIZE_FORMAT,

                small_chunk,

                small_chunk->free_word_size());

   Metachunk* medium_chunk = chunks_in_use(MediumIndex);

   st->print("medium chunk " PTR_FORMAT, medium_chunk);

   Metachunk* tail = current_chunk();

   st->print_cr(" current chunk " PTR_FORMAT, tail);

   Metachunk* head = chunks_in_use(HumongousIndex);

   st->print_cr("humongous chunk " PTR_FORMAT, head);

   vs_list()->chunk_manager()->locked_print_free_chunks(st);

   vs_list()->chunk_manager()->locked_print_sum_free_chunks(st);

 }

 size_t SpaceManager::calc_chunk_size(size_t word_size) {

   // Decide between a small chunk and a medium chunk.  Up to

   // _small_chunk_limit small chunks can be allocated but

   // once a medium chunk has been allocated, no more small

   // chunks will be allocated.

   size_t chunk_word_size;

   if (chunks_in_use(MediumIndex) == NULL &&

       (!has_small_chunk_limit() ||

        sum_count_in_chunks_in_use(SmallIndex) < _small_chunk_limit)) {

     chunk_word_size = (size_t) SpaceManager::SmallChunk;

     if (word_size + Metachunk::overhead() > SpaceManager::SmallChunk) {

       chunk_word_size = MediumChunk;

     }

   } else {

     chunk_word_size = MediumChunk;

   }

   // Might still need a humongous chunk

   chunk_word_size =

     MAX2((size_t) chunk_word_size, word_size + Metachunk::overhead());

   if (TraceMetadataHumongousAllocation &&

       SpaceManager::is_humongous(word_size)) {

     gclog_or_tty->print_cr("Metadata humongous allocation:");

     gclog_or_tty->print_cr("  word_size " PTR_FORMAT, word_size);

     gclog_or_tty->print_cr("  chunk_word_size " PTR_FORMAT,

                            chunk_word_size);

     gclog_or_tty->print_cr("    block overhead " PTR_FORMAT

                            " chunk overhead " PTR_FORMAT,

                            Metablock::overhead(),

                            Metachunk::overhead());

   }

   return chunk_word_size;

 }

 Metablock* SpaceManager::grow_and_allocate(size_t word_size) {

   assert(vs_list()->current_virtual_space() != NULL,

          "Should have been set");

   assert(current_chunk() == NULL ||

          current_chunk()->allocate(word_size) == NULL,

          "Don't need to expand");

   MutexLockerEx cl(SpaceManager::expand_lock(), Mutex::_no_safepoint_check_flag);

   if (TraceMetadataChunkAllocation && Verbose) {

     gclog_or_tty->print_cr("SpaceManager::grow_and_allocate for " SIZE_FORMAT

                            " words " SIZE_FORMAT " space left",

                             word_size, current_chunk() != NULL ?

                               current_chunk()->free_word_size() : 0);

   }

   // Get another chunk out of the virtual space

   size_t grow_chunks_by_words = calc_chunk_size(word_size);

   Metachunk* next = vs_list()->get_new_chunk(word_size, grow_chunks_by_words);

   // If a chunk was available, add it to the in-use chunk list

   // and do an allocation from it.

   if (next != NULL) {

     Metadebug::deallocate_chunk_a_lot(this, grow_chunks_by_words);

     // Add to this manager's list of chunks in use.

     add_chunk(next, false);

     return next->allocate(word_size);

   }

   return NULL;

 }

 void SpaceManager::print_on(outputStream* st) const {

   for (ChunkIndex i = SmallIndex;

        i < NumberOfFreeLists ;

        i = next_chunk_index(i) ) {

     st->print_cr("  chunks_in_use " PTR_FORMAT " chunk size " PTR_FORMAT,

                  chunks_in_use(i),

                  chunks_in_use(i) == NULL ? 0 : chunks_in_use(i)->word_size());

   }

   st->print_cr("    waste:  Small " SIZE_FORMAT " Medium " SIZE_FORMAT

                " Humongous " SIZE_FORMAT,

                sum_waste_in_chunks_in_use(SmallIndex),

                sum_waste_in_chunks_in_use(MediumIndex),

                sum_waste_in_chunks_in_use(HumongousIndex));

   // Nothing in them yet

   // block_freelists()->print_on(st);

 }

 SpaceManager::SpaceManager(Mutex* lock, VirtualSpaceList* vs_list) :

   _vs_list(vs_list),

   _allocation_total(0),

   _lock(lock) {

   Metadebug::init_allocation_fail_alot_count();

   for (ChunkIndex i = SmallIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

     _chunks_in_use[i] = NULL;

   }

   _current_chunk = NULL;

   if (TraceMetadataChunkAllocation && Verbose) {

     gclog_or_tty->print_cr("SpaceManager(): " PTR_FORMAT, this);

   }

 }

 SpaceManager::~SpaceManager() {

   MutexLockerEx fcl(SpaceManager::expand_lock(),

                     Mutex::_no_safepoint_check_flag);

   ChunkManager* chunk_manager = vs_list()->chunk_manager();

   chunk_manager->locked_verify();

   if (TraceMetadataChunkAllocation && Verbose) {

     gclog_or_tty->print_cr("~SpaceManager(): " PTR_FORMAT, this);

     locked_print_chunks_in_use_on(gclog_or_tty);

   }

   // Have to update before the chunks_in_use lists are emptied

   // below.

   chunk_manager->inc_free_chunks_total(sum_capacity_in_chunks_in_use(),

                                        sum_count_in_chunks_in_use());

 #ifdef ASSERT

   // Mangle freed memory.

   mangle_freed_chunks();

 #endif // ASSERT

   // Add all the chunks in use by this space manager

   // to the global list of free chunks.

   // Small chunks.  There is one _current_chunk for each

   // Metaspace.  It could point to a small or medium chunk.

   // Rather than determine which it is, follow the list of

   // small chunks to add them to the free list

   Metachunk* small_chunk = chunks_in_use(SmallIndex);

   chunk_manager->free_small_chunks()->add_at_head(small_chunk);

   set_chunks_in_use(SmallIndex, NULL);

   // After the small chunk are the medium chunks

   Metachunk* medium_chunk = chunks_in_use(MediumIndex);

   assert(medium_chunk == NULL ||

          medium_chunk->word_size() == MediumChunk,

          "Chunk is on the wrong list");

   if (medium_chunk != NULL) {

     Metachunk* head = medium_chunk;

     // If there is a medium chunk then the _current_chunk can only

     // point to the last medium chunk.

     Metachunk* tail = current_chunk();

     chunk_manager->free_medium_chunks()->add_at_head(head, tail);

     set_chunks_in_use(MediumIndex, NULL);

   }

   // Humongous chunks

   // Humongous chunks are never the current chunk.

   Metachunk* humongous_chunks = chunks_in_use(HumongousIndex);

   if (humongous_chunks != NULL) {

     chunk_manager->free_humongous_chunks()->add_at_head(humongous_chunks);

     set_chunks_in_use(HumongousIndex, NULL);

   }

   chunk_manager->locked_verify();

 }

 void SpaceManager::deallocate(MetaWord* p) {

   assert_lock_strong(_lock);

   ShouldNotReachHere();  // Where is this needed.

 #ifdef DEALLOCATE_BLOCKS

   Metablock* block = Metablock::metablock_from_data(p);

   // This is expense but kept it until integration JJJ

   assert(contains((address)block), "Block does not belong to this metaspace");

   block_freelists()->return_block(block, word_size);

 #endif

 }

 // Adds a chunk to the list of chunks in use.

 void SpaceManager::add_chunk(Metachunk* new_chunk, bool make_current) {

   assert(new_chunk != NULL, "Should not be NULL");

   assert(new_chunk->next() == NULL, "Should not be on a list");

   new_chunk->reset_empty();

   // Find the correct list and and set the current

   // chunk for that list.

   switch (new_chunk->word_size()) {

   case SpaceManager::SmallChunk :

     if (chunks_in_use(SmallIndex) == NULL) {

       // First chunk to add to the list

       set_chunks_in_use(SmallIndex, new_chunk);

     } else {

       assert(current_chunk()->word_size() == SpaceManager::SmallChunk,

         err_msg( "Incorrect mix of sizes in chunk list "

         SIZE_FORMAT " new chunk " SIZE_FORMAT,

         current_chunk()->word_size(), new_chunk->word_size()));

       current_chunk()->set_next(new_chunk);

     }

     // Make current chunk

     set_current_chunk(new_chunk);

     break;

   case SpaceManager::MediumChunk :

     if (chunks_in_use(MediumIndex) == NULL) {

       // About to add the first medium chunk so teminate the

       // small chunk list.  In general once medium chunks are

       // being added, we're past the need for small chunks.

       if (current_chunk() != NULL) {

         // Only a small chunk or the initial chunk could be

         // the current chunk if this is the first medium chunk.

         assert(current_chunk()->word_size() == SpaceManager::SmallChunk ||

           chunks_in_use(SmallIndex) == NULL,

           err_msg("Should be a small chunk or initial chunk, current chunk "

           SIZE_FORMAT " new chunk " SIZE_FORMAT,

           current_chunk()->word_size(), new_chunk->word_size()));

         current_chunk()->set_next(NULL);

       }

       // First chunk to add to the list

       set_chunks_in_use(MediumIndex, new_chunk);

     } else {

       // As a minimum the first medium chunk added would

       // have become the _current_chunk

       // so the _current_chunk has to be non-NULL here

       // (although not necessarily still the first medium chunk).

       assert(current_chunk()->word_size() == SpaceManager::MediumChunk,

              "A medium chunk should the current chunk");

       current_chunk()->set_next(new_chunk);

     }

     // Make current chunk

     set_current_chunk(new_chunk);

     break;

   default: {

     // For null class loader data and DumpSharedSpaces, the first chunk isn't

     // small, so small will be null.  Link this first chunk as the current

     // chunk.

     if (make_current) {

       // Set as the current chunk but otherwise treat as a humongous chunk.

       set_current_chunk(new_chunk);

     }

     // Link at head.  The _current_chunk only points to a humongous chunk for

     // the null class loader metaspace (class and data virtual space managers)

     // any humongous chunks so will not point to the tail

     // of the humongous chunks list.

     new_chunk->set_next(chunks_in_use(HumongousIndex));

     set_chunks_in_use(HumongousIndex, new_chunk);

     assert(new_chunk->word_size() > MediumChunk, "List inconsistency");

   }

   }

   assert(new_chunk->is_empty(), "Not ready for reuse");

   if (TraceMetadataChunkAllocation && Verbose) {

     gclog_or_tty->print("SpaceManager::add_chunk: %d) ",

                         sum_count_in_chunks_in_use());

     new_chunk->print_on(gclog_or_tty);

     vs_list()->chunk_manager()->locked_print_free_chunks(tty);

   }

 }

 MetaWord* SpaceManager::allocate(size_t word_size) {

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   size_t block_overhead = Metablock::overhead();

   // If only the dictionary is going to be used (i.e., no

   // indexed free list), then there is a minimum size requirement.

   // MinChunkSize is a placeholder for the real minimum size JJJ

   size_t byte_size_with_overhead = (word_size + block_overhead) * BytesPerWord;

 #ifdef DEALLOCATE_BLOCKS

   size_t raw_bytes_size = MAX2(ARENA_ALIGN(byte_size_with_overhead),

                                MinChunkSize * BytesPerWord);

 #else

   size_t raw_bytes_size = ARENA_ALIGN(byte_size_with_overhead);

 #endif

   size_t raw_word_size = raw_bytes_size / BytesPerWord;

   assert(raw_word_size * BytesPerWord == raw_bytes_size, "Size problem");

   BlockFreelist* fl =  block_freelists();

   Metablock* block = NULL;

   // Allocation from the dictionary is expensive in the sense that

   // the dictionary has to be searched for a size.  Don't allocate

   // from the dictionary until it starts to get fat.  Is this

   // a reasonable policy?  Maybe an skinny dictionary is fast enough

   // for allocations.  Do some profiling.  JJJ

   if (fl->totalSize() > allocation_from_dictionary_limit) {

     block = fl->get_block(raw_word_size);

   }

   if (block == NULL) {

     block = allocate_work(raw_word_size);

     if (block == NULL) {

       return NULL;

     }

   }

   Metadebug::deallocate_block_a_lot(this, raw_word_size);

   // Push the allocation past the word containing the size and leader.

 #ifdef ASSERT

   MetaWord* result =  block->data();

   return result;

 #else

   return (MetaWord*) block;

 #endif

 }

 // Returns the address of spaced allocated for "word_size".

 // This methods does not know about blocks (Metablocks)

 Metablock* SpaceManager::allocate_work(size_t word_size) {

   assert_lock_strong(_lock);

 #ifdef ASSERT

   if (Metadebug::test_metadata_failure()) {

     return NULL;

   }

 #endif

   // Is there space in the current chunk?

   Metablock* result = NULL;

   // For DumpSharedSpaces, only allocate out of the current chunk which is

   // never null because we gave it the size we wanted.   Caller reports out

   // of memory if this returns null.

   if (DumpSharedSpaces) {

     assert(current_chunk() != NULL, "should never happen");

     inc_allocation_total(word_size);

     return current_chunk()->allocate(word_size); // caller handles null result

   }

   if (current_chunk() != NULL) {

     result = current_chunk()->allocate(word_size);

   }

   if (result == NULL) {

     result = grow_and_allocate(word_size);

   }

   if (result > 0) {

     inc_allocation_total(word_size);

     assert(result != (Metablock*) chunks_in_use(MediumIndex), "Head of the list is being allocated");

     assert(result->word_size() == word_size, "Size not set correctly");

   }

   return result;

 }

 void SpaceManager::verify() {

   // If there are blocks in the dictionary, then

   // verfication of chunks does not work since

   // being in the dictionary alters a chunk.

   if (block_freelists()->totalSize() == 0) {

     // Skip the small chunks because their next link points to

     // medium chunks.  This is because the small chunk is the

     // current chunk (for allocations) until it is full and the

     // the addition of the next chunk does not NULL the next

     // like of the small chunk.

     for (ChunkIndex i = MediumIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {

       Metachunk* curr = chunks_in_use(i);

       while (curr != NULL) {

         curr->verify();

         curr = curr->next();

       }

     }

   }

 }

 #ifdef ASSERT

 void SpaceManager::verify_allocation_total() {

 #if 0

   // Verification is only guaranteed at a safepoint.

   if (SafepointSynchronize::is_at_safepoint()) {

     gclog_or_tty->print_cr("Chunk " PTR_FORMAT " allocation_total " SIZE_FORMAT

                            " sum_used_in_chunks_in_use " SIZE_FORMAT,

                            this,

                            allocation_total(),

                            sum_used_in_chunks_in_use());

   }

   MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);

   assert(allocation_total() == sum_used_in_chunks_in_use(),

     err_msg("allocation total is not consistent %d vs %d",

             allocation_total(), sum_used_in_chunks_in_use()));

 #endif

 }

 #endif

 void SpaceManager::dump(outputStream* const out) const {

   size_t curr_total = 0;

   size_t waste = 0;

   uint i = 0;

   size_t used = 0;

   size_t capacity = 0;

   // Add up statistics for all chunks in this SpaceManager.

   for (ChunkIndex index = SmallIndex;

        index < NumberOfFreeLists;

        index = next_chunk_index(index)) {

     for (Metachunk* curr = chunks_in_use(index);

          curr != NULL;

          curr = curr->next()) {

       out->print("%d) ", i++);

       curr->print_on(out);

       if (TraceMetadataChunkAllocation && Verbose) {

         block_freelists()->print_on(out);

       }

       curr_total += curr->word_size();

       used += curr->used_word_size();

       capacity += curr->capacity_word_size();

       waste += curr->free_word_size() + curr->overhead();;

     }

   }

   size_t free = current_chunk()->free_word_size();

   // Free space isn't wasted.

   waste -= free;

   out->print_cr("total of all chunks "  SIZE_FORMAT " used " SIZE_FORMAT

                 " free " SIZE_FORMAT " capacity " SIZE_FORMAT

                 " waste " SIZE_FORMAT, curr_total, used, free, capacity, waste);

 }

 #ifndef PRODUCT

 void SpaceManager::mangle_freed_chunks() {

   for (ChunkIndex index = SmallIndex;

        index < NumberOfFreeLists;

        index = next_chunk_index(index)) {

     for (Metachunk* curr = chunks_in_use(index);

          curr != NULL;

          curr = curr->next()) {

       // Try to detect incorrectly terminated small chunk

       // list.

       assert(index == MediumIndex || curr != chunks_in_use(MediumIndex),

              err_msg("Mangling medium chunks in small chunks? "

                      "curr " PTR_FORMAT " medium list " PTR_FORMAT,

                      curr, chunks_in_use(MediumIndex)));

       curr->mangle();

     }

   }

 }

 #endif // PRODUCT

 // MetaspaceAux

 size_t MetaspaceAux::used_in_bytes(Metaspace::MetadataType mdtype) {

   size_t used = 0;

   ClassLoaderDataGraphMetaspaceIterator iter;

   while (iter.repeat()) {

     Metaspace* msp = iter.get_next();

     // Sum allocation_total for each metaspace

     if (msp != NULL) {

       used += msp->used_words(mdtype);

     }

   }

   return used * BytesPerWord;

 }

 size_t MetaspaceAux::free_in_bytes(Metaspace::MetadataType mdtype) {

   size_t free = 0;

   ClassLoaderDataGraphMetaspaceIterator iter;

   while (iter.repeat()) {

     Metaspace* msp = iter.get_next();

     if (msp != NULL) {

       free += msp->free_words(mdtype);

     }

   }

   return free * BytesPerWord;

 }

 // The total words available for metadata allocation.  This

 // uses Metaspace capacity_words() which is the total words

 // in chunks allocated for a Metaspace.

 size_t MetaspaceAux::capacity_in_bytes(Metaspace::MetadataType mdtype) {

   size_t capacity = free_chunks_total(mdtype);

   ClassLoaderDataGraphMetaspaceIterator iter;

   while (iter.repeat()) {

     Metaspace* msp = iter.get_next();

     if (msp != NULL) {

       capacity += msp->capacity_words(mdtype);

     }

   }

   return capacity * BytesPerWord;

 }

 size_t MetaspaceAux::reserved_in_bytes(Metaspace::MetadataType mdtype) {

   size_t reserved = (mdtype == Metaspace::ClassType) ?

                        Metaspace::class_space_list()->virtual_space_total() :

                        Metaspace::space_list()->virtual_space_total();

   return reserved * BytesPerWord;

 }

 size_t MetaspaceAux::min_chunk_size() { return SpaceManager::MediumChunk; }

 size_t MetaspaceAux::free_chunks_total(Metaspace::MetadataType mdtype) {

   ChunkManager* chunk = (mdtype == Metaspace::ClassType) ?

                             Metaspace::class_space_list()->chunk_manager() :

                             Metaspace::space_list()->chunk_manager();

   chunk->verify_free_chunks_total();

   return chunk->free_chunks_total();

 }

 size_t MetaspaceAux::free_chunks_total_in_bytes(Metaspace::MetadataType mdtype) {

   return free_chunks_total(mdtype) * BytesPerWord;

 }

 void MetaspaceAux::print_metaspace_change(size_t prev_metadata_used) {

   gclog_or_tty->print(", [Metaspace:");

   if (PrintGCDetails && Verbose) {

     gclog_or_tty->print(" "  SIZE_FORMAT

                         "->" SIZE_FORMAT

                         "("  SIZE_FORMAT "/" SIZE_FORMAT ")",

                         prev_metadata_used,

                         used_in_bytes(),

                         capacity_in_bytes(),

                         reserved_in_bytes());

   } else {

     gclog_or_tty->print(" "  SIZE_FORMAT "K"

                         "->" SIZE_FORMAT "K"

                         "("  SIZE_FORMAT "K/" SIZE_FORMAT "K)",

                         prev_metadata_used / K,

                         used_in_bytes()/ K,

                         capacity_in_bytes()/K,

                         reserved_in_bytes()/ K);

   }

   gclog_or_tty->print("]");

 }

 // This is printed when PrintGCDetails

 void MetaspaceAux::print_on(outputStream* out) {

   Metaspace::MetadataType ct = Metaspace::ClassType;

   Metaspace::MetadataType nct = Metaspace::NonClassType;

   out->print_cr(" Metaspace total "

                 SIZE_FORMAT "K, used " SIZE_FORMAT "K,"

                 " reserved " SIZE_FORMAT "K",

                 capacity_in_bytes()/K, used_in_bytes()/K, reserved_in_bytes()/K);

   out->print_cr("  data space     "

                 SIZE_FORMAT "K, used " SIZE_FORMAT "K,"

                 " reserved " SIZE_FORMAT "K",

                 capacity_in_bytes(nct)/K, used_in_bytes(nct)/K, reserved_in_bytes(nct)/K);

   out->print_cr("  class space    "

                 SIZE_FORMAT "K, used " SIZE_FORMAT "K,"

                 " reserved " SIZE_FORMAT "K",