rev 57625 : [mq]: metaspace-improvement

   1 /*
   2  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
  26 #define SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/metaspace.hpp"
  30 #include "memory/metaspace/blockFreelist.hpp"
  31 #include "memory/metaspace/chunkAllocSequence.hpp"
  32 #include "memory/metaspace/chunkManager.hpp"
  33 #include "memory/metaspace/metachunk.hpp"
  34 #include "memory/metaspace/metaspaceCommon.hpp"


  35 
  36 class outputStream;
  37 class Mutex;
  38 
  39 namespace metaspace {
  40 
  41 class SpaceManagerStatistics;



  42 
  43 // The SpaceManager:
  44 // - keeps a list of chunks-in-use by the class loader, as well as a current chunk used
  45 //   to allocate from
  46 // - keeps a dictionary of free MetaBlocks. Those can be remnants of a retired chunk or
  47 //   allocations which were not needed anymore for some reason (e.g. releasing half-allocated
  48 //   structures when class loading fails)
  49 
  50 class SpaceManager : public CHeapObj<mtClass> {
  51 
  52   // Lock handed down from the associated ClassLoaderData.
  53   //  Protects allocations from this space.
  54   Mutex* const _lock;
  55 
  56   // The chunk manager to allocate chunks from.
  57   ChunkManager* const _chunk_manager;
  58 
  59   // The chunk allocation strategy to use.
  60   const ChunkAllocSequence* const _chunk_alloc_sequence;
  61 
  62   // List of chunks in use by this SpaceManager.  Allocations
  63   // are done from the current chunk.  The list is used for deallocating
  64   // chunks when the SpaceManager is freed.
  65   MetachunkList _chunks;
  66   Metachunk* _current_chunk;
  67 
  68   // Prematurely released metablocks.
  69   BlockFreelist* _block_freelist;





























  70 
  71   Mutex* lock() const                           { return _lock; }
  72   ChunkManager* chunk_manager() const           { return _chunk_manager; }
  73   const ChunkAllocSequence* chunk_alloc_sequence() const    { return _chunk_alloc_sequence; }








  74 
  75   BlockFreelist* block_freelist() const         { return _block_freelist; }
  76   void create_block_freelist();
  77 
  78   // The current chunk is unable to service a request. The remainder of the chunk is
  79   // chopped into blocks and fed into the _block_freelists, in the hope of later reuse.
  80   void retire_current_chunk();
  81 
  82   // Given a requested word size, will allocate a chunk large enough to at least fit that
  83   // size, but may be larger according to the rules in the ChunkAllocSequence.
  84   // Updates counters and adds the chunk to the head of the chunk list.
  85   Metachunk* allocate_chunk_to_fit(size_t requested_word_size);
  86 
  87 public:

  88 
  89   SpaceManager(ChunkManager* chunk_manager, const ChunkAllocSequence* alloc_sequence, Mutex* lock);

  90 




  91   ~SpaceManager();
  92 
  93   // Allocate memory from Metaspace. Will attempt to allocate from the _block_freelists,
  94   // failing that, from the current chunk; failing that, attempt to get a new chunk from
  95   // the associated ChunkManager.

















































  96   MetaWord* allocate(size_t word_size);
  97 
  98   // Prematurely returns a metaspace allocation to the _block_freelists because it is not
  99   // needed anymore.


 100   void deallocate(MetaWord* p, size_t word_size);
 101 
 102   // Update statistics. This walks all in-use chunks.


































 103   void add_to_statistics(SpaceManagerStatistics* out) const;
 104 
 105   // Run verifications. slow=true: verify chunk-internal integrity too.
 106   DEBUG_ONLY(void verify(bool slow) const;)
 107 
 108 };

 109 
 110 } // namespace metaspace
 111 
 112 #endif // SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
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