1 /*
   2  * Copyright (c) 2001, 2008, 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
  21  * questions.
  22  *
  23  */
  24 
  25 // A FreeBlockDictionary is an abstract superclass that will allow
  26 // a number of alternative implementations in the future.
  27 class FreeBlockDictionary: public CHeapObj {
  28  public:
  29   enum Dither {
  30     atLeast,
  31     exactly,
  32     roughly
  33   };
  34   enum DictionaryChoice {
  35     dictionaryBinaryTree = 0,
  36     dictionarySplayTree  = 1,
  37     dictionarySkipList   = 2
  38   };
  39 
  40  private:
  41   NOT_PRODUCT(Mutex* _lock;)
  42 
  43  public:
  44   virtual void       removeChunk(FreeChunk* fc) = 0;
  45   virtual FreeChunk* getChunk(size_t size, Dither dither = atLeast) = 0;
  46   virtual void       returnChunk(FreeChunk* chunk) = 0;
  47   virtual size_t     totalChunkSize(debug_only(const Mutex* lock)) const = 0;
  48   virtual size_t     maxChunkSize()   const = 0;
  49   virtual size_t     minSize()        const = 0;
  50   // Reset the dictionary to the initial conditions for a single
  51   // block.
  52   virtual void       reset(HeapWord* addr, size_t size) = 0;
  53   virtual void       reset() = 0;
  54 
  55   virtual void       dictCensusUpdate(size_t size, bool split, bool birth) = 0;
  56   virtual bool       coalDictOverPopulated(size_t size) = 0;
  57   virtual void       beginSweepDictCensus(double coalSurplusPercent,
  58                        float inter_sweep_current, float inter_sweep_estimate,
  59                        float intra__sweep_current) = 0;
  60   virtual void       endSweepDictCensus(double splitSurplusPercent) = 0;
  61   virtual FreeChunk* findLargestDict() const = 0;
  62   // verify that the given chunk is in the dictionary.
  63   virtual bool verifyChunkInFreeLists(FreeChunk* tc) const = 0;
  64 
  65   // Sigma_{all_free_blocks} (block_size^2)
  66   virtual double sum_of_squared_block_sizes() const = 0;
  67 
  68   virtual FreeChunk* find_chunk_ends_at(HeapWord* target) const = 0;
  69   virtual void inc_totalSize(size_t v) = 0;
  70   virtual void dec_totalSize(size_t v) = 0;
  71 
  72   NOT_PRODUCT (
  73     virtual size_t   sumDictReturnedBytes() = 0;
  74     virtual void     initializeDictReturnedBytes() = 0;
  75     virtual size_t   totalCount() = 0;
  76   )
  77 
  78   virtual void       reportStatistics() const {
  79     gclog_or_tty->print("No statistics available");
  80   }
  81 
  82   virtual void       printDictCensus() const = 0;
  83   virtual void       print_free_lists(outputStream* st) const = 0;
  84 
  85   virtual void       verify()         const = 0;
  86 
  87   Mutex* par_lock()                const PRODUCT_RETURN0;
  88   void   set_par_lock(Mutex* lock)       PRODUCT_RETURN;
  89   void   verify_par_locked()       const PRODUCT_RETURN;
  90 };