1 /*
   2  * Copyright (c) 2001, 2012, 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 #ifndef SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP
  26 #define SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "runtime/mutex.hpp"
  30 #include "utilities/debug.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 #include "utilities/ostream.hpp"
  33 
  34 // A FreeBlockDictionary is an abstract superclass that will allow
  35 // a number of alternative implementations in the future.
  36 template <class Chunk>
  37 class FreeBlockDictionary: public CHeapObj<mtGC> {
  38  public:
  39   enum Dither {
  40     atLeast,
  41     exactly,
  42     roughly
  43   };
  44   enum DictionaryChoice {
  45     dictionaryBinaryTree = 0,
  46     dictionarySplayTree  = 1,
  47     dictionarySkipList   = 2
  48   };
  49 
  50  private:
  51   // This field is added and can be set to point to the
  52   // the Mutex used to synchronize access to the
  53   // dictionary so that assertion checking can be done.
  54   // For example it is set to point to _parDictionaryAllocLock.
  55   NOT_PRODUCT(Mutex* _lock;)
  56 
  57  public:
  58   virtual void       remove_chunk(Chunk* fc) = 0;
  59   virtual Chunk*     get_chunk(size_t size, Dither dither = atLeast) = 0;
  60   virtual void       return_chunk(Chunk* chunk) = 0;
  61   virtual size_t     total_chunk_size(debug_only(const Mutex* lock)) const = 0;
  62   virtual size_t     max_chunk_size()   const = 0;
  63   virtual size_t     min_size()        const = 0;
  64   // Reset the dictionary to the initial conditions for a single
  65   // block.
  66   virtual void       reset(HeapWord* addr, size_t size) = 0;
  67   virtual void       reset() = 0;
  68 
  69   virtual void       dict_census_update(size_t size, bool split, bool birth) = 0;
  70   virtual bool       coal_dict_over_populated(size_t size) = 0;
  71   virtual void       begin_sweep_dict_census(double coalSurplusPercent,
  72                        float inter_sweep_current, float inter_sweep_estimate,
  73                        float intra__sweep_current) = 0;
  74   virtual void       end_sweep_dict_census(double splitSurplusPercent) = 0;
  75   virtual Chunk*     find_largest_dict() const = 0;
  76   // verify that the given chunk is in the dictionary.
  77   virtual bool verify_chunk_in_free_list(Chunk* tc) const = 0;
  78 
  79   // Sigma_{all_free_blocks} (block_size^2)
  80   virtual double sum_of_squared_block_sizes() const = 0;
  81 
  82   virtual Chunk* find_chunk_ends_at(HeapWord* target) const = 0;
  83   virtual void inc_total_size(size_t v) = 0;
  84   virtual void dec_total_size(size_t v) = 0;
  85 
  86   NOT_PRODUCT (
  87     virtual size_t   sum_dict_returned_bytes() = 0;
  88     virtual void     initialize_dict_returned_bytes() = 0;
  89     virtual size_t   total_count() = 0;
  90   )
  91 
  92   virtual void       report_statistics() const {
  93     gclog_or_tty->print("No statistics available");
  94   }
  95 
  96   virtual void       print_dict_census() const = 0;
  97   virtual void       print_free_lists(outputStream* st) const = 0;
  98 
  99   virtual void       verify()         const = 0;
 100 
 101   Mutex* par_lock()                const PRODUCT_RETURN0;
 102   void   set_par_lock(Mutex* lock)       PRODUCT_RETURN;
 103   void   verify_par_locked()       const PRODUCT_RETURN;
 104 };
 105 
 106 #endif // SHARE_VM_MEMORY_FREEBLOCKDICTIONARY_HPP