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
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  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_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSMARKSWEEPDECORATOR_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSMARKSWEEPDECORATOR_HPP
  27 
  28 #include "gc_implementation/shared/mutableSpace.hpp"
  29 
  30 //
  31 // A PSMarkSweepDecorator is used to add "ParallelScavenge" style mark sweep operations
  32 // to a MutableSpace.
  33 //
  34 
  35 class ObjectStartArray;
  36 
  37 class PSMarkSweepDecorator: public CHeapObj<mtGC> {
  38  private:
  39   static PSMarkSweepDecorator* _destination_decorator;
  40 
  41  protected:
  42   MutableSpace* _space;
  43   ObjectStartArray* _start_array;
  44   HeapWord* _first_dead;
  45   HeapWord* _end_of_live;
  46   HeapWord* _compaction_top;
  47   size_t _allowed_dead_ratio;
  48 
  49   bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q,
  50                         size_t word_len);
  51 
  52  public:
  53   PSMarkSweepDecorator(MutableSpace* space, ObjectStartArray* start_array,
  54                        size_t allowed_dead_ratio) :
  55     _space(space), _start_array(start_array),
  56     _allowed_dead_ratio(allowed_dead_ratio) { }
  57 
  58   // During a compacting collection, we need to collapse objects into
  59   // spaces in a given order. We want to fill space A, space B, and so
  60   // on. The code that controls that order is in the following methods.
  61   static void set_destination_decorator_tenured();
  62   static void advance_destination_decorator();
  63   static PSMarkSweepDecorator* destination_decorator();
  64 
  65   // Accessors
  66   MutableSpace* space()                     { return _space; }
  67   ObjectStartArray* start_array()           { return _start_array; }
  68 
  69   HeapWord* compaction_top()                { return _compaction_top; }
  70   void set_compaction_top(HeapWord* value)  { _compaction_top = value; }
  71 
  72   size_t allowed_dead_ratio()               { return _allowed_dead_ratio; }
  73   void set_allowed_dead_ratio(size_t value) { _allowed_dead_ratio = value; }
  74 
  75   // Work methods
  76   void adjust_pointers();
  77   void precompact();
  78   void compact(bool mangle_free_space);
  79 };
  80 
  81 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSMARKSWEEPDECORATOR_HPP