view src/share/vm/gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp @ 1091:6aa7255741f3

6906727: UseCompressedOops: some card-marking fixes related to object arrays Summary: Introduced a new write_ref_array(HeapWords* start, size_t count) method that does the requisite MemRegion range calculation so (some of the) clients of the erstwhile write_ref_array(MemRegion mr) do not need to worry. This removed all external uses of array_size(), which was also simplified and made private. Asserts were added to catch other possible issues. Further, less essential, fixes stemming from this investigation are deferred to CR 6904516 (to follow shortly in hs17). Reviewed-by: kvn, coleenp, jmasa
author ysr
date Thu, 03 Dec 2009 15:01:57 -0800
parents ad8c8ca4ab0f
children c18cbe5936b8
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/*
 * Copyright 2001-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

//
// A PSMarkSweepDecorator is used to add "ParallelScavenge" style mark sweep operations
// to a MutableSpace.
//

class ObjectStartArray;

class PSMarkSweepDecorator: public CHeapObj {
 private:
  static PSMarkSweepDecorator* _destination_decorator;

 protected:
  MutableSpace* _space;
  ObjectStartArray* _start_array;
  HeapWord* _first_dead;
  HeapWord* _end_of_live;
  HeapWord* _compaction_top;
  size_t _allowed_dead_ratio;

  bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q,
                        size_t word_len);

 public:
  PSMarkSweepDecorator(MutableSpace* space, ObjectStartArray* start_array,
                       size_t allowed_dead_ratio) :
    _space(space), _start_array(start_array),
    _allowed_dead_ratio(allowed_dead_ratio) { }

  // During a compacting collection, we need to collapse objects into
  // spaces in a given order. We want to fill space A, space B, and so
  // on. The code that controls that order is in the following methods.
  static void set_destination_decorator_tenured();
  static void set_destination_decorator_perm_gen();
  static void advance_destination_decorator();
  static PSMarkSweepDecorator* destination_decorator();

  // Accessors
  MutableSpace* space()                     { return _space; }
  ObjectStartArray* start_array()           { return _start_array; }

  HeapWord* compaction_top()                { return _compaction_top; }
  void set_compaction_top(HeapWord* value)  { _compaction_top = value; }

  size_t allowed_dead_ratio()               { return _allowed_dead_ratio; }
  void set_allowed_dead_ratio(size_t value) { _allowed_dead_ratio = value; }

  // Work methods
  void adjust_pointers();
  void precompact();
  void compact(bool mangle_free_space);
};