view src/share/vm/gc_implementation/g1/g1MarkSweep.hpp @ 453:c96030fff130

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa
author ysr
date Thu, 20 Nov 2008 16:56:09 -0800
parents 37f87013dfd8
children c18cbe5936b8
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/*
 * Copyright 2001-2007 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.
 *
 */

class ReferenceProcessor;

// G1MarkSweep takes care of global mark-compact garbage collection for a
// G1CollectedHeap using a four-phase pointer forwarding algorithm.  All
// generations are assumed to support marking; those that can also support
// compaction.
//
// Class unloading will only occur when a full gc is invoked.


class G1MarkSweep : AllStatic {
  friend class VM_G1MarkSweep;
  friend class Scavenge;

 public:

  static void invoke_at_safepoint(ReferenceProcessor* rp,
                                  bool clear_all_softrefs);

 private:

  // Mark live objects
  static void mark_sweep_phase1(bool& marked_for_deopt,
                                bool clear_all_softrefs);
  // Calculate new addresses
  static void mark_sweep_phase2();
  // Update pointers
  static void mark_sweep_phase3();
  // Move objects to new positions
  static void mark_sweep_phase4();

  static void allocate_stacks();
};