001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.mmtk.plan.concurrent.marksweep;
014    
015    import org.mmtk.plan.*;
016    import org.mmtk.plan.concurrent.Concurrent;
017    import org.mmtk.policy.MarkSweepSpace;
018    import org.mmtk.policy.Space;
019    import org.mmtk.utility.heap.VMRequest;
020    
021    import org.vmmagic.pragma.*;
022    import org.vmmagic.unboxed.ObjectReference;
023    
024    /**
025     * This class implements the global state of a concurrent mark-sweep collector.
026     */
027    @Uninterruptible
028    public class CMS extends Concurrent {
029    
030      /****************************************************************************
031       * Constants
032       */
033    
034      /****************************************************************************
035       * Class variables
036       */
037    
038      /**
039       *
040       */
041      public static final MarkSweepSpace msSpace = new MarkSweepSpace("ms", VMRequest.create());
042      public static final int MARK_SWEEP = msSpace.getDescriptor();
043    
044      static {
045        msSpace.makeAllocAsMarked();
046        smallCodeSpace.makeAllocAsMarked();
047        nonMovingSpace.makeAllocAsMarked();
048      }
049    
050      /****************************************************************************
051       * Instance variables
052       */
053    
054      /**
055       *
056       */
057      public final Trace msTrace = new Trace(metaDataSpace);
058    
059      /*****************************************************************************
060       *
061       * Collection
062       */
063    
064      /**
065       * {@inheritDoc}
066       */
067      @Override
068      @Inline
069      public void collectionPhase(short phaseId) {
070        if (phaseId == PREPARE) {
071          super.collectionPhase(phaseId);
072          msTrace.prepareNonBlocking();
073          msSpace.prepare(true);
074          return;
075        }
076    
077        if (phaseId == RELEASE) {
078          msTrace.release();
079          msSpace.release();
080          super.collectionPhase(phaseId);
081          return;
082        }
083    
084        super.collectionPhase(phaseId);
085      }
086    
087      /*****************************************************************************
088       *
089       * Accounting
090       */
091    
092      /**
093       * {@inheritDoc}
094       * The superclass accounts for its spaces, we just
095       * augment this with the mark-sweep space's contribution.
096       */
097      @Override
098      public int getPagesUsed() {
099        return (msSpace.reservedPages() + super.getPagesUsed());
100      }
101    
102      @Override
103      public boolean willNeverMove(ObjectReference object) {
104        if (Space.isInSpace(MARK_SWEEP, object))
105          return true;
106        return super.willNeverMove(object);
107      }
108    }