/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Common Public License (CPL);
* You may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.opensource.org/licenses/cpl1.0.php
*
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership.
*/
package org.mmtk.plan.concurrent.marksweep;
import org.mmtk.plan.*;
import org.mmtk.plan.concurrent.Concurrent;
import org.mmtk.policy.MarkSweepSpace;
import org.mmtk.policy.Space;
import org.mmtk.utility.heap.VMRequest;
import org.vmmagic.pragma.*;
import org.vmmagic.unboxed.ObjectReference;
/**
* This class implements the global state of a concurrent mark-sweep collector.
*/
@Uninterruptible
public class CMS extends Concurrent {
/****************************************************************************
* Constants
*/
/****************************************************************************
* Class variables
*/
public static final MarkSweepSpace msSpace = new MarkSweepSpace("ms", DEFAULT_POLL_FREQUENCY, VMRequest.create(0.6f));
public static final int MARK_SWEEP = msSpace.getDescriptor();
/****************************************************************************
* Instance variables
*/
public final Trace msTrace = new Trace(metaDataSpace);
/*****************************************************************************
*
* Collection
*/
/**
* Perform a (global) collection phase.
*
* @param phaseId Collection phase to execute.
*/
@Inline
public void collectionPhase(short phaseId) {
if (phaseId == PREPARE) {
super.collectionPhase(phaseId);
msTrace.prepareNonBlocking();
msSpace.prepare();
return;
}
if (phaseId == RELEASE) {
msTrace.release();
msSpace.release();
super.collectionPhase(phaseId);
return;
}
super.collectionPhase(phaseId);
}
/*****************************************************************************
*
* Accounting
*/
/**
* Return the number of pages reserved for use given the pending
* allocation. The superclass accounts for its spaces, we just
* augment this with the mark-sweep space's contribution.
*
* @return The number of pages reserved given the pending
* allocation, excluding space reserved for copying.
*/
public int getPagesUsed() {
return (msSpace.reservedPages() + super.getPagesUsed());
}
/**
* Calculate the number of pages a collection is required to free to satisfy
* outstanding allocation requests.
*
* @return the number of pages a collection is required to free to satisfy
* outstanding allocation requests.
*/
public int getPagesRequired() {
return super.getPagesRequired() + msSpace.requiredPages();
}
/**
* @see org.mmtk.plan.Plan#willNeverMove
*
* @param object Object in question
* @return True if the object will never move
*/
@Override
public boolean willNeverMove(ObjectReference object) {
if (Space.isInSpace(MARK_SWEEP, object))
return true;
return super.willNeverMove(object);
}
}