/*
* This file is part of the Jikes RVM project (http://jikesrvm.org).
*
* This file is licensed to You under the Eclipse Public License (EPL);
* 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/eclipse-1.0.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.ConcurrentMutator;
import org.mmtk.policy.MarkSweepLocal;
import org.mmtk.policy.Space;
import org.mmtk.utility.alloc.Allocator;
import org.mmtk.vm.VM;
import org.vmmagic.pragma.*;
import org.vmmagic.unboxed.*;
/**
* This class implements <i>per-mutator thread</i> behavior
* and state for the <i>CMS</i> plan, which implements a full-heap
* concurrent mark-sweep collector.<p>
*
* FIXME The SegregatedFreeList class (and its descendants such as
* MarkSweepLocal) does not properly separate mutator and collector
* behaviors, so the ms field below should really not exist in
* this class as there is no collection-time allocation in this
* collector.
*
* @see CMS
* @see CMSCollector
* @see StopTheWorldMutator
* @see MutatorContext
*/
@Uninterruptible
public class CMSMutator extends ConcurrentMutator {
/****************************************************************************
* Instance fields
*/
/**
*
*/
private final MarkSweepLocal ms;
private final TraceWriteBuffer remset;
/****************************************************************************
*
* Initialization
*/
/**
* Constructor
*/
public CMSMutator() {
ms = new MarkSweepLocal(CMS.msSpace);
remset = new TraceWriteBuffer(global().msTrace);
}
/****************************************************************************
*
* Mutator-time allocation
*/
/**
* {@inheritDoc}<p>
*
* This class handles the default allocator from the mark sweep space, and
* delegates everything else to the superclass.
*/
@Inline
@Override
public Address alloc(int bytes, int align, int offset, int allocator, int site) {
if (allocator == CMS.ALLOC_DEFAULT) {
return ms.alloc(bytes, align, offset);
}
return super.alloc(bytes, align, offset, allocator, site);
}
/**
* {@inheritDoc}<p>
*
* Initialize the object header for objects in the mark-sweep space,
* and delegate to the superclass for other objects.
*/
@NoInline
@Override
public void postAlloc(ObjectReference ref, ObjectReference typeRef,
int bytes, int allocator) {
switch (allocator) {
case CMS.ALLOC_DEFAULT: CMS.msSpace.initializeHeader(ref, true); break;
default:
super.postAlloc(ref, typeRef, bytes, allocator);
break;
}
}
@Override
public Allocator getAllocatorFromSpace(Space space) {
if (space == CMS.msSpace) return ms;
return super.getAllocatorFromSpace(space);
}
/****************************************************************************
*
* Collection
*/
/**
* {@inheritDoc}
*/
@Override
@Inline
public void collectionPhase(short phaseId, boolean primary) {
if (phaseId == CMS.PREPARE) {
super.collectionPhase(phaseId, primary);
ms.prepare();
return;
}
if (phaseId == CMS.RELEASE) {
ms.release();
super.collectionPhase(phaseId, primary);
return;
}
super.collectionPhase(phaseId, primary);
}
@Override
public void flushRememberedSets() {
remset.flush();
ms.flush();
}
/****************************************************************************
*
* Write and read barriers.
*/
/**
* {@inheritDoc}
*/
@Override
protected void checkAndEnqueueReference(ObjectReference ref) {
if (ref.isNull()) return;
if (barrierActive) {
if (!ref.isNull()) {
if (Space.isInSpace(CMS.MARK_SWEEP, ref)) CMS.msSpace.traceObject(remset, ref);
else if (Space.isInSpace(CMS.IMMORTAL, ref)) CMS.immortalSpace.traceObject(remset, ref);
else if (Space.isInSpace(CMS.LOS, ref)) CMS.loSpace.traceObject(remset, ref);
else if (Space.isInSpace(CMS.NON_MOVING, ref)) CMS.nonMovingSpace.traceObject(remset, ref);
else if (Space.isInSpace(CMS.SMALL_CODE, ref)) CMS.smallCodeSpace.traceObject(remset, ref);
else if (Space.isInSpace(CMS.LARGE_CODE, ref)) CMS.largeCodeSpace.traceObject(remset, ref);
}
}
if (VM.VERIFY_ASSERTIONS) {
if (!ref.isNull() && !Plan.gcInProgress()) {
if (Space.isInSpace(CMS.MARK_SWEEP, ref)) VM.assertions._assert(CMS.msSpace.isLive(ref));
else if (Space.isInSpace(CMS.IMMORTAL, ref)) VM.assertions._assert(CMS.immortalSpace.isLive(ref));
else if (Space.isInSpace(CMS.LOS, ref)) VM.assertions._assert(CMS.loSpace.isLive(ref));
else if (Space.isInSpace(CMS.NON_MOVING, ref)) VM.assertions._assert(CMS.nonMovingSpace.isLive(ref));
else if (Space.isInSpace(CMS.SMALL_CODE, ref)) VM.assertions._assert(CMS.smallCodeSpace.isLive(ref));
else if (Space.isInSpace(CMS.LARGE_CODE, ref)) VM.assertions._assert(CMS.largeCodeSpace.isLive(ref));
}
}
}
/****************************************************************************
*
* Miscellaneous
*/
/** @return The active global plan as a <code>Gen</code> instance. */
@Inline
private static CMS global() {
return (CMS) VM.activePlan.global();
}
}