org.mmtk.plan.marksweep

Class MSTraceLocal

java.lang.Object

org.mmtk.plan.TransitiveClosure

org.mmtk.plan.TraceLocal

org.mmtk.plan.marksweep.MSTraceLocal

public final class MSTraceLocal
extends TraceLocal

This class implements the thread-local functionality for a transitive closure over a mark-sweep space.

Field Summary

Fields

Modifier and Type	Field and Description
private ObjectReferenceDeque	modBuffer

Fields inherited from class org.mmtk.plan.TraceLocal

rootLocations, values

Fields inherited from class org.mmtk.plan.TransitiveClosure

specializedScan

Constructor Summary

Constructors

Constructor and Description
MSTraceLocal(Trace trace, ObjectReferenceDeque modBuffer)

Method Summary

Modifier and Type	Method and Description
boolean	isLive(ObjectReference object) Is the specified object live?
protected void	processRememberedSets() Process any remembered set entries.
ObjectReference	traceObject(ObjectReference object) This method is the core method during the trace of the object graph.

Methods inherited from class org.mmtk.plan.TraceLocal

completeTrace, flush, getForwardedFinalizable, getForwardedReference, getForwardedReferenceType, getForwardedReferent, incrementalTrace, isReachable, isReferentLive, logMessage, overwriteReferenceDuringTrace, prepare, processEdge, processInteriorEdge, processNode, processRootEdge, processRoots, readyToFinalize, release, reportDelayedRootEdge, retainForFinalize, retainReferent, scanObject, traceObject, willNotMoveInCurrentCollection

Methods inherited from class org.mmtk.plan.TransitiveClosure

getSpecializedScanClass, registerSpecializedScan

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

modBuffer

private final ObjectReferenceDeque modBuffer

Constructor Detail

MSTraceLocal

public MSTraceLocal(Trace trace,
                    ObjectReferenceDeque modBuffer)

Method Detail

isLive

public boolean isLive(ObjectReference object)

Is the specified object live?

Overrides:

isLive in class TraceLocal

Parameters:

object - The object.

Returns:

true if the object is live.

traceObject

public ObjectReference traceObject(ObjectReference object)

This method is the core method during the trace of the object graph. The role of this method is to:

1. Ensure the traced object is not collected.
2. If this is the first visit to the object enqueue it to be scanned.
3. Return the forwarded reference to the object.

In this instance, we refer objects in the mark-sweep space to the msSpace for tracing, and defer to the superclass for all others.

Overrides:

traceObject in class TraceLocal

Parameters:

object - The object to be traced.

Returns:

The new reference to the same object instance.

processRememberedSets

protected void processRememberedSets()

Process any remembered set entries. This means enumerating the mod buffer and for each entry, marking the object as unlogged (we don't enqueue for scanning since we're doing a full heap GC).

Overrides:

processRememberedSets in class TraceLocal