org.mmtk.plan.semispace

Class SSCollector

java.lang.Object

org.mmtk.plan.CollectorContext

org.mmtk.plan.ParallelCollector

org.mmtk.plan.SimpleCollector

org.mmtk.plan.StopTheWorldCollector

org.mmtk.plan.semispace.SSCollector

Direct Known Subclasses:

GCTraceCollector, SSGCspyCollector, UsePrimitiveWriteBarriersCollector

public class SSCollector
extends StopTheWorldCollector

This class implements per-collector thread behavior and state for the SS plan, which implements a full-heap semi-space collector.

Specifically, this class defines SS collection behavior (through trace and the collectionPhase method), and collection-time allocation (copying of objects).

See SS for an overview of the semi-space algorithm.

See Also:

SS, SSMutator, StopTheWorldCollector, CollectorContext

Field Summary

Fields

Modifier and Type	Field and Description
protected LargeObjectLocal	los
protected CopyLocal	ss
protected SSTraceLocal	trace

Fields inherited from class org.mmtk.plan.SimpleCollector

sanityLocal

Fields inherited from class org.mmtk.plan.ParallelCollector

group

Fields inherited from class org.mmtk.plan.CollectorContext

log

Constructor Summary

Constructors

Modifier	Constructor and Description
	SSCollector() Constructor
protected	SSCollector(SSTraceLocal tr) Constructor

Method Summary

Modifier and Type	Method and Description
Address	allocCopy(ObjectReference original, int bytes, int align, int offset, int allocator) Allocate space for copying an object (this method does not copy the object, it only allocates space)
void	collectionPhase(short phaseId, boolean primary) Perform a (local, i.e.per-collector) collection phase.
TraceLocal	getCurrentTrace()
private static SS	global()
static boolean	isSemiSpaceObject(ObjectReference object) Return true if the given reference is to an object that is within one of the semi-spaces.
void	postCopy(ObjectReference object, ObjectReference typeRef, int bytes, int allocator) Perform any post-copy actions.

Methods inherited from class org.mmtk.plan.StopTheWorldCollector

collect, concurrentCollect, concurrentCollectionPhase

Methods inherited from class org.mmtk.plan.ParallelCollector

parallelWorkerCount, parallelWorkerOrdinal, park, rendezvous, run

Methods inherited from class org.mmtk.plan.CollectorContext

copyCheckAllocator, getId, getLog, initCollector

Methods inherited from class java.lang.Object

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

Field Detail

trace

protected final SSTraceLocal trace

ss

protected final CopyLocal ss

los

protected final LargeObjectLocal los

Constructor Detail

SSCollector

public SSCollector()

Constructor

SSCollector

protected SSCollector(SSTraceLocal tr)

Constructor

Parameters:

tr - The trace to use

Method Detail

allocCopy

public Address allocCopy(ObjectReference original,
                         int bytes,
                         int align,
                         int offset,
                         int allocator)

Allocate space for copying an object (this method does not copy the object, it only allocates space)

Overrides:

allocCopy in class CollectorContext

Parameters:

original - The object that is being copied.

bytes - The size of the space to be allocated (in bytes)

align - Required alignment for the copy

offset - Offset associated with the alignment.

allocator - The allocator associated with this request

Returns:

The address of the first byte of the allocated region

postCopy

public void postCopy(ObjectReference object,
                     ObjectReference typeRef,
                     int bytes,
                     int allocator)

Description copied from class: CollectorContext

Perform any post-copy actions.

Overrides:

postCopy in class CollectorContext

Parameters:

object - The newly allocated object.

typeRef - the type reference for the instance being created.

bytes - The size of the space to be allocated (in bytes).

allocator - The allocator statically assigned to this allocation.

collectionPhase

public void collectionPhase(short phaseId,
                            boolean primary)

Perform a (local, i.e.per-collector) collection phase.

Overrides:

collectionPhase in class SimpleCollector

Parameters:

phaseId - The unique phase identifier

primary - Should this thread be used to execute any single-threaded local operations?

isSemiSpaceObject

public static boolean isSemiSpaceObject(ObjectReference object)

Return true if the given reference is to an object that is within one of the semi-spaces.

Parameters:

object - The object in question

Returns:

true if the given reference is to an object that is within one of the semi-spaces.

global

private static SS global()

Returns:

The active global plan as an SS instance.

getCurrentTrace

public TraceLocal getCurrentTrace()

Overrides:

getCurrentTrace in class ParallelCollector

Returns:

The current trace instance.