org.mmtk.plan.concurrent.marksweep

Class CMSMutator

java.lang.Object

org.mmtk.plan.MutatorContext

org.mmtk.plan.SimpleMutator

org.mmtk.plan.concurrent.ConcurrentMutator

org.mmtk.plan.concurrent.marksweep.CMSMutator

public class CMSMutator
extends ConcurrentMutator

This class implements per-mutator thread behavior and state for the CMS plan, which implements a full-heap concurrent mark-sweep collector.

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 Also:

CMS, CMSCollector, StopTheWorldMutator, MutatorContext

Field Summary

Fields

Modifier and Type	Field and Description
private MarkSweepLocal	ms
private TraceWriteBuffer	remset

Fields inherited from class org.mmtk.plan.concurrent.ConcurrentMutator

barrierActive, newMutatorBarrierActive

Fields inherited from class org.mmtk.plan.MutatorContext

immortal, lgcode, log, los, nonmove, smcode

Constructor Summary

Constructors

Constructor and Description
CMSMutator() Constructor

Method Summary

Modifier and Type	Method and Description
Address	alloc(int bytes, int align, int offset, int allocator, int site) Allocate memory for an object.
protected void	checkAndEnqueueReference(ObjectReference ref) Process a reference that may require being enqueued as part of a concurrent collection.
void	collectionPhase(short phaseId, boolean primary) Perform a per-mutator collection phase.
void	flushRememberedSets() Flush per-mutator remembered sets into the global remset pool.
Allocator	getAllocatorFromSpace(Space space) Return the allocator instance associated with a space space, for this plan instance.
private static CMS	global()
void	postAlloc(ObjectReference ref, ObjectReference typeRef, int bytes, int allocator) Perform post-allocation actions.

Methods inherited from class org.mmtk.plan.concurrent.ConcurrentMutator

javaLangReferenceReadBarrier, objectReferenceBulkCopy, objectReferenceTryCompareAndSwap, objectReferenceWrite

Methods inherited from class org.mmtk.plan.MutatorContext

addressBulkCopy, addressRead, addressTryCompareAndSwap, addressWrite, assertRemsetsFlushed, booleanBulkCopy, booleanRead, booleanWrite, byteBulkCopy, byteRead, byteWrite, charBulkCopy, charRead, charWrite, checkAllocator, deinitMutator, doubleBulkCopy, doubleRead, doubleWrite, extentBulkCopy, extentRead, extentWrite, floatBulkCopy, floatRead, floatWrite, flush, getId, getLog, initMutator, intBulkCopy, intRead, intTryCompareAndSwap, intWrite, longBulkCopy, longRead, longTryCompareAndSwap, longWrite, objectReferenceNonHeapRead, objectReferenceNonHeapWrite, objectReferenceRead, offsetBulkCopy, offsetRead, offsetWrite, shortBulkCopy, shortRead, shortWrite, wordBulkCopy, wordRead, wordTryCompareAndSwap, wordWrite

Methods inherited from class java.lang.Object

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

Field Detail

ms

private final MarkSweepLocal ms

remset

private final TraceWriteBuffer remset

Constructor Detail

CMSMutator

public CMSMutator()

Constructor

Method Detail

alloc

public Address alloc(int bytes,
                     int align,
                     int offset,
                     int allocator,
                     int site)

Allocate memory for an object.

This class handles the default allocator from the mark sweep space, and delegates everything else to the superclass.

Overrides:

alloc in class MutatorContext

Parameters:

bytes - The number of bytes required for the object.

align - Required alignment for the object.

offset - Offset associated with the alignment.

allocator - The allocator associated with this request.

site - Allocation site

Returns:

The low address of the allocated chunk.

postAlloc

public void postAlloc(ObjectReference ref,
                      ObjectReference typeRef,
                      int bytes,
                      int allocator)

Perform post-allocation actions. For many allocators none are required.

Initialize the object header for objects in the mark-sweep space, and delegate to the superclass for other objects.

Overrides:

postAlloc in class MutatorContext

Parameters:

ref - 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 number to be used for this allocation

getAllocatorFromSpace

public Allocator getAllocatorFromSpace(Space space)

Description copied from class: MutatorContext

Return the allocator instance associated with a space space, for this plan instance.

Overrides:

getAllocatorFromSpace in class MutatorContext

Parameters:

space - The space for which the allocator instance is desired.

Returns:

The allocator instance associated with this plan instance which is allocating into space, or null if no appropriate allocator can be established.

collectionPhase

public void collectionPhase(short phaseId,
                            boolean primary)

Perform a per-mutator collection phase.

Overrides:

collectionPhase in class ConcurrentMutator

Parameters:

phaseId - The unique phase identifier

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

flushRememberedSets

public void flushRememberedSets()

Description copied from class: MutatorContext

Flush per-mutator remembered sets into the global remset pool.

Overrides:

flushRememberedSets in class MutatorContext

checkAndEnqueueReference

protected void checkAndEnqueueReference(ObjectReference ref)

Process a reference that may require being enqueued as part of a concurrent collection.

Specified by:

checkAndEnqueueReference in class ConcurrentMutator

Parameters:

ref - The reference to check.

global

private static CMS global()

Returns:

The active global plan as a Gen instance.