org.mmtk.plan.semispace.gcspy

Class SSGCspyMutator

java.lang.Object

org.mmtk.plan.MutatorContext

org.mmtk.plan.SimpleMutator

org.mmtk.plan.StopTheWorldMutator

org.mmtk.plan.semispace.SSMutator

org.mmtk.plan.semispace.gcspy.SSGCspyMutator

public class SSGCspyMutator
extends SSMutator

This class implements per-mutator thread behavior and state for the SSGCspy plan. See SSGCspy for an overview of the GC-spy mechanisms.

See Also:

SSMutator, SSGCspy, SSGCspyCollector, StopTheWorldMutator, MutatorContext

Field Summary

Fields

Modifier and Type	Field and Description
private static boolean	DEBUG
private BumpPointer	gcspy Per-mutator allocator into GCspy's space
private static boolean	LOS_FROMSPACE
private static boolean	LOS_TOSPACE

Fields inherited from class org.mmtk.plan.semispace.SSMutator

ss

Fields inherited from class org.mmtk.plan.MutatorContext

immortal, lgcode, log, los, nonmove, smcode

Constructor Summary

Constructors

Constructor and Description
SSGCspyMutator()

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.
void	collectionPhase(short phaseId, boolean primary) Perform a per-mutator collection phase.
private void	debugSpaces(CopySpace scannedSpace) Debugging info for the semispaces
private void	gatherImmortal(int event) Gather data for the immortal space
private void	gcspyGatherData(int event) Gather data for GCspy for the semispaces, the immortal space and the large object space.
Allocator	getAllocatorFromSpace(Space space) Return the allocator instance associated with a space space, for this plan instance.
void	postAlloc(ObjectReference object, ObjectReference typeRef, int bytes, int allocator) Perform post-allocation actions.
private LinearSpaceDriver	toSpaceDriver()

Methods inherited from class org.mmtk.plan.semispace.SSMutator

initMutator, show

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, flushRememberedSets, getId, getLog, intBulkCopy, intRead, intTryCompareAndSwap, intWrite, javaLangReferenceReadBarrier, longBulkCopy, longRead, longTryCompareAndSwap, longWrite, objectReferenceBulkCopy, objectReferenceNonHeapRead, objectReferenceNonHeapWrite, objectReferenceRead, objectReferenceTryCompareAndSwap, objectReferenceWrite, 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

DEBUG

private static final boolean DEBUG

See Also:

Constant Field Values

LOS_TOSPACE

private static final boolean LOS_TOSPACE

See Also:

Constant Field Values

LOS_FROMSPACE

private static final boolean LOS_FROMSPACE

See Also:

Constant Field Values

gcspy

private final BumpPointer gcspy

Per-mutator allocator into GCspy's space

Constructor Detail

SSGCspyMutator

public SSGCspyMutator()

Method Detail

alloc

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

Allocate memory for an object.

Overrides:

alloc in class SSMutator

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 object,
                      ObjectReference typeRef,
                      int bytes,
                      int allocator)

Description copied from class: MutatorContext

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

Overrides:

postAlloc in class SSMutator

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 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 SSMutator

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 final void collectionPhase(short phaseId,
                                  boolean primary)

Perform a per-mutator collection phase. Before a collection, we need to discover

• the tospace objects copied by the collector in the last GC cycle
• the ojects allocated since by the mutator.
• all immortal objects allocated by the mutator
• all large objects allocated by the mutator

After the semispace has been copied, we need to discover

• the tospace objects copied by the collector
• all immortal objects allocated by the mutator
• all large objects allocated by the mutator

Overrides:

collectionPhase in class SSMutator

Parameters:

phaseId - The unique phase identifier

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

gcspyGatherData

private void gcspyGatherData(int event)

Gather data for GCspy for the semispaces, the immortal space and the large object space.

This method sweeps the semispace under consideration to gather data. Alternatively and more efficiently, 'used space' can obviously be discovered in constant time simply by comparing the start and the end addresses of the semispace. However, per-object information can only be gathered by sweeping through the space and we do this here for tutorial purposes.

Parameters:

event - The event, either BEFORE_COLLECTION, SEMISPACE_COPIED or AFTER_COLLECTION

gatherImmortal

private void gatherImmortal(int event)

Gather data for the immortal space

Parameters:

event - The event, either BEFORE_COLLECTION, SEMISPACE_COPIED or AFTER_COLLECTION

debugSpaces

private void debugSpaces(CopySpace scannedSpace)

Debugging info for the semispaces

Parameters:

scannedSpace - the space to output debug for.

toSpaceDriver

private LinearSpaceDriver toSpaceDriver()

Returns:

the driver for toSpace