org.mmtk.utility.alloc

Class SegregatedFreeList<S extends SegregatedFreeListSpace>

java.lang.Object

org.mmtk.utility.alloc.Allocator

org.mmtk.utility.alloc.SegregatedFreeList<S>

Direct Known Subclasses:

SegregatedFreeListLocal

public abstract class SegregatedFreeList<S extends SegregatedFreeListSpace>
extends Allocator

This abstract class implements the fast past for a segregated free list.

Field Summary

Fields

Modifier and Type	Field and Description
protected AddressArray	freeList The current free lists for the size classes
protected S	space The space

Constructor Summary

Constructors

Constructor and Description
SegregatedFreeList(S space) Constructor

Method Summary

Modifier and Type	Method and Description
Address	alloc(int bytes, int align, int offset) Allocate bytes contiguous bytes of zeroed memory.
private int	getSizeClass(int bytes) Get the size class for a given number of bytes.
protected S	getSpace() Return the space this allocator is currently bound to.
private int	sizeClassCount() The number of distinct size classes.

Methods inherited from class org.mmtk.utility.alloc.Allocator

alignAllocation, alignAllocation, alignAllocationNoFill, allocSlow, allocSlowInline, allocSlowOnce, determineCollectionAttempts, fillAlignmentGap, getMaximumAlignedSize, getMaximumAlignedSize

Methods inherited from class java.lang.Object

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

Field Detail

space

protected final S extends SegregatedFreeListSpace space

The space

freeList

protected final AddressArray freeList

The current free lists for the size classes

Constructor Detail

SegregatedFreeList

public SegregatedFreeList(S space)

Constructor

Parameters:

space - The space with which this allocator will be associated

Method Detail

getSpace

protected final S getSpace()

Description copied from class: Allocator

Return the space this allocator is currently bound to.

Specified by:

getSpace in class Allocator

Returns:

The Space.

alloc

public final Address alloc(int bytes,
                           int align,
                           int offset)

Allocate bytes contiguous bytes of zeroed memory.

This code implements the fast path, and on failure delegates to the slow path.

Parameters:

bytes - The size of the object to occupy this space, in bytes.

align - The requested alignment.

offset - The alignment offset.

Returns:

The address of the first word or zero on failure

sizeClassCount

private int sizeClassCount()

The number of distinct size classes.

NOTE: For optimal performance this call must be implemented in a way it can be inlined and optimized within the allocation sequence.

Returns:

the number of distinct size classes

getSizeClass

private int getSizeClass(int bytes)

Get the size class for a given number of bytes.

NOTE: For optimal performance this call must be implemented in a way it can be inlined and optimized within the allocation sequence.

Parameters:

bytes - The number of bytes required to accommodate the object

Returns:

The size class capable of accommodating the allocation request.