org.mmtk.utility.alloc

Class LargeObjectAllocator

java.lang.Object

org.mmtk.utility.alloc.Allocator

org.mmtk.utility.alloc.LargeObjectAllocator

Direct Known Subclasses:

LargeObjectLocal

public abstract class LargeObjectAllocator
extends Allocator

This abstract class implements core functionality for a generic large object allocator. The shared VMResource used by each instance is the point of global synchronization, and synchronization only occurs at the granularity of acquiring (and releasing) chunks of memory from the VMResource. Subclasses may require finer grained synchronization during a marking phase, for example.

This is a first cut implementation, with plenty of room for improvement...

Field Summary

Fields

Modifier and Type	Field and Description
protected BaseLargeObjectSpace	space

Constructor Summary

Constructors

Constructor and Description
LargeObjectAllocator(BaseLargeObjectSpace space) Constructor

Method Summary

Modifier and Type	Method and Description
Address	alloc(int bytes, int align, int offset) Allocate space for an object
protected Address	allocSlowOnce(int bytes, int align, int offset) Allocate a large object.
protected BaseLargeObjectSpace	getSpace() Return the space this allocator is currently bound to.
void	show() Miscellaneous

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

alignAllocation, alignAllocation, alignAllocationNoFill, allocSlow, allocSlowInline, 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 BaseLargeObjectSpace space

Constructor Detail

LargeObjectAllocator

public LargeObjectAllocator(BaseLargeObjectSpace space)

Constructor

Parameters:

space - The space with which this large object allocator will be associated.

Method Detail

getSpace

protected final BaseLargeObjectSpace 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 space for an object

Parameters:

bytes - The number of bytes allocated

align - The requested alignment.

offset - The alignment offset.

Returns:

The address of the first byte of the allocated cell Will not return zero.

allocSlowOnce

protected final Address allocSlowOnce(int bytes,
                                      int align,
                                      int offset)

Allocate a large object. Large objects are directly allocted and freed in page-grained units via the vm resource. This routine returned zeroed memory.

Specified by:

allocSlowOnce in class Allocator

Parameters:

bytes - The required size of this space in bytes.

offset - The alignment offset.

align - The requested alignment.

Returns:

The address of the start of the newly allocated region at least bytes bytes in size.

show

public void show()

Miscellaneous