org.mmtk.utility.alloc

Class ImmixAllocator

java.lang.Object

org.mmtk.utility.alloc.Allocator

org.mmtk.utility.alloc.ImmixAllocator

Direct Known Subclasses:

MutatorLocal

public class ImmixAllocator
extends Allocator

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	copy
private Address	cursor bump pointer
private boolean	hot
private Address	largeCursor bump pointer for large objects
private Address	largeLimit limit for bump pointer for large objects
private Address	limit limit for bump pointer
private int	line
private int	lineUseCount approximation to bytes allocated (measured at 99% accurate) 07/10/30
private Address	markTable
private Address	recyclableBlock
private boolean	recyclableExhausted
private boolean	requestForLarge is the current request for large or small?
protected ImmixSpace	space space this allocator is associated with
private boolean	straddle did the last allocation straddle a line?

Constructor Summary

Constructors

Constructor and Description
ImmixAllocator(ImmixSpace space, boolean hot, boolean copy) Constructor.

Method Summary

Modifier and Type	Method and Description
private boolean	acquireRecyclableBlock()
private boolean	acquireRecyclableBlockAddressOrder()
private boolean	acquireRecyclableLines(int bytes, int align, int offset)
Address	alloc(int bytes, int align, int offset) Allocate space for a new object.
private Address	allocSlowHot(int bytes, int align, int offset) Internal allocation slow path.
protected Address	allocSlowOnce(int bytes, int align, int offset) External allocation slow path (called by superclass when slow path is actually taken.
boolean	getLastAllocLineStraddle()
Space	getSpace() Return the space this allocator is currently bound to.
Address	overflowAlloc(int bytes, int align, int offset) Allocate space for a new object.
void	reset() Reset the allocator.
void	show() Print out the status of the allocator (for debugging)
private void	zeroBlock(Address block)

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 ImmixSpace space

space this allocator is associated with

hot

private final boolean hot

copy

private final boolean copy

cursor

private Address cursor

bump pointer

limit

private Address limit

limit for bump pointer

largeCursor

private Address largeCursor

bump pointer for large objects

largeLimit

private Address largeLimit

limit for bump pointer for large objects

requestForLarge

private boolean requestForLarge

is the current request for large or small?

straddle

private boolean straddle

did the last allocation straddle a line?

lineUseCount

private int lineUseCount

approximation to bytes allocated (measured at 99% accurate) 07/10/30

markTable

private Address markTable

recyclableBlock

private Address recyclableBlock

line

private int line

recyclableExhausted

private boolean recyclableExhausted

Constructor Detail

ImmixAllocator

public ImmixAllocator(ImmixSpace space,
                      boolean hot,
                      boolean copy)

Constructor.

Parameters:

space - The space to bump point into.

hot - TODO

copy - TODO

Method Detail

reset

public void reset()

Reset the allocator. Note that this does not reset the space.

alloc

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

Allocate space for a new object. This is frequently executed code and the coding is deliberately sensitive to the optimizing compiler. After changing this, always check the IR/MC that is generated.

Parameters:

bytes - The number of bytes allocated

align - The requested alignment

offset - The offset from the alignment

Returns:

The address of the first byte of the allocated region

overflowAlloc

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

Allocate space for a new object. This is frequently executed code and the coding is deliberately sensitive to the optimizing compiler. After changing this, always check the IR/MC that is generated.

Parameters:

bytes - The number of bytes allocated

align - The requested alignment

offset - The offset from the alignment

Returns:

The address of the first byte of the allocated region

getLastAllocLineStraddle

public final boolean getLastAllocLineStraddle()

allocSlowOnce

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

External allocation slow path (called by superclass when slow path is actually taken. This is necessary (rather than a direct call from the fast path) because of the possibility of a thread switch and corresponding re-association of bump pointers to kernel threads.

Specified by:

allocSlowOnce in class Allocator

Parameters:

bytes - The number of bytes allocated

align - The requested alignment

offset - The offset from the alignment

Returns:

The address of the first byte of the allocated region or zero on failure

allocSlowHot

private Address allocSlowHot(int bytes,
                             int align,
                             int offset)

Internal allocation slow path. This is called whenever the bump pointer reaches the internal limit. The code is forced out of line. If required we perform an external slow path take, which we inline into this method since this is already out of line.

Parameters:

bytes - The number of bytes allocated

align - The requested alignment

offset - The offset from the alignment

Returns:

The address of the first byte of the allocated region

acquireRecyclableLines

private boolean acquireRecyclableLines(int bytes,
                                       int align,
                                       int offset)

acquireRecyclableBlock

private boolean acquireRecyclableBlock()

acquireRecyclableBlockAddressOrder

private boolean acquireRecyclableBlockAddressOrder()

zeroBlock

private void zeroBlock(Address block)

getSpace

public final Space getSpace()

Description copied from class: Allocator

Return the space this allocator is currently bound to.

Specified by:

getSpace in class Allocator

Returns:

the space associated with this squish allocator

show

public final void show()

Print out the status of the allocator (for debugging)