org.apache.hadoop.hdfs.shortcircuit

Class ShortCircuitShm.Slot

java.lang.Object

org.apache.hadoop.hdfs.shortcircuit.ShortCircuitShm.Slot

Enclosing class:

ShortCircuitShm

public class ShortCircuitShm.Slot
extends Object

A slot containing information about a replica. The format is: word 0 bit 0:32 Slot flags (see below). bit 33:63 Anchor count. word 1:7 Reserved for future use, such as statistics. Padding is also useful for avoiding false sharing. Little-endian versus big-endian is not relevant here since both the client and the server reside on the same computer and use the same orientation.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addAnchor() Try to add an anchor for a given slot.
org.apache.hadoop.hdfs.ExtendedBlockId	getBlockId() Get the ExtendedBlockId associated with this slot.
ShortCircuitShm	getShm() Get the short-circuit memory segment associated with this Slot.
ShortCircuitShm.SlotId	getSlotId() Get the SlotId of this slot, containing both shmId and slotIdx.
int	getSlotIdx() Get the Slot index.
boolean	isAnchorable()
boolean	isAnchored()
boolean	isValid()
void	makeAnchorable()
void	makeInvalid()
void	makeUnanchorable()
void	makeValid()
void	removeAnchor() Remove an anchor for a given slot.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

getShm

public ShortCircuitShm getShm()

Get the short-circuit memory segment associated with this Slot.

Returns:

The enclosing short-circuit memory segment.

getBlockId

public org.apache.hadoop.hdfs.ExtendedBlockId getBlockId()

Get the ExtendedBlockId associated with this slot.

Returns:

The ExtendedBlockId of this slot.

getSlotId

public ShortCircuitShm.SlotId getSlotId()

Get the SlotId of this slot, containing both shmId and slotIdx.

Returns:

The SlotId of this slot.

getSlotIdx

public int getSlotIdx()

Get the Slot index.

Returns:

The index of this slot.

isValid

public boolean isValid()

makeValid

public void makeValid()

makeInvalid

public void makeInvalid()

isAnchorable

public boolean isAnchorable()

makeAnchorable

public void makeAnchorable()

makeUnanchorable

public void makeUnanchorable()

isAnchored

public boolean isAnchored()

addAnchor

public boolean addAnchor()

Try to add an anchor for a given slot. When a slot is anchored, we know that the block it refers to is resident in memory.

Returns:

True if the slot is anchored.

removeAnchor

public void removeAnchor()

Remove an anchor for a given slot.

toString

public String toString()

Overrides:

toString in class Object