alluxio.client.file.cache.cuckoofilter

Class SegmentedLock

java.lang.Object

alluxio.client.file.cache.cuckoofilter.SegmentedLock

public class SegmentedLock
extends java.lang.Object

A segmented lock that supports methods to lock/unlock multiple buckets in order to avoid dead lock.

Constructor Summary

Constructors

Constructor and Description
SegmentedLock(int numLocks, int numBuckets) Create a segmented lock with specified locks.

Method Summary

Modifier and Type	Method and Description
int	getNumBucketsPerSegment()
int	getNumLocks()
int	getSegmentIndex(int bucket)
int	getSegmentStartPos(int index)
void	readLock(int bucket1, int bucket2) Non-exclusively acquires the locks of two buckets, blocking if necessary until available.
void	unlockRead(int bucket1, int bucket2) Releases the read locks of two buckets if they are held.
void	unlockWrite(int bucket) Releases the write lock of bucket if it is held.
void	unlockWrite(int bucket1, int bucket2) Releases the write locks of two buckets if they are held.
void	unlockWrite(int bucket1, int bucket2, int bucket3) Releases the write locks of three buckets if they are held.
void	unlockWriteSegment(int index) Releases the write lock of the ith segment if it is held.
void	writeLock(int bucket) Exclusively acquires the lock of the bucket, blocking if necessary until available.
void	writeLock(int b1, int b2) Exclusively acquires the locks of two buckets, blocking if necessary until available.
void	writeLock(int bucket1, int bucket2, int bucket3) Exclusively acquires the locks of three buckets, blocking if necessary until available.
void	writeLockSegment(int index) Exclusively acquires the lock of the ith segment, blocking if necessary until available.

Methods inherited from class java.lang.Object

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

Constructor Detail

SegmentedLock

public SegmentedLock(int numLocks,
                     int numBuckets)

Create a segmented lock with specified locks.

Parameters:

numBuckets - the number of buckets

numLocks - the number of locks

Method Detail

readLock

public void readLock(int bucket1,
                     int bucket2)

Non-exclusively acquires the locks of two buckets, blocking if necessary until available.

Parameters:

bucket1 - the first bucket to be locked

bucket2 - the second bucket to be locked

unlockRead

public void unlockRead(int bucket1,
                       int bucket2)

Releases the read locks of two buckets if they are held.

Parameters:

bucket1 - the first bucket to be unlocked

bucket2 - the second bucket to be unlocked

writeLock

public void writeLock(int bucket)

Exclusively acquires the lock of the bucket, blocking if necessary until available.

Parameters:

bucket - the bucket to be locked

writeLock

public void writeLock(int b1,
                      int b2)

Exclusively acquires the locks of two buckets, blocking if necessary until available.

Parameters:

b1 - the first bucket to be locked

b2 - the second bucket to be locked

writeLock

public void writeLock(int bucket1,
                      int bucket2,
                      int bucket3)

Exclusively acquires the locks of three buckets, blocking if necessary until available.

Parameters:

bucket1 - the first bucket to be locked

bucket2 - the second bucket to be locked

bucket3 - the third bucket to be locked

unlockWrite

public void unlockWrite(int bucket)

Releases the write lock of bucket if it is held.

Parameters:

bucket - the bucket to be unlocked

unlockWrite

public void unlockWrite(int bucket1,
                        int bucket2)

Releases the write locks of two buckets if they are held.

Parameters:

bucket1 - the first bucket to be unlocked

bucket2 - the second bucket to be unlocked

unlockWrite

public void unlockWrite(int bucket1,
                        int bucket2,
                        int bucket3)

Releases the write locks of three buckets if they are held.

Parameters:

bucket1 - the first bucket to be unlocked

bucket2 - the second bucket to be unlocked

bucket3 - the third bucket to be unlocked

writeLockSegment

public void writeLockSegment(int index)

Exclusively acquires the lock of the ith segment, blocking if necessary until available.

Parameters:

index - of the segment to be locked

unlockWriteSegment

public void unlockWriteSegment(int index)

Releases the write lock of the ith segment if it is held.

Parameters:

index - of the segment to be unlocked

getNumLocks

public int getNumLocks()

Returns:

the number of locks/segments

getNumBucketsPerSegment

public int getNumBucketsPerSegment()

Returns:

the number of buckets per segment guards

getSegmentStartPos

public int getSegmentStartPos(int index)

Parameters:

index - index of the segment

Returns:

the start index of ith segment

getSegmentIndex

public int getSegmentIndex(int bucket)

Parameters:

bucket - the bucket

Returns:

the segment index which the bucket belongs to