org.apache.cassandra.utils.memory

Class BufferPool

java.lang.Object

org.apache.cassandra.utils.memory.BufferPool

public class BufferPool
extends java.lang.Object

A pool of ByteBuffers that can be recycled. TODO: document the semantics of this class carefully Notably: we do not automatically release from the local pool any chunk that has been incompletely allocated from

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BufferPool.LocalPool A thread local class that grabs chunks from the global pool for this thread allocations.

Field Summary

Fields

Modifier and Type	Field and Description
static long	MEMORY_USAGE_THRESHOLD
static int	NORMAL_ALLOCATION_UNIT
static int	NORMAL_CHUNK_SIZE The size of a page aligned buffer, 128KiB
static int	TINY_ALLOCATION_LIMIT
static int	TINY_ALLOCATION_UNIT
static int	TINY_CHUNK_SIZE

Constructor Summary

Constructors

Constructor and Description
BufferPool()

Method Summary

Modifier and Type	Method and Description
static void	debug(org.apache.cassandra.utils.memory.BufferPool.Debug setDebug)
static java.nio.ByteBuffer	get(int size, BufferType bufferType)
static java.nio.ByteBuffer	getAtLeast(int size, BufferType bufferType)
static void	put(java.nio.ByteBuffer buffer)
static void	putUnusedPortion(java.nio.ByteBuffer buffer)
static int	roundUp(int size)
static int	roundUp(int size, int unit)
static void	setRecycleWhenFreeForCurrentThread(boolean recycleWhenFree)
static void	shutdownLocalCleaner(long timeout, java.util.concurrent.TimeUnit unit)
static long	sizeInBytes()
static java.nio.ByteBuffer	tryGet(int size) Unlike the get methods, this will return null if the pool is exhausted
static java.nio.ByteBuffer	tryGetAtLeast(int size)
static long	unsafeGetBytesInUse()

Methods inherited from class java.lang.Object

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

Field Detail

NORMAL_CHUNK_SIZE

public static final int NORMAL_CHUNK_SIZE

The size of a page aligned buffer, 128KiB

See Also:

Constant Field Values

NORMAL_ALLOCATION_UNIT

public static final int NORMAL_ALLOCATION_UNIT

See Also:

Constant Field Values

TINY_CHUNK_SIZE

public static final int TINY_CHUNK_SIZE

See Also:

Constant Field Values

TINY_ALLOCATION_UNIT

public static final int TINY_ALLOCATION_UNIT

See Also:

Constant Field Values

TINY_ALLOCATION_LIMIT

public static final int TINY_ALLOCATION_LIMIT

See Also:

Constant Field Values

MEMORY_USAGE_THRESHOLD

public static long MEMORY_USAGE_THRESHOLD

Constructor Detail

BufferPool

public BufferPool()

Method Detail

get

public static java.nio.ByteBuffer get(int size,
                                      BufferType bufferType)

getAtLeast

public static java.nio.ByteBuffer getAtLeast(int size,
                                             BufferType bufferType)

tryGet

public static java.nio.ByteBuffer tryGet(int size)

Unlike the get methods, this will return null if the pool is exhausted

tryGetAtLeast

public static java.nio.ByteBuffer tryGetAtLeast(int size)

put

public static void put(java.nio.ByteBuffer buffer)

putUnusedPortion

public static void putUnusedPortion(java.nio.ByteBuffer buffer)

setRecycleWhenFreeForCurrentThread

public static void setRecycleWhenFreeForCurrentThread(boolean recycleWhenFree)

sizeInBytes

public static long sizeInBytes()

debug

public static void debug(org.apache.cassandra.utils.memory.BufferPool.Debug setDebug)

roundUp

public static int roundUp(int size)

roundUp

public static int roundUp(int size,
                          int unit)

shutdownLocalCleaner

public static void shutdownLocalCleaner(long timeout,
                                        java.util.concurrent.TimeUnit unit)
                                 throws java.lang.InterruptedException,
                                        java.util.concurrent.TimeoutException

Throws:

java.lang.InterruptedException

java.util.concurrent.TimeoutException

unsafeGetBytesInUse

public static long unsafeGetBytesInUse()