org.apache.flink.core.memory

Class MemorySegmentFactory

java.lang.Object

org.apache.flink.core.memory.MemorySegmentFactory

@Internal
public final class MemorySegmentFactory
extends Object

A factory for (hybrid) memory segments (HybridMemorySegment).

The purpose of this factory is to make sure that all memory segments for heap data are of the same type. That way, the runtime does not mix the various specializations of the MemorySegment. Not mixing them has shown to be beneficial to method specialization by the JIT and to overall performance.

Constructor Summary

Constructors

Constructor and Description
MemorySegmentFactory()

Method Summary

Modifier and Type	Method and Description
static MemorySegment	allocateUnpooledSegment(int size) Allocates some unpooled memory and creates a new memory segment that represents that memory.
static MemorySegment	allocateUnpooledSegment(int size, Object owner) Allocates some unpooled memory and creates a new memory segment that represents that memory.
static MemorySegment	wrap(byte[] buffer) Creates a new memory segment that targets the given heap memory region.
static MemorySegment	wrapPooledHeapMemory(byte[] memory, Object owner) Creates a memory segment that wraps the given byte array.
static MemorySegment	wrapPooledOffHeapMemory(ByteBuffer memory, Object owner) Creates a memory segment that wraps the off-heap memory backing the given ByteBuffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

MemorySegmentFactory

public MemorySegmentFactory()

Method Detail

wrap

public static MemorySegment wrap(byte[] buffer)

Creates a new memory segment that targets the given heap memory region.

This method should be used to turn short lived byte arrays into memory segments.

Parameters:

buffer - The heap memory region.

Returns:

A new memory segment that targets the given heap memory region.

allocateUnpooledSegment

public static MemorySegment allocateUnpooledSegment(int size)

Allocates some unpooled memory and creates a new memory segment that represents that memory.

This method is similar to allocateUnpooledSegment(int, Object), but the memory segment will have null as the owner.

Parameters:

size - The size of the memory segment to allocate.

Returns:

A new memory segment, backed by unpooled heap memory.

allocateUnpooledSegment

public static MemorySegment allocateUnpooledSegment(int size,
                                                    Object owner)

Allocates some unpooled memory and creates a new memory segment that represents that memory.

This method is similar to allocateUnpooledSegment(int), but additionally sets the owner of the memory segment.

Parameters:

size - The size of the memory segment to allocate.

owner - The owner to associate with the memory segment.

Returns:

A new memory segment, backed by unpooled heap memory.

wrapPooledHeapMemory

public static MemorySegment wrapPooledHeapMemory(byte[] memory,
                                                 Object owner)

Creates a memory segment that wraps the given byte array.

This method is intended to be used for components which pool memory and create memory segments around long-lived memory regions.

Parameters:

memory - The heap memory to be represented by the memory segment.

owner - The owner to associate with the memory segment.

Returns:

A new memory segment representing the given heap memory.

wrapPooledOffHeapMemory

public static MemorySegment wrapPooledOffHeapMemory(ByteBuffer memory,
                                                    Object owner)

Creates a memory segment that wraps the off-heap memory backing the given ByteBuffer. Note that the ByteBuffer needs to be a direct ByteBuffer.

This method is intended to be used for components which pool memory and create memory segments around long-lived memory regions.

Parameters:

memory - The byte buffer with the off-heap memory to be represented by the memory segment.

owner - The owner to associate with the memory segment.

Returns:

A new memory segment representing the given off-heap memory.