ForwardAllocator Class Reference

An arena allocator, which is optimized to not be able to free individual entries, only the entire allocator. More...

#include <ForwardAllocator.hxx>

Public Member Functions
void *	allocate (size_t size, size_t align)
	Allocates a block of memory.

Public Attributes
size_t	allocSize_ {0}
	Total number of bytes allocated.
size_t	allocWasted_ {0}
	Number of bytes lost due to alignment and end-of-block chunks.

Static Public Attributes
static constexpr size_t	BLOCK_BYTE_SIZE = 1024
	Allocated blocks will be this size.

Private Types
typedef uint64_t	primitive_t
	A primitive type that has sufficient alignment to what we support.
typedef primitive_t	AlignedPayload[BLOCK_BYTE_SIZE/sizeof(primitive_t)]
	An array type with the BLOCK_BYTE_SIZE size.
typedef Buffer< AlignedPayload >	BufferType
	Buffer type that we will be allocating from the pool.

Private Member Functions
uint8_t *	head_ptr ()

Private Attributes
TypedQueue< BufferType >	allocatedBlocks_
	Holds all blocks that we allocated (ever).
size_t	offsetInLast_ {BLOCK_BYTE_SIZE + 1}
	Points into the last allocated block to the next emtpy space.
OSMutex	lock_
	Lock that protects the offset in last variable and the queue of blocks.

Static Private Attributes
static DynamicPool *	kbytePool_
	This buffer pool will have one bucket to allocate 1kb objects each and kep them on a free list.

Detailed Description

An arena allocator, which is optimized to not be able to free individual entries, only the entire allocator.

Integrated with a buffer pool to reuse large blocks of heap memory without being exposed to heap fragmentation.

Definition at line 51 of file ForwardAllocator.hxx.

Member Typedef Documentation

AlignedPayload

typedef primitive_t ForwardAllocator::AlignedPayload[BLOCK_BYTE_SIZE/sizeof(primitive_t)]

private

An array type with the BLOCK_BYTE_SIZE size.

Definition at line 74 of file ForwardAllocator.hxx.

BufferType

typedef Buffer<AlignedPayload> ForwardAllocator::BufferType

private

Buffer type that we will be allocating from the pool.

Definition at line 78 of file ForwardAllocator.hxx.

primitive_t

typedef uint64_t ForwardAllocator::primitive_t

private

A primitive type that has sufficient alignment to what we support.

Definition at line 72 of file ForwardAllocator.hxx.

Constructor & Destructor Documentation

ForwardAllocator()

ForwardAllocator::ForwardAllocator

(

)

Definition at line 56 of file ForwardAllocator.cxx.

~ForwardAllocator()

ForwardAllocator::~ForwardAllocator

(

)

Definition at line 60 of file ForwardAllocator.cxx.

Member Function Documentation

allocate()

void * ForwardAllocator::allocate	(	size_t	size,
		size_t	align
	)

Allocates a block of memory.

Thread-safe.

Parameters

size	the number of bytes to allocate.
align	alignment of allocated object in bytes (1 to 8).

Definition at line 69 of file ForwardAllocator.cxx.

head_ptr()

uint8_t * ForwardAllocator::head_ptr ( )

inlineprivate

Returns

pointer to the beginning of the memory area in the latest allocated block, cast to uint8_t*, or nullptr if no block has been allocated yet.

Definition at line 83 of file ForwardAllocator.hxx.

Member Data Documentation

allocatedBlocks_

TypedQueue<BufferType> ForwardAllocator::allocatedBlocks_

private

Holds all blocks that we allocated (ever).

They will all be freed in the destructor.

Definition at line 94 of file ForwardAllocator.hxx.

allocSize_

size_t ForwardAllocator::allocSize_ {0}

Total number of bytes allocated.

Definition at line 100 of file ForwardAllocator.hxx.

allocWasted_

size_t ForwardAllocator::allocWasted_ {0}

Number of bytes lost due to alignment and end-of-block chunks.

Definition at line 102 of file ForwardAllocator.hxx.

BLOCK_BYTE_SIZE

constexpr size_t ForwardAllocator::BLOCK_BYTE_SIZE = 1024

staticconstexpr

Allocated blocks will be this size.

Definition at line 55 of file ForwardAllocator.hxx.

kbytePool_

DynamicPool * ForwardAllocator::kbytePool_

staticprivate

Initial value:

=
    new DynamicPool(Bucket::init(sizeof(BufferType), 0))

This buffer pool will have one bucket to allocate 1kb objects each and kep them on a free list.

The freelist is shared between different allocators.

Definition at line 110 of file ForwardAllocator.hxx.

lock_

OSMutex ForwardAllocator::lock_

private

Lock that protects the offset in last variable and the queue of blocks.

Definition at line 106 of file ForwardAllocator.hxx.

offsetInLast_

size_t ForwardAllocator::offsetInLast_ {BLOCK_BYTE_SIZE + 1}

private

Points into the last allocated block to the next emtpy space.

Definition at line 96 of file ForwardAllocator.hxx.

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The documentation for this class was generated from the following files:

• ForwardAllocator.hxx
• ForwardAllocator.cxx