holoscan::FirstFitAllocatorBase

Memory management helper class using first-fit allocation strategy.

This class keeps track of allocated and free regions within a large memory chunk and can efficiently find the first available block that fits a requested size. It works only with indices and relies on an external class to hold the actual memory.

Internally, it uses a binary segment tree to track the largest available block in any given area of memory. All operations have logarithmic time complexity.

#include <holoscan/first_fit_allocator_base.hpp>

Constructors

FirstFitAllocatorBase

holoscan::FirstFitAllocatorBase::FirstFitAllocatorBase()holoscan::FirstFitAllocatorBase::FirstFitAllocatorBase()

Default constructor.

Methods

allocate

expected_t<void> holoscan::FirstFitAllocatorBase::allocate(
    int32_t size
)

Allocate internal data structures to handle memory requests for a given size.

Requires 32 * 2^ceil(log2(size)) bytes of memory for internal bookkeeping.

Returns: Success or error status. Error::kInvalidSize if size is invalid.

Parameters

acquire

expected_t<int32_t> holoscan::FirstFitAllocatorBase::acquire(
    int32_t size
)

Acquire a contiguous block of memory of the specified size.

If such a contiguous block exists, returns the lowest index where the block starts. This block will be marked as allocated until a call to release() is made.

Returns: Index of the allocated block on success, Error::kOutOfMemory if no suitable block exists.

Parameters

release

expected_t<void> holoscan::FirstFitAllocatorBase::release(
    int32_t index
)

Release a previously acquired block of memory.

The block must have been previously acquired using acquire(). Once released, the memory becomes available for future allocations.

Returns: Success or error status. Error::kBlockNotAllocated if the block was not previously allocated.

Parameters

propagate_to_root

void holoscan::FirstFitAllocatorBase::propagate_to_root(
    int32_t idx
)

Update the tree path from a given node to the root.

Parameters

update

void holoscan::FirstFitAllocatorBase::update(
    int32_t left,
    int32_t right,
    int32_t free
)

Update a segment of the tree and mark it as free or allocated.

Parameters

Types

Typedefs

Error

Error codes used by the first-fit allocator classes.

Member variables

Inner classes

Memory

struct holoscan::FirstFitAllocatorBase::Memory

Helper data structure for efficient memory block searching.

Represents a node in a binary segment tree used to track free and allocated memory regions.