Module `Tolk.Tlsf`

Two-Level Segregated Fit allocator.

Manages a contiguous address range with O(1) best-fit allocation and O(1) deallocation with coalescing. Free blocks are indexed by two levels of buckets:

Level 1 is the most significant bit of the block size.
Level 2 subdivides each L1 range into 2{^l2_cnt} entries.

Allocation finds the smallest free block that fits, splitting the remainder. Deallocation merges the freed block with its neighbours.

Types

type t

The type for TLSF allocators. Mutable.

Constructors

val create : 
  size:int ->
  ?base:int ->
  ?block_size:int ->
  ?lv2_cnt:int ->
  unit ->
  t

create ~size ?base ?block_size ?lv2_cnt () is a TLSF allocator managing size bytes starting at virtual address base.

base defaults to 0. block_size is the minimum allocation granularity and defaults to 16. lv2_cnt is the number of level-2 subdivisions per level-1 bucket and defaults to 16.

Operations

val alloc : t -> int -> ?align:int -> unit -> int

alloc t size ?align () is the start address of a newly allocated region of size bytes. The returned address is a multiple of align.

align defaults to 1. The actual allocation is at least block_size bytes.

Raises Out_of_memory if no free block can satisfy the request.

val free : t -> int -> unit

free t addr returns the block at addr to the free pool and merges it with any adjacent free blocks. addr must have been previously returned by alloc on the same allocator.