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0.1.0 Aug 22, 2022

#439 in Memory management

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Bare-metal allocators.

This crate provides allocators that are suitable for use on bare metal or with OS allocation facilities like mmap(2)/brk(2).

The following allocator types are available:

  • Buddy, a binary-buddy allocator. O(log2_levels_) worst-case allocation and deallocation. Supports splitting and coalescing blocks by powers of 2. Good choice for periodic medium-to-large allocations.
  • Bump, a bump allocator. O(1) allocation. Extremely fast to allocate and flexible in terms of allocation layout, but unable to deallocate individual items. Good choice for allocations that will never be deallocated or that will be deallocated en masse.
  • Slab, a slab allocator. O(1) allocation and deallocation. All allocated blocks are the same size, making this allocator a good choice when allocating many similarly-sized objects.


All allocators provided by this crate are available in a #![no_std], #![cfg(no_global_oom_handling)] environment. Additional functionality is available when enabling feature flags:

Flag Default? Requires nightly? Description
sptr Yes No Uses the sptr polyfill for Strict Provenance.
unstable No Yes Exposes constructors for allocators backed by implementors of the unstable Allocator trait, and enables the internal use of nightly-only Rust features. Obviates sptr.
alloc No No Exposes constructors for allocators backed by the global allocator.


This crate includes stable-compatible polyfills for a number of unstable standard-library APIs whose implementations are reproduced verbatim here. These features are listed below along with their authors and/or maintainers:

This crate also depends on sptr (also authored by Gankra) to reproduce strict provenance for normal pointers on stable Rust.

If I've misattributed any of this work, or a contributor to these features is missing, please open an issue!


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.