On Tue Jul 15, 2025 at 3:58 PM CEST, Vitaly Wool wrote:
> pub unsafe trait Allocator {
> - /// Allocate memory based on `layout` and `flags`.
> + /// Allocate memory based on `layout`, `flags` and `nid`.
> ///
> /// On success, returns a buffer represented as `NonNull<[u8]>` that satisfies the layout
> /// constraints (i.e. minimum size and alignment as specified by `layout`).
> @@ -153,13 +180,21 @@ pub unsafe trait Allocator {
> ///
> /// Additionally, `Flags` are honored as documented in
> /// <https://docs.kernel.org/core-api/mm-api.html#mm-api-gfp-flags>.
> - fn alloc(layout: Layout, flags: Flags) -> Result<NonNull<[u8]>, AllocError> {
> + fn alloc(layout: Layout, flags: Flags, nid: NumaNode) -> Result<NonNull<[u8]>, AllocError> {
> // SAFETY: Passing `None` to `realloc` is valid by its safety requirements and asks for a
> // new memory allocation.
> - unsafe { Self::realloc(None, layout, Layout::new::<()>(), flags) }
> + unsafe { Self::realloc(None, layout, Layout::new::<()>(), flags, nid) }
> }
>
> - /// Re-allocate an existing memory allocation to satisfy the requested `layout`.
> + /// Re-allocate an existing memory allocation to satisfy the requested `layout` and
> + /// a specific NUMA node request to allocate the memory for.
> + ///
> + /// Systems employing a Non Uniform Memory Access (NUMA) architecture contain collections of
> + /// hardware resources including processors, memory, and I/O buses, that comprise what is
> + /// commonly known as a NUMA node.
> + ///
> + /// `nid` stands for NUMA id, i. e. NUMA node identifier, which is a non-negative integer
> + /// if a node needs to be specified, or [`NumaNode::NO_NODE`] if the caller doesn't care.
> ///
> /// If the requested size is zero, `realloc` behaves equivalent to `free`.
> ///
> @@ -196,6 +231,7 @@ unsafe fn realloc(
> layout: Layout,
> old_layout: Layout,
> flags: Flags,
> + nid: NumaNode,
> ) -> Result<NonNull<[u8]>, AllocError>;
>
> /// Free an existing memory allocation.
> @@ -211,7 +247,15 @@ unsafe fn free(ptr: NonNull<u8>, layout: Layout) {
> // SAFETY: The caller guarantees that `ptr` points at a valid allocation created by this
> // allocator. We are passing a `Layout` with the smallest possible alignment, so it is
> // smaller than or equal to the alignment previously used with this allocation.
> - let _ = unsafe { Self::realloc(Some(ptr), Layout::new::<()>(), layout, Flags(0)) };
> + let _ = unsafe {
> + Self::realloc(
> + Some(ptr),
> + Layout::new::<()>(),
> + layout,
> + Flags(0),
> + NumaNode::NO_NODE,
> + )
> + };
> }
> }
Regarding the change in the Allocator trait, we also have to consider
the Cmalloc allocator in rust/kernel/alloc/allocator_test.rs, which is there to
support userspace tests.
While we're planning to remove this (see also [1]), we still have to consider
it for now.
[1] https://lore.kernel.org/rust-for-linux/20250726180750.2735836-1-ojeda@xxxxxxxxxx/
