Re: [PATCH v2 3/3] rust: alloc: make `ReallocFunc::call` inline

[Danilo Krummrich <dakr@kernel.org>]

On Sun, Jan 05, 2025 at 07:40:06PM +0000, Gary Guo wrote:
> This function can be called with different function pointers when
> different allocator (e.g. Kmalloc, Vmalloc, KVmalloc), however since
> this function is not polymorphic, only one instance is generated,
> and function pointers are used. Given that this function is called
> for any Rust-side allocation/deallocation, performance matters a lot,
> so making this function inlineable.
> 
> This is discovered when doing helper inlining work, since it's discovered
> that even with helpers inlined, rust_helper_ symbols are still present
> in final vmlinux binary, and it turns out this function is inhibiting
> the inlining, and introducing indirect function calls.
> 
> Signed-off-by: Gary Guo <gary@garyguo.net>

Acked-by: Danilo Krummrich <dakr@kernel.org>

> ---
>  rust/kernel/alloc/allocator.rs | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
> index 439985e29fbc..aa2dfa9dca4c 100644
> --- a/rust/kernel/alloc/allocator.rs
> +++ b/rust/kernel/alloc/allocator.rs
> @@ -80,6 +80,7 @@ impl ReallocFunc {
>      /// This method has the same guarantees as `Allocator::realloc`. Additionally
>      /// - it accepts any pointer to a valid memory allocation allocated by this function.
>      /// - memory allocated by this function remains valid until it is passed to this function.
> +    #[inline]
>      unsafe fn call(
>          &self,
>          ptr: Option<NonNull<u8>>,
> -- 
> 2.47.0
>