Re: [PATCH v12 4/8] mm: rust: add lock_vma_under_rcu

Andreas Hindborg
2025-01-20T13:59:04Z

"Alice Ryhl" <aliceryhl@google.com> writes:

> Currently, the binder driver always uses the mmap lock to make changes
> to its vma. Because the mmap lock is global to the process, this can
> involve significant contention. However, the kernel has a feature called
> per-vma locks, which can significantly reduce contention. For example,
> you can take a vma lock in parallel with an mmap write lock. This is
> important because contention on the mmap lock has been a long-term
> recurring challenge for the Binder driver.
>
> This patch introduces support for using `lock_vma_under_rcu` from Rust.
> The Rust Binder driver will be able to use this to reduce contention on
> the mmap lock.
>
> Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> (for mm bits)
> Reviewed-by: Jann Horn <jannh@google.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>

Best regards,
Andreas Hindborg