Re: [RFC PATCH v3] locking/atomic: Implement atomic{,64,_long}_{fetch_,}{andnot_or}{,_relaxed,_acquire,_release}()

[Arnd Bergmann]

On Thu, Jul 29, 2021 at 11:56 AM Will Deacon <will@xxxxxxxxxx> wrote:
> On Thu, Jul 29, 2021 at 05:30:03PM +0800, Rui Wang wrote:
> > This patch introduce a new atomic primitive andnot_or:
>
> Please see my other comments on the other patches you posted:
>
> https://lore.kernel.org/r/20210729093923.GD21151@willie-the-truck
>
> Overall, I'm not thrilled to bits by extending the atomics API with
> operations that cannot be implemented efficiently on any (?) architectures
> and are only used by the qspinlock slowpath on machines with more than 16K
> CPUs.

Wouldn't this also help improve set_mask_bits()? That one at least has
a handful of users in the kernel.

       Arnd