[PATCH RFC] Avoid memory barrier in read_seqcount() through load acquire

Linus Torvalds torvalds at linux-foundation.org
Tue Aug 13 12:48:09 PDT 2024


On Tue, 13 Aug 2024 at 12:01, Waiman Long <longman at redhat.com> wrote:
>
> Do we need a new ARCH flag?

I'm confused by that question.

That's clearly exactly what that ARCH_HAS_ACQUIRE_RELEASE is.

Obviously all architectures "have" it - in the sense that we always
have access to a "smp_load_acquire()/smp_store_release()".

But if the architecture doesn't support it natively, the old rmb/wmb
model may be preferred.

Although maybe we're at the point where we don't even care about that.

              Linus



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