Re: [PATCH v3 tip/perf/core 1/4] mm: introduce mmap_lock_speculation_{start|end}

[Suren Baghdasaryan]

On Thu, Oct 24, 2024 at 2:57 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Wed, Oct 23, 2024 at 03:17:01PM -0700, Suren Baghdasaryan wrote:
>
> > > Or better yet, just use seqcount...
> >
> > Yeah, with these changes it does look a lot like seqcount now...
> > I can take another stab at rewriting this using seqcount_t but one
> > issue that Jann was concerned about is the counter being int vs long.
> > seqcount_t uses unsigned, so I'm not sure how to address that if I
> > were to use seqcount_t. Any suggestions how to address that before I
> > move forward with a rewrite?
>
> So if that issue is real, it is not specific to this case. Specifically
> preemptible seqcount will be similarly affected. So we should probably
> address that in the seqcount implementation.

Sounds good. Let me try rewriting this patch using seqcount_t and I'll
work with Jann on a separate patch to change seqcount_t.
Thanks for the feedback!

>