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

[Peter Zijlstra]

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.