Re: [PATCH 6.18.y] mm/damon/paddr: drop last same folio access check reuse optimization

[sashiko-bot@kernel.org]

> It can race when multiple kdamonds are being used.  The problem from the
> race is doubtful, but the gain from the optimization is also doubtful.
> Simply drop the optimization in favor of code simplicity.
> 
> The user impact is doubtfully trivial.  After all, this kind of
> interference can happen only by intentional user setup.  Even if it
> happens, it will be rare, and the consequence is degradation of the
> best-effort monitoring results.  No critical consequences like kernel
> panic or memory corruption happen.
> 
> The race was discovered [1] by Sashiko.
> 
> Link: https://lore.kernel.org/20260715031002.108504-5-sj@kernel.org
> Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1]
> Fixes: a28397beb55b ("mm/damon: implement primitives for physical address space monitoring")
> Signed-off-by: SJ Park <sj@kernel.org>
> Cc: <stable@vger.kernel.org> # 5.16.x
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> (cherry picked from commit f23f0aa62b2f32c2b12f95959fc4603ef81678b2)
> Signed-off-by: SJ Park <sj@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260909053834.248582-1-sj@kernel.org?part=1