Re: [PATCH 3/8] mm/damon/paddr: respect folio end for DAMOS actions except STAT

[sashiko-bot@kernel.org]

> A few functions for applying DAMOS actions including pageout,
> lru_[de]prio and migrate_{hot,cold} in DAMON physical address space
> operation set (paddr) collect folios of the given region by getting the
> folios of region-internal addresses.  Then, those functions apply the
> action to the collected folios at once.  The collection starts from the
> region start address and advances the address by the size of the folio
> of the address until it goes out of the region.  If the start address is
> in the middle of a large folio, and if the next folios are small, some
> of the next folios could be skipped.  Fix the issue by advancing the
> address to exactly the start address of the next folio.
> 
> The user impact is that DAMOS action is applied to less than expected
> amount of memory.  Given the best effort nature of DAMON, it is no big
> problem, but it is clearly a bug that is better to be fixed.
> 
> The issue was discovered [1] by Sashiko.
> 
> [1] https://lore.kernel.org/20260517234112.89245-1-sj@kernel.org
> 
> Fixes: 3a06696305e7 ("mm/damon/ops: have damon_get_folio return folio even for tail pages")
> Cc: <stable@vger.kernel.org> # 6.15.x
> Signed-off-by: SJ Park <sj@kernel.org>

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20260901131850.98037-1-sj@kernel.org?part=3