Re: [PATCH v3 3/7] mm/mglru: enhance cold/hot inversion handling in inc_min_seq()

[Baolin Wang]

On 9/2/26 7:24 AM, Barry Song (Xiaomi) wrote:
> During aging, a folio's generation may already have been updated by
> folio_update_gen(), even though it has not yet been moved to the
> corresponding generation list. Such folios are hotter than those
> already in that generation.
>
> It makes sense for inc_min_seq() to increment the generation of
> folios that were never promoted during aging and move them to the
> tail of the new oldest generation. However, folios that were already
> promoted should instead be moved to the head of their updated
> generation, just as sort_folio() does in scan_folios().
>
> Otherwise, promoted folios could end up behind folios that were
> never promoted, effectively inverting their hot/cold ordering.
>
> Signed-off-by: Barry Song (Xiaomi) <baohua@xxxxxxxxxx>
> Reviewed-by: Kairui Song <kasong@xxxxxxxxxxx>
> Tested-by: Xueyuan Chen <xueyuan.chen21@xxxxxxxxx>
> Reviewed-by: Ridong Chen <ridong.chen@xxxxxxxxx>
> Reviewed-by: Lian Wang <lianux.mm@xxxxxxxxx>
> ---

Good catch. Make sense to me.
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>