Re: [PATCH mm-new] mm/mglru: clarify the generation placement in lru_gen_folio_seq()

[Barry Song]

On Tue, Oct 20, 2026 at 10:36 AM Ridong Chen <ridong.chen@xxxxxxxxx> wrote:
>
> From: Ridong Chen <chenridong@xxxxxxxxxx>
>
> lru_gen_folio_seq() computes how many generations below max_seq a
> folio should be added to, but stores it in a variable named "gen".
> Elsewhere in MGLRU "gen" means an index into lrugen->folios[], i.e.
> seq % MAX_NR_GENS, so reusing the name for a relative offset is
> confusing.
>
> The comment table above the code also no longer matches it. It only
> covers the PG_active and the final branch, leaving out the reclaiming
> and "can't evict yet" cases, and it lists LRU_REFS_FLAGS as an input
> although lru_gen_folio_seq() never looks at it.
>
> Rename the local variable to "age", redraw the table so that each
> branch maps to the age and seq it produces, and note that the result
> is clamped to min_seq[type].
>
> No functional change.
>
> Assisted-by: LLM
> Signed-off-by: Ridong Chen <chenridong@xxxxxxxxxx>
> ---

Hi Ridong,

The cleanup might be right, but this part is changing rapidly
with Kairui's MGLRU-FG series. Maybe we should wait until
that series lands and then see if this cleanup is still needed?

Best Regards
Barry