Re: [PATCH v6 00/14] mm/mglru: improve reclaim loop and dirty folio handling

[Barry Song (Xiaomi)]

On Sat, Apr 25, 2026 at 9:30 PM Kairui Song <ryncsn@xxxxxxxxx> wrote:
[...]
>
> I just ran a matrix of for kernels (mainline, mm-new HEAD, before this
> series, after this series) X 3 different memcg configs (-j96 3G, -j48
> 2G, -j24 1G), and none of these showed any regression but all
> improvement. That's really odd.
>
> One possibility is that I removed the:
>
> if (evictable_min_seq(lrugen->min_seq, swappiness) + MIN_NR_GENS >
> lrugen->max_seq)
>     scanned = 0;
>
> Which will make the reclaim loop go further and trigger aging.
> Previously if reclaim drained the LRU's cold gens, it may go reclaim
> slab instead. So idle inodes will be dropped with the mapping and
> reclaim more file, and we won't see any refault data from that since
> the mapping itself is gone. Sys will be lower too, as IO isn't counted
> as sys. Checking your data, despite sys is higher, real is acutually
> lower, which matches my guess.
>
> Will the following patch help? I'm not sure if this is the problem,
> but this added back that early abort, personally I don't think this
> really makes much sense as it's more like a workaround for other
> issues, but if that helps we might better keep it.

Hi Kairui, after five hours of sleep I’m feeling much more
refreshed and should have identified the issue. I think the
problem will be clear once you look at the patch below.
Feel free to include it in the new version if you find it
helpful.