Re: [PATCH v6 0/2] mm/vmscan: fix NR_ISOLATED accounting and throttle MGLRU eviction

[Hui Zhu]

在 2026/10/15 07:09, Andrew Morton:
> On Wed, 14 Oct 2026 17:00:22 +0800 Hui Zhu <hui.zhu@xxxxxxxxx> wrote:
>
> > The legacy reclaim path has two mechanisms around isolated folios that
> > MGLRU lacks:
> >
> > 1. NR_ISOLATED_ANON/FILE counters are updated when folios are isolated
> >     from the inactive lists. Compaction's too_many_isolated() relies on
> >     them to decide when to back off. The MGLRU reclaim path never
> >     updates them, so compaction cannot see MGLRU's in-flight isolation.
> >
> > 2. shrink_inactive_list() throttles direct reclaim via
> >     too_many_isolated() when isolated folios pile up. MGLRU's
> >     evict_folios() isolates folios without any such check, so many
> >     concurrent reclaimers can over-isolate the same (oldest) generation,
> >     leading to unnecessary swapping, thrashing and premature memcg OOM.
> >
> > Patch 1 fixes the counter accounting in the MGLRU isolation path.
> > Patch 2 adds a per-lruvec throttle, mirroring the legacy behavior but
> > adapted to MGLRU's per-lruvec contention and its dynamic type
> > selection/fallback.
> Thanks.  Questions for yourself and maintainers:
>
> [1/2] is nice and simple and reviewed.  How about I queue this for
> second week of the upcoming merge window?
>
> [2/2] is much more code, isn't reviewed and has a Sashiko whine[*].  So
> I'm thinking this is 7.4-rcX material.
>
>
> [*] https://sashiko.dev/#/patchset/cover.1791968227.git.zhuhui@xxxxxxxxxx
Hi Andrew,

Sounds good to me. Thanks.

Best,
Hui