From: Andrew Morton <akpm@linux-foundation.org>
To: Hui Zhu <hui.zhu@linux.dev>
Cc: Kairui Song <kasong@tencent.com>, Qi Zheng <qi.zheng@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Hui Zhu <zhuhui@kylinos.cn>
Subject: Re: [PATCH v6 0/2] mm/vmscan: fix NR_ISOLATED accounting and throttle MGLRU eviction
Date: Wed, 14 Oct 2026 16:09:10 -0700 [thread overview]
Message-ID: <20261014160910.eeaa24697b614d1b94806d0d@linux-foundation.org> (raw)
In-Reply-To: <cover.1791968227.git.zhuhui@kylinos.cn>
On Wed, 14 Oct 2026 17:00:22 +0800 Hui Zhu <hui.zhu@linux.dev> 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@kylinos.cn
next prev parent reply other threads:[~2026-10-14 23:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-14 9:00 [PATCH v6 0/2] mm/vmscan: fix NR_ISOLATED accounting and throttle MGLRU eviction Hui Zhu
2026-10-14 9:00 ` [PATCH v6 1/2] mm/vmscan: fix missing NR_ISOLATED counter update in MGLRU reclaim path Hui Zhu
2026-10-14 9:00 ` [PATCH v6 2/2] mm/vmscan: throttle MGLRU eviction when isolated folios pile up Hui Zhu
2026-10-14 23:09 ` Andrew Morton [this message]
2026-10-15 6:24 ` [PATCH v6 0/2] mm/vmscan: fix NR_ISOLATED accounting and throttle MGLRU eviction Hui Zhu
2026-10-15 6:45 ` Barry Song
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