From: Andrew Morton <akpm@linux-foundation.org>
To: Max Kellermann <max.kellermann@ionos.com>
Cc: Ridong Chen <ridong.chen@linux.dev>,
kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev,
baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com,
weixugc@google.com, baoquan.he@linux.dev,
baolin.wang@linux.alibaba.com, david@kernel.org, ljs@kernel.org,
liam@infradead.org, vbabka@kernel.org, rppt@kernel.org,
surenb@google.com, mhocko@suse.com, hannes@cmpxchg.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
rcu@vger.kernel.org
Subject: Re: [PATCH 3/5] mm/mglru: cache the last memcg node, make tail insertion constant time
Date: Sun, 1 Nov 2026 13:50:47 -0800 [thread overview]
Message-ID: <20261101135047.61fc3f209b3235ed6fc96183@linux-foundation.org> (raw)
In-Reply-To: <CAKPOu+83bH2CRtiAio+1VTTQrYFF9th5XfG5wL45ujEavPS3Dg@mail.gmail.com>
On Wed, 14 Oct 2026 05:58:28 +0200 Max Kellermann <max.kellermann@ionos.com> wrote:
> On Wed, Oct 14, 2026 at 5:31 AM Ridong Chen <ridong.chen@linux.dev> wrote:
> > I've also submitted an RFC patch that addresses this issue.
>
> Oh, interesting! I did not know but your patch, but it looks very
> similar to mine (but without the hlist_nulls refactoring so yours
> comes with some code duplicating the hlist_nulls header).
>
> Too bad your RFC went nowhere, that would have saved us from a
> production incident... Anyway, even if neither gets merged, I'll keep
> my patches on our internal kernel fork, because they do help a lot
> with our workload.
hm, this was a bit of a fail, sorry about that.
We had a fairly modest RFC-stage patch which would have addressed the
issues you've encountered in 6.18.x. That got waylaid into more
ambitious re-engineering project which wouldn't have been backportable
and now this series which also won't be backportable.
So. Can someone please propose a nice simple quick-fix which we can
backport into the -stable stream while we work on the larger
rearchitecting projects?
I think that might be Max's [5/5]? Max, do you know whether that patch
alone will fix up 6.18.x, or do we also need to addressed that lengthy
spinlocked tail insertion?
If you think [5/5] is sufficient for -stable then please propose that as
a standalone cc:stable thing then we can look at the broader changes on
top.
next prev parent reply other threads:[~2026-11-01 21:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-12 20:54 [PATCH 0/5] mm: multi-gen LRU: reduce memcg rotation overhead Max Kellermann
2026-10-12 20:54 ` [PATCH 1/5] include/linux/rculist_nulls: add hlist_nulls_add_behind_rcu() Max Kellermann
2026-10-14 23:58 ` Paul E. McKenney
2026-11-01 21:07 ` Barry Song
2026-10-12 20:54 ` [PATCH 2/5] mm/vmscan: move code to lru_gen_{add,del}_memcg() Max Kellermann
2026-11-01 21:03 ` Barry Song
2026-11-02 8:27 ` Max Kellermann
2026-10-12 20:54 ` [PATCH 3/5] mm/mglru: cache the last memcg node, make tail insertion constant time Max Kellermann
2026-10-14 3:31 ` Ridong Chen
2026-10-14 3:58 ` Max Kellermann
2026-10-14 4:46 ` Barry Song
2026-11-01 21:50 ` Andrew Morton [this message]
2026-11-02 8:26 ` Max Kellermann
2026-10-12 20:54 ` [PATCH 4/5] mm/mglru: avoid redundant rotations of young memcgs Max Kellermann
2026-10-12 20:54 ` [PATCH 5/5] mm/mglru: reschedule between memcg reclaim attempts Max Kellermann
2026-11-02 1:15 ` Barry Song
2026-11-02 8:32 ` Max Kellermann
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