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Date: Tue, 22 Sep 2026 18:35:47 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Qinyun Tan <qinyuntan@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>,
 Roman Gushchin <roman.gushchin@linux.dev>, Shakeel Butt
 <shakeel.butt@linux.dev>, Muchun Song <muchun.song@linux.dev>, Michal
 =?ISO-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>, David Hildenbrand
 <david@kernel.org>, Zi Yan <ziy@nvidia.com>, Baolin Wang
 <baolin.wang@linux.alibaba.com>, Usama Arif <usama.arif@linux.dev>, Dave
 Chinner <david@fromorbit.com>, Qi Zheng <qi.zheng@linux.dev>, Yosry Ahmed
 <yosry@kernel.org>, Nhat Pham <nphamcs@gmail.com>, Chengming Zhou
 <chengming.zhou@linux.dev>, Xunlei Pang <xlpang@linux.alibaba.com>,
 cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/4] mm: restore per-memcg reclaim for NONSLAB
 shrinkers under nokmem
Message-Id: <20260922183547.788d21b89868bf820e94cc62@linux-foundation.org>
In-Reply-To: <20260910080722.3961351-1-qinyuntan@linux.alibaba.com>
References: <20260910080722.3961351-1-qinyuntan@linux.alibaba.com>
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On Thu, 10 Sep 2026 16:07:18 +0800 Qinyun Tan <qinyuntan@linux.alibaba.com> wrote:

> With cgroup.memory=nokmem, the THP deferred split shrinker and the
> zswap shrinker are degraded in two ways.

Obvious question which may have recently been addressed:

Why are we keeping nokmem around?  How useful are its memory savings
and is anyone actually using it?

Clearly it isn't well tested and it increases our testing space (beyond
out testing resources, apparently).

If the right answer here is "kill it" then this patchset is introducing
risk into the main codepaths in order to fix codepaths which shouldn't
be there anyway, yes?