From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: "Barry Song (Xiaomi)" <baohua@kernel.org>, akpm@linux-foundation.org
Cc: axelrasmussen@google.com, baoquan.he@linux.dev, david@kernel.org,
hannes@cmpxchg.org, kasong@tencent.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org,
mhocko@kernel.org, qi.zheng@linux.dev, ridong.chen@linux.dev,
shakeel.butt@linux.dev, weixugc@google.com, yuanchu@google.com,
yuzhao@google.com, Chuanhua Han <hanchuanhua802@gmail.com>
Subject: Re: [PATCH] mm/mglru: restore accidentally removed seq < max_seq check
Date: Wed, 16 Sep 2026 11:23:59 +0800 [thread overview]
Message-ID: <7afc2108-710d-4f54-9472-6b9f156ce945@linux.alibaba.com> (raw)
In-Reply-To: <20260915101556.50467-1-baohua@kernel.org>
On 9/15/26 6:15 PM, Barry Song (Xiaomi) wrote:
> Since commit 798c0330c2ca ("mm/mglru: rework aging feedback"),
> the following sanity check was accidentally removed:
> if (seq < max_seq)
> return 0;
>
> That means we can perform aging for any value less than or equal to
> max_gen_nr.
>
> This has been inconsistent with
> Documentation/admin-guide/mm/multigen_lru.rst, which states:
>
> Users can write the following command to ``lru_gen`` to create a new
> generation ``max_gen_nr+1``:
>
> ``+ memcg_id node_id max_gen_nr [can_swap [force_scan]]``
>
> The correct semantics are that writing a value smaller than
> max_gen_nr should return 0, since the requested generation already
> exists.
>
> Fixes: 798c0330c2ca ("mm/mglru: rework aging feedback")
> Reported-by: Chuanhua Han <hanchuanhua802@gmail.com>
> Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
> ---
LGTM.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
next prev parent reply other threads:[~2026-09-16 3:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-15 10:15 [PATCH] mm/mglru: restore accidentally removed seq < max_seq check Barry Song (Xiaomi)
2026-09-16 3:23 ` Baolin Wang [this message]
2026-09-16 8:41 ` Kairui Song
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