From: Johannes Weiner <hannes@cmpxchg.org>
To: Qi Zheng <qi.zheng@linux.dev>
Cc: Harry Yoo <harry@kernel.org>,
akpm@linux-foundation.org, david@kernel.org, kasong@tencent.com,
shakeel.butt@linux.dev, baohua@kernel.org,
axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com,
muchun.song@linux.dev, peiyang_he@smail.nju.edu.cn,
mhocko@kernel.org, roman.gushchin@linux.dev, ljs@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Qi Zheng <zhengqi.arch@bytedance.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v3] mm: mglru: fix stale batch updates after memcg reparenting
Date: Fri, 26 Jun 2026 05:39:56 -0400 [thread overview]
Message-ID: <aj5I7JAXWlTHRyEW@cmpxchg.org> (raw)
In-Reply-To: <c0e366ec-ee5d-42d9-ba33-7c630660e8af@linux.dev>
On Fri, Jun 26, 2026 at 03:04:17PM +0800, Qi Zheng wrote:
> On 6/26/26 2:48 PM, Harry Yoo wrote:
> > On 6/26/26 3:24 PM, Qi Zheng wrote:
> >> On 6/26/26 12:59 PM, Harry Yoo wrote:
> >>> Observing a dying cgroup should be rare anyway, it's worth focusing
> >>> more on readability?
> >>
> >> While it's rare to encounter consecutive dying memcgs, it can still
> >> happen, right?
> >
> > But is worth saving a few instruction in a basic block that is
> > unlikely() to be executed?
>
> I don't have a strong opinion here. Hi Johannes, I'll leave the decision
> up to you. If necessary, I can send out the v4.
Yes, I was thinking what Harry actually bothered to spell out ;)
The race is rare, multiple levels even rarer, and even *then*
mem_cgroup_lruvec() is a quick inline.
This way you have one block to handle that one rare race
condition. One place to put the comment. No labels, no goto.
Simplicity wins :)
next prev parent reply other threads:[~2026-06-26 9:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-25 15:15 [PATCH v3] mm: mglru: fix stale batch updates after memcg reparenting Qi Zheng
2026-06-25 18:41 ` Johannes Weiner
2026-06-26 2:27 ` Qi Zheng
2026-06-26 4:43 ` Harry Yoo
2026-06-26 4:48 ` Qi Zheng
2026-06-26 4:59 ` Harry Yoo
2026-06-26 6:24 ` Qi Zheng
2026-06-26 6:48 ` Harry Yoo
2026-06-26 7:04 ` Qi Zheng
2026-06-26 7:09 ` Harry Yoo
2026-06-26 9:39 ` Johannes Weiner [this message]
2026-06-26 11:21 ` Qi Zheng
2026-06-26 17:08 ` Shakeel Butt
2026-06-25 20:22 ` Shakeel Butt
2026-06-26 2:39 ` Qi Zheng
2026-06-26 4:29 ` Peiyang He
2026-06-26 4:50 ` Qi Zheng
2026-06-26 7:15 ` Harry Yoo
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