From: Yosry Ahmed <yosryahmed@google.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Xiu Jianfeng <xiujianfeng@huawei.com>,
hannes@cmpxchg.org, roman.gushchin@linux.dev,
shakeel.butt@linux.dev, muchun.song@linux.dev,
akpm@linux-foundation.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] mm: memcg: remove redundant seq_buf_has_overflowed()
Date: Thu, 27 Jun 2024 04:33:50 -0700 [thread overview]
Message-ID: <CAJD7tkZfkE6EyDAXetjSAKb7Zx2Mw-2naUNHRK=ihegZyZ2mHA@mail.gmail.com> (raw)
In-Reply-To: <Zn0RGTZxrEUnI1KZ@tiehlicka>
On Thu, Jun 27, 2024 at 12:13 AM Michal Hocko <mhocko@suse.com> wrote:
>
> On Wed 26-06-24 09:42:32, Xiu Jianfeng wrote:
> > Both the end of memory_stat_format() and memcg_stat_format() will call
> > WARN_ON_ONCE(seq_buf_has_overflowed()). However, memory_stat_format()
> > is the only caller of memcg_stat_format(), when memcg is on the default
> > hierarchy, seq_buf_has_overflowed() will be executed twice, so remove
> > the reduntant one.
>
> Shouldn't we rather remove both? Are they giving us anything useful
> actually? Would a simpl pr_warn be sufficient? Afterall all we care
> about is to learn that we need to grow the buffer size because our stats
> do not fit anymore. It is not really important whether that is an OOM or
> cgroupfs interface path.
Is it possible for userspace readers to break if the stats are
incomplete? If yes, I think WARN_ON_ONCE() may be prompted to make it
easier to catch and fix before deployment.
next prev parent reply other threads:[~2024-06-27 11:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-26 9:42 Xiu Jianfeng
2024-06-27 7:13 ` Michal Hocko
2024-06-27 8:33 ` xiujianfeng
2024-06-27 11:20 ` Michal Hocko
2024-06-27 11:43 ` xiujianfeng
2024-06-27 11:54 ` Michal Hocko
2024-06-28 2:20 ` xiujianfeng
2024-06-28 7:09 ` Michal Hocko
2024-06-27 11:33 ` Yosry Ahmed [this message]
2024-06-27 11:56 ` Michal Hocko
2024-06-27 12:00 ` Yosry Ahmed
2024-06-27 12:28 ` Michal Hocko
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