linux-kernel - Re: [RFC PATCH v2 1/3] misc_cgroup: add support for nofile limit

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Message-ID: <YQEKNPrrOuyxTarN@mtj.duckdns.org>
Date:   Tue, 27 Jul 2021 21:41:40 -1000
From:   Tejun Heo <tj@...nel.org>
To:     brookxu <brookxu.cn@...il.com>
Cc:     viro@...iv.linux.org.uk, lizefan.x@...edance.com,
        hannes@...xchg.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, cgroups@...r.kernel.org
Subject: Re: [RFC PATCH v2 1/3] misc_cgroup: add support for nofile limit

On Wed, Jul 28, 2021 at 11:17:08AM +0800, brookxu wrote:
> Yeah we can adjust file-max through sysctl, but in many cases we adjust it according
> to the actual load of the machine, not for abnormal tasks. Another problem is that in
> practical applications, kmem_limit will cause some minor problems. In many cases,
> kmem_limit is disabled. Limit_in_bytes mainly counts user pages and pagecache, which
> may cause files_cache to be out of control. In this case, if file-max is set to MAX,
> we may have a risk in the abnormal scene, which prevents us from recovering from the
> abnormal scene. Maybe I missed something.

Kmem control is always on in cgroup2 and has been in wide production use for
years now. If there are problems with it, we need to fix them. That really
doesn't justify adding another feature.

Thanks.

-- 
tejun