linux-kernel - Re: Prevent inode/dentry trashing?

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Message-ID: <88451906-e537-0ac3-b8f2-16bfc4d77ea6@metux.net>
Date:   Mon, 28 Jun 2021 11:40:39 +0200
From:   "Enrico Weigelt, metux IT consult" <lkml@...ux.net>
To:     Michal Koutný <mkoutny@...e.com>,
        Philipp Hahn <pmhahn+lkml@...ahn.de>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "cgroups@...r.kernel.org" <cgroups@...r.kernel.org>
Subject: Re: Prevent inode/dentry trashing?

On 25.06.21 17:55, Michal Koutný wrote:
>> Is it possible to prevent inode/dentry trashing for example by limiting the
>> cache per process(-group)?
> 
> Yes. Unless you have disabled it with CONFIG_MEMCG_KMEM or
> cgroup.memory=nokmem, dentries and inodes are charged to respective
> cgroups. And you can limit overall memory of a cgroup, see
> memory.{max,high} attributes. (You suggest this inode/dentry consumption
> is dominant enough to affect other jobs, so the limit would keep it
> constrained as you intend).

Could you please tell a bit more how this really works ?
(maybe some pointers to the code)

I'm curios what happens if those cache objects are used by different
cgroups - are they accounted to multiple times (once per cgroup) ?
What happens when one cgroup using some cache object reaching its limit,
wile another one does not ?


--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@...ux.net -- +49-151-27565287