linux-kernel - RE: 答复: PROBLEM: cgroup cost too much memory when transfer small files to tmpfs

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Date:   Mon, 27 Jul 2020 03:14:28 +0000
From:   jingrui <jingrui@...wei.com>
To:     Michal Hocko <mhocko@...nel.org>
CC:     "tj@...nel.org" <tj@...nel.org>, Lizefan <lizefan@...wei.com>,
        "hannes@...xchg.org" <hannes@...xchg.org>,
        "vdavydov.dev@...il.com" <vdavydov.dev@...il.com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "cgroups@...r.kernel.org" <cgroups@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        caihaomin <caihaomin@...wei.com>,
        "Weiwei (N)" <wick.wei@...wei.com>,
        "Fangxiuning (Jack, EulerOS)" <fangxiuning@...wei.com>
Subject: RE: 答复: PROBLEM: cgroup cost too much memory when transfer small files to tmpfs

Cc Fangxiuning

On Fri 24-07-20 09:35:26, jingrui wrote:
> 
> On Friday, July 24, 2020 3:55 PM, Michal Hocko wrote:
> 
> > What is the reason to run under !root cgroup in those sessions if you do not care about accounting anyway? 
> 
> The systemd not support run those sessions under root cgroup, disable 
> pam-systemd will not create session/cgroup, but this is not safe and 
> make systemd-logind not work.

Could you be more specific please?

As I know, when user call sftp client to send files, the server will call pam-systemd.so lib to create session and cgroup.
We can skip call pam-systemd.so by config /etc/pam.d/password-auth drop the line " -session     optional      pam_systemd.so".
But this config is global,  and will affect other services, such as ssh login. We don’t find a way just don’t  create cgroup dir for sftp.

@Xiuning Would you please take a look and give some suggestion?

--
Michal Hocko
SUSE Labs