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From: Aaron Tomlin <atomlin@redhat.com>
To: Michal Hocko <mhocko@suse.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	hannes@cmpxchg.org, vdavydov.dev@gmail.com,
	Andrew Morton <akpm@linux-foundation.org>,
	cgroups@vger.kernel.org, linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] memcg: add support to generate the total count of children from root
Date: Tue, 24 Nov 2020 13:36:00 +0000	[thread overview]
Message-ID: <CANfR36hBxRsHV+JZfT6_RZRXBvCu0p=4xUOSxzco-BvrTEP37w@mail.gmail.com> (raw)
In-Reply-To: <20201124112612.GV27488@dhcp22.suse.cz>

On Tue, 24 Nov 2020 at 11:26, Michal Hocko <mhocko@suse.com> wrote:
>
> On Tue 24-11-20 10:58:36, Aaron Tomlin wrote:
> > Each memory-controlled cgroup is assigned a unique ID and the total
> > number of memory cgroups is limited to MEM_CGROUP_ID_MAX.
> >
> > This patch provides the ability to determine the number of
> > memory cgroups from the root memory cgroup, only.
> > A value of 1 (i.e. self count) is returned if there are no children.
> > For example, the number of memory cgroups can be established by
> > reading the /sys/fs/cgroup/memory/memory.total_cnt file.
>

Hi Michal,

> Could you add some explanation why is this information useful for
> userspace? Who is going to use it and why a simple scripting on top of
> cgroupfs is insufficient.

Thank you for your feedback.

Indeed, one can use a command/script to manually calculate this.
Having said that, one that creates a significant number of
memory-controlled cgroups may prefer a quick, simple and reliable method
to generate the aforementioned data, for management purposes only.
As such, I thought this patch might be particularly useful.

Kind regards,
-- 
Aaron Tomlin


  reply	other threads:[~2020-11-24 13:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-24 10:58 [PATCH] memcg: add support to generate the total count of children from root Aaron Tomlin
2020-11-24 11:26 ` Michal Hocko
2020-11-24 13:36   ` Aaron Tomlin [this message]
     [not found]   ` <CANfR36hyrqXjk2tL03GzCk6rn6sCD7Sd811soBsZC3dHY0h9fQ@mail.gmail.com>
2020-11-24 13:36     ` Michal Hocko
2020-11-24 13:47       ` Aaron Tomlin
2020-11-26 11:02         ` Aaron Tomlin

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