linux-kernel - Re: [PATCH v2] cgroup-v1: add disabled controller check in cgroup1_parse

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Message-ID: <d4ba14b0-ee06-b793-a840-2c2ff369d890@huawei.com>
Date:   Thu, 14 Jan 2021 22:08:19 +0800
From:   chenzhou <chenzhou10@...wei.com>
To:     Michal Koutný <mkoutny@...e.com>
CC:     <tj@...nel.org>, <lizefan.x@...edance.com>, <hannes@...xchg.org>,
        <cgroups@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] cgroup-v1: add disabled controller check in
 cgroup1_parse_param()

Hi Michal,

On 2021/1/14 21:12, Michal Koutný wrote:
> Hello Chen.
>
> On Fri, Dec 18, 2020 at 02:17:55PM +0800, Chen Zhou <chenzhou10@...wei.com> wrote:
>> When mounting a cgroup hierarchy with disabled controller in cgroup v1,
>> all available controllers will be attached.
> Not sure if I understand the situation -- have you observed a v1
> controller attached to a hierarchy while specifying cgroup_no_v1= kernel
> cmdline arg?
Yeah, this is the situation.
In this case, at the beginning of function check_cgroupfs_options(), the mask
ctx->subsys_mask will be 0. And if we mount without 'none' and 'name=' options,
then in check_cgroupfs_options(), the flag ctx->all_ss will be set, that is, select all the subsystems.

Thanks,
Chen Zhou
>
> AFAICS, the disabled controllers are honored thanks to
> check_cgroupfs_options().
>
> Michal