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Date:   Thu, 3 Oct 2019 16:51:06 +0200
From:   Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
To:     Tejun Heo <tj@kernel.org>
Cc:     hannes@cmpxchg.org, clm@fb.com, dennisz@fb.com,
        Josef Bacik <jbacik@fb.com>, kernel-team@fb.com,
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        Paolo Valente <paolo.valente@linaro.org>,
        Rik van Riel <riel@surriel.com>, josef@toxicpanda.com,
        cgroups@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/10] blkcg: implement blk-iocost
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Hi (and apology for relatively late reply).

On Tue, Sep 10, 2019 at 09:08:55AM -0700, Tejun Heo <tj@kernel.org> wrote:
> I can implement the switching if so.
I see the "conflict" is solved by the switching.

> Initially, I put them under block device sysfs but it was too clumsy
> with different config file formats and all.
Do you have any more details on that? In the end, it all boils down to a
daemon/setup utility writing into the control files and it can use
whatever config files it decides, can't it?

> I think it's better to have global controller configs at the root
> cgroup.
I agree with the "global controller" configs, however, does it also hold
for "global controller per-device" configs? They seem closer to the
device than the controller. Potentially, the parameters could be used by
some other consumers in the future. (I'm not opposing the current form,
I just want to explore the space before an API is fixed.)


> Not at all.  These are system-wide configs.  cgroup namespaces
> shouldn't have anything which aren't in non-root cgroups.
Thanks, I understand the cgroup namespaces are not meant to be
transparent to their members.

Michal

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