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From: "Michal Koutný" <mkoutny@suse.com>
To: Yu Kuai <yukuai3@huawei.com>
Cc: tj@kernel.org, axboe@kernel.dk, cgroups@vger.kernel.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	yi.zhang@huawei.com
Subject: Re: [RFC PATCH] blk-throttle: enable io throttle for root in cgroup v2
Date: Fri, 17 Sep 2021 19:41:03 +0200	[thread overview]
Message-ID: <20210917174103.GC13346@blackbody.suse.cz> (raw)
In-Reply-To: <20210909140815.2600858-1-yukuai3@huawei.com>

Hello Yu.

On Thu, Sep 09, 2021 at 10:08:15PM +0800, Yu Kuai <yukuai3@huawei.com> wrote:
> I'm not sure why this feature is disabled in the first place, is
> there any problem or design constraint?

The idea for v2 is that in the root cgroup remain only kernel threads that
provide "global" services and any user workload that should be
constrained is put into non-root cgroups. Additionally, if kernel
threads carry out work associated with a cgroup they can charge it to
the respective cgroup.

[snip]
> We want to limit the overall iops/bps of the device in cgroup v2,

Cui bono? (I mean what is the reason for throttling on the global level
when there's no other entity utiliting the residual?
<joke>Your drives are too fast?</joke>)

Michal

  parent reply	other threads:[~2021-09-17 17:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09 14:08 [RFC PATCH] blk-throttle: enable io throttle for root in cgroup v2 Yu Kuai
2021-09-15  8:20 ` yukuai (C)
2021-09-17 17:41 ` Michal Koutný [this message]
2021-09-17 19:58   ` Khazhy Kumykov
2021-09-19 10:31     ` yukuai (C)
2021-09-21 13:44       ` Michal Koutný
2021-09-27 17:08         ` Tejun Heo

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