Re: [PATCH 18/21] blkcg: move blkio_group_conf->weight to cfq

From: Tejun Heo
Date: Sun Apr 01 2012 - 17:23:12 EST


Hello, Vivek.

On Sun, Apr 01, 2012 at 05:09:56PM -0400, Vivek Goyal wrote:
> blkio_cgroup->weight can be thought of in a more generic manner and that
> is sytem wide cgroup weight. And more than one policy should be allowed
> to make use of it. That's a differnt thing that currently only CFQ makes
> use of it.
>
> For example, Fengguang posted RFC patches to try to make use of blkcg->weight
> and differentiate between buffered write bandwidth.
>
> https://lkml.org/lkml/2012/3/28/275

I don't think that's a good idea. It makes it fuzzy which knob
controls what. If we're gonna have single set of controls followed by
all controllers, fine, but I really don't think we should be mixing
different layers of configurations. I mean, what about blkcg.read_bps
then? Let's just give this one to cfq. If someone else wants weight,
let it use its own weight config.

Thanks.

--
tejun
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