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

From: Vivek Goyal
Date: Sun Apr 01 2012 - 17:10:15 EST


On Wed, Mar 28, 2012 at 03:51:28PM -0700, Tejun Heo wrote:
> blkio_group_conf->weight is owned by cfq and has no reason to be
> defined in blkcg core. Replace it with cfq_group->dev_weight and let
> conf setting functions directly set it. If dev_weight is zero, the
> cfqg doesn't have device specific weight configured.
>
> Also, rename BLKIO_WEIGHT_* constants to CFQ_WEIGHT_* and rename
> blkio_cgroup->weight to blkio_cgroup->cfq_weight. We eventually want
> per-policy storage in blkio_cgroup but just mark the ownership of the
> field for now.

Hi Tejun,

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

Thanks
Vivek
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