From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH] cgroups: Do not show inactive devices in cgroups
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Date: Wed, 26 Jun 2013 18:23:47 -0700
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To: Anatol Pomozov <anatol.pomozov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>

On Wed, Jun 26, 2013 at 06:23:04PM -0700, Tejun Heo wrote:
> Hello,
> 
> On Wed, Jun 26, 2013 at 05:37:38PM -0700, Anatol Pomozov wrote:
> > Bottom line: when we set weight for a device then it creates cfq_group
> > and initializes device stats with zero. Later that zero stat is shown
> > even if no activity happened on the device. Both CFQ and our custom IO
> > scheduler have this problem. And because we write set weight for all
> > devices in all cgroups we endup with a lot of zero useless stats.
> > 
> > What is the right fix in this situation?
> 
> Yeah, I think yours is fine.  You're just configuring each blkg during
> init.  Please just update the u64 case and repost.

BTW, if there are a lot of users which ignore 0 u64, it may be cleaner
to introduce a wrapper around the existing prfill.

Thanks.

-- 
tejun