linux-kernel - Re: odd timing bug with cgroups -- solved

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Date:	Mon, 16 Jun 2008 15:29:46 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	"Chris Friesen" <cfriesen@...tel.com>
CC:	Valdis.Kletnieks@...edu, linux-kernel@...r.kernel.org,
	vatsa@...ux.vnet.ibm.com, a.p.zijlstra@...llo.nl
Subject: Re: odd timing bug with cgroups -- solved

Chris Friesen wrote:

> I was thinking something like this as well, like maybe we can't move the 
> child to another group until it gets scheduled in once, or something 
> similar.

Well, it appears I was way off base.  My main task is SCHED_RR, and my 
child tasks put themselves into SCHED_OTHER.  I didn't have any realtime 
groups configured, so it was bailing out in the first conditional in 
cpu_cgroup_can_attach().

By also having the parent put the children into SCHED_OTHER, my testcase 
will handle both cases (parent or child runs first) and everything seems 
to be working fine.

Chris
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