Message-ID: <4856DB4A.8020708@nortel.com>
Date: Mon, 16 Jun 2008 15:29:46 -0600
From: "Chris Friesen" <cfriesen@nortel.com>
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To: "Chris Friesen" <cfriesen@nortel.com>
CC: Valdis.Kletnieks@vt.edu, linux-kernel@vger.kernel.org,
       vatsa@linux.vnet.ibm.com, a.p.zijlstra@chello.nl
Subject: Re: odd timing bug with cgroups -- solved
References: <4852E8D5.3000503@nortel.com> <47364.1213416931@turing-police.cc.vt.edu> <48569895.7020701@nortel.com>
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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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