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Date: Mon, 10 Jan 2011 14:46:22 +0530
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: Mike Galbraith <efault@gmx.de>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org
Subject: autogroup: sched_setscheduler() fails
Message-ID: <20110110091622.GF2772@in.ibm.com>
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Hi,

With autogroup ON, sched_setscheduler() fails when I try to change the
scheduling policy of a normal task to either RR or FIFO.

sched_setscheduler() returns -EPERM when it finds that the group doesn't
have any rt bandwidth. This is expected because with autogroup, the task
is in an autogroup for which task_group(p)->rt_bandwidth.rt_runtime is 0.

I guess the task needs to be moved to appropriate cgroup (from its current
autogroup) when such policy change is requested, but I wasn't sure if
group change from sched_setscheduler() can be achieved easily.

Regards,
Bharata.