From: Yong Zhang <yong.zhang0@gmail.com>
Date: Sun, 20 Feb 2011 07:08:14 +0000 (+0800)
Subject: sched, autogroup: Stop going ahead if autogroup is disabled
X-Git-Tag: v2.6.39-rc1~509^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=800d4d30c8f20bd728e5741a3b77c4859a613f7c;p=pandora-kernel.git

sched, autogroup: Stop going ahead if autogroup is disabled

when autogroup is disable from the beginning,
sched_autogroup_create_attach()
  autogroup_move_group()                    <== 1
    sched_move_task()                       <== 2
      task_move_group_fair()
        set_task_rq()
          task_group()
            autogroup_task_group()

We go the whole path without doing anything useful.

Then stop going further if autogroup is disabled.

But there will be a race window between 1 and 2, in which
sysctl_sched_autogroup_enabled is enabled. This issue
will be toke by following patch.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1298185696-4403-4-git-send-email-yong.zhang0@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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