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Date: Tue, 1 Feb 2011 18:46:02 +0800
From: Yong Zhang <yong.zhang0@gmail.com>
To: Kazuhisa Ichikawa <ki@epsilou.com>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: Why one of the 2 patches to fix "autogroup" sched problem on
 UP machines is missing in -rc3?
Message-ID: <20110201104602.GA3397@zhy>
Reply-To: Yong Zhang <yong.zhang0@gmail.com>
References: <AANLkTikYw73nixqMtNSDzus2M5RCN2Zy4PzfbPAxtTBC@mail.gmail.com>
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On Tue, Feb 01, 2011 at 06:05:23PM +0900, Kazuhisa Ichikawa wrote:
> Hi Yong,
> 
> Now 2.6.38-rc3 is out, and I think one of the 2 patches you wrote to
> fix "autogroup" sched problem on UP machines is missing there.

Actually the merged one hide the initialising problem.
Because when we enqueue a process to an empty group, update_cfs_shares()
will be called, thus tg->se->load is updated.
enqueue_task_fair()
  update_cfs_shares()
    reweight_entity()
      update_load_set()

> 
> More precisely, your first patch for kernel/sched.c (titled:?sched:
> tg->se->load should be initialised to tg->shares) is missing, while
> the second one for kernel/sched_fair.c (titled:?sched: Fix poor
> interactivity on UP systems due to group scheduler nice tune bug) is
> in -rc3.

See my above answer.

> 
> So what happened to the first patch? Was it superseded and made
> obsolete by the second patch?

Yes.

> 
> # Sorry for not replying to your original post. I'm not subscribing to
> linux kernel mailing list.

Thanks for taking care of this issue :)

Thanks,
Yong