Date: Wed, 24 Jul 2013 12:49:31 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Rakib Mullick <rakib.mullick@gmail.com>, mingo@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched: update_top_cache_domain only at the times of
 building sched domain.
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On Wed, Jul 24, 2013 at 04:34:39PM +0800, Michael Wang wrote:
> But your patch will run the risk to get a freed sd, since you make
> 'sd_llc' wrong for a period of time (between destroy and rebuild) IMO.
> 
> I guess I get you point, you are trying to save one time update since
> you think this will be done twice, but actually the result of this two
> time update was different, it's not redo and it's in order to sync
> 'sd_llc' with 'rq->sd'.

Michael is right, you cannot skip update_top_cache_domain() when
destroying things.
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