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Date: Mon, 09 Jul 2012 10:53:27 -0400
From: Rik van Riel <riel@redhat.com>
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To: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        Paul Turner <pjt@google.com>,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Mike Galbraith <efault@gmx.de>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Lai Jiangshan <laijs@cn.fujitsu.com>, Dan Smith <danms@us.ibm.com>,
        Bharata B Rao <bharata.rao@gmail.com>,
        Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [RFC][PATCH 25/26] sched, numa: Only migrate long-running entities
References: <20120316144028.036474157@chello.nl>  <20120316144241.749359061@chello.nl> <4FF9D29D.8030903@redhat.com> <1341836787.3462.64.camel@twins>
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On 07/09/2012 08:26 AM, Peter Zijlstra wrote:
> On Sun, 2012-07-08 at 14:34 -0400, Rik van Riel wrote:

>> Do we really want to calculate the amount of CPU time used
>> by a process, and start migrating after just one second?
>>
>> Or would it be ok to start migrating once a process has
>> been scanned once or twice by the NUMA code?
>
> You mean, the 2-3rd time we try and migrate this task, not the memory
> scanning thing as per Andrea, right?

Indeed.  That way we can simply keep a flag somewhere,
instead of iterating over the threads in a process.

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