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Subject: Re: [PATCH v2 4/5] mm: use node_page_state_snapshot to avoid
 deviation
To: Christopher Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        Johannes Weiner <hannes@cmpxchg.org>,
        YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Nikolay Borisov <nborisov@suse.com>,
        Pavel Tatashin <pasha.tatashin@oracle.com>,
        David Rientjes <rientjes@google.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Dave <dave.hansen@linux.intel.com>, Andi Kleen <andi.kleen@intel.com>,
        Tim Chen <tim.c.chen@intel.com>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Ying Huang <ying.huang@intel.com>, Aaron Lu <aaron.lu@intel.com>,
        Aubrey Li <aubrey.li@intel.com>, Linux MM <linux-mm@kvack.org>,
        Linux Kernel <linux-kernel@vger.kernel.org>
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 <1f3a6d05-2756-93fd-a380-df808c94ece8@intel.com>
 <alpine.DEB.2.20.1712200956080.7506@nuc-kabylake>
From: kemi <kemi.wang@intel.com>
Message-ID: <1f0d8933-60a3-e2e0-f7a3-36e98ade48bb@intel.com>
Date: Thu, 21 Dec 2017 09:39:01 +0800
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On 2017年12月20日 23:58, Christopher Lameter wrote:
> On Wed, 20 Dec 2017, kemi wrote:
> 
>>> You are making numastats special and I yet haven't heard any sounds
>>> arguments for that. But that should be discussed in the respective
>>> patch.
>>>
>>
>> That is because we have much larger threshold size for NUMA counters, that means larger
>> deviation. So, the number in local cpus may not be simply ignored.
> 
> Some numbers showing the effect of these changes would be helpful. You can
> probably create some in kernel synthetic tests to start with which would
> allow you to see any significant effects of those changes.
> 
> Then run the larger testsuites (f.e. those that Mel has published) and
> benchmarks to figure out how behavior of real apps *may* change?
> 

OK.
I will do that when available.
Let's just drop this patch in this series and consider this issue
in another patch.