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From:   Joonsoo Kim <js1304@gmail.com>
Date:   Fri, 20 Mar 2020 16:33:54 +0900
Message-ID: <CAAmzW4OC56g-37SghVVsN=4tnxMwfavkK2z31abZnBh5o9J4ag@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] mm/page_alloc: use ac->high_zoneidx for classzone_idx
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     David Rientjes <rientjes@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Minchan Kim <minchan@kernel.org>,
        Mel Gorman <mgorman@techsingularity.net>, kernel-team@lge.com,
        Ye Xiaolong <xiaolong.ye@intel.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
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2020=EB=85=84 3=EC=9B=94 19=EC=9D=BC (=EB=AA=A9) =EC=98=A4=ED=9B=84 9:21, V=
lastimil Babka <vbabka@suse.cz>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On 3/19/20 9:57 AM, Joonsoo Kim wrote:
> >> Curious: is this only an issue when vm.numa_zonelist_order is set to N=
ode?
> >
> > Do you mean "/proc/sys/vm/numa_zonelist_order"? It looks like it's gone=
 now.
> >
> > Thanks.
>
> Yes it's gone now, but indeed, AFAIU on older kernels with zone order ins=
tead of
> node order, this problem wouldn't manifest.

Yes. In this case, preferred_zone of an allocation is the populated highest=
 zone
among all nodes so classzone_idx will the same.

Thanks.