Date: Tue, 11 Apr 2017 10:41:42 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Igor Mammedov <imammedo@redhat.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Jerome Glisse <jglisse@redhat.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com,
        Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com,
        Joonsoo Kim <js1304@gmail.com>, Andi Kleen <ak@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Daniel Kiper <daniel.kiper@oracle.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Dan Williams <dan.j.williams@gmail.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Lai Jiangshan <laijs@cn.fujitsu.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Tobias Regnery <tobias.regnery@gmail.com>
Subject: Re: [PATCH -v2 0/9] mm: make movable onlining suck less
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On Tue 11-04-17 10:01:52, Igor Mammedov wrote:
> On Mon, 10 Apr 2017 16:56:39 +0200
> Michal Hocko <mhocko@kernel.org> wrote:
[...]
> > > #echo online_kernel > memory32/state
> > > write error: Invalid argument
> > > // that's not what's expected  
> > 
> > this is proper behavior with the current implementation. Does anything
> > depend on the zone reusing?
> if we didn't have zone imbalance issue in design,
> the it wouldn't matter but as it stands it's not
> minore issue.
> 
> Consider following,
> one hotplugs some memory and onlines it as movable,
> then one needs to hotplug some more but to do so 
> one one needs more memory from zone NORMAL and to keep
> zone balance some memory in MOVABLE should be reonlined
> as NORMAL

Is this something that we absolutely have to have right _now_? Or are you
OK if I address this in follow up series? Because it will make the
current code slightly more complex and to be honest I would rather like
to see this "core" merge and build more on top.
-- 
Michal Hocko
SUSE Labs