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Subject: Re: [RFC v1 00/19] Modify zonelist to nodelist v1
From:   Qian Cai <cai@lca.pw>
In-Reply-To: <20191126154101.GJ20912@dhcp22.suse.cz>
Date:   Tue, 26 Nov 2019 14:04:06 -0500
Cc:     Pengfei Li <fly@kernel.page>,
        "lixinhai.lxh@gmail.com" <lixinhai.lxh@gmail.com>,
        akpm <akpm@linux-foundation.org>,
        mgorman <mgorman@techsingularity.net>,
        Vlastimil Babka <vbabka@suse.cz>, cl <cl@linux.com>,
        "iamjoonsoo.kim" <iamjoonsoo.kim@lge.com>, guro <guro@fb.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>
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References: <20191125083948.GC31714@dhcp22.suse.cz>
 <828BAB69-4B46-418F-A5E2-35B0756340D0@lca.pw>
 <20191126154101.GJ20912@dhcp22.suse.cz>
To:     Michal Hocko <mhocko@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
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> On Nov 26, 2019, at 10:41 AM, Michal Hocko <mhocko@kernel.org> wrote:
>=20
> On Tue 26-11-19 10:30:56, Qian Cai wrote:
>>=20
>>=20
>>> On Nov 25, 2019, at 3:39 AM, Michal Hocko <mhocko@kernel.org> wrote:
>>>=20
>>> People do care about ZONE_MOVABLE and if there is a non-movable =
memory
>>> sitting there then it is a bug. Please report that.
>>=20
>> It is trivial to test yourself if you ever care. Just pass =
kernelcore=3D
>> to as many NUMA machines you could find, an then test if ever =
possible
>> to offline those memory.
>=20
> I definitely do care if you can provide more details (ideally in a
> separate email thread). I am using movable memory for memory hotplug
> usecases and so far I do not remember any kernel/non-movable =
allocations
> would make it in - modulo bugs when somebody might use __GFP_MOVABLE
> when it is not appropriate.
>=20

I don=E2=80=99t think it is anything to do with __GFP_MOVABLE. It is =
about booting a kernel
with either passing kernelcore=3D or movablecore=3D. Then, those =
ZONE_MOVABLE will
have non-movable pages which looks like those from vmemmap_populate(). =
How
do you create ZONE_MOVALBLE in this first place?=20=