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From: Wei Yang <richard.weiyang@gmail.com>
Date: Sat, 10 Jun 2017 10:20:00 +0800
Message-ID: <CADZGycYTBJ8QoecdLJspO2S113B03mwAGvTa9cpuf0YBb2C3Sg@mail.gmail.com>
Subject: Re: [PATCH -v4 0/14] mm: make movable onlining suck less
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Linux-MM <linux-mm@kvack.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>,
        Igor Mammedov <imammedo@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Balbir Singh <bsingharora@gmail.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Tobias Regnery <tobias.regnery@gmail.com>,
        Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
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On Fri, Jun 9, 2017 at 6:49 PM, Michal Hocko <mhocko@kernel.org> wrote:
> On Fri 09-06-17 17:51:24, Wei Yang wrote:
>> Hi, Michal
>>
>> I am not that familiar with hotplug and trying to catch up the issue
>>  and your solution.
>>
>> One potential issue I found is we don't check the physical boundary
>> when add_memory_resource().
>>
>> For example, on x86-64, only 64T physical memory is supported currently.
>> Looks it is expanded after 5-level pagetable is introduced. While there is
>> still some limitations on this. But we don't check the boundary I think.
>>
>> During the bootup, this is ensured by the max_pfn which is guaranteed to
>> be under MAX_ARCH_PFN. I don't see some limitation on this when doing
>>  hotplug.
>
> This might be true and I would have to double check but this rework
> doesn't change anything in that regards. Or do I miss something?

Ah, yes, I believe your patch set don't touch this area.

This is just related to hotplug.

> --
> Michal Hocko
> SUSE Labs