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Date:   Mon, 16 Jul 2018 22:05:17 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     David Hildenbrand <david@redhat.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Balbir Singh <bsingharora@gmail.com>,
        Baoquan He <bhe@redhat.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Young <dyoung@redhat.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hari Bathini <hbathini@linux.vnet.ibm.com>,
        Huang Ying <ying.huang@intel.com>,
        Hugh Dickins <hughd@google.com>,
        Ingo Molnar <mingo@kernel.org>,
        Jaewon Kim <jaewon31.kim@samsung.com>, Jan Kara <jack@suse.cz>,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Juergen Gross <jgross@suse.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Mel Gorman <mgorman@suse.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Miles Chen <miles.chen@mediatek.com>,
        Oscar Salvador <osalvador@techadventures.net>,
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        Thomas Gleixner <tglx@linutronix.de>,
        Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v1 00/10] mm: online/offline 4MB chunks controlled by
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On Mon 16-07-18 21:48:59, David Hildenbrand wrote:
> On 11.06.2018 14:33, David Hildenbrand wrote:
> > On 11.06.2018 13:56, Michal Hocko wrote:
> >> On Mon 11-06-18 13:53:49, David Hildenbrand wrote:
> >>> On 24.05.2018 23:07, David Hildenbrand wrote:
> >>>> On 24.05.2018 16:22, Michal Hocko wrote:
> >>>>> I will go over the rest of the email later I just wanted to make this
> >>>>> point clear because I suspect we are talking past each other.
> >>>>
> >>>> It sounds like we are now talking about how to solve the problem. I like
> >>>> that :)
> >>>>
> >>>
> >>> Hi Michal,
> >>>
> >>> did you have time to think about the details of your proposed idea?
> >>
> >> Not really. Sorry about that. It's been busy time. I am planning to
> >> revisit after merge window closes.
> >>
> > 
> > Sure no worries, I still have a bunch of other things to work on. But it
> > would be nice to clarify soon in which direction I have to head to get
> > this implemented and upstream (e.g. what I proposed, what you proposed
> > or maybe something different).
> > 
> I would really like to make progress here.
> 
> I pointed out basic problems/questions with the proposed alternative. I
> think I answered all your questions. But you also said that you are not
> going to accept the current approach. So some decision has to be made.
> 
> Although it's very demotivating and frustrating (I hope not all work in
> the MM area will be like this), if there is no guidance on how to
> proceed, I'll have to switch to adding/removing/onlining/offlining whole
> segments. This is not what I want, but maybe this has a higher chance of
> getting reviews/acks.
> 
> Understanding that you are busy, please if you make suggestions, follow
> up on responses.

I plan to get back to this. It's busy time with too many things
happening both upstream and on my work table as well. Sorry about that.
I do understand your frustration but there is only that much time I
have. There are not that many people to review this code unfortunately.

In principle though, I still maintain my position that the memory
hotplug code is way too subtle to add more on top. Maybe the code can be
reworked to be less section oriented but that will be a lot of work.
If you _really_ need a smaller granularity I do not have a better
suggestion than to emulate that on top of sections. I still have to go
back to your last emails though.
-- 
Michal Hocko
SUSE Labs