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Date:   Tue, 7 May 2019 19:54:19 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Sasha Levin <sashal@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Alexander Duyck <alexander.duyck@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        stable <stable@vger.kernel.org>,
        Mikhail Zaslonko <zaslonko@linux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@de.ibm.com>,
        Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>,
        Pasha Tatashin <Pavel.Tatashin@microsoft.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Sasha Levin <alexander.levin@microsoft.com>,
        linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH AUTOSEL 4.14 62/95] mm, memory_hotplug: initialize struct
 pages for the full memory section
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On Tue 07-05-19 13:45:14, Sasha Levin wrote:
[...]
> We're going to have (quite a) large amount of systems with "weird"
> memory layouts that do memory hotplug quite frequently in production, so
> this whole "tends to work usually" thing kinda scares me.

Memory hotplug is simply not production ready for those cases,
unfortunately. It tends to work just fine with properly section
aligned systems with memory being in the movable zones or for zone
device. Everything beyond that is kinda long way to get there...
-- 
Michal Hocko
SUSE Labs