From: oliver <oohall@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
Mel Gorman <mgorman@techsingularity.net>
Subject: Re: [RFC PATCH] mm/init: fix zone boundary creation
Date: Fri, 27 May 2016 18:03:42 +1000 [thread overview]
Message-ID: <CAOSf1CHFYeTEQ2-Fr+mdziJLTgf5=cgJKUXAFqREo5rMgWYEDQ@mail.gmail.com> (raw)
In-Reply-To: <20160526142142.b16f7f3f18204faf0823ac65@linux-foundation.org>
On Fri, May 27, 2016 at 7:21 AM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> hm, this is all ten year old Mel code.
>
> What's the priority on this? What are the user-visible runtime
> effects, how many people are affected, etc?
Low priority. To get bitten by this you need to enable a zone that appears
after ZONE_MOVABLE in the zone_type enum. As far as I can tell this means
running a kernel with ZONE_DEVICE or ZONE_CMA enabled, so I can't see this
affecting too many people.
I only noticed this because I've been fiddling with ZONE_DEVICE on powerpc and
4.6 broke my test kernel. This bug, in conjunction with the changes in Taku
Izumi's kernelcore=mirror patch (d91749c1dda71) and powerpc being the odd
architecture which initialises max_zone_pfn[] to ~0ul instead of 0 caused all
of system memory to be placed into ZONE_DEVICE at boot, followed a
panic since device memory cannot be used for kernel allocations. I've already
submitted a patch to fix the powerpc specific bits, but I figured this should
be fixed too.
oliver
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next prev parent reply other threads:[~2016-05-27 8:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 7:57 Oliver O'Halloran
2016-05-26 21:21 ` Andrew Morton
2016-05-27 8:03 ` oliver [this message]
2016-05-30 9:15 ` Mel Gorman
2016-05-30 13:18 ` oliver
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