linux-kernel - Re: [PATCH v1] mm: migrate: don't rely on PageMovable() of newpage after unlocking it

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Date:   Tue, 29 Jan 2019 11:01:35 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
        Jan Kara <jack@...e.cz>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Dominik Brodowski <linux@...inikbrodowski.net>,
        Matthew Wilcox <willy@...radead.org>,
        Vratislav Bendel <vbendel@...hat.com>,
        Rafael Aquini <aquini@...hat.com>,
        Konstantin Khlebnikov <k.khlebnikov@...sung.com>,
        Minchan Kim <minchan@...nel.org>, stable@...r.kernel.org
Subject: Re: [PATCH v1] mm: migrate: don't rely on PageMovable() of newpage
 after unlocking it

On 29.01.19 08:18, Michal Hocko wrote:
> On Mon 28-01-19 22:09:14, David Hildenbrand wrote:
>> On 28.01.19 21:19, Michal Hocko wrote:
> [...]
>>> David, could you reformulate the changelog accordingly please? My ack
>>> still holds.
>>
>> You mean reformulating + resending for stable kernels only?
> 
> I would merge your patch even if it doesn't fix any real problem _now_.
> If for not other reasons it makes the code less subtle because we no
> longer depend on this crazy __PageMovable is special. If the movable
> flag is supposed to be synchronized with the page lock then do not do
> tricks and make code more robust because the next time somebody would
> like to fix up the current semantic he might reintroduce the bug easily.
> 

Sounds good to me, I'll rephrase and resend. I'll also have a look if I
can easily refactor the whole PageMovable logic or if this is more involved.

Thanks!

-- 

Thanks,

David / dhildenb