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Subject: Re: [PATCH v4 00/16] Overhaul multi-page lookups for THP
From:   Marek Szyprowski <m.szyprowski@samsung.com>
To:     Matthew Wilcox <willy@infradead.org>,
        Hugh Dickins <hughd@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, Jan Kara <jack@suse.cz>,
        William Kucharski <william.kucharski@oracle.com>,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, hch@lst.de,
        hannes@cmpxchg.org, yang.shi@linux.alibaba.com,
        dchinner@redhat.com, linux-kernel@vger.kernel.org
Message-ID: <0107bae8-baaa-9d39-5349-8174cb8abbbe@samsung.com>
Date:   Thu, 3 Dec 2020 18:27:26 +0100
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References: <20201112212641.27837-1-willy@infradead.org>
        <alpine.LSU.2.11.2011160128001.1206@eggly.anvils>
        <20201117153947.GL29991@casper.infradead.org>
        <alpine.LSU.2.11.2011170820030.1014@eggly.anvils>
        <20201117191513.GV29991@casper.infradead.org>
        <20201117234302.GC29991@casper.infradead.org>
        <20201125023234.GH4327@casper.infradead.org>
        <bb95be97-2a50-b345-fc2c-3ff865b60e08@samsung.com>
        <CGME20201203172725eucas1p2fddec1d269c55095859d490942b78b93@eucas1p2.samsung.com>
Precedence: bulk

Hi

On 03.12.2020 16:46, Marek Szyprowski wrote:
> On 25.11.2020 03:32, Matthew Wilcox wrote:
>> On Tue, Nov 17, 2020 at 11:43:02PM +0000, Matthew Wilcox wrote:
>>> On Tue, Nov 17, 2020 at 07:15:13PM +0000, Matthew Wilcox wrote:
>>>> I find both of these functions exceptionally confusing.  Does this
>>>> make it easier to understand?
>>> Never mind, this is buggy.  I'll send something better tomorrow.
>> That took a week, not a day.  *sigh*.  At least this is shorter.
>>
>> commit 1a02863ce04fd325922d6c3db6d01e18d55f966b
>> Author: Matthew Wilcox (Oracle) <willy@infradead.org>
>> Date:   Tue Nov 17 10:45:18 2020 -0500
>>
>>      fix mm-truncateshmem-handle-truncates-that-split-thps.patch
>
> This patch landed in todays linux-next (20201203) as commit 
> 8678b27f4b8b ("8678b27f4b8bfc130a13eb9e9f27171bcd8c0b3b"). Sadly it 
> breaks booting of ANY of my ARM 32bit test systems, which use initrd. 
> ARM64bit based systems boot fine. Here is example of the crash:

One more thing. Reverting those two:

1b1aa968b0b6 mm-truncateshmem-handle-truncates-that-split-thps-fix-fix

8678b27f4b8b mm-truncateshmem-handle-truncates-that-split-thps-fix

on top of linux next-20201203 fixes the boot issues.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland