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Date: Fri, 18 Mar 2016 00:17:18 +0900
Message-ID: <CAAmzW4M2uLE0VJ91BfveNR4_crsaUEPpLB6HW393jhpF4=G73Q@mail.gmail.com>
Subject: Re: Page migration issue with UBIFS
From: Joonsoo Kim <js1304@gmail.com>
To: Richard Weinberger <richard@nod.at>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Christoph Hellwig <hch@infradead.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        Maxime Ripard <maxime.ripard@free-electrons.com>,
        David Gstir <david@sigma-star.at>, Dave Chinner <david@fromorbit.com>,
        Artem Bityutskiy <dedekind1@gmail.com>,
        Alexander Kaplan <alex@nextthing.co>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        Sasha Levin <sasha.levin@oracle.com>, rvaswani@codeaurora.org,
        "Luck, Tony" <tony.luck@intel.com>,
        Shailendra Verma <shailendra.capricorn@gmail.com>,
        s.strogin@partner.samsung.com, Hugh Dickins <hughd@google.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Vlastimil Babka <vbabka@suse.cz>
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2016-03-17 17:13 GMT+09:00 Richard Weinberger <richard@nod.at>:
> Am 17.03.2016 um 08:11 schrieb Joonsoo Kim:
>>> It is still not clear why UBIFS has to provide a >migratepage() and what the expected semantics
>>> are.
>>> What we know so far is that the fall back migration function is broken. I'm sure not only on UBIFS.
>>>
>>> Can CMA folks please clarify? :-)
>>
>> Hello,
>>
>> As you mentioned earlier, this issue would not be directly related
>> to CMA. It looks like it is more general issue related to interaction
>> between MM and FS. Your first error log shows that error happens when
>> ubifs_set_page_dirty() is called in try_to_unmap_one() which also
>> can be called by reclaimer (kswapd or direct reclaim). Quick search shows
>> that problem also happens on reclaim. Is that fixed?
>>
>> http://www.spinics.net/lists/linux-fsdevel/msg79531.html
>
> Well, this problem happened only on a tainted kernel and never popped up again.
> So, I really don't know. :-)
>
>> I think that you need to CC other people who understand interaction
>> between MM and FS perfectly.
>
> Who is missing on the CC list?

Vlastimil already added Hugh and Mel to other relevant thread but I think
this thread has more information about the problem so I add them here.

Thanks.