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Date: Tue, 17 Nov 2009 19:32:36 +0900
Message-ID: <28c262360911170232i307144cnb4ddea2a5389bd8e@mail.gmail.com>
Subject: Re: [PATCH 2/7] mmc: Don't use PF_MEMALLOC
From: Minchan Kim <minchan.kim@gmail.com>
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Sender: owner-linux-mm@kvack.org
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, linux-mmc@vger.kernel.org
List-ID: <linux-mm.kvack.org>

On Tue, Nov 17, 2009 at 7:29 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> On Tue, 17 Nov 2009 16:17:50 +0900 (JST)
> KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
>
>> Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
>> memory, anyone must not prevent it. Otherwise the system cause
>> mysterious hang-up and/or OOM Killer invokation.
>
> So now what happens if we are paging and all our memory is tied up for
> writeback to a device or CIFS etc which can no longer allocate the memory
> to complete the write out so the MM can reclaim ?
>
> Am I missing something or is this patch set not addressing the case where
> the writeback thread needs to inherit PF_MEMALLOC somehow (at least for
> the I/O in question and those blocking it)
>

I agree.
At least, drivers for writeout is proper for using PF_MEMALLOC, I think.


> Alan
>
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--=20
Kind regards,
Minchan Kim

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