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Date: Mon, 29 Aug 2011 23:17:25 +0800
Message-ID: <CAF1ivSZxAuVaivJyoZ=gnMu-YY7AcnBwCWtD74DqPuYAASxTxA@mail.gmail.com>
Subject: Re: [RFC PATCH v2] support ioctl for tunable user request
From: Lin Ming <lxy@ss.pku.edu.cn>
To: Kyungmin Park <kmpark@infradead.org>
Cc: Jaehoon Chung <jh80.chung@samsung.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jens Axboe <jaxboe@fusionio.com>,
        Arnd Bergmann <arnd.bergmann@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>
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On Mon, Aug 29, 2011 at 10:01 PM, Kyungmin Park <kmpark@infradead.org> wrote:
> On Mon, Aug 29, 2011 at 7:11 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi
>>
>> Lin Ming wrote:
>>> On Mon, Aug 29, 2011 at 4:15 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>>>> This patch is added the ioctl for tunable user request.
>>>
>>> Hi,
>>>
>>> What's the use case for this new ioctl?
>
> The below is the just mmc example.
>
> The main reason is that there's no way to know system or I/O idle, so
> user provides the hint. Using user based I/O, device can TUNE the
> device itself. In case of MMC, background operation can be used.
>
> and another difference from other user request, it's just trigger the
> device tune request, no need to wait the request is done.

OK.

After read the previous patch at:
http://marc.info/?l=linux-mmc&m=131407402925988&w=2

I now get better understanding what "tunable user request" mean.

Thanks.

>
> Thank you,
> Kyungmin Park