Re: [RFC PATCH v2] support ioctl for tunable user request

[Kyungmin Park]

On Mon, Aug 29, 2011 at 7:11 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
> Hi
>
> Lin Ming wrote:
>> On Mon, Aug 29, 2011 at 4:15 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> 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.

Thank you,
Kyungmin Park
>>
> In my case, this ioctl is used the background operation for eMMC.
> In eMMC's case, background operation(BKOPS) is supported.
> (but that is running with only card notifier, so i added new ioctl for user request)
>
> if we send the BKOPS request, card is notified to need the BKOPS.
> then running background operation. (Then user's responsibility is done)
>
> In future, i think that other block device should be used this ioctl.
> (if supported like BKOPS)
>
> Regard,
> Jaehoon Chung
>
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