Re: [PATCH] umem: fix up unplugging.

[Tao Guo]

On Wed, Apr 4, 2012 at 4:18 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
> On 2012-04-04 16:20, Tao Guo wrote:
>> Hi Andrew,
>>
>> Thanks for your reply.
>>
>> Yes, without this patch the umem driver just doesn't work.
>> It is a bug introduced by commit 7eaceaccab5f40bbfda044629a6298616aeaed50.
>> In that patch, Jens removed the whole mm_unplug_device() function,
>> which used to be
>> the trigger to make umem start to work.
>
> Hmm indeed, that's isn't terribly useful. Why aren't we just calling
> activate_card() on addition of a bio?
>
It is the original design idea, the umem driver also wants to do batch
IO the same as
hard disk drive to fully utilize the IO bandwidth.

Thanks,
-Tao
> But your patch looks fine too, if it's tested it beats what we have.
>
> --
> Jens Axboe
>
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