Re: [Qemu-devel] buffer alignment for block backends

[Stefano Stabellini]

Gerd Hoffmann wrote:

> On 04/09/09 17:21, Samuel Thibault wrote:
>> Gerd Hoffmann, le Thu 09 Apr 2009 15:54:34 +0200, a écrit :
>>> On 04/09/09 15:30, Stefano Stabellini wrote:
>>>> The userspace\kernelspace distinction does not make much sense in
>>>> minios, but yes it provides an interface to communicate with blkback in
>>>> dom0. This interface is used by block-vbd in qemu instead of
>>>> block-raw-posix when run in minios.
>>> Sit back, look again.  Do you really need it being page-aligned?
>> Page aligned is an optimization which comes for free when you can
>> already choose the alignment.
> 
> Ok, so you don't have to.
> 
> Does it have an effect positive actually?  i.e. do you have requests 
> which would fit into one page but actually span two due to the misalignment?


Yep, I can see many here.