Re: Integration of SCST in the mainstream Linux kernel

James Bottomley
2008-02-04T17:06:51Z

On Mon, 2008-02-04 at 19:25 +0300, Vladislav Bolkhovitin wrote:
> James Bottomley wrote:
> >>Vladislav Bolkhovitin wrote:
> >>So, James, what is your opinion on the above? Or the overall SCSI target
> >>project simplicity doesn't matter much for you and you think it's fine
> >>to duplicate Linux page cache in the user space to keep the in-kernel
> >>part of the project as small as possible?
> >
> >
> > The answers were pretty much contained here
> >
> > http://marc.info/?l=linux-scsi&m=120164008302435
> >
> > and here:
> >
> > http://marc.info/?l=linux-scsi&m=120171067107293
> >
> > Weren't they?
>
> No, sorry, it doesn't look so for me. They are about performance, but
> I'm asking about the overall project's architecture, namely about one
> part of it: simplicity. Particularly, what do you think about
> duplicating Linux page cache in the user space to have zero-copy cached
> I/O? Or can you suggest another architectural solution for that problem
> in the STGT's approach?

Isn't that an advantage of a user space solution? It simply uses the
backing store of whatever device supplies the data. That means it takes
advantage of the existing mechanisms for caching.

James