Re: [PATCH] PAGE_SIZE IO for RAW (RAW VARY)

Jens Axboe
2002-01-10T10:22:59Z

On Thu, Jan 10 2002, Andrea Arcangeli wrote:
> On Wed, Jan 09, 2002 at 11:28:39AM -0800, Badari Pulavarty wrote:
> > Ben,
> >
> > By any chance do you have a list of drivers that assume this ?
> > What does it take to fix them ?
> >
> > I think Jens BIO changes for 2.5 will fix this problem. But
> > 2.4 needs a solution in this area too. This patch showed
> > significant improvement for database workloads.
>
> I didn't checked the implementation but as far as the blkdev is
> concerned the b_size changes without notification as soon as you 'mkfs
> -b somethingelse' and then mount the fs. So it cannot break as far I can
> tell. The only important thing is that b_size stays between 512 and 4k.

The concern is/was differently sized buffer_heads in the same request,
ie b_size changing as you iterate through the chunks of one request.

--
Jens Axboe