Messages in this thread | | | Date | Thu, 10 Jan 2002 11:47:04 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH] PAGE_SIZE IO for RAW (RAW VARY) |
| |
On Thu, Jan 10, 2002 at 11:22:25AM +0100, Jens Axboe wrote: > 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.
ok, I don't expect problems there. It can happen for example if you create a snapshot with 4k and then you switch back the original volume to 1k. the physical volume will get mixed b_size colaesced into the same request.
Andrea - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |