Re: direct-IO writes strange behavior

[Andrew Morton <akpm@xxxxxxxx>]

Alberto Nava <beto@xxxxxxxxxxx> wrote:
>
> I've done some more digging on this issue. The reason the
>  request is going in 4k pages is that the direct-io code is
>  giving up in do_direct_IO() and the request is issued as buffer IO :-(.

You seem to be using a -mm kernel.  It has extensive and not-quite-complete
and not-really-tested-at-all-with-XFS direct-io changes.

It would be best to concentrate on stock Linus direct-io for now - wait
until we think we've completed the direct-io rework in -mm and have tested
it decently with XFS.