Re: [Xen-devel] [PATCH 0001/001] xen: multi page ring support for block devices

[Ian Campbell <Ian.Campbell@citrix.com>]

On Thu, 2012-03-15 at 08:03 +0000, Jan Beulich wrote:
> >>> On 14.03.12 at 18:01, Justin Gibbs <justing@spectralogic.com> wrote:
> > While we're talking about fixing ring data structures, can RING_IDX
> > be defined as a "uint32_t" instead of "unsigned int".  The structure
> > padding in the ring macros assumes RING_IDX is exactly 4 bytes,
> > so this should be made explicit.  ILP64 machines may still be a way
> > out, but the use of non-fixed sized types in places where size really
> > matters just isn't clean.
> 
> Yes, if we're going to rev the interface, then any such flaws should be
> corrected.

There has been talk of doing something similar for netif too. IIRC the
netchannel2 work included a new generic ring scheme with support for
variable sized req/rsp elements and such.

If we are going to rev the rings then should we try and use a common
ring mechanism? I think so. If so then we could do worse than to start
from the netchannel2 ring stuff and/or concepts?

Looks like that is
http://xenbits.xen.org/ext/netchannel2/linux-2.6.18/log/075f6677a290/include/xen/interface/io/uring.h
still a bit nc2 specific though.

Ian.