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Re: [Xen-devel] xen-unstable: TX/RX ring buffer exhaustion and NR_GRANT_FRAMES


domUs are yet not allowed to run more than 3 NICs as far as I can see
when running tests with 3.0, and the 'old' way to provide more
interfaces by enhancing the grant table structures do not work anymore
(see below).  I'd really appreciate any suggestions where I could modify
the source to get more NICs.

Am Freitag, den 11.11.2005, 12:11 +0000 schrieb harry:
> The xenidc code has the concept of a buffer resource provider which
> implements an anti-deadlock resource reservation.  Each client has uses
> a pool with it's own buffer resource provider and the anti-deadlock
> resource reservations decouple the clients from one another.  The
> underlying implementation of the buffer resource provider is currently
> trivial (individual resource pools) but the intention is that the buffer
> resource providers will share resources from a common underlying pool.
> This resource management strategy allows you to make better use of
> constrained resources like grant tables whilst avoiding deadlock.

Interesting thing, but I could not find documentation on xenidc - where
do I get it?  Where is the code, is it already inside Xen?

> On Fri, 2005-11-11 at 10:48 +0000, Keir Fraser wrote:
> > On 11 Nov 2005, at 08:59, Birger Toedtmann wrote:
> > 
> > > message - see bug #183.  It was pointed out to me that it might be
> > > possible to adjust this manually in xen/include/xen/grant_table.h,
> > > however, setting ORDER_GRANT_FRAMES to 3 to get more pages of grant
> > > tables doesn't change anything.  Sooo, question #1: how can I alter the
> > > code to get more grant tables such that more nics per domU will become
> > > available?  Question #2: is it planned to make this configurable, e.g.
> > > by boot option for dom0?
> > 
> > 1: you need to edit NR_GRANT_FRAMES in linux/include/asm-xen/gnttab.h
> > 
> > 2: yes, it will eventually be manually configurable with a higher 
> > default 'maximum'

Unfortunately, this method does not work anymore since November/
December.  After modifying NR_GRANT_FRAMES etc., the dom0 would say
"g.e. still in use!" on boot and halt after this message.  Any hints how
I can adjust the grant tables to get more NICs?

Birger Tödtmann                   email:btoedtmann@xxxxxxxxxxxxxx
Technik der Rechnernetze, Institut für Experimentelle Mathematik
Universität Duisburg-Essen, Campus Essen, Germany.
skype:birger.toedtmann  pgp:0x6FB166C9  phone: +49-(0)201-1837662

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