WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] (repeatable) cross-domain networking failure

To: mukesh agrawal <xen.sourceforge.net@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] (repeatable) cross-domain networking failure
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Sun, 16 Jan 2005 21:09:12 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxxx, Nivedita Singhvi <niv@xxxxxxxxxx>
Delivery-date: Sun, 16 Jan 2005 21:15:14 +0000
Envelope-to: xen+James.Bulpin@xxxxxxxxxxxx
In-reply-to: Your message of "Sun, 16 Jan 2005 15:49:31 EST." <Pine.LNX.4.61.0501161442300.21950@xxxxxxxxxxxxxxxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
> Also, let me add some more detail to my original report:
> 
> 1. The networking fails after the 128th UDP packet received in dom0, even 
> if I restart domU. Specifically:
> 
>       - If I send one UDP packet from domU to dom0, shut down domU, and
>         start a fresh domU, then I can only send 127 (rather than
>         128) UDP packets from the new domU before networking will fail.
> 
>       - If I shut down domU after the networking failure, and start a
>            new domU, networking between the new domU and dom0 does not
>            work.
> 

This corroborates my intial guess that the backend driver (in DOM0) is
sending the packets into the DOM0 networking layer, and never hearing
back when the packet is freed. Normally this would trigger a response
to be sent back to the domU and resources in the backend driver would
get freed up. This isn't happening and you eventually hit a limit on
the number of packets that the driver will simultaneously put in
flight. 

Either those UDP packets are queued up somewhere in the DOM0 network
stack, or the destructor callback is not getting called for some
reason or has got overwritten(!).

 -- Keir


-------------------------------------------------------
The SF.Net email is sponsored by: Beat the post-holiday blues
Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek.
It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel