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/
Home Products Support Community News


[Xen-devel] unfair servicing of DomU vbd requests

To: "xen devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] unfair servicing of DomU vbd requests
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Thu, 3 Mar 2011 13:25:04 +1100
Delivery-date: Wed, 02 Mar 2011 18:25:57 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcvZSjRsjGymIKsxQ9G5mKdZivK1Iw==
Thread-topic: unfair servicing of DomU vbd requests
A user of GPLPV (see thread "blue screen in windows balloon driver") is
getting a bug check in Windows under extremely high memory usage and
swapfile thrashing tests across multiple DomU's. Responses to my query
on the ntdev mailing list say that this would happen if an IO request is
not completed after 70 seconds during high memory/pagefile pressure,
which is what is happening.

It appears that Dom0 is not servicing vbd requests from DomU's fairly so
one or two end up getting stalled while the others are mostly okay. How
are vbd requests supposed to be serviced? Is there potential for one to
be overlooked for a long period of time? Is there some settings that
could be changed to avoid this happening?



Xen-devel mailing list