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


Re: [Xen-ia64-devel] One unstablity in fast syscall path

To: Alex Williamson <alex.williamson@xxxxxx>
Subject: Re: [Xen-ia64-devel] One unstablity in fast syscall path
From: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Date: Tue, 13 Jun 2006 20:12:36 +0900
Cc: xen-ia64-devel <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 13 Jun 2006 04:12:48 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <1150170557.5653.3.camel@lappy>
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
References: <386718549BA50E498DA75F3C0518CEEC0F1E46@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <1150170557.5653.3.camel@lappy>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/
On Mon, Jun 12, 2006 at 09:49:17PM -0600, Alex Williamson wrote:
> On Tue, 2006-06-13 at 08:36 +0800, Tian, Kevin wrote:
> > That's the real problem, though we're not sure why this phenomenon is 
> > easier to be reproduced after creating VTI domain. Quick/easy solution 
> > can be to roll back above changeset to ensure tree stability first, and
> > then 
> > community needs to think more robust solution later.
> Hi Kevin,
>    Thanks for tracking this down, I've seen some instability lately too.
> Isaku, should we back this one out until it can be stabilized or do you
> have a more direct solution?  Thanks,

Sorry for the regression. Please back it out.
The correctness has higher priority than performance,
the patch should be backed out since it focuses on only performance.

There are the following choices for right fix, I think.

A. use hypercall instead of hyperprivop.
B. introduce new flag for hyperprivop instread VPSR.ic as Tristan proposed.
C. use one of itr to map vDSO.
D. abondan vDSO paravirtualization.


Xen-ia64-devel mailing list