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-ia64-devel

Re: [Xen-ia64-devel] [PATCH] fix oops message from timer_interrupt on VT

To: Aron Griffis <aron@xxxxxx>
Subject: Re: [Xen-ia64-devel] [PATCH] fix oops message from timer_interrupt on VTI domain
From: Alex Williamson <alex.williamson@xxxxxx>
Date: Tue, 23 Jan 2007 14:57:12 -0700
Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 23 Jan 2007 13:56:37 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20070123214426.GB4304@xxxxxxxxx>
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>
Organization: HP OSLO R&D
References: <200701230038.l0N0cFhm026217@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <20070123214426.GB4304@xxxxxxxxx>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Tue, 2007-01-23 at 16:44 -0500, Aron Griffis wrote:
> Atsushi SAKAI wrote:  [Mon Jan 22 2007, 07:36:55PM EST]
> > Oops: timer tick before it's due (itc=ed98bb5849,itm=ed98bb5849)
> > Oops: timer tick before it's due (itc=f20bca8ca3,itm=f20bca8ca3)
> > Oops: timer tick before it's due (itc=f4ea4e2b32,itm=f4ea4e2b32)
> ...
> > 
> > These oops messages are generated
> > because timer_interrupt checks the condition itc > itm.
> 
> Is that the right comparison though?  itc isn't guaranteed to return
> different values on subsequent fetches, and the interrupt is generated
> when itc == itm, right?  So shouldn't the condition be itc >= itm?

   Good point.  With the slower ITC on a Montecito system, I don't know
if anything would prevent you hitting the interrupt handler when itc ==
itm.  Perhaps a Montecito fix for Linux-ia64 to use time_after_eq()
would eliminate this problem.

        Alex
-- 
Alex Williamson                             HP Open Source & Linux Org.


_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel