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] Re: [PATCH] xen: events: do not unmask polled ipis on re

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH] xen: events: do not unmask polled ipis on restore.
From: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>
Date: Fri, 29 Oct 2010 18:45:08 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 29 Oct 2010 10:45:59 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4CCB0789.4040203@xxxxxxxx>
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>
Organization: Citrix Systems, Inc.
References: <1288341238-3059-1-git-send-email-ian.campbell@xxxxxxxxxx> <4CCAF9E1.70902@xxxxxxxx> <1288373709.8069.23.camel@xxxxxxxxxxxxxxxxxxxxx> <4CCB0789.4040203@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Fri, 2010-10-29 at 18:42 +0100, Jeremy Fitzhardinge wrote:
> On 10/29/2010 10:35 AM, Ian Campbell wrote:
> > On Fri, 2010-10-29 at 17:44 +0100, Jeremy Fitzhardinge wrote:
> >> On 10/29/2010 01:33 AM, Ian Campbell wrote:
> >>> The Xen PV spinlock backend attempts to setup an IPI to IRQ binding
> >>> which is only to be used via xen_poll_irq rather received directly.
> >>>
> >>> Unfortunately restore_cpu_ipis unconditionally unmasks each IPI
> >>> leading to:
> >> Gosh I wonder why we hadn't seen this before?
> > I must admit I don't normally enable CONFIG_PARAVIRT_SPINLOCKS I
> > happened to be running someone else's config when I noticed this.
> >
> > Possibly relates to switching to the edge triggered handler and the
> > related mask/unmask vs clear etc frobbing?
> 
> Possibly.  Did you see my comment further down?

No! Going back now...

Ian.



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