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-devel] [PATCH][REPOST] Additional states for Xenbus:Suspend/Res

To: "Stefan Berger" <stefanb@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH][REPOST] Additional states for Xenbus:Suspend/Resume
From: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Date: Tue, 24 Jan 2006 18:05:33 -0000
Delivery-date: Tue, 24 Jan 2006 18:14:10 +0000
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcYdgKmvG1cL966+S5OcAsXd4eXeyADj18uw
Thread-topic: [Xen-devel] [PATCH][REPOST] Additional states for Xenbus:Suspend/Resume
> I have previously posted a version of this patch. The problem 
> that I have encountered with driver backends was that they 
> were unaware of the reason why a frontend was disappearing or 
> why it was created. The following patch allows the backend to 
> see whether a frontend is going into suspend mode and 
> disappearing vs. disappearing due to domain destruction or 
> being created due to a resume vs a domain creation. I have 
> separated out the code that actually uses this awareness in 
> the TPM driver for another patch. Backend drivers can now be 
> written such that it allows hotplug scripts to react 
> differently depending on this reason.

Its not clear that having an explicit suspend state is a good thing: The
recovery mechanism that kicks in upon restore is also used for
recovering from backend restarts, which can happen at any time in any
state (as a result of a crash). Having an explicit suspend notification
may actually send the wrong message to driver writers. Further, you
don't want to be doing things like running hotplug scripts during a time
critical operation like the final suspend/resume commit stage.


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>
  • RE: [Xen-devel] [PATCH][REPOST] Additional states for Xenbus:Suspend/Resume, Ian Pratt <=