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] XenStore Watch Behavior

To: John McCullough <jmccullo@xxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] XenStore Watch Behavior
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Sun, 27 Aug 2006 15:57:06 +0100
Delivery-date: Sun, 27 Aug 2006 07:57:26 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20060826203222.GA2835@xxxxxxxxxxx>
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: AcbJ6RAFTmqz3TXcEdukHgAKle7CWA==
Thread-topic: [Xen-devel] XenStore Watch Behavior
User-agent: Microsoft-Entourage/

On 26/8/06 9:32 pm, "John McCullough" <jmccullo@xxxxxxxxxxx> wrote:

>     What is the intended behavior of watches on the XenStore?  Should
> only one watch be allowed on a given sub-hierarchy?  Should the most
> specific watch be triggered alone?  Should all watches be triggered?

I believe it's all supposed to work in a very obvious and simple way: All
watches registered on a prefix of the updated node's path should be fired. A
single transaction can fire the same watch multiple times if that watch is
on a common prefix of a number of nodes updated by that transaction (since
each firing event specifies the full path of the modified node, so events
can't really be merged).

If you observe different behaviour from this then it is most likely a bug
and we would love to receive patches!

 -- Keir

Xen-devel mailing list