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] Support swap a page from user spacetools --

To: Jan Beulich <jbeulich@xxxxxxxxxx>, Yunhong Jiang <yunhong.jiang@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH] Support swap a page from user spacetools -- Was RE: [RFC][PATCH] Basic support for page offline
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 20 Mar 2009 09:42:24 +0000
Cc: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 20 Mar 2009 02:42:58 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <49C37206.76E4.0078.0@xxxxxxxxxx>
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcmpP3CjhnZ885hGSnaaDBqeewsVlQAALt+i
Thread-topic: [Xen-devel] Re: [PATCH] Support swap a page from user spacetools -- Was RE: [RFC][PATCH] Basic support for page offline
User-agent: Microsoft-Entourage/12.15.0.081119
On 20/03/2009 09:37, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

>> 5) After update all page tables, user space tools will try to exchange the
>> old page with the new page. If the new mfn has no
>> reference anymore (i.e. count_info & count_mask = 1), the exchange will
>> update the m2p and return success, otherwise it will
>> return fail. (the page may be referenced by other domain, like grant table or
>> foreign mapped).
> 
> Hmm, if you consider the possibility of this case, then you should also
> consider the possibility of a page still being accessible by another domain at
> the point where you copy its content, but no longer in use when you do the
> exchange (which means that the content may have changed between the two points
> in time).

Since the guest is suspended, would that matter? Any I/Os that were in
flight on suspend will get resubmitted on resume. So the potential races
might all be benign.

 -- Keir



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

<Prev in Thread] Current Thread [Next in Thread>