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] memory_reservation bug?

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] memory_reservation bug?
From: Mick Jordan <Mick.Jordan@xxxxxxx>
Date: Wed, 11 Mar 2009 12:34:39 -0700
Cc: xen-devel-list <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 11 Mar 2009 12:35:13 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C5DDAE97.4D02%keir.fraser@xxxxxxxxxxxxx>
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>
References: <C5DDAE97.4D02%keir.fraser@xxxxxxxxxxxxx>
Reply-to: Mick.Jordan@xxxxxxx
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (X11/20080807)
On 03/11/09 11:08, Keir Fraser wrote:
On 11/03/2009 17:32, "Mick Jordan" <Mick.Jordan@xxxxxxx> wrote:

I've looked at the code in memory.c and page_alloc.c and Xen certainly
thinks tot_pages > max_pages for the domain when it reports the error.

The extent_order on the reservations is 0.

Any ideas?

Just because you called decrease_reservation() doesn't mean the pages
necessarily really got freed. If you still have mappings to them squirrelled
away then the free can be deferred.
Ah, that explains it, thank you. I was taking the fact that the return value equaled the number I tried to decrease meant that it really did decrease by that amount. But, owing to a bug, I do in fact have mappings still lying around.

Xen really does need a developer manual -;)


Xen-devel mailing list