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-users

Re: [Xen-users] dom0 incorrect mem size

To: Robbie Garertt <rgarrett@xxxxxxxxxxxxxx>
Subject: Re: [Xen-users] dom0 incorrect mem size
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Fri, 12 Mar 2010 11:33:13 +0200
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 12 Mar 2010 01:34:03 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <67C84CCFBA7570459B81345BA19100052C8A@xxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <67C84CCFBA7570459B81345BA19100052C8A@xxxxxxxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.18 (2008-05-17)
On Thu, Mar 11, 2010 at 07:04:49PM -0500, Robbie Garertt wrote:
>    Hey all,
> 
>    just compiled xen 3.4.2 and linux 2.6.31.12.  I followed the instructions
>    on the Xen wiki to get the install running.
> 
>    my issue here is that in my grub memnu config i set dom0_mem=512M
>    when i login to the dom0 and i do a free -m i get that the system only has
>    432 under the total section.
> 

Try reading "xm dmesg", or capturing that to a file at boot time using a serial 
console.

>    booting into the stock debian kernel 2.6.26-2-amd64 kernel gives me 8192
>    free memory for i did not limit that.
>    when i run xm info |grep memory under the xen kernel I get the following.
>    total_memory           : 8191
>    free_memory            : 7578
>    node_to_memory         : node0:7578
> 

What does "xm list" show about dom0 memory?

8GB is 8192 MB, so 8191 MB total memory sounds correct. 
8191 - 7578 = 613 MB.

If dom0 has 432 MB, then there's 181 MB used for something else.
Xen hypervisor (or was it dom0 kernel?) allocates some memory as a 
DMA reserve, and there's some overhead per every MB of memory, and per every 
vcpu.

-- Pasi

>    the server only has 8gb of memory installed which is confirmed via the
>    system bios.
> 
>    is there anyway to figure out what is going on here?
> 
> 

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

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

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