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] amd64 system only seeing 3.5gb instead of 4gb of memory

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] amd64 system only seeing 3.5gb instead of 4gb of memory
From: Rafał Kupka <rkupka+Listy.Xen@xxxxxxxxxxxxx>
Date: Fri, 15 Jun 2007 09:37:24 +0200
Delivery-date: Fri, 15 Jun 2007 00:34:58 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <AEC6C66638C05B468B556EA548C1A77D01166ACE@trantor>
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/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Mail-followup-to: xen-users@xxxxxxxxxxxxxxxxxxx
References: <AEC6C66638C05B468B556EA548C1A77D01166ACE@trantor>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.13 (2006-08-11)
On Fri, Jun 15, 2007 at 03:38:24PM +1000, James Harper wrote:
Hello,

> I've just had a server upgraded to 4gb of memory... BIOS reports 4gb of
> memory but xen only sees 3.5gb (3583mb)

What about plain linux kernel? How much it see?

> I was under the impression that an amd64 server should be able to see
> well over 4gb of memory. I believe that PCI space and other stuff gets
> mapped to the very top of memory... is there some setting somewhere that
> I might need to set to get that .5gb mapped to somewhere visible?

Only BIOS can do that. Search for "PCI memory hole" or some memory
remapping option (maybe with values: continuous/discontig).

By "amd64" you mean AMD processor[1]? Some older Inter chipsets cannot
remap RAM above 4G.

If problem persists please post e820 memory map from xm dmesg (that
lines after "(XEN) Physical RAM map:") and from plain linux kernel.

Kupson
[1] Debian uses amd64 as arch name, instead of x86-64.
-- 
Great software without the knowledge to run it is pretty useless.
(Linux Gazette #1)

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