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] [PATCH] Make "xm mem-set" be lower bound on domX-min-mem

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Make "xm mem-set" be lower bound on domX-min-mem
From: Gareth S Bestor <bestor@xxxxxxxxxx>
Date: Sun, 21 May 2006 20:28:50 -0700
Cc: xensource-cim@xxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, xen-cim@xxxxxxxxxxxxxxxxxx
Delivery-date: Sun, 21 May 2006 20:24:51 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <acb483b259783a310dc856b9ba7670fe@xxxxxxxxxxxx>
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

Bugger. :-)

But this is good to know! Obviously it stresses the need to keep track of the initial memory allocation, to set limits on subsequent shrinking. Fortunately we already do this in the (new) Xen CIM provider model by maintaining both the so-called 'recorded' memory allocation size/settings (aka initial size) as well as the 'current' memory allocation size/setting (eg after ballooning). So at least we have the data needed to enforce a lower limit.


- Gareth

Dr. Gareth S. Bestor
IBM Linux Technology Center
M/S DES2-01
15300 SW Koll Parkway, Beaverton, OR 97006
503-578-3186, T/L 775-3186, Fax 503-578-3186

Inactive hide details for Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>

          Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>

          05/21/06 01:45 AM


Gareth S Bestor/Beaverton/IBM@IBMUS




Re: [Xen-devel] [PATCH] Make "xm mem-set" be lower bound on domX-min-mem

On 20 May 2006, at 22:27, Gareth S Bestor wrote:

>  An absolute limit might be easier to handle - and expose to users -
> than a relative one, especially up-front in CIM where it exposes
> min/max limits on resource allocations. Or is it really <2% of
> whatever the original memory allocation is when things go to
> kabluwey... ?

Unfortunately so: some critical kernel data structures are sized
proportional to the maximum amount of memory that may be allocated to
the guest. These data structures do not shrink as you remove memory
from the guest.

 -- Keir

GIF image

Xen-devel mailing list