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] Disallow setting maxmem to higher value than to

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Disallow setting maxmem to higher value than total physical memory size
From: Michal Novotny <minovotn@xxxxxxxxxx>
Date: Wed, 01 Sep 2010 17:10:15 +0200
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 01 Sep 2010 08:09:52 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4C7E86920200007800013C1C@xxxxxxxxxxxxxxxxxx>
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: <4C7E47B2.9010805@xxxxxxxxxx> <1283345049.12544.9494.camel@xxxxxxxxxxxxxxxxxxxxxx> <4C7E4EAD.3060106@xxxxxxxxxx> <1283348230.12544.9506.camel@xxxxxxxxxxxxxxxxxxxxxx> <4C7E60D0.8050706@xxxxxxxxxx> <4C7E7ED30200007800013BF0@xxxxxxxxxxxxxxxxxx> <4C7E6833.5000509@xxxxxxxxxx> <4C7E86920200007800013C1C@xxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4
On 09/01/2010 05:00 PM, Jan Beulich wrote:
On 01.09.10 at 16:50, Michal Novotny<minovotn@xxxxxxxxxx>  wrote:
On 09/01/2010 04:26 PM, Jan Beulich wrote:
On 01.09.10 at 16:18, Michal Novotny<minovotn@xxxxxxxxxx>   wrote:

Oh, ok. It's not limited to dom0 nevertheless I don't see anything to be

And how does this play together with physical memory hotplug?


Well, it's reading the physical memory size using the xc.physinfo() call
so if this is handled correctly by hypervisor (since this  basically
issues a hypercall) then it should be working fine.
Meaning the tools would auto-adjust maxmem_kb' for Dom0 when
new memory got added? I can't see where that happens.


It's all based on xc.physinfo() call which is basically a hypercall. If there's a valid value coming from the hypervisor then it would be working fine.

You can see the call is there always on this line of my patch:

+ total_mem = int(xc.physinfo()['total_memory'])

If this is handled correctly by hypervisor then we're good in user-space as can be seen in tools/python/xen/lowlevel/xc/xc.c and tools/libxl/libxl.c where call to tools/libxc/xc_misc.c:xc_physinfo() resides.


Michal Novotny<minovotn@xxxxxxxxxx>, RHCE
Virtualization Team (xen userspace), Red Hat

Xen-devel mailing list

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