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


[Xen-devel] Re: [RFC PATCH 0/4] (Take 2): transcendent memory ("tmem") f

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: [Xen-devel] Re: [RFC PATCH 0/4] (Take 2): transcendent memory ("tmem") for Linux
From: Rik van Riel <riel@xxxxxxxxxx>
Date: Thu, 09 Jul 2009 18:45:36 -0400
Cc: npiggin@xxxxxxx, akpm@xxxxxxxx, jeremy@xxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, tmem-devel@xxxxxxxxxxxxxx, kurt.hackel@xxxxxxxxxx, Rusty Russell <rusty@xxxxxxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, dave.mccracken@xxxxxxxxxx, linux-mm@xxxxxxxxx, chris.mason@xxxxxxxxxx, sunil.mushran@xxxxxxxxxx, Avi Kivity <avi@xxxxxxxxxx>, Anthony Liguori <anthony@xxxxxxxxxxxxx>, Schwidefsky <schwidefsky@xxxxxxxxxx>, Marcelo Tosatti <mtosatti@xxxxxxxxxx>, alan@xxxxxxxxxxxxxxxxxxx, Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 09 Jul 2009 15:46:29 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <7cb22078-f200-45e3-a265-10cce2ae8224@default>
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>
Organization: Red Hat, Inc
References: <7cb22078-f200-45e3-a265-10cce2ae8224@default>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (X11/20080915)
Dan Magenheimer wrote:

But this means that either the content of that page must have been
preserved somewhere or the discard fault handler has sufficient
information to go back and get the content from the source (e.g.
the filesystem).  Or am I misunderstanding?

The latter.  Only pages which can be fetched from
source again are marked as volatile.

But IMHO this is a corollary of the fundamental difference.  CMM2's
is more the "VMware" approach which is that OS's should never have
to be modified to run in a virtual environment.

Actually, the CMM2 mechanism is quite invasive in
the guest operating system's kernel.

( I don't see why CMM2 provides more flexibility.

I don't think anyone is arguing that.  One thing
that people have argued is that CMM2 can be more
efficient, and easier to get the policy right in
the face of multiple guest operating systems.

All rights reversed.

Xen-devel mailing list