From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932169AbZHUIOv (ORCPT ); Fri, 21 Aug 2009 04:14:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932103AbZHUIOu (ORCPT ); Fri, 21 Aug 2009 04:14:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34517 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932100AbZHUIOt (ORCPT ); Fri, 21 Aug 2009 04:14:49 -0400 Date: Fri, 21 Aug 2009 04:14:47 -0400 (EDT) From: Miroslav Rezanina To: Jeremy Fitzhardinge Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, Gianluca Guida Message-ID: <1378245818.61101250842487688.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> In-Reply-To: <1152394510.61021250842386600.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> Subject: Re: [PATCH][v2.6.29][XEN] Return unused memory to hypervisor MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.5.5.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ----- From: "Jeremy Fitzhardinge" To: "Miroslav Rezanina" Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, "Gianluca Guida" Sent: Thursday, August 20, 2009 6:39:02 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna Subject: Re: [PATCH][v2.6.29][XEN] Return unused memory to hypervisor On 08/20/09 00:47, Miroslav Rezanina wrote: >> there is handled e820 map in guest. However, this patch informs >> hypervisor, that guest uses less memory than was assigned to it. >> If hypervisor is not informed, memory is reserved for guest that >> do not need it. If hypervisor is informed, he decrease memory >> reservation for guest and unused memory is marked as free >> for use by other guests. >> > > Yes. But the guest will modify its own e820 map for a number of > reasons; for example: reducing its own memory, or clearing a space for > the PCI hole. In general we want to free any underlying pages which > don't correspond to E820_RAM regions. > > J I agree. However, I'm not sure if xen supports such a precise handling. -- Miroslav Rezanina Software Engineer - Virtualization Team - XEN kernel