From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751313Ab1A0O7V (ORCPT ); Thu, 27 Jan 2011 09:59:21 -0500 Received: from adelie.canonical.com ([91.189.90.139]:59763 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751723Ab1A0O7S (ORCPT ); Thu, 27 Jan 2011 09:59:18 -0500 Message-ID: <4D41883A.3020603@canonical.com> Date: Thu, 27 Jan 2011 15:59:06 +0100 From: Stefan Bader User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: Daniel Kiper CC: linux-kernel@vger.kernel.org, stable@kernel.org, x86@kernel.org, xen-devel@lists.xensource.com, jeremy@goop.org, konrad.wilk@oracle.com, mingo@redhat.com, mingo@elte.hu Subject: Re: [PATCH] xen: convert p2m to a 3 level tree - partial revert References: <20110127144843.GA23746@router-fw-old.local.net-space.pl> In-Reply-To: <20110127144843.GA23746@router-fw-old.local.net-space.pl> X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/27/2011 03:48 PM, Daniel Kiper wrote: > Hi, > > Durning work on Xen memory hotplug I discoverd that > 2.6.38-rc2 does not boot on domU. After some investigation > it appeared that 58e05027b530ff081ecea68e38de8d59db8f87e0 > commit changed CONFIG_XEN_MAX_DOMAIN_MEMORY constant value > to 128. This change does not allow to boot kernel on domU > with small memory size (I could confirm that it is even > not possible to boot kernel on domU with 2 GiB). Guest > crash silently without any warning. Durning further > research I found out that there is another commit published > recently (8e1b4cf2108488ccfb9a3e7ed7cd85a435e01d4b) which attempts > to fix this issue, however, it does not work on my platform. > I decided to reenable CONFIG_XEN_MAX_DOMAIN_MEMORY option in > kernel config and enable users to choose resonable values for > their machines until better fix will be published. I think this > solution is good because allow users to boot domU with newest > kernel and allow developers to continue their work without > time presure which could lead to new bugs. > Have you tried with a version that contains commit 8e1b4cf2108488ccfb9a3e7ed7cd85a435e01d4b Author: Stefan Bader Date: Thu Jan 20 15:38:23 2011 +0100 xen: p2m: correctly initialize partial p2m leaf I still may need to send a follow up to add a matching RESERVE_BRK, but at least I was able to boot small DomU's again. -Stefan > This patch applies cleanly to current Linus' kernel tree. > > Signed-off-by: Daniel Kiper > --- > arch/x86/xen/Kconfig | 11 +++++++---- > 1 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig > index 5b54892..a234b9a 100644 > --- a/arch/x86/xen/Kconfig > +++ b/arch/x86/xen/Kconfig > @@ -29,12 +29,15 @@ config XEN_PVHVM > depends on X86_LOCAL_APIC > > config XEN_MAX_DOMAIN_MEMORY > - int > - default 128 > + int "Maximum allowed size of a domain in gigabytes" > + default 8 if X86_32 > + default 32 if X86_64 > depends on XEN > help > - This only affects the sizing of some bss arrays, the unused > - portions of which are freed. > + The pseudo-physical to machine address array is sized > + according to the maximum possible memory size of a Xen > + domain. This array uses 1 page per gigabyte, so there's no > + need to be too stingy here. > > config XEN_SAVE_RESTORE > bool