From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751506Ab1A0PUE (ORCPT ); Thu, 27 Jan 2011 10:20:04 -0500 Received: from router-fw.net-space.pl ([89.174.63.77]:42287 "EHLO router-fw.net-space.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809Ab1A0PUD (ORCPT ); Thu, 27 Jan 2011 10:20:03 -0500 Date: Thu, 27 Jan 2011 16:19:21 +0100 From: Daniel Kiper To: Stefan Bader Cc: Daniel Kiper , 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 Message-ID: <20110127151921.GB23746@router-fw-old.local.net-space.pl> References: <20110127144843.GA23746@router-fw-old.local.net-space.pl> <4D41883A.3020603@canonical.com> <4D418907.2030708@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D418907.2030708@canonical.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, Jan 27, 2011 at 04:02:31PM +0100, Stefan Bader wrote: > On 01/27/2011 03:59 PM, Stefan Bader wrote: > > 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. > > Sorry, did not read careful enough. So you did. Maybe you could actually try to > make the additional change of > > --- a/arch/x86/xen/p2m.c > +++ b/arch/x86/xen/p2m.c > @@ -61,6 +61,7 @@ static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_T > > RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PE > RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MI > +RESERVE_BRK(p2m_node, PAGE_SIZE); > > static inline unsigned p2m_top_index(unsigned long pfn) > { > > This one I missed and probably that has more effects on big memory values. No, it does not work (CONFIG_XEN_MAX_DOMAIN_MEMORY=128). Daniel