From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756742AbbCSRQF (ORCPT ); Thu, 19 Mar 2015 13:16:05 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58776 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756004AbbCSRQC (ORCPT ); Thu, 19 Mar 2015 13:16:02 -0400 Message-ID: <550B0450.6000209@suse.com> Date: Thu, 19 Mar 2015 18:16:00 +0100 From: Juergen Gross User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: David Vrabel , linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, daniel.kiper@oracle.com Subject: Re: [Xen-devel] [PATCH 1/2] xen: prepare p2m list for memory hotplug References: <1426775462-981-1-git-send-email-jgross@suse.com> <1426775462-981-2-git-send-email-jgross@suse.com> <550AF6BA.7060209@citrix.com> In-Reply-To: <550AF6BA.7060209@citrix.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/19/2015 05:18 PM, David Vrabel wrote: > On 19/03/15 14:31, Juergen Gross wrote: >> Commit 054954eb051f35e74b75a566a96fe756015352c8 ("xen: switch to linear >> virtual mapped sparse p2m list") introduced a regression regarding to >> memory hotplug for a pv-domain: as the virtual space for the p2m list >> is allocated for the to be expected memory size of the domain only, >> hotplugged memory above that size will not be usable by the domain. >> >> Correct this by using a configurable size for the p2m list in case of >> memory hotplug enabled (default supported memory size is 512 GB for >> 64 bit domains and 4 GB for 32 bit domains). > [...] >> --- a/arch/x86/xen/p2m.c >> +++ b/arch/x86/xen/p2m.c >> @@ -91,6 +91,17 @@ EXPORT_SYMBOL_GPL(xen_p2m_size); >> unsigned long xen_max_p2m_pfn __read_mostly; >> EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); >> >> +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT >> +#ifdef CONFIG_X86_32 >> +BUILD_BUG_ON_MSG(CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT > 64) >> +#endif >> +#define P2M_LIMIT max(xen_max_p2m_pfn, \ >> + ((unsigned long)((u64)CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT * \ >> + 1024 * 1024 * 1024 / PAGE_SIZE))) >> +#else >> +#define P2M_LIMIT xen_max_p2m_pfn >> +#endif > > Can you arrange the #ifdef's to set xen_max_p2m_pfn to the right value > instead of introducing P2M_LIMIT? Hmm, this would require additional checks in setup.c. What about: #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT #define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT #else #define P2M_LIMIT 0 #endif and do the max(...) calculation in xen_vmalloc_p2m_tree()? Juergen