Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751547AbaKKRsF (ORCPT ); Tue, 11 Nov 2014 12:48:05 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:57307 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751018AbaKKRsD (ORCPT ); Tue, 11 Nov 2014 12:48:03 -0500 X-IronPort-AV: E=Sophos;i="5.07,362,1413244800"; d="scan'208";a="191676575" Message-ID: <54624BCB.9040300@citrix.com> Date: Tue, 11 Nov 2014 17:47:55 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 To: Juergen Gross , , , , , , , , , Subject: Re: [Xen-devel] [PATCH V3 7/8] xen: switch to linear virtual mapped sparse p2m list References: <1415684626-18590-1-git-send-email-jgross@suse.com> <1415684626-18590-8-git-send-email-jgross@suse.com> In-Reply-To: <1415684626-18590-8-git-send-email-jgross@suse.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11/14 05:43, Juergen Gross wrote: > At start of the day the Xen hypervisor presents a contiguous mfn list > to a pv-domain. In order to support sparse memory this mfn list is > accessed via a three level p2m tree built early in the boot process. > Whenever the system needs the mfn associated with a pfn this tree is > used to find the mfn. > > Instead of using a software walked tree for accessing a specific mfn > list entry this patch is creating a virtual address area for the > entire possible mfn list including memory holes. The holes are > covered by mapping a pre-defined page consisting only of "invalid > mfn" entries. Access to a mfn entry is possible by just using the > virtual base address of the mfn list and the pfn as index into that > list. This speeds up the (hot) path of determining the mfn of a > pfn. > > Kernel build on a Dell Latitude E6440 (2 cores, HT) in 64 bit Dom0 > showed following improvements: > > Elapsed time: 32:50 -> 32:35 > System: 18:07 -> 17:47 > User: 104:00 -> 103:30 > > Tested on 64 bit dom0 and 32 bit domU. Reviewed-by: David Vrabel Can you please test this with the following guests/scenarios. * 64 bit dom0 with PCI devices with high MMIO BARs. * 32 bit domU with PCI devices assigned. * 32 bit domU with 64 GiB of memory. * domU that starts pre-ballooned and is subsequently ballooned up. * 64 bit domU that is saved and restored (or local host migration) * 32 bit domU that is saved and restored (or local host migration) Thanks. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/