Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752108AbaGaRoB (ORCPT ); Thu, 31 Jul 2014 13:44:01 -0400 Received: from smtp.citrix.com ([66.165.176.89]:60062 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750859AbaGaRoA (ORCPT ); Thu, 31 Jul 2014 13:44:00 -0400 X-IronPort-AV: E=Sophos;i="5.01,773,1400025600"; d="scan'208";a="157609883" Message-ID: <53DA805D.4020300@citrix.com> Date: Thu, 31 Jul 2014 18:43:57 +0100 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: Matt Rushton , , CC: , , , Matt Rushton Subject: Re: [PATCH v2 2/2] xen/setup: Remap Xen Identity Mapped RAM References: <1405814495-10868-1-git-send-email-mrushton@amazon.com> <1405814495-10868-2-git-send-email-mrushton@amazon.com> In-Reply-To: <1405814495-10868-2-git-send-email-mrushton@amazon.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/07/14 01:01, Matt Rushton wrote: > Instead of ballooning up and down dom0 memory this remaps the existing mfns > that were replaced by the identity map. The reason for this is that the > existing implementation ballooned memory up and and down which caused dom0 > to have discontiguous pages. In some cases this resulted in the use of bounce > buffers which reduced network I/O performance significantly. This change will > honor the existing order of the pages with the exception of some boundary > conditions. > > To do this we need to update both the Linux p2m table and the Xen m2p table. > Particular care must be taken when updating the p2m table since it's important > to limit table memory consumption and reuse the existing leaf pages which get > freed when an entire leaf page is set to the identity map. To implement this, > mapping updates are grouped into blocks with table entries getting cached > temporarily and then released. > > On my test system before: > Total pages: 2105014 > Total contiguous: 1640635 > > After: > Total pages: 2105014 > Total contiguous: 2098904 Applied to devel/for-linus-3.17 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/