From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754554AbaHZUkO (ORCPT ); Tue, 26 Aug 2014 16:40:14 -0400 Received: from mail-pa0-f48.google.com ([209.85.220.48]:50649 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752427AbaHZUkN (ORCPT ); Tue, 26 Aug 2014 16:40:13 -0400 Message-ID: <53FCF0A9.60400@gmail.com> Date: Tue, 26 Aug 2014 13:40:09 -0700 From: Matthew Rushton User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: David Vrabel , konrad.wilk@oracle.com, boris.ostrovsky@oracle.com CC: msw@amazon.com, linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, 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> <53DA805D.4020300@citrix.com> <53DBA9AC.8000302@citrix.com> In-Reply-To: <53DBA9AC.8000302@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 08/01/14 07:52, David Vrabel wrote: > On 31/07/14 18:43, David Vrabel wrote: >> 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 > Unfortunately, this produces too many WARNINGs on some boxes or > with certain configurations. > > I will remove this patch from the queue for 3.17. > Have you had a chance to try the v3 patch set?