From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758483Ab2DZSPv (ORCPT ); Thu, 26 Apr 2012 14:15:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35166 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757030Ab2DZSPu (ORCPT ); Thu, 26 Apr 2012 14:15:50 -0400 Message-ID: <4F9990D9.10300@redhat.com> Date: Thu, 26 Apr 2012 14:15:53 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: lwoodman@redhat.com CC: Linux Kernel Mailing List , linux-mm@kvack.org, Christoph Lameter , Motohiro Kosaki , Andrew Morton Subject: Re: [PATCH -mm V3] do_migrate_pages() calls migrate_to_node() even if task is already on a correct node References: <4F998FDE.5020104@redhat.com> In-Reply-To: <4F998FDE.5020104@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/26/2012 02:11 PM, Larry Woodman wrote: > This patch changes do_migrate_pages() to only preserve the relative > layout inside the > program if the number of NUMA nodes in the source and destination mask > are the > same. If the number is different, we do a much more efficient migration > by not touching > memory that is in an allowed node. > > This preserves the old behaviour for programs that want it, while > allowing a userspace > NUMA placement tool to use the new, faster migration. This improves > performance in > our tests by up to a factor of 7. > Signed-off-by: Larry Woodman Reviewed-by: Rik van Riel