From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934285Ab2GLV1w (ORCPT ); Thu, 12 Jul 2012 17:27:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44567 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934268Ab2GLV1t (ORCPT ); Thu, 12 Jul 2012 17:27:49 -0400 Message-ID: <4FFF40D8.10000@redhat.com> Date: Thu, 12 Jul 2012 17:25:44 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: Andrea Arcangeli CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hillf Danton , Dan Smith , Peter Zijlstra , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Paul Turner , Suresh Siddha , Mike Galbraith , "Paul E. McKenney" , Lai Jiangshan , Bharata B Rao , Lee Schermerhorn , Johannes Weiner , Srivatsa Vaddagiri , Christoph Lameter , Alex Shi , Mauricio Faria de Oliveira , Konrad Rzeszutek Wilk , Don Morris , Benjamin Herrenschmidt Subject: Re: [PATCH 28/40] autonuma: make khugepaged pte_numa aware References: <1340888180-15355-1-git-send-email-aarcange@redhat.com> <1340888180-15355-29-git-send-email-aarcange@redhat.com> <4FF12284.4040109@redhat.com> <20120712185031.GN20382@redhat.com> In-Reply-To: <20120712185031.GN20382@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 07/12/2012 02:50 PM, Andrea Arcangeli wrote: > On Mon, Jul 02, 2012 at 12:24:36AM -0400, Rik van Riel wrote: >> On 06/28/2012 08:56 AM, Andrea Arcangeli wrote: >>> If any of the ptes that khugepaged is collapsing was a pte_numa, the >>> resulting trans huge pmd will be a pmd_numa too. >> >> Why? >> >> If some of the ptes already got faulted in and made really >> resident again, why do you want to incur a new NUMA fault >> on the newly collapsed hugepage? > > If we don't set pmd_numa on the collapsed hugepage, the result is that > we'll understimate the thread NUMA affinity to the node where the > hugepage is located (mm affinity is recorded independently by the NUMA > hinting page faults). > > If it's better or worse I guess depends on luck, we just lose > information. Fair enough. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx155.postini.com [74.125.245.155]) by kanga.kvack.org (Postfix) with SMTP id CE72E6B005D for ; Thu, 12 Jul 2012 17:27:35 -0400 (EDT) Message-ID: <4FFF40D8.10000@redhat.com> Date: Thu, 12 Jul 2012 17:25:44 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 28/40] autonuma: make khugepaged pte_numa aware References: <1340888180-15355-1-git-send-email-aarcange@redhat.com> <1340888180-15355-29-git-send-email-aarcange@redhat.com> <4FF12284.4040109@redhat.com> <20120712185031.GN20382@redhat.com> In-Reply-To: <20120712185031.GN20382@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hillf Danton , Dan Smith , Peter Zijlstra , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Paul Turner , Suresh Siddha , Mike Galbraith , "Paul E. McKenney" , Lai Jiangshan , Bharata B Rao , Lee Schermerhorn , Johannes Weiner , Srivatsa Vaddagiri , Christoph Lameter , Alex Shi , Mauricio Faria de Oliveira , Konrad Rzeszutek Wilk , Don Morris , Benjamin Herrenschmidt On 07/12/2012 02:50 PM, Andrea Arcangeli wrote: > On Mon, Jul 02, 2012 at 12:24:36AM -0400, Rik van Riel wrote: >> On 06/28/2012 08:56 AM, Andrea Arcangeli wrote: >>> If any of the ptes that khugepaged is collapsing was a pte_numa, the >>> resulting trans huge pmd will be a pmd_numa too. >> >> Why? >> >> If some of the ptes already got faulted in and made really >> resident again, why do you want to incur a new NUMA fault >> on the newly collapsed hugepage? > > If we don't set pmd_numa on the collapsed hugepage, the result is that > we'll understimate the thread NUMA affinity to the node where the > hugepage is located (mm affinity is recorded independently by the NUMA > hinting page faults). > > If it's better or worse I guess depends on luck, we just lose > information. Fair enough. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org