From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752517Ab3KKAXM (ORCPT ); Sun, 10 Nov 2013 19:23:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:18573 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372Ab3KKAXG (ORCPT ); Sun, 10 Nov 2013 19:23:06 -0500 Message-ID: <52802361.5040601@redhat.com> Date: Sun, 10 Nov 2013 19:22:57 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Mel Gorman CC: Andrew Morton , Alex Thorlton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: numa: Return the number of base pages altered by protection changes References: <20131109143718.GC5040@suse.de> In-Reply-To: <20131109143718.GC5040@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/09/2013 09:37 AM, Mel Gorman wrote: > Commit 0255d491 (mm: Account for a THP NUMA hinting update as one PTE > update) was added to account for the number of PTE updates when marking > pages prot_numa. task_numa_work was using the old return value to track > how much address space had been updated. Altering the return value causes > the scanner to do more work than it is configured or documented to in a > single unit of work. > > This patch reverts 0255d491 and accounts for the number of THP updates > separately in vmstat. It is up to the administrator to interpret the pair > of values correctly. This is a straight-forward operation and likely to > only be of interest when actively debugging NUMA balancing problems. > > The impact of this patch is that the NUMA PTE scanner will scan slower when > THP is enabled and workloads may converge slower as a result. On the flip > size system CPU usage should be lower than recent tests reported. This is > an illustrative example of a short single JVM specjbb test Reviewed-by: Rik van Riel -- All rights reversed