From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id 0CBD16B018E for ; Sun, 10 Nov 2013 19:23:03 -0500 (EST) Received: by mail-pa0-f53.google.com with SMTP id kx10so4552003pab.26 for ; Sun, 10 Nov 2013 16:23:03 -0800 (PST) Received: from psmtp.com ([74.125.245.111]) by mx.google.com with SMTP id dl5si14017792pbd.56.2013.11.10.16.23.01 for ; Sun, 10 Nov 2013 16:23:02 -0800 (PST) Message-ID: <52802361.5040601@redhat.com> Date: Sun, 10 Nov 2013 19:22:57 -0500 From: Rik van Riel MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , Alex Thorlton , linux-kernel@vger.kernel.org, linux-mm@kvack.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 -- 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