From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f199.google.com (mail-wr0-f199.google.com [209.85.128.199]) by kanga.kvack.org (Postfix) with ESMTP id 2DA6D6B0069 for ; Mon, 18 Sep 2017 01:50:29 -0400 (EDT) Received: by mail-wr0-f199.google.com with SMTP id h16so8270417wrf.0 for ; Sun, 17 Sep 2017 22:50:29 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id c2si895060edi.385.2017.09.17.22.50.28 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 17 Sep 2017 22:50:28 -0700 (PDT) Date: Mon, 18 Sep 2017 07:50:23 +0200 From: Michal Hocko Subject: Re: [PATCH 1/3] mm, sysctl: make VM stats configurable Message-ID: <20170918055023.ikvocc5q4i4rmq2p@dhcp22.suse.cz> References: <1505467406-9945-1-git-send-email-kemi.wang@intel.com> <1505467406-9945-2-git-send-email-kemi.wang@intel.com> <20170915114952.czb7nbsioqguxxk3@dhcp22.suse.cz> <8cb99df9-3db3-99fc-8fc1-c9f14b2d9017@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8cb99df9-3db3-99fc-8fc1-c9f14b2d9017@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: kemi Cc: "Luis R . Rodriguez" , Kees Cook , Andrew Morton , Jonathan Corbet , Mel Gorman , Johannes Weiner , Christopher Lameter , Sebastian Andrzej Siewior , Vlastimil Babka , Dave , Tim Chen , Andi Kleen , Jesper Dangaard Brouer , Ying Huang , Aaron Lu , Proc sysctl , Linux MM , Linux Kernel On Mon 18-09-17 11:22:37, kemi wrote: > > > On 2017a1'09ae??15ae?JPY 19:49, Michal Hocko wrote: > > On Fri 15-09-17 17:23:24, Kemi Wang wrote: > >> This patch adds a tunable interface that allows VM stats configurable, as > >> suggested by Dave Hansen and Ying Huang. > >> > >> When performance becomes a bottleneck and you can tolerate some possible > >> tool breakage and some decreased counter precision (e.g. numa counter), you > >> can do: > >> echo [C|c]oarse > /proc/sys/vm/vmstat_mode > >> > >> When performance is not a bottleneck and you want all tooling to work, you > >> can do: > >> echo [S|s]trict > /proc/sys/vm/vmstat_mode > >> > >> We recommend automatic detection of virtual memory statistics by system, > >> this is also system default configuration, you can do: > >> echo [A|a]uto > /proc/sys/vm/vmstat_mode > >> > >> The next patch handles numa statistics distinctively based-on different VM > >> stats mode. > > > > I would just merge this with the second patch so that it is clear how > > those modes are implemented. I am also wondering why cannot we have a > > much simpler interface and implementation to enable/disable numa stats > > (btw. sysctl_vm_numa_stats would be more descriptive IMHO). > > > > Apologize for resending it, because I found my previous reply mixed with > Michal's in many email client. > > The motivation is that we propose a general tunable interface for VM stats. > This would be more scalable, since we don't have to add an individual > Interface for each type of counter that can be configurable. Can you envision which other counters would fall into the same category? > In the second patch, NUMA stats, as an example, can benefit for that. > If you still hold your idea, I don't mind to merge them together. Well, I would prefer simplicy in the first place. -- Michal Hocko SUSE Labs -- 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