From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752185AbeDLGTD (ORCPT ); Thu, 12 Apr 2018 02:19:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:49878 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750743AbeDLGTC (ORCPT ); Thu, 12 Apr 2018 02:19:02 -0400 Date: Thu, 12 Apr 2018 08:18:59 +0200 From: Michal Hocko To: Naoya Horiguchi Cc: linux-mm@kvack.org, Zi Yan , "Kirill A. Shutemov" , Andrew Morton , Vlastimil Babka , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 0/2] mm: migrate: vm event counter for hugepage migration Message-ID: <20180412061859.GR23400@dhcp22.suse.cz> References: <1523434167-19995-1-git-send-email-n-horiguchi@ah.jp.nec.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1523434167-19995-1-git-send-email-n-horiguchi@ah.jp.nec.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 11-04-18 17:09:25, Naoya Horiguchi wrote: > Hi everyone, > > I wrote patches introducing separate vm event counters for hugepage migration > (both for hugetlb and thp.) > Hugepage migration is different from normal page migration in event frequency > and/or how likely it succeeds, so maintaining statistics for them in mixed > counters might not be helpful both for develors and users. This is quite a lot of code to be added se we should better document what it is intended for. Sure I understand your reasonaning about huge pages are more likely to fail but is this really worth a separate counter? Do you have an example of how this would be useful? If we are there then what about different huge page sizes (for hugetlb)? Do we need per-hstate stats? In other words, is this really worth it? > include/linux/vm_event_item.h | 7 +++ > mm/migrate.c | 103 +++++++++++++++++++++++++++++++++++------- > mm/vmstat.c | 8 ++++ > 3 files changed, 102 insertions(+), 16 deletions(-) -- Michal Hocko SUSE Labs