From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 012B7C32788 for ; Thu, 11 Oct 2018 12:02:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B613F205C9 for ; Thu, 11 Oct 2018 12:02:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B613F205C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728110AbeJKT3I (ORCPT ); Thu, 11 Oct 2018 15:29:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:44118 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727182AbeJKT3I (ORCPT ); Thu, 11 Oct 2018 15:29:08 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 20EFAACE1; Thu, 11 Oct 2018 12:02:11 +0000 (UTC) Date: Thu, 11 Oct 2018 14:02:09 +0200 From: Michal Hocko To: "Kirill A. Shutemov" Cc: Joel Fernandes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@android.com, minchan@google.com, hughd@google.com, lokeshgidra@google.com, Andrew Morton , Greg Kroah-Hartman , Kate Stewart , Philippe Ombredanne , Thomas Gleixner Subject: Re: [PATCH] mm: Speed up mremap on large regions Message-ID: <20181011120209.GV5873@dhcp22.suse.cz> References: <20181009201400.168705-1-joel@joelfernandes.org> <20181009220222.26nzajhpsbt7syvv@kshutemo-mobl1> <20181009230447.GA17911@joelaf.mtv.corp.google.com> <20181010100011.6jqjvgeslrvvyhr3@kshutemo-mobl1> <20181011004618.GA237677@joelaf.mtv.corp.google.com> <20181011081719.77f7ihcy6mu2vkkc@kshutemo-mobl1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181011081719.77f7ihcy6mu2vkkc@kshutemo-mobl1> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 11-10-18 11:17:19, Kirill A. Shutemov wrote: [...] > > The thing is its quite a lot of change, I wrote a coccinelle script to do it > > tree wide, following is the diffstat: > > 48 files changed, 91 insertions(+), 124 deletions(-) > > > > Imagine then having to add the address argument back in the future in case > > its ever needed. Is it really worth doing it? > > This is the point. It will get us chance to consider if the optimization > is still safe. > > And it shouldn't be hard: [partially] revert the commit and get the address > back into the interface. I agree with Kirill. This will also remove quite a lot of pointless code and make it more clear. It is impossible to see what is the address good for and I couldn't really trace back to commit introducing it to guess that either. So making sure nobody does anything with it is a good pre-requisite to make further changes on top. The chage itself is really interesting, I still have to digest it completely to see there are no cornercases but from a quick glance it looks reasonable. -- Michal Hocko SUSE Labs