From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id 2AF036B0006 for ; Thu, 11 Oct 2018 08:02:13 -0400 (EDT) Received: by mail-ed1-f70.google.com with SMTP id x44-v6so4988666edd.17 for ; Thu, 11 Oct 2018 05:02:13 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 14-v6si10086214ejj.220.2018.10.11.05.02.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Oct 2018 05:02:11 -0700 (PDT) Date: Thu, 11 Oct 2018 14:02:09 +0200 From: Michal Hocko 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> Sender: owner-linux-mm@kvack.org List-ID: 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 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