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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 7EFF1ECDFB0 for ; Fri, 13 Jul 2018 13:46:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 430E220849 for ; Fri, 13 Jul 2018 13:46:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 430E220849 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.com 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 S1729770AbeGMOBb (ORCPT ); Fri, 13 Jul 2018 10:01:31 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:57761 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729632AbeGMOBb (ORCPT ); Fri, 13 Jul 2018 10:01:31 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fdyPG-0004jk-6d; Fri, 13 Jul 2018 07:46:46 -0600 Received: from [97.119.167.31] (helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fdyP0-0000N2-Qc; Fri, 13 Jul 2018 07:46:46 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Pavel Emelyanov Cc: Adrian Reber , linux-kernel@vger.kernel.org, Andrew Morton , Oleg Nesterov , Andrei Vagin , Hendrik Brueckner , Cyrill Gorcunov , Kees Cook , Linux Containers References: <20180712130733.11510-1-adrian@lisas.de> <87sh4o5s82.fsf@xmission.com> <23f87cb4-cdf5-0f9c-c7b9-a0abb228b77f@virtuozzo.com> Date: Fri, 13 Jul 2018 08:46:25 -0500 In-Reply-To: <23f87cb4-cdf5-0f9c-c7b9-a0abb228b77f@virtuozzo.com> (Pavel Emelyanov's message of "Fri, 13 Jul 2018 11:35:50 +0300") Message-ID: <87sh4nz1se.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1fdyP0-0000N2-Qc;;;mid=<87sh4nz1se.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=97.119.167.31;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19GJK7D/fXrYfqF2UfCPrzI329Bl//Hnlg= X-SA-Exim-Connect-IP: 97.119.167.31 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH] kconfig: remove EXPERT from CHECKPOINT_RESTORE X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pavel Emelyanov writes: > On 07/12/2018 07:33 PM, Eric W. Biederman wrote: >> >> Adrian Reber writes: >> >>> The CHECKPOINT_RESTORE configuration option was introduced in 2012 and >>> combined with EXPERT. CHECKPOINT_RESTORE is already enabled in many >>> distribution kernels and also part of the defconfigs of various >>> architectures. >>> >>> To make it easier for distributions to enable CHECKPOINT_RESTORE this >>> removes EXPERT and moves the configuration option out of the EXPERT >>> block. >> >> I think we should change the help text at the same time, to match >> our improve understanding of the situation. >> >> Does anyone remember why this option was added at all? > > Sure! Quoting Andrew's ~7 years ago akpm branch merge e-mail: > > However I'm less confident than the developers that it will all > eventually work! So what I'm asking them to do is to wrap each piece > of new code inside CONFIG_CHECKPOINT_RESTORE. So if it all > eventually comes to tears and the project as a whole fails, it should > be a simple matter to go through and delete all trace of it. > > the best link with full e-mail I googled for is > https://gitlab.imag.fr/kaunetem/linux-kaunetem/commit/099469502f62fbe0d7e4f0b83a2f22538367f734 Good explanation. Thank you. At this point we even have not CRIU users of some of the pieces. The project as a whole has not failed. The code is old enough an common enough (enabled in some distros) that we need to do the whole watch out for regressions if we remove any part of it. Which is a long way of saying the original justifiction for CONFIG_CHECKPOINT_RESTORE is gone. So please let's remove the entire config option and simplify everyone's lives who has to test this stuff. Unless someone can come up with a justification for keeping some of this behind a config option. Eric