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 2F554ECDFB1 for ; Fri, 13 Jul 2018 20:55:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEEDB208A6 for ; Fri, 13 Jul 2018 20:55:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BEEDB208A6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.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 S1731931AbeGMVL7 (ORCPT ); Fri, 13 Jul 2018 17:11:59 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35280 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731616AbeGMVL7 (ORCPT ); Fri, 13 Jul 2018 17:11:59 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.9.92]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 1F814CC2; Fri, 13 Jul 2018 20:55:42 +0000 (UTC) Date: Fri, 13 Jul 2018 13:55:41 -0700 From: Andrew Morton To: ebiederm@xmission.com (Eric W. Biederman) Cc: Adrian Reber , linux-kernel@vger.kernel.org, Oleg Nesterov , Pavel Emelyanov , Andrei Vagin , Hendrik Brueckner , Cyrill Gorcunov , Kees Cook , Linux Containers Subject: Re: [PATCH] kconfig: remove EXPERT from CHECKPOINT_RESTORE Message-Id: <20180713135541.7ada72437862c32f4563a9a8@linux-foundation.org> In-Reply-To: <87sh4o5s82.fsf@xmission.com> References: <20180712130733.11510-1-adrian@lisas.de> <87sh4o5s82.fsf@xmission.com> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 12 Jul 2018 11:33:33 -0500 ebiederm@xmission.com (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? Because at the time it was quite unclear that the overall project would produce a viable result. But the code is splattered over so many places that getting it all going out-of-tree was impractical. So the #ifdef CONFIG_CHECKPOINT_RESTORE markers were initially there to a) identify places where we should go if we decide to rip the whole thing out and to b) ensure that the kernel would still compile and work OK after that removal. This caution eventually proved to be unnecessary. > Why this option was placed under expert? Dunno. > What is the value of disabling this functionality ever? > > Is there any reason why we don't just delete CONFIG_CHECKPOINT_RESTORE > entirely? For the vast number of Linux machines which aren't servers? Check out some defconfigs - only one of arm's 119 defconfigs selects it.