From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 9192E6B000E for ; Thu, 19 Apr 2018 11:04:30 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id k76-v6so197282lfg.9 for ; Thu, 19 Apr 2018 08:04:30 -0700 (PDT) Received: from mx2.yrkesakademin.fi (mx2.yrkesakademin.fi. [85.134.45.195]) by mx.google.com with ESMTPS id n14si1511499ljg.43.2018.04.19.08.04.27 for (version=TLS1_2 cipher=AES128-GCM-SHA256 bits=128/128); Thu, 19 Apr 2018 08:04:28 -0700 (PDT) Subject: Re: [PATCH AUTOSEL for 4.14 015/161] printk: Add console owner and waiter logic to load balance console writes References: <20180409001936.162706-15-alexander.levin@microsoft.com> <20180409082246.34hgp3ymkfqke3a4@pathway.suse.cz> <20180415144248.GP2341@sasha-vm> <20180416093058.6edca0bb@gandalf.local.home> <20180416113629.2474ae74@gandalf.local.home> <20180416160200.GY2341@sasha-vm> <20180416121224.2138b806@gandalf.local.home> <20180416161911.GA2341@sasha-vm> <7d5de770-aee7-ef71-3582-5354c38fc176@mageia.org> <20180419135943.GC16862@kroah.com> From: Thomas Backlund Message-ID: <6425991f-7d7f-b1f9-ba37-3212a01ad6cf@mageia.org> Date: Thu, 19 Apr 2018 18:04:26 +0300 MIME-Version: 1.0 In-Reply-To: <20180419135943.GC16862@kroah.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Greg KH , Thomas Backlund Cc: Sasha Levin , Steven Rostedt , Linus Torvalds , Petr Mladek , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , Cong Wang , Dave Hansen , Johannes Weiner , Mel Gorman , Michal Hocko , Vlastimil Babka , Peter Zijlstra , Jan Kara , Mathieu Desnoyers , Tetsuo Handa , Byungchul Park , Tejun Heo , Pavel Machek Den 19.04.2018 kl. 16:59, skrev Greg KH: > On Thu, Apr 19, 2018 at 02:41:33PM +0300, Thomas Backlund wrote: >> Den 16-04-2018 kl. 19:19, skrev Sasha Levin: >>> On Mon, Apr 16, 2018 at 12:12:24PM -0400, Steven Rostedt wrote: >>>> On Mon, 16 Apr 2018 16:02:03 +0000 >>>> Sasha Levin wrote: >>>> >>>>> One of the things Greg is pushing strongly for is "bug compatibility": >>>>> we want the kernel to behave the same way between mainline and stable. >>>>> If the code is broken, it should be broken in the same way. >>>> >>>> Wait! What does that mean? What's the purpose of stable if it is as >>>> broken as mainline? >>> >>> This just means that if there is a fix that went in mainline, and the >>> fix is broken somehow, we'd rather take the broken fix than not. >>> >>> In this scenario, *something* will be broken, it's just a matter of >>> what. We'd rather have the same thing broken between mainline and >>> stable. >>> >> >> Yeah, but _intentionally_ breaking existing setups to stay "bug compatible" >> _is_ a _regression_ you _really_ _dont_ want in a stable >> supported distro. Because end-users dont care about upstream breaking >> stuff... its the distro that takes the heat for that... >> >> Something "already broken" is not a regression... >> >> As distro maintainer that means one now have to review _every_ patch that >> carries "AUTOSEL", follow all the mail threads that comes up about it, then >> track if it landed in -stable queue, and read every response and possible >> objection to all patches in the -stable queue a second time around... then >> check if it still got included in final stable point relase and then either >> revert them in distro kernel or go track down all the follow-up fixes >> needed... >> >> Just to avoid being "bug compatible with master" > > I've done this "bug compatible" "breakage" more than the AUTOSEL stuff > has in the past, so you had better also be reviewing all of my normal > commits as well :) > Yeah, I do... and same goes there ... if there is a known issue, then same procedure... Either revert, or try to track down fixes... > Anyway, we are trying not to do this, but it does, and will, > occasionally happen. Look, we just did that for one platform for > 4.9.94! And the key to all of this is good testing, which we are now > doing, and hopefully you are also doing as well. Yeah, but having to test stuff with known breakages is no fun, so we try to avoid that -- Thomas