From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 6C7757AA for ; Wed, 3 Aug 2016 13:15:33 +0000 (UTC) Received: from cloudserver094114.home.net.pl (cloudserver094114.home.net.pl [79.96.170.134]) by smtp1.linuxfoundation.org (Postfix) with SMTP id 12613231 for ; Wed, 3 Aug 2016 13:15:31 +0000 (UTC) From: "Rafael J. Wysocki" To: Greg KH Date: Wed, 03 Aug 2016 15:20:44 +0200 Message-ID: <1600610.QIejSIJ3WK@vostro.rjw.lan> In-Reply-To: <20160803110935.GA26270@kroah.com> References: <87oa5aqjmq.fsf@intel.com> <20160803110935.GA26270@kroah.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Cc: ksummit-discuss@lists.linuxfoundation.org, James Bottomley , Trond Myklebust Subject: Re: [Ksummit-discuss] [CORE TOPIC] stable workflow List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wednesday, August 03, 2016 01:09:35 PM Greg KH wrote: > On Wed, Aug 03, 2016 at 12:36:29PM +0300, Jani Nikula wrote: > > On Wed, 03 Aug 2016, "Rafael J. Wysocki" wrote: > > > On Tuesday, August 02, 2016 04:34:00 PM Mark Brown wrote: > > >> On Tue, Aug 02, 2016 at 05:12:47PM +0300, Jani Nikula wrote: > > >> > > >> > Generally adding cc: stable is like, this is clearly a fix to a bug that > > >> > is present in stable kernels, and the bug should be fixed, but I have no > > >> > idea nor resources to review or test if this is the right fix across all > > >> > stable kernels. You end up relying on your gut feeling too much to be > > >> > comfortable. You have to make the call too early in the process. > > >> > > >> I think the problems here are more in the process of how things go from > > >> being tagged stable to appearing in a stable release - the QA or lack > > >> thereof and so on. While I do share some of your misgivings here I do > > >> also really like the fact that it's really easy for people to push > > >> things out for the attention of those working on backports. It's > > >> essentially the same as the question I often find myself asking people > > >> who don't upstream - "why would this fix not benefit other users?". > > > > > > Agreed, and I think that's exactly where the expectations don't match what's > > > delivered in the long-term-stable trees. > > > > > > It should be made clear that "stable" doesn't mean "no regressions". What > > > it reall means is "hey, if you care about backports, this is the stuff to take > > > into consideration in the first place". > > > > I think this interpretation matches reality better than what > > Documentation/stable_kernel_rules.txt leads you to believe about adding > > cc: stable tag. > > really? Honestly, I think so. > Yes, we have regressions at times in stable kernels, but > really, our % is _very_ low. Probably less than "normal" releases, but > that's just a random guess, it would be good for someone to try to do > research on this before guessing... Jon did some of that at LWN (http://lwn.net/Articles/692866/) and he got regression rate estimates for various -stable lines in the range between 0.6-1.4% (4.6) and 2.2-9.6% (3.14). Of course, whether or not these numbers are significant is a matter of discussion, but they are clearly nonzero. Now, I understand why there are regressions in -stable and to me it would be just fine to say that they will be there occasionally, so as to prevent supporting the "no regressions in -stable at all" expectation that (a) is unrealistic today and (b) seems to be quite widespread. Or do we really want to meet that expectation? Thanks, Rafael