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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CD0BAC433B4 for ; Mon, 3 May 2021 14:54:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9678E611BF for ; Mon, 3 May 2021 14:54:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229992AbhECOzm (ORCPT ); Mon, 3 May 2021 10:55:42 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:57092 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229596AbhECOzl (ORCPT ); Mon, 3 May 2021 10:55:41 -0400 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 143EsaBc017067 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 3 May 2021 10:54:36 -0400 Received: by cwcc.thunk.org (Postfix, from userid 15806) id D763515C39C4; Mon, 3 May 2021 10:54:35 -0400 (EDT) Date: Mon, 3 May 2021 10:54:35 -0400 From: "Theodore Ts'o" To: "Maciej W. Rozycki" Cc: Linus Torvalds , Tom Stellard , Nick Desaulniers , Masahiro Yamada , Nathan Chancellor , Linux Kernel Mailing List , clang-built-linux , Fangrui Song , Serge Guelton , Sylvestre Ledru Subject: Re: Very slow clang kernel config .. Message-ID: References: <1c5e05fa-a246-9456-ff4e-287960acb18c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 03, 2021 at 10:38:12AM -0400, Theodore Ts'o wrote: > On Mon, May 03, 2021 at 03:03:31AM +0200, Maciej W. Rozycki wrote: > > > > People went through great efforts to support shared libraries, sacrificed > > performance for it even back then when the computing power was much lower > > than nowadays. > > That was because memory was *incredibly* restrictive in those days. > My first Linux server had one gig of memory, and so shared libraries > provided a huge performance boost --- because otherwise systems would > be swapping or paging their brains out. Correction. My bad, my first Linux machine had 16 megs of memory.... - Ted > > However, these days, many if not most developers aren't capable of the > discpline needed to maintained the ABI stability needed for shared > libraries to work well. I can think several packages where if you > used shared libraries, the major version number would need to be > bumped at every releases, because people don't know how to spell ABI, > never mind be able to *preserve* ABI. Heck, it's the same reason that > we don't promise kernel ABI compatibility for kernel modules! > > https://www.kernel.org/doc/Documentation/process/stable-api-nonsense.rst > > And in the case of Debian, use of shared libraries means that every > time you release a new version of, say, f2fs-tools, things can get > stalled for months or in one case, over a year, due to the new package > review process (a shared library version bump means a new binary > package, and that in turn requires a full review of the entire source > package for GPL compliance from scratch, and f2fs-tools has bumped > their shared library major version *every* *single* *release*) --- > during which time, security bug fixes were being held up due to the > new package review tarpit. > > If people could actually guarantee stable ABI's, then shared libraries > might make sense. E2fsprogs hasn't had a major version bump in shared > libraries for over a decade (although some developers whine and > complain about how I reject function signature changes in the > libext2fs library to provide that ABI stability). But how many > userspace packages can make that claim? > > - Ted