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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 BBB1AC433E1 for ; Mon, 20 Jul 2020 09:41:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EE86208E4 for ; Mon, 20 Jul 2020 09:41:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cGw1MLyg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728268AbgGTJlI (ORCPT ); Mon, 20 Jul 2020 05:41:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728088AbgGTJlH (ORCPT ); Mon, 20 Jul 2020 05:41:07 -0400 Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com [IPv6:2607:f8b0:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3827C061794 for ; Mon, 20 Jul 2020 02:41:07 -0700 (PDT) Received: by mail-oi1-x242.google.com with SMTP id x83so13916335oif.10 for ; Mon, 20 Jul 2020 02:41:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ZlSWX3kEKIVtH3Ty/sQ1R+KtTQUTPa6eMcEinYxdwjs=; b=cGw1MLyg8nvEL2n5ObAVNMtFCCDs4tRZwFLvRut5ODbQeKh3ZN1feqi80KP/0+weXA zo/VbZgcLyQwKaeQw0fYG6sx2I8QjriLT4flEyy4c16kW4WEtYhcC8IeR0aDf3NNjpyZ hxkYfMZaWGurvdgZB0m7CWT/eMwL9+ZnYOUBsbRTVVjLlSllTkLS40RiyXzx6LhE88ge DBF6sXuhKoelMt07Ocgsf6yXVb44/rkOuM1kVyciCDwHm10kFptpxoPf5MNW7WEWJCWW y/2K6eGWHt5uHb5EYJcex9nMM5s3h1zJrOimRejUsM0VtOfwmrfZI14IeWv8jUMIZJ9L qWEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ZlSWX3kEKIVtH3Ty/sQ1R+KtTQUTPa6eMcEinYxdwjs=; b=N9SnzNziTtLa9IulvOnymOtoCQJTHN5er0QgRZH7cGtryE5m6oryf/uDmrIMy0IEOX yZha4iVy2u040T3apFyAV7K/Ua3nAbTxIKtcENu1y3t8FMGz+OSjOF1OxZZyiMlKcTuv kuUfPU/glXbaHGGYmc9awfr3KEJ/97/smkU2JK+jFe6a7TPNj2vdALa+AF37lktmgZX4 8hMxX2o+nRyGV6ibVNVUJdf3NPIY0dODQQr8MaFZ1XriYB2cLSiHYs1P67sZ2hwWvFaY iKkGwkQh+vYkHq3FVn3T7CFgAZHzCHVALU+YgM9HQpTPx0hblxD11iwnO9fbkEk/EVB/ UI9Q== X-Gm-Message-State: AOAM5317+WiEUCo8AdnVyffsCuHQk5fVyFX/vfiwMiE7fqd2xNCanUvN d0WRn2o1DQvIRt+KbgxDDOioLZLuojTLqOnPa3Egrg== X-Google-Smtp-Source: ABdhPJw7Rpzewc4ms74dHaYrrggRaeNJqLHtIwdbLvxFsTbeqVUEjiuDarE9DlHUbYMVVBXXtBHfY7qNOkAXLP5EHi0= X-Received: by 2002:aca:cf4f:: with SMTP id f76mr17083895oig.172.1595238066764; Mon, 20 Jul 2020 02:41:06 -0700 (PDT) MIME-Version: 1.0 References: <20200709132344.760-1-john.ogness@linutronix.de> <20200709132344.760-5-john.ogness@linutronix.de> <20200718121053.GA691245@elver.google.com> <20200719034312.GA566736@jagdpanzerIV.localdomain> <20200720064303.GA2144711@elver.google.com> <20200720084102.GC463@jagdpanzerIV.localdomain> In-Reply-To: <20200720084102.GC463@jagdpanzerIV.localdomain> From: Marco Elver Date: Mon, 20 Jul 2020 11:40:52 +0200 Message-ID: Subject: Re: [PATCH v5 4/4] printk: use the lockless ringbuffer To: Sergey Senozhatsky Cc: John Ogness , Petr Mladek , Peter Zijlstra , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Greg Kroah-Hartman , Andrea Parri , Thomas Gleixner , Paul McKenney , kexec@lists.infradead.org, LKML , Dmitry Vyukov , Andy Shevchenko Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Jul 2020 at 10:41, Sergey Senozhatsky wrote: > > On (20/07/20 08:43), Marco Elver wrote: > > On Sun, Jul 19, 2020 at 12:43PM +0900, Sergey Senozhatsky wrote: > > > > As I said, a number of debugging tools use them to format reports to be > > more readable (visually separate title and report body, and separate > > parts of the report). Also, such reports are often parsed by CI systems, > > and by changing the reports, these CI systems may break. But those are > > just the usecases I'm acutely aware of > > Can you give example of such CI systems? // that's a real question // None of ours should break; I agree the CI system is brittle if it relies on newlines. Parsed and displayed reports are changing, however -- what irks me is now all the reports sent to the LKML look ugly. Some random KASAN reports (just compare formatting): next (ugly): https://lore.kernel.org/lkml/000000000000c87b7305aadb6dba@google.com/ mainline (normal): https://lore.kernel.org/lkml/000000000000f4ef6a05aa92ec6c@google.com/ The same problem exists with lockdep reports, KCSAN reports, ... If newline-printks to insert blank lines are now banned, what are we to do? Send dozens of patches to switch everyone to printk(" \n")? Or some better suggestion? I cannot yet see how that is an improvement. (And if the behaviour is not reverted, please document the new behaviour.) That also doesn't yet address the ~400 other newline-printk users, and somebody needs to do the due diligence to understand if it's just a flush, or an intentional blank line. Thanks, -- Marco