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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 54D07C3F2CF for ; Fri, 28 Feb 2020 04:50:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BA832469D for ; Fri, 28 Feb 2020 04:50:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="aJ5yBLp8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725871AbgB1EuV (ORCPT ); Thu, 27 Feb 2020 23:50:21 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:37270 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725730AbgB1EuU (ORCPT ); Thu, 27 Feb 2020 23:50:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description; bh=s+QeEHYSNi44+hIO/8Apj4mw7x3KWr0g5BcyFCnqi+s=; b=aJ5yBLp8XFs2+ptHMnR8pdSRrR D9z0gqDLHni+NJct/om5lD6wRQzjxCNtIoXut7UDYgtIUDIBpllTDUzXlMcLBrNB05af4mS/q4HSD cIvsgLOu2yNKeJmW2xe1UWdHzgyXUQzYMlEj3DTtOCGVpU40Ik2B7FVUFfRa1S4HC2Q1BJUrIi+4S rIxADQT5/NEVz8HQZZ2kNP/QzikKuWSaGM2rsMLRw2Uxx7lNw/FkiBvs8R+eF5DE768hB8hzzBH/H tj6xB4BLACEK2NFHiohlqmyhhmAuxDr/1VgYkr1j/ryX3dKf/CTt4DHYINv3CP31X/x3i/zaQNu+Z qhy/jcMA==; Received: from [2601:1c0:6280:3f0::19c2] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7XbQ-0007eT-EV; Fri, 28 Feb 2020 04:50:20 +0000 Subject: Re: [PATCH 1/2] Documentation: bootconfig: Update boot configuration documentation To: Masami Hiramatsu , Jonathan Corbet Cc: Steven Rostedt , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Markus Elfring References: <158278834245.14966.6179457011671073018.stgit@devnote2> <158278835238.14966.16157216423901327777.stgit@devnote2> From: Randy Dunlap Message-ID: Date: Thu, 27 Feb 2020 20:50:19 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <158278835238.14966.16157216423901327777.stgit@devnote2> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, A few more comments for you: On 2/26/20 11:25 PM, Masami Hiramatsu wrote: > Update boot configuration documentation. > > - Not using "config" abbreviation but configuration or description. > - Rewrite descriptions of node and its maxinum number. > - Add a section of use cases of boot configuration. > - Move how to use bootconfig to earlier section. > - Fix some typos, indents and format mistakes. > > Signed-off-by: Masami Hiramatsu > --- > Documentation/admin-guide/bootconfig.rst | 172 +++++++++++++++++++----------- > Documentation/trace/boottime-trace.rst | 2 > 2 files changed, 112 insertions(+), 62 deletions(-) > > diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst > index cf2edcd09183..4bac98250bc0 100644 > --- a/Documentation/admin-guide/bootconfig.rst > +++ b/Documentation/admin-guide/bootconfig.rst > @@ -11,19 +11,98 @@ Boot Configuration > Overview > ======== > > -The boot configuration expands the current kernel command line to support > +Boot configuration expands the current kernel command line to support > additional key-value data when booting the kernel in an efficient way. maybe s/when/while/ > -This allows administrators to pass a structured-Key config file. > +This allows administrators to pass a structured-Key configuration file > +as a way to supplement the kernel command line to pass system boot parameters. > > -Config File Syntax > -================== > +Compared with the kernel command line, the boot configuration can provide > +scalability (up to 32 KiB configurations), readability (structured This makes it sound like bootconfig supports 32 thousand configurations, but (I think) it allows up to 32 KiB of configuration data. > +configuration with comments) and compact expression of option groups. > + > +When to Use the Boot Configuration? > +----------------------------------- > + > +The boot configuration supports kernel command line options and init daemon > +boot options. All sub-keys under "kernel" root key are passed as a part of > +kernel command line [1]_, and one under "init" root key are passed as a part ones {or those} > +of init command line. For example, :: > + > + root=UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82 ro quiet splash console=ttyS0,115200n8 console=tty0 > + > +This can be written as following boot configuration file.:: > + > + kernel { > + root = "UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82" # nvme0n1p3 > + ro # mount rootfs as read only > + quiet # No console log > + splash # show splash image on boot screen > + console = "ttyS0,115200n8" # 1st console to serial device > + console += tty0 # add 2nd console > + } > + > +If you think that kernel/init options becomes too long to write in boot-loader > +configuration file or want to comment on each options, you can use this on each option, > +boot configuration. If unsure, you can still continue to use the legacy > +kernel command line. > + > +Also, some subsystem may depend on the boot configuration, and it has own > +root key. For example, ftrace boot-time tracer uses "ftrace" root key to > +describe their options [2]_. In this case, you need to use the boot its > +configuration. > + > +.. [1] See :ref:`Documentation/admin-guide/kernel-parameters.rst ` > +.. [2] See :ref:`Documentation/trace/boottime-trace.rst ` -- ~Randy