From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id C8DCF7D089 for ; Wed, 5 Dec 2018 14:22:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727025AbeLEOWA (ORCPT ); Wed, 5 Dec 2018 09:22:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24339 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726918AbeLEOWA (ORCPT ); Wed, 5 Dec 2018 09:22:00 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C7B59653C4; Wed, 5 Dec 2018 14:21:59 +0000 (UTC) Received: from localhost.localdomain (ovpn-12-56.pek2.redhat.com [10.72.12.56]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 870C06014F; Wed, 5 Dec 2018 14:21:49 +0000 (UTC) Subject: Re: [PATCH 1/2 v2] kdump: add the vmcoreinfo documentation To: Dave Young Cc: Borislav Petkov , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, akpm@linux-foundation.org, bhe@redhat.com, Jonathan Corbet , linux-doc@vger.kernel.org, Kazuhito Hagio References: <20181202030839.29945-1-lijiang@redhat.com> <20181202030839.29945-2-lijiang@redhat.com> <20181203150809.GA4794@zn.tnic> <779dbae7-f6e2-e9e4-bdd0-0a9e6ec62487@redhat.com> <20181205101653.GA6940@dhcp-128-65.nay.redhat.com> From: lijiang Message-ID: <72c311b4-1946-0bcf-54d9-9fcd7f6e630c@redhat.com> Date: Wed, 5 Dec 2018 22:21:46 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181205101653.GA6940@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 05 Dec 2018 14:22:00 +0000 (UTC) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 在 2018年12月05日 18:16, Dave Young 写道: >>>> +init_uts_ns >>>> +=========== >>>> +This is the UTS namespace, which is used to isolate two specific elements >>>> +of the system that relate to the uname system call. The UTS namespace is >>>> +named after the data structure used to store information returned by the >>>> +uname system call. >>> >>> Those non-obvious exports should also have a short explanation why >>> they're part of VMCOREINFO. >>> >>>> + >>>> +node_online_map >>>> +=============== >>>> +It is a macro definition, actually it is an arrary node_states[N_ONLINE], >>>> +and it represents the set of online node in a system, one bit position >>>> +per node number. >>> >>> Ditto. >>> >>> So yeah, people can find out what those things are but I think it is >>> more important to state here *why* they're part of VMCOREINFO and how >>> they're used and why they're exported. >>> >> >> This is a good question. >> >> For these two *why*, it should be easy to understand. Because user-space tools >> need to know basic information, such as the symbol values, field offset, structure >> size, etc. Otherwise, these tools won't know how to analyze the memory of the crash >> kernel. >> >> For the second question 'how they are used', we can get the answer from user-space >> tools, such as makedumpfile, crash tools. Therefore, it may not need to explain any >> more in kernel document. On the other hand, if we must put these contents into kernel >> document, i have to say, that would be a hard task. > > It should be a good chance to learn how makedumpfile works :), Maybe it is > hard to get *all* of them, but it would be good to dig and find the > thing you can find then explain it. And leave those *unknown* part as > FIXME or TODO, people can add description later. > Thank you, Dave. It looks like a good idea. Regards, Lianbo > Added Kazu in cc as well.. > > Thanks > Dave >