From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754925AbZA0L4Z (ORCPT ); Tue, 27 Jan 2009 06:56:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753068AbZA0L4Q (ORCPT ); Tue, 27 Jan 2009 06:56:16 -0500 Received: from charlotte.tuxdriver.com ([70.61.120.58]:43560 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753003AbZA0L4Q (ORCPT ); Tue, 27 Jan 2009 06:56:16 -0500 Date: Tue, 27 Jan 2009 06:55:52 -0500 From: Neil Horman To: Andrew Morton Cc: Vivek Goyal , linux-kernel@vger.kernel.org, hbabu@us.ibm.com, kexec@lists.infradead.org, horms@verge.net.au Subject: Re: [PATCH]: add dmesg log symbols to /proc/vmcoreinfo lists Message-ID: <20090127115552.GA3898@hmsreliant.think-freely.org> References: <20090119212127.GA13157@hmsreliant.think-freely.org> <20090120141551.GA5125@redhat.com> <20090120150958.GB18207@hmsreliant.think-freely.org> <20090120152255.GB5125@redhat.com> <20090127001211.f847ea5a.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090127001211.f847ea5a.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-Spam-Score: -1.4 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 27, 2009 at 12:12:11AM -0800, Andrew Morton wrote: > On Tue, 20 Jan 2009 10:22:56 -0500 Vivek Goyal wrote: > > > On Tue, Jan 20, 2009 at 10:09:58AM -0500, Neil Horman wrote: > > > On Tue, Jan 20, 2009 at 09:15:51AM -0500, Vivek Goyal wrote: > > > > On Mon, Jan 19, 2009 at 04:21:27PM -0500, Neil Horman wrote: > > > > > Hey all- > > > > > It would be nice to be able to extract the dmesg log from a vmcore file > > > > > without needing to keep the debug symbols for the running kernel handy all the > > > > > time. We have a facility to do this in /proc/vmcore. This patch adds the > > > > > log_buf and log_end symbols to the vmcoreinfo area so that tools (like > > > > > makedumpfile) can easily extract the dmesg logs from a vmcore image. > > > > > > > > > > > > > It would be nice to get dmesg log if debug symbols are not around. Can't > > > > we use System.map for getting symbol addresses? vmcoreinfo had started > > > > small and seems to be growing now. I am thinking down the line will making > > > > use of System.map for such cases make sense? > > > > > > > > > > System.map only include exported and public symbols. log_buf and log_end are > > > static, and not reported in the System.map. Its a nice idea, but not > > > comprehensive for everything in the kernel. > > > > > > > > > > > > > > > Will it be an issue if we make log_buf and log_end non static and directly > > > > access these in kexec.c? > > > > > > > I had considered that, but was a bit hesitant to do so, since it exposes the > > > internal implementation of the dmesg buffer. In the event someone disables > > > CONFIG_PRINTK, thats just more code we need to ifdef. With this implementation > > > we just stub out the log_buf_setup function, and let that be that. It seems > > > more consice to me this way. > > > > > > > Makes sense to me. > > > > Acked-by: Vivek Goyal > > > > I rewrote the title to > > kexec: add dmesg log symbols to /proc/vmcoreinfo lists > > it's nice to identify which subsystem is responsible for a patch. > > I also did all the below. Please check it. (Is anyone else reading all > this stuff??) > > Hey Andrew- Yes, that all looks fine, thank. I'm not sure of the advantage of an inline over a #define in the event that CONFIG_PRINTK isn't defined, but its fine with me either way. Much appreciated! Neil >