From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754214Ab1AZW5J (ORCPT ); Wed, 26 Jan 2011 17:57:09 -0500 Received: from xenotime.net ([72.52.115.56]:59868 "HELO xenotime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753328Ab1AZW5H (ORCPT ); Wed, 26 Jan 2011 17:57:07 -0500 Date: Wed, 26 Jan 2011 14:57:03 -0800 From: Randy Dunlap To: Andrew Morton Cc: Mandeep Singh Baines , linux-kernel@vger.kernel.org, Ingo Molnar , Linus Torvalds , olofj@chromium.org Subject: Re: [PATCH] printk: allow setting DEFAULT_MESSAGE_LEVEL via Kconfig Message-Id: <20110126145703.a0f5add5.rdunlap@xenotime.net> In-Reply-To: <20110126144910.ce0646ec.akpm@linux-foundation.org> References: <20110125235700.GR8008@google.com> <20110126144910.ce0646ec.akpm@linux-foundation.org> Organization: YPO4 X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.6; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 26 Jan 2011 14:49:10 -0800 Andrew Morton wrote: > On Tue, 25 Jan 2011 15:57:00 -0800 > Mandeep Singh Baines wrote: > > > We've been burned by regressions/bugs which we later realized could > > have been triaged quicker if only we'd paid closer attention to > > dmesg. To make it easier to audit dmesg, we'd like to make > > DEFAULT_MESSAGE_LEVEL Kconfig-settable. That way we can set it to > > KERN_NOTICE and audit any messages <= KERN_WARNING. > > > > Signed-off-by: Mandeep Singh Baines > > --- > > kernel/printk.c | 2 +- > > lib/Kconfig.debug | 12 ++++++++++++ > > 2 files changed, 13 insertions(+), 1 deletions(-) > > > > diff --git a/kernel/printk.c b/kernel/printk.c > > index 5ddd291..f91a7fd 100644 > > --- a/kernel/printk.c > > +++ b/kernel/printk.c > > @@ -59,7 +59,7 @@ void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) > > #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) > > > > /* printk's without a loglevel use this.. */ > > -#define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */ > > +#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL > > > > /* We show everything that is MORE important than this.. */ > > #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 28b42b9..67b42fa 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -9,6 +9,18 @@ config PRINTK_TIME > > operations. This is useful for identifying long delays > > in kernel startup. > > > > +config DEFAULT_MESSAGE_LOGLEVEL > > + int "Default message log level (1-7)" > > + range 1 7 > > + depends on PRINTK > > + default "4" > > + help > > + Default log level for printk statements with no specified priority. > > + > > + This was hard-coded to KERN_WARNING since at least 2.6.10 but folks > > + that are auditing their logs closely may want to set it to a lower > > + priority. > > + > > config ENABLE_WARN_DEPRECATED > > bool "Enable __deprecated logic" > > default y > > I'm a bit surprised that this wasn't already tunable at boot-time > and/or at runtime. As WANG Cong replied: Why? We already have "loglevel=" kernel parameter. > I think it's generally superior to be able to tune this sort of thing > via kernel boot parameters and/or /proc knobs, rather than requiring a > recompile. That might be a problem in this specific case, if we have > printks which are occurring before __setup() parsing has completed. > > > Poeple often complain that they want things settable in Kconfig because > for some reason it's all too hard to set the kernel boot command line. > Next time someone says this I'll suggest that they fix the problem > permanently by implementing a CONFIG_CMDLINE string, which gets > inserted into the kernel boot command line at compile time ;) --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***