Re: [RFC] New kernel-message logging API

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To: Joe Perches <joe@...>
Cc: Vegard Nossum <vegard.nossum@...>, LKML <linux-kernel@...>, holzheu <holzheu@...>, Rob Landley <rob@...>, Dick Streefland <dick.streefland@...>
Date: Saturday, September 22, 2007 - 11:43 pm

On Sep 22, 2007, at 20:47:21, Joe Perches wrote:

For starters, I think "its all opinion" is bogus; the value of each  
log level is pretty standardly defined for the kernel:
EMERG:   The system is completely failing right NOW.  Immediate admin  
action is definitely required
ALERT:   The system is about to fail or halfway-failing.  Immediate  
admin action may be required.
ERR:     Something went badly wrong.  We are able to continue without  
endangering the overall system.
NOTICE:  Something unusual happened but it's either not a device/code  
failure or it's an expected failure.
INFO:    Something useful happened, like a device probe or a major  
system-wide event
DEBUG:   Something happened that only a developer or somebody looking  
for bugs would care about.

All of those are basically defined as: "This is how much the admin  
probably wants to see this message".  If you find a message which  
doesn't seem to match the log level it's logged at, please submit a  
patch.

Even assuming its not a bogus argument, what you actually want is  
*NOT* "Show me INFO and DEBUG, but not EMERG, ALERT, ERR, or NOTICE",  
you actually want multiple metrics by which to measure things.  We  
already have multiple ways of filtering log messages:
   1)  Log-level (greater than $LEVEL).
   2)  Userspace textual post-processing filters and classifiers (EG:  
logcheck)
   3)  CONFIG_${SUBSYS}_DEBUG and CONFIG_${DRIVER}_DEBUG

Perhaps what you want is something like the syslog "facility" parameter?

The only real reason to add more kconfig options for logging is to  
decrease the size of the kernel binary; most anything else can be  
better done in userspace in something like logcheck.  If you're going  
to add new kconfig options then you aren't going to configure them  
generically since they're inherently subsystem/driver specific.  In  
that case you might add a per-driver "CONFIG_${DRIVER}_NOLOG" for the  
drivers you care about or a "CONFIG_MAX_LOG_LEVEL" to globally limit  
by severity but any other qualifiers inherently don't fit in a single  
scalar

Cheers,
Kyle Moffett

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Messages in current thread:
[RFC] New kernel-message logging API, Vegard Nossum, (Sat Sep 22, 3:27 pm)
Re: [RFC] New kernel-message logging API, Jesse Barnes, (Mon Sep 24, 2:26 pm)
Re: [RFC] New kernel-message logging API, Michael Holzheu, (Mon Sep 24, 5:22 am)
Re: [RFC] New kernel-message logging API, Joe Perches, (Mon Sep 24, 11:19 am)
Re: [RFC] New kernel-message logging API, Michael Holzheu, (Tue Sep 25, 4:57 am)
Re: [RFC] New kernel-message logging API, Rob Landley, (Mon Sep 24, 7:51 pm)
Re: [RFC] New kernel-message logging API, Joe Perches, (Mon Sep 24, 8:10 pm)
Re: [RFC] New kernel-message logging API, Rob Landley, (Mon Sep 24, 9:46 pm)
Re: [RFC] New kernel-message logging API, Vegard Nossum, (Mon Sep 24, 12:43 pm)
Re: [RFC] New kernel-message logging API, Joe Perches, (Mon Sep 24, 1:00 pm)
Re: [RFC] New kernel-message logging API, Vegard Nossum, (Mon Sep 24, 4:37 pm)
Re: [RFC] New kernel-message logging API, Rob Landley, (Mon Sep 24, 9:18 pm)
Re: [RFC] New kernel-message logging API, Rob Landley, (Sun Sep 23, 4:05 pm)
Re: [RFC] New kernel-message logging API, Miguel Ojeda, (Sat Sep 22, 9:05 pm)
Re: [RFC] New kernel-message logging API, Vegard Nossum, (Tue Sep 25, 1:27 am)
Re: [RFC] New kernel-message logging API, Miguel Ojeda, (Tue Sep 25, 1:24 pm)
Re: [RFC] New kernel-message logging API, Joe Perches, (Sat Sep 22, 8:13 pm)
Re: [RFC] New kernel-message logging API, Vegard Nossum, (Sun Sep 23, 4:39 am)
Re: [RFC] New kernel-message logging API, Joe Perches, (Sun Sep 23, 3:25 pm)
Re: [RFC] New kernel-message logging API, Jan Engelhardt, (Sun Sep 23, 4:45 am)
Re: [RFC] New kernel-message logging API, Joe Perches, (Sun Sep 23, 3:23 pm)
Re: [RFC] New kernel-message logging API, Vegard Nossum, (Sun Sep 23, 5:20 am)
Re: [RFC] New kernel-message logging API, Jan Engelhardt, (Sun Sep 23, 5:38 am)
Re: [RFC] New kernel-message logging API, Kyle Moffett, (Sat Sep 22, 8:40 pm)
Re: [RFC] New kernel-message logging API, Joe Perches, (Sat Sep 22, 8:47 pm)
Re: [RFC] New kernel-message logging API, Kyle Moffett, (Sat Sep 22, 11:43 pm)