Reduce boot time console messages?
narkewoody at gmail.com
Sun Aug 4 23:07:26 EDT 2013
On Sat, Aug 03, 2013 at 10:08:42AM -0400, Valdis.Kletnieks at vt.edu wrote:
> On Sat, 03 Aug 2013 20:27:55 +0800, Woody Wu said:
> > Hi,
> > My kernel is printing too many messages at boot time from a special
> > device driver (j2ffs filesystem). I belive these kernel messages are
> > level DEBUG. If don't change the kernel code, is there anyway to print
> > only some higher level of messages?
> In your kernel source tree, there's a file called Documentation/kernel-parameters.txt
> and in it, we find documentation of the following two boot-time parameters:
> ignore_loglevel [KNL]
> Ignore loglevel setting - this will print /all/
> kernel messages to the console. Useful for debugging.
> We also add it as printk module parameter, so users
> could change it dynamically, usually by
> loglevel= All Kernel Messages with a loglevel smaller than the
> console loglevel will be printed to the console. It can
> also be changed with klogd or other programs. The
> loglevels are defined as follows:
> 0 (KERN_EMERG) system is unusable
> 1 (KERN_ALERT) action must be taken immediately
> 2 (KERN_CRIT) critical conditions
> 3 (KERN_ERR) error conditions
> 4 (KERN_WARNING) warning conditions
> 5 (KERN_NOTICE) normal but significant condition
> 6 (KERN_INFO) informational
> 7 (KERN_DEBUG) debug-level messages
Valdis, thank you very much. I just passed loglevel=7 as kernel command
line and hope it can suspress KERN_DEBUG messages printed out to console
at boot time. But, it seems not work. A lot of debug level messages from
jffs2 module still print out. I will go to check where is wrong.
> In addition, there may or may not be a module parameter to control the
> logging level of the particular module - look for the word 'debug' in that
> file. There's also the 'dynamic debugging' facility which the module may
> be coded to support....
I can't go back to yesterday - because I was a different person then
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