linux - difference between console log level and default log lovel -

in module programming read ,

if log level

  less console log level displayed ,    higher mentioned in log files ,  

if dont specify log level in printk statement default log level taken .

i saw default , console log level

by

cat /proc/sys/kernel/printk

and result

4 4 1 7

here both default , console same .

i dont understand why default log level created . going use default log level in anywhere .

what exact difference between console log level , default log level .

i new module programming.

as know have different kernel level logs:

#define kern_emerg "<0>" /* system unusable*/ #define kern_alert "<1>" /* action must taken immediately*/ #define kern_crit "<2>" /* critical conditions*/ #define kern_err "<3>" /* error conditions*/ #define kern_warning "<4>" /* warning conditions*/ #define kern_notice "<5>" /* normal significant condition*/ #define kern_info "<6>" /* informational*/ #define kern_debug "<7>" /* debug-level messages*/ 

okay let put discussion separately:

console log level used set log levels can displayed on console window with log levels(printk) < console log level(4 taken considering wrt case).

i.e., print kernel messages printk using log levels 0,1,2 , 3. rest 4 7 logged in circular buffer maintained kernel - can seen issuing "dmesg".

now if move on default log level:

whenever use printk without log level info, eg:

printk("insmod first driver\n"); // log level set "kern_warning"(as default log level 4).

so difference console log used decide needed printed on console , default log level used log level taken default if not mentioned printk during kernel module programming.