Re: about printk and console_loglevel

Andrzej Kardas <andrzej-kardas@xxxxx> · Sat, 05 Mar 2011 23:22:28 +0100



    On 05.03.2011 19:42, Siddu wrote:
    Hi all,

      Hi all,
      

      I am little stuck understanding this piece of code below and
        the way its been working 

        
        Question: since KERN_INFO = 6 # which is msg_log_level

        and as per code
        
          
          msg_log_level < console_loglevel
        

         this line of printk is not supposed to show up in the
          dmesg log ? but it is showing up . Why 

        
    console_loglevel concern messages that should display on the CONSOLE
    not "dmesg" and controls if message is enough important (read: have
    prioryty below console_loglevel) to display it on the
    console. You must know that, kernel logs its messages into buffer
    (into the RAM) which have constant size, when you type dmesg, you
    simply read messages from that buffer (ring-buffer), so that why you
    see your line in dmesg.

    
    What is more, there is deamon called syslog (rsyslog) which reads
    this buffer periodically and saves messages in appropriate log file
    on the hard drive e.g. /var/log/kern.log or /var/log/messages etc.
    You can configure rsyslog as you wish, to log certain types messages
    into logfiles.

    
    --

    regards

    Andrzej Kardas

    http://www.linux.mynotes.pl

  
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