linux-kernel - [patch 0/3] dynamic printk

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Date:	Tue, 1 Apr 2008 15:48:36 -0400
From:	Jason Baron <jbaron@...hat.com>
To:	linux-kernel@...r.kernel.org
Subject: [patch 0/3] dynamic printk

hi,

Add the ability to dynamically enable/disable pr_debug()/dev_dbg() in the
kernel. Yes, these calls could be converted to printk(KERN_DEBUG), but there
are enough to cause overhead. Additionally, the logs become difficult to read.
Here, one can turn on and off these messages per .c source file via:

echo "add file.c" > /sys/kernel/debug/dynamic_printk/files
echo "remove file.c" > /sys/kernel/debug/dynamic_printk/files

There is also a special 'all' value that turns on all the debugging messages.

I hope that these patches are useful for people writing new kernel code, for
system debugging and testing. In enabling the 'all' feature on the kernel I was
running i got a bunch of messages... (i'm not sure what they mean, but they
could point out an error or a kernel optimization that could be made, which I 
didn't necessarily know about otherwise).

thanks,

-Jason

Apr  1 10:33:38 dhcp83-106 kernel: Already setup manip DST for ct ffff81007d800140
Apr  1 10:33:38 dhcp83-106 kernel: Already setup manip SRC for ct ffff81007d800140
Apr  1 10:33:38 dhcp83-106 kernel: Already setup manip DST for ct ffff81007d800a00
Apr  1 10:33:38 dhcp83-106 kernel: Already setup manip SRC for ct ffff81007d800a00
Apr  1 10:33:39 dhcp83-106 kernel: Already setup manip DST for ct ffff81007d800a00
Apr  1 10:33:39 dhcp83-106 kernel: Already setup manip SRC for ct ffff81007d800a00
Apr  1 10:33:39 dhcp83-106 kernel: Already setup manip DST for ct ffff81007d800a00
Apr  1 10:33:39 dhcp83-106 kernel: Already setup manip SRC for ct ffff81007d800a00
Apr  1 10:33:40 dhcp83-106 kernel: Already setup manip DST for ct ffff810071851dc0
Apr  1 10:33:40 dhcp83-106 kernel: Already setup manip SRC for ct ffff810071851dc0
Apr  1 10:33:40 dhcp83-106 kernel: Already setup manip DST for ct ffff81007d800a00
Apr  1 10:33:40 dhcp83-106 kernel: Already setup manip SRC for ct ffff81007d800a00

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