[PATCH] printk time parameter
Currently, enabling/disabling printk timestamps is only possible through
reboot (bootparam) or recompile. I normally do not run with timestamps
(since syslog handles that in a good manner), but for measuring small
kernel delays (e.g. irq probing - see parport thread) I needed subsecond
precision, but then again, just for some minutes rather than all kernel
messages to come. The following patch adds a module_param() with which the
timestamps can be en-/disabled in a live system through
/sys/modules/printk/parameters/printk_time.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/printk.c b/kernel/printk.c
index 6b89dd9..95b7fe1 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -24,6 +24,7 @@
#include <linux/console.h>
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/moduleparam.h>
#include <linux/interrupt.h> /* For in_interrupt() */
#include <linux/config.h>
#include <linux/delay.h>
@@ -439,6 +440,7 @@
#else
static int printk_time = 0;
#endif
+module_param(printk_time, int, S_IRUGO | S_IWUSR);
static int __init printk_time_setup(char *str)
{