linux 查看kernel log Linux Kernel Log

Kernel Log, 可找到定义,

kernel/printk.c:

/* printk's without a loglevel use this.. */

#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL

/* We show everything that is MORE important than this.. */

#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */

#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */

int console_printk[4] = {

DEFAULT_CONSOLE_LOGLEVEL,/* console_loglevel */

DEFAULT_MESSAGE_LOGLEVEL,/* default_message_loglevel */

MINIMUM_CONSOLE_LOGLEVEL,/* minimum_console_loglevel */

DEFAULT_CONSOLE_LOGLEVEL,/* default_console_loglevel */

};

include/linux/kern_level.h:

#define KERN_EMERGKERN_SOH "0"/* system is unusable */

#define KERN_ALERTKERN_SOH "1"/* action must be taken immediately */

#define KERN_CRITKERN_SOH "2"/* critical conditions */

#define KERN_ERRKERN_SOH "3"/* error conditions */

#define KERN_WARNINGKERN_SOH "4"/* warning conditions */

#define KERN_NOTICEKERN_SOH "5"/* normal but significant condition */

#define KERN_INFOKERN_SOH "6"/* informational */

#define KERN_DEBUGKERN_SOH "7"/* debug-level messages */

(1) config

在.config中定义 CONFIG_DEFAULT_MESSAGE_LOGLEVEL(0-7)

(2) debug

# cat /proc/sys/kernel/printk

7 4 1 7

-> 对应上面console_printk数组中的值

#echo 8 > /proc/sys/kernel/printk

-> 显示所有LOG, 即高于KERN_DEBUG的.

(3) printk log添加LOGLEVEL

printk(KERN_INFO "...")

printk(KERN_DEBUG "...")