From 04d2c8c83d0e3ac5f78aeede51babb3236200112 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 30 Jul 2012 14:40:17 -0700 Subject: [PATCH] printk: convert the format for KERN_ to a 2 byte pattern Instead of "<.>", use an ASCII SOH for the KERN_ prefix initiator. This saves 1 byte per printk, thousands of bytes in a normal kernel. No output changes are produced as vprintk_emit converts these uses to "<.>". Signed-off-by: Joe Perches Cc: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kern_levels.h | 25 ++++++++++++++----------- include/linux/printk.h | 4 ++-- 2 files changed, 16 insertions(+), 13 deletions(-) diff --git a/include/linux/kern_levels.h b/include/linux/kern_levels.h index 337e56ff5332..8c719a955b5b 100644 --- a/include/linux/kern_levels.h +++ b/include/linux/kern_levels.h @@ -1,22 +1,25 @@ #ifndef __KERN_LEVELS_H__ #define __KERN_LEVELS_H__ -#define KERN_EMERG "<0>" /* system is unusable */ -#define KERN_ALERT "<1>" /* action must be 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 but significant condition */ -#define KERN_INFO "<6>" /* informational */ -#define KERN_DEBUG "<7>" /* debug-level messages */ +#define KERN_SOH "\001" /* ASCII Start Of Header */ +#define KERN_SOH_ASCII '\001' + +#define KERN_EMERG KERN_SOH "0" /* system is unusable */ +#define KERN_ALERT KERN_SOH "1" /* action must be taken immediately */ +#define KERN_CRIT KERN_SOH "2" /* critical conditions */ +#define KERN_ERR KERN_SOH "3" /* error conditions */ +#define KERN_WARNING KERN_SOH "4" /* warning conditions */ +#define KERN_NOTICE KERN_SOH "5" /* normal but significant condition */ +#define KERN_INFO KERN_SOH "6" /* informational */ +#define KERN_DEBUG KERN_SOH "7" /* debug-level messages */ + +#define KERN_DEFAULT KERN_SOH "d" /* the default kernel loglevel */ -/* Use the default kernel loglevel */ -#define KERN_DEFAULT "" /* * Annotation for a "continued" line of log printout (only done after a * line that had no enclosing \n). Only to be used by core/arch code * during early bootup (a continued line is not SMP-safe otherwise). */ -#define KERN_CONT "" +#define KERN_CONT KERN_SOH "c" #endif diff --git a/include/linux/printk.h b/include/linux/printk.h index fea2de37b645..93a231f9835c 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -9,7 +9,7 @@ extern const char linux_proc_banner[]; static inline int printk_get_level(const char *buffer) { - if (buffer[0] == '<' && buffer[1] && buffer[2] == '>') { + if (buffer[0] == KERN_SOH_ASCII && buffer[1]) { switch (buffer[1]) { case '0' ... '7': case 'd': /* KERN_DEFAULT */ @@ -27,7 +27,7 @@ static inline const char *printk_skip_level(const char *buffer) case '0' ... '7': case 'd': /* KERN_DEFAULT */ case 'c': /* KERN_CONT */ - return buffer + 3; + return buffer + 2; } } return buffer; -- 2.39.5