The patch titled Subject: printk: convert the format for KERN_<LEVEL> to a 2 byte pattern has been added to the -mm tree. Its filename is printk-convert-the-format-for-kern_level-to-a-2-byte-pattern.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Joe Perches <joe@xxxxxxxxxxx> Subject: printk: convert the format for KERN_<LEVEL> to a 2 byte pattern Instead of "<.>", use an ASCII SOH for the KERN_<LEVEL> 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 <joe@xxxxxxxxxxx> Cc: Kay Sievers <kay.sievers@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kern_levels.h | 25 ++++++++++++++----------- include/linux/printk.h | 4 ++-- kernel/printk.c | 3 ++- 3 files changed, 18 insertions(+), 14 deletions(-) diff -puN include/linux/kern_levels.h~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern include/linux/kern_levels.h --- a/include/linux/kern_levels.h~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern +++ a/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 "<d>" /* * 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 "<c>" +#define KERN_CONT KERN_SOH "c" #endif diff -puN include/linux/printk.h~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern include/linux/printk.h --- a/include/linux/printk.h~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern +++ a/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_le case '0' ... '7': case 'd': /* KERN_DEFAULT */ case 'c': /* KERN_CONT */ - return buffer + 3; + return buffer + 2; } } return buffer; diff -puN kernel/printk.c~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern kernel/printk.c --- a/kernel/printk.c~printk-convert-the-format-for-kern_level-to-a-2-byte-pattern +++ a/kernel/printk.c @@ -1342,9 +1342,10 @@ asmlinkage int vprintk_emit(int facility case 'd': /* KERN_DEFAULT */ prefix = true; case 'c': /* KERN_CONT */ + break; } text_len -= end_of_header - text; - text = end_of_header; + text = (char *)end_of_header; } if (level == -1) _ Subject: Subject: printk: convert the format for KERN_<LEVEL> to a 2 byte pattern Patches currently in -mm which might be from joe@xxxxxxxxxxx are linux-next.patch maintainers-whitespace-fixes.patch printk-add-generic-functions-to-find-kern_level-headers.patch printk-add-kern_levelsh-to-make-kern_level-available-for-asm-use.patch arch-remove-direct-definitions-of-kern_level-uses.patch btrfs-use-printk_get_level-and-printk_skip_level-add-__printf-fix-fallout.patch btrfs-use-printk_get_level-and-printk_skip_level-add-__printf-fix-fallout-checkpatch-fixes.patch sound-use-printk_get_level-and-printk_skip_level.patch staging-wlags49_h2-remove-direct-declarations-of-kern_level-prefixes.patch printk-convert-the-format-for-kern_level-to-a-2-byte-pattern.patch printk-only-look-for-prefix-levels-in-kernel-messages.patch printk-remove-the-now-unnecessary-c-annotation-for-kern_cont.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html