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
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------------------------------------------------------
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
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