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authorJoe Perches <joe@perches.com>2008-02-27 06:08:42 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2008-04-20 06:10:19 +0400
commit1429db83e276c2a16c7ea83bdcf0dcd3a36e406d (patch)
treee3960d6e7c19f5c29accbf5db11edb93d2cea28f /include/linux/kernel.h
parent00a41db522c77af33ea5ee9837d4f043ce150249 (diff)
downloadlinux-1429db83e276c2a16c7ea83bdcf0dcd3a36e406d.tar.xz
driver core: Convert debug functions declared inline __attribute__((format (printf,x,y) to statement expression macros
When DEBUG is not defined, pr_debug and dev_dbg and some other local debugging functions are specified as: "inline __attribute__((format (printf, x, y)))" This is done to validate printk arguments when not debugging. Converting these functions to macros or statement expressions "do { if (0) printk(fmt, ##arg); } while (0)" or "({ if (0) printk(fmt, ##arg); 0; }) makes at least gcc 4.2.2 produce smaller objects. This has the additional benefit of allowing the optimizer to avoid calling functions like print_mac that might have been arguments to the printk. defconfig x86 current: $ size vmlinux text data bss dec hex filename 4716770 474560 618496 5809826 58a6a2 vmlinux all converted: (More patches follow) $ size vmlinux text data bss dec hex filename 4716642 474560 618496 5809698 58a622 vmlinux Even kernel/sched.o, which doesn't even use these functions, becomes smaller. It appears that merely having an indirect include of <linux/device.h> can cause bigger objects. $ size sched.inline.o sched.if0.o text data bss dec hex filename 31385 2854 328 34567 8707 sched.inline.o 31366 2854 328 34548 86f4 sched.if0.o The current preprocessed only kernel/sched.i file contains: # 612 "include/linux/device.h" static inline __attribute__((always_inline)) int __attribute__ ((format (printf, 2, 3))) dev_dbg(struct device *dev, const char *fmt, ...) { return 0; } # 628 "include/linux/device.h" static inline __attribute__((always_inline)) int __attribute__ ((format (printf, 2, 3))) dev_vdbg(struct device *dev, const char *fmt, ...) { return 0; } Removing these unused inlines from sched.i shrinks sched.o Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include/linux/kernel.h')
-rw-r--r--include/linux/kernel.h6
1 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2df44e773270..cd6d02cf854d 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -293,10 +293,8 @@ extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
#define pr_debug(fmt, arg...) \
printk(KERN_DEBUG fmt, ##arg)
#else
-static inline int __attribute__ ((format (printf, 1, 2))) pr_debug(const char * fmt, ...)
-{
- return 0;
-}
+#define pr_debug(fmt, arg...) \
+ ({ if (0) printk(KERN_DEBUG fmt, ##arg); 0; })
#endif
/*