commit e0e817392b9a ("CRED: Add some configurable debugging [try #6]")
added the kdebug mechanism to this file back in 2009.
The kdebug macro calls no_printk which always evaluates arguments.
Most of the kdebug uses have an unnecessary call of
atomic_read(&cred->usage)
Make the kdebug macro do nothing by defining it with
do { if (0) no_printk(...); } while (0)
when not enabled.
$ size kernel/cred.o* (defconfig x86-64)
text data bss dec hex filename
2748 336 8 3092 c14 kernel/cred.o.new
2788 336 8 3132 c3c kernel/cred.o.old
Miscellanea:
o Neaten the #define kdebug macros while there
Signed-off-by: Joe Perches <[email protected]>
---
kernel/cred.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/cred.c b/kernel/cred.c
index ec1c076..71179a0 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -20,11 +20,16 @@
#include <linux/cn_proc.h>
#if 0
-#define kdebug(FMT, ...) \
- printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid
,##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ printk("[%-5.5s%5u] " FMT "\n", \
+ current->comm, current->pid, ##__VA_ARGS__)
#else
-#define kdebug(FMT, ...) \
- no_printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid
,##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+do { \
+ if (0) \
+ no_printk("[%-5.5s%5u] " FMT "\n", \
+ current->comm, current->pid, ##__VA_ARGS__); \
+} while (0)
#endif
static struct kmem_cache *cred_jar;
--
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