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| author | Joe Perches <joe@perches.com> | 2015-09-10 01:36:09 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-10 23:29:01 +0300 |
| commit | 52aa8536f8f41367d5f2938ad67aa87957e70010 (patch) | |
| tree | 55070d401000b7ab501b3b4a51883401f3a8adc3 | |
| parent | 2307e1a3c0780d7b908f6809f34034a04f954806 (diff) | |
| download | linux-52aa8536f8f41367d5f2938ad67aa87957e70010.tar.xz | |
kernel/cred.c: remove unnecessary kdebug atomic reads
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 <joe@perches.com>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/cred.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index ec1c07667ec1..71179a09c1d6 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; |