From 52aa8536f8f41367d5f2938ad67aa87957e70010 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Wed, 9 Sep 2015 15:36:09 -0700 Subject: [PATCH] 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 Cc: David Howells Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 #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; -- 2.7.4