As Segher pointed out, inline asm is better than the volatile casting all over the place. From the PowerPC patch description: Also use inline functions instead of macros; this actually improves code generation (some code becomes a little smaller, probably because of improved alias information -- just a few hundred bytes total on a default kernel build, nothing shocking). My config with march=k8 and gcc (GCC) 4.1.2 (Gentoo 4.1.2): text data bss dec hex filename 4002473 385936 474440 4862849 4a3381 atomic_normal/vmlinux 4002587 385936 474440 4862963 4a33f3 atomic_inlineasm/vmlinux 4003911 385936 474440 4864287 4a391f atomic_volatile/vmlinux 4003959 385936 474440 4864335 4a394f atomic_volatile_inline/vmlinux Signed-off-by: Sebastian Siewior --- a/include/asm-x86_64/atomic.h +++ b/include/asm-x86_64/atomic.h @@ -29,19 +29,34 @@ typedef struct { int counter; } atomic_t /** * atomic_read - read atomic variable * @v: pointer of type atomic_t - * + * * Atomically reads the value of @v. - */ -#define atomic_read(v) ((v)->counter) + */ +static __inline__ int atomic_read(const atomic_t *v) +{ + int t; + + __asm__ __volatile__( + "movl %1, %0" + : "=r"(t) + : "m"(v->counter)); + return t; +} /** * atomic_set - set atomic variable * @v: pointer of type atomic_t * @i: required value - * + * * Atomically sets the value of @v to @i. - */ -#define atomic_set(v,i) (((v)->counter) = (i)) + */ +static __inline__ void atomic_set(atomic_t *v, int i) +{ + __asm__ __volatile__( + "movl %1, %0" + : "=m"(v->counter) + : "ir"(i)); +} /** * atomic_add - add integer to atomic variable @@ -206,7 +221,7 @@ static __inline__ int atomic_sub_return( /* An 64bit atomic type */ -typedef struct { volatile long counter; } atomic64_t; +typedef struct { long counter; } atomic64_t; #define ATOMIC64_INIT(i) { (i) } @@ -217,7 +232,16 @@ typedef struct { volatile long counter; * Atomically reads the value of @v. * Doesn't imply a read memory barrier. */ -#define atomic64_read(v) ((v)->counter) +static __inline__ long atomic64_read(const atomic64_t *v) +{ + long t; + + __asm__ __volatile__( + "movq %1, %0" + : "=r"(t) + : "m"(v->counter)); + return t; +} /** * atomic64_set - set atomic64 variable @@ -226,7 +250,13 @@ typedef struct { volatile long counter; * * Atomically sets the value of @v to @i. */ -#define atomic64_set(v,i) (((v)->counter) = (i)) +static __inline__ void atomic64_set(atomic64_t *v, long i) +{ + __asm__ __volatile__( + "movq %1, %0" + : "=m"(v->counter) + : "ir"(i)); +} /** * atomic64_add - add integer to atomic64 variable -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/