On 11/06/2012 01:28 AM, Andrew Morton wrote: > On Thu, 1 Nov 2012 16:07:35 +0400 > Glauber Costa <glom...@parallels.com> wrote: > >> +static __always_inline struct kmem_cache * >> +memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) > > I still don't understand why this code uses __always_inline so much. > > I don't recall seeing the compiler producing out-of-line versions of > "static inline" functions (and perhaps it has special treatment for > functions which were defined in a header file?). > > And if the compiler *does* decide to uninline the function, perhaps it > knows best, and the function shouldn't have been declared inline in the > first place. > > > If it is indeed better to use __always_inline in this code then we have > a heck of a lot of other "static inline" definitions whcih we need to > convert! So, what's going on here? >
The original motivation is indeed performance related. We want to make sure it is inline so it will figure out quickly the "I am not a memcg user" case and keep it going. The slub, for instance, is full of __always_inline functions to make sure that the fast path contains absolutely no function calls. So I was just following this here. I can remove the marker without a problem and leave it to the compiler if you think it is best -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
