Hi Sri, On Fri, Sep 24, 2010 at 3:56 PM, Sri Ram Vemulpali wrote: > Hi all, > > I am encountering alot macros in the code. I did not understand what > those macro means. > > Can anyone explain them and the use of them putting them like that. > > "unlikely" This has to do with branch prediction. If the architecture that you're building for supports branch prediction then this provides a hint to say that the following test is unlikely to pass, so the branch prediction will be setup to take the likely path. > "always_inline" -- defined at the signature of the function. Exactly what it says - always make the function an inline function. The inline keyword is normally just a hint or suggestion to the compiler, whereas the always_inline says that the function should always be inlined, even if optimizations to perform function inlining is disabled. <http://gcc.gnu.org/onlinedocs/gcc-4.0.4/gcc/Function-Attributes.html> > "inline" -- I know inline keyword in compiler is used to place the > code in to the caller function at the time of compiler, but why > declared as macro There are some CONFIG options which allow inline behaviour to be tweaked: <http://cateee.net/lkddb/web-lkddb/OPTIMIZE_INLINING.html> -- Dave Hylands Shuswap, BC, Canada http://www.DaveHylands.com/ -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
