Hi All,
What do likely() and unlikely() mean ?
I see that it says :
linux-2.6.30.2\linux-2.6.30.2\include\linux\compiler.h"
/*
* Using __builtin_constant_p(x) to ignore cases where the return
* value is always the same. This idea is taken from a similar patch
* written by Daniel Walker.
*/
# ifndef likely
# define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
# endif
# ifndef unlikely
# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
# endif
but can't easliy recognize what is actually intended when likely() and unlikely() is used ??
for instance :
here
if (likely((atomic_read(&files->count) == 1)))
Regards,
Leena //
