On Fri, Jul 26, 2013 at 11:38:29PM +0100, Russell King - ARM Linux wrote:

On Sat, Jul 27, 2013 at 12:28:09AM +0200, Domenico Andreoli wrote:

quoted

I've got the point but didn't fully understand why would be so wrong to
walk one more subdir even if nothing is going to be built.

Consider what would happen if we decended the 61 mach- subdirectories
on every build run when only one was really required.  Even though
kbuild tries to be fast, there's still a non-zero amount of time
involved with finding out there's nothing to be done - and you
will still end up generating a built-in.o file even though there's
no other objects, which will then also be included in the final
link - again, adding to the work which has to be done.

crystal clear. thanks.

Domenico