Rebuild a changed kernel quickly with make?

[Martin Kepplinger]

Hi.

When I change something in the kernel and just hit make from toplevel
dir, it always compiles everything again, no matter if it wasn't changed
at all in the meantime.
I thought make should be able to make a second build time really quick.
What am I doing wrong? Is there a make target I don't know of? I don't
type in any, just make.

thanks,

                    martin