Messages in this thread | | | From | Gerd Knorr <> | Subject | Re: kbuild 2.5 is ready for inclusion in the 2.5 kernel | Date | 3 May 2002 12:05:01 GMT |
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Keith Owens wrote: > On 3 May 2002 10:06:04 GMT, > Gerd Knorr <kraxel@bytesex.org> wrote: > >> Do it with NO_MAKEFILE_GEN=1 for much, much! faster builds. > > > >What exactly is the reason for this hack, i.e. why kbuild wants to > >rebuild the Makefiles every time? Isn't it enougth to do that only > >if .config has been touched? > > Or any of the Makefile.in files have changed.
.config + all Makefile.in's is still a small number of files where make has to check the timestamp to see whenever a rebuild of the global makefile is needed.
> Or any of the command line options have changed.
Which command line options?
> Or various environment variables have changed. > Or the compiler has changed.
Which environment variables? CC / CFLAGS? Well, with other CFLAGS and/or compiler you have to do a full rebuild anyway, thus using "make clean" would work equally well ...
> Or a target file has been altered outside kbuild control.
Which is the users fault IMO. I don't see the point in trying to catch this and make kbuild idiot proof. I doubt it is possible to make kbuild clever enougth to handle all evil things a user could do. AI isn't that good.
> Coding a special case to work out if the existing global makefile can > be reused is horribly error prone.
Special case? I'd say it is the common case when doing kernel development. At least I don't use another compiler for every second make. I usually hack some piece of code and recompile the module then.
Gerd
-- You can't please everybody. And usually if you _try_ to please everybody, the end result is one big mess. -- Linus Torvalds, 2002-04-20 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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