Re: [PATCH 0/3] build system: section garbage collection for vmlinux

Adrian Bunk
2007-09-05T19:31:59Z

On Wed, Sep 05, 2007 at 08:14:12PM +0100, Denys Vlasenko wrote:
> On Wednesday 05 September 2007 19:38, Daniel Walker wrote:
> > > > You version doesn't work with CONFIG_MODULES right?
> > >
> > > It works with CONFIG_MODULES.
> >
> > Really? Take a look at this version,
> >
> > http://lkml.org/lkml/2006/6/4/169
> >
> > Marcello had to implement a two pass build to add back symbol used in
> > modules which got removed from the main kernel.. You don't appear to do
> > that. Marcelo also claims better size reduction than you.
>
> This will discard EXPORT_SYMBOLs potentially used by
> out-of-tree modules.
>
> I also saw ~10% size reductions, but then at run-time test modules
> failed to load, they didn't find needed symbols.
>
> OTOH if I know that I am not going to be using such modules,
> then this can be done. Will require another CONFIG_xxx, though.

One point to keep in mind is that the space penalty of CONFIG_MODULES=y
is so big that CONFIG_MODULES=n is actually the most interesting case
for small systems that really need small kernels.

> vda

cu
Adrian

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