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

From: Adrian Bunk
Date: Wed Sep 05 2007 - 15:32:00 EST


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

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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