Date: Mon, 10 Sep 2007 21:14:02 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Denys Vlasenko <vda.linux@googlemail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] build system: section garbage collection for vmlinux
Message-ID: <20070910191402.GB31541@uranus.ravnborg.org>
References: <200709051443.21522.vda.linux@googlemail.com> <200709061155.52661.vda.linux@googlemail.com> <20070910120140.GA29077@uranus.ravnborg.org> <200709102002.15383.vda.linux@googlemail.com>
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On Mon, Sep 10, 2007 at 08:02:15PM +0100, Denys Vlasenko wrote:
> On Monday 10 September 2007 13:01, Sam Ravnborg wrote:
> > > 
> > > > Doing a normal kernel build will link vmlinux three or four times.
> > > > If we introduce --gc-sections we should add a preparational link of
> > > > vmlinux where we use --gc-sections and skip it for the rest of the links
> > > > assuming that --gc-sections takes some time for ld to do.
> > > 
> > > Yes, this will speed up things a bit.
> > 
> > If we do the --gc-sections trick during the preparational link then we do
> > not use the arch supplied linker script.
> > Will it be possible to create a dedicated linker script that is valid
> > for all architectures and which only include the KEEP() directives for
> > the diverse sections?
> 
> Unfortunately, -r and --gc-sections don't mix.
> 
> x86_64-pc-linux-gnu-ld: --gc-sections and -r may not be used together
OK - so much for that optimization :-(

But then we need to annotate ALL arch linker script before introducing this.
And that bring me back to that we should put some sanity into these first.

	Sam
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