[PATCH] build without PCI or VIO

Linas Vepstas linas at austin.ibm.com
Fri Feb 11 04:52:53 EST 2005

On Thu, Feb 10, 2005 at 12:39:42AM -0600, Olof Johansson was heard to remark:
> On Wed, Feb 09, 2005 at 06:34:37PM +1100, Stephen Rothwell wrote:
> > Hi Anton, all,
> > 
> > This patch (on top of my previous dma fix up patch) allows you to build
> > pSeries without CONFIG_PCI or CONFIG_VIO or both and iSeries without PCI. 
> > Don't look to closely at the include/asm-ppc64/floppy.h patch :-).
> > 
> > Please comment.
> 6.8% difference for a kernel completely without drivers.

... A penny here and a penny there and pretty soon it adds up to real
money.  If someone else reduces things by 5% in a couple of other
places, then the original 6.8% savings becomes even larger.

> Does the amount of added #ifdefs to C code justify the savings? How

The patch didn't strike me as excessively intrusive.  Although I don't
know of the particular application for this, past experience says that
little things like this make the difference between a "joke" and a
"serious contender".   I once lost a linux-embedded contract because
I was unable to make the kernel small enough, even after turning
*everything* off.  (Back then I couldn't turn tcp/ip off, even though the
embedded app had absolutely no need for tcp/ip).


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