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Date: Thu, 6 Oct 2022 15:45:33 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: Re: [PATCH v3 5/6] powerpc/64: Add support for out-of-line static calls
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On Thu, Oct 06, 2022 at 06:38:00PM +0000, Christophe Leroy wrote:
> Le 06/10/2022 à 20:22, Segher Boessenkool a écrit :
> > Long ago I built kernels that fit together with the boot firmware and a
> > root fs (busybox+dropbear essentially) in 4MB, but I doubt we can get
> > close to that at all these days :-)
> 
> 4MB, not easy. But 8M still achievable. Well our smaller board has 32M, 
> we have thousands of it spread all over Europe and have to keep it up to 
> date ....

The smallest of these systems had 256MB RAM.  This 4MB is flash ROM :-)

> > What is the overhead if you enable modules but do not use them, these
> > days?
> 
> On the 8xx it is mainly the instruction TLB miss handler:

I meant just an indicative code size number...  100 bytes, 100kB, 100MB,
or something like that :-)  And, on 64 bit, which is what the question
was about!


Segher