Re: CONFIG_SWAPPING?

Graham Stoney (greyham@research.canon.com.au)
Fri, 28 Apr 2000 18:35:24 +1000 (EST)

lars brinkhoff writes:
> I think this comment, found elsewhere, by Russel King answers
> my question:
>
> Naik, Uday writes:
> > I seem to be getting a kernel panic in kswapd. Since I don't
> > have a harddisk, I would like to turn swapping off. How do
> > I build the kernel that way. I don't see a configuration option
> > for it.
>
> The short answer is: no. The long answer is: swapping is an
> embedded part of the Linux kernel, and is not trivial to turn
> off. The fact that you don't have any swap space doesn't mean
> that this code is redundant. This code is also used to page
> out clean pages when memory gets tight. These pages are areas
> such as the text sections of user executables and libraries which
> have not been written to by user code.

I think this is a matter of degree. Certainly the non-trivial sys_swapon and
sys_swapoff functions could easily be wrapped in a hypothetical
#ifdef CONFIG_SWAPPING, and my --function-sections patch would then take out
whatever other parts of the swap & vm code then become unused, without any
further #ifdef's. Only a medium sized saving perhaps, but it sounds like a
good idea to me.

Regards,
Graham

-- 
Graham Stoney
Principal Hardware/Software Engineer
Canon Information Systems Research Australia
Ph: +61 2 9805 2909  Fax: +61 2 9805 2929


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