Re: Module-based setup vs. monolithic kernel
Jamie Lokier (lkd@tantalophile.demon.co.uk)
Fri, 26 Nov 1999 12:16:40 +0100
Tuukka Toivonen wrote:
> >What are the advantages vs. disadvantages of going with either a
> >modular-based setup vs. a monolithic kernel with all necessary options
> >built in?
>
> The only bad thing in modular drivers is, AFAIK, that each module
> allocates integer number of pages. Ie. you lose an average of pagesize/2
> bytes of memory when you load a module, instead of having the driver
> compiled into kernel. On PC this is 4kB/2 = 2kB.
On x86, modules use orderinary 4k pages while non-module kernel pages
use 4M pages. On Sparc, non-module kernel pages bypass page tables. In
both cases, this makes modules a little slower than builtin drivers. I
think the difference is negligable though.
-- Jamie
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