SLUG Mailing List Archives
Re: [SLUG] Memory usage in gateway system.
- To: Mike Holland <myk@xxxxxxxxxxxxxxxxxxx>
- Subject: Re: [SLUG] Memory usage in gateway system.
- From: Jean-Francois Dive <jef@xxxxxxxxxxx>
- Date: Fri Sep 21 12:28:02 2001
- Cc: Keiran Sweet <keiranj@xxxxxxxxxxxxxxxx>, <slug@xxxxxxxxxxx>
On Fri, 21 Sep 2001, Mike Holland wrote:
> On Fri, 21 Sep 2001, Keiran Sweet wrote:
> > I have recompiled the kernel to disable modules, statically include the
> > network card drivers, and all other hardware drivers, plus include all
> > needed netfilter support.
> Why bother with all that? Whats wrong with modules?
If modules are not needed because the configuration is fixed, then it is
better to remove the support for a simple reason: security measure. Nasty
stuffs can be done when module support is enabled on a machine: load a
nice rootkit module and that's it, you own the machine from it's real
root. Modules does save memory simply because you can choose to only
load what you need at a time, but not by it's nature: a driver loaded in a
module will use the same ressources as if it was statically included in
> > All of this managed to get the kernel size down from about 2 megs(plus
> > modules) to about 722k.
> I'm surprised - I thought modules were supposed to keep memory use down.
> Too many non-modules drivers in the kernel?
> Still, I dont think you need have bothered. 64MB is more than plenty for
> your purpose.
> > My question is why i am constantly noticing that
> > the systems memory is always
> > becoming highly used, upon boot it uses 17megs of the 64 availiable, and
> > i'll check back a day later to see it using about 62 megs of memory.
> > I have asked a few people about this, and they have advised me that its
> > due to HDD caching ect, ie, more writing/reading activity the more RAM
> You just answered your own question. Unused memory will fill with disk
> cache. What does the command "free -m" tell you?
> Also "ps aux" will tell you pre-process memory use (virtual & resident).
> > I have looked through a few books and havent been able to find much
> dead trees? STFW , e.g.
> Mike Holland <myk@xxxxxxxxxxxxxxxxxxx>
> "Everybody is talking about the weather but nobody does anything
> about it." -- Mark Twain
> SLUG - Sydney Linux User Group Mailing List - http://slug.org.au/
> More Info: http://lists.slug.org.au/listinfo/slug