Subject: Re: Swap overcommit (was Re: Replacement for grep(1) (part 2))
To: None <dillon@apollo.backplane.com, sean.witham@asa.co.uk>
From: Daniel Eischen <eischen@vigrid.com>
List: tech-userlevel
Date: 07/16/1999 13:16:40
> I'm sorry, but when you write code for a safety related system you
> do not dynamically allocate memory at all. It's all essentially static.
> There is no issue with the memory resource. Besides, none of the BSD's are
> certified for any of that stuff that I know of.
Sometimes it's not feasible to statically allocate memory. You
dynamically allocate all the memory you need at program initialization
(and no, we don't want to manage a pool of memory ourselves - that's
what the OS is for).
Note that languages such as Ada raise exceptions when memory allocation
fails. The underlying run-time relies on malloc returning null in
order to raise an exception. Normally, programs written in Ada
take great care to gracefully handle these exceptions. All the C
programs that we've ever written also take great care in handling
NULL returns from malloc.
I have no problem with overcommit, but I can see the need that
some folks have for turning it off. If you don't want to write
the code to allow this, that's fine - you don't want/need it,
so why should you? But if other folks see a need for it, let
_them_ write the hooks for it :-)
Dan Eischen
eischen@vigrid.com