Re: 2.0, loggings, cpu quotas, 2.1 issues, etc.

Matthias Urlichs (
Tue, 11 Jun 1996 12:37:15 +0100

In, article <Pine.LNX.3.93.960611014506.3875A-100000@b=
Kevin M Bealer <> writes:
> As for the CPU quotas I like the idea of "no more than 20% of the CPU=
" at
> once, but I don't know how implementable it would be. As for "only n=

It's implementable. The kernel needs a "struct userinfo" per logged-in =
for that to work. The same structure could also hold total memory usage=
which would enable us to finally block most of the more malicious
fork/malloc bombs.

> of CPU use per user", I don't see why this couldn't be better done in=
> space... unless you mean absolute, cumulative time spent by the CPU f=
or that
> user only -- and you can, say, ftp for a _long_ time (with a 14.4 any=
> before you show significant time on "top". -- most users won't be doi=
> really intensive stuff.
I don't think that's too useful. We can already count how much CPU the =
burned. Capping the amount of "live" memory for the user (so as to prev=
a "mmap() as much of /dev/zero as we're allowed to, and then randomly
write to bytes thereof" attack) would be better.

But then, if you have that kind of user population where this is a
significant problem, your money is better spent on educating these guys=
Not Do That (and kick the few people who can't understand the words "ce=
and desist" off the system).

It were better to perish than to continue schoolmastering.
-- Thomas Carlyle
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