Re: Where is RLIMIT_RT_CPU?

From: Esben Nielsen
Date: Sun Jul 16 2006 - 05:42:26 EST

On Sun, 16 Jul 2006, Jean-Marc Valin wrote:

I don't think it's a problem. If the admin does not want non-root users
to be able to lock up the machine, just don't put them in the realtime

What if the admin *wants* non-root users to have good quality audio, and
just doesn't want them to crash the system (voluntarily and especially
accidentally). Enforcing CPU limits *is* possible and it has already
been done independently by both Ingo and Con. I'm just waiting for the
feature to be available out-of-the box, which is not for today if kernel
space keeps pointing at userspace and vice versa. :-(


You can't have "random" users scheduling thing at real-time priorities.
A real-time system can only work if it is set up as whole and all real-time tasks are taken into consideration. If you allow a user to start another real-time task, that task might destroy the real-time properties of all the rest by taking too much cpu.

As I see it the only thing you can do is to use sudo to run anything,
which needs real-time priority, with higher priviliges, than what a normal user have. Then he can only start specific audio programs and can't crash the system (unless those programs have a bug).

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