Re: [LAD] Realtime threads and security

From: Olivier Guilyardi <list@email-addr-hidden>
Date: Fri Feb 25 2011 - 18:40:36 EET

On 02/25/2011 05:32 PM, Paul Davis wrote:
> On Fri, Feb 25, 2011 at 10:53 AM, Olivier Guilyardi <list@email-addr-hidden> wrote:
>
>> Let's now consider that clients runs as user(s) which do not have realtime
>> privileges by default, but that it's JACK which grant them such privileges and
>> assign them a certain CPU time share dynamically. In this scenario could also
>> refuse connections if it considers that there isn't enough resources.
>
> sure, but granting RT privs to a client is not the goal. you want to
> actually set the scheduling policy for specific threads.

Hmm, then..
1. a program calls jack_client_open()
2. libjack talks to jackd to request RT privs
3. jackd grants privs, with cgroup, runtime, period, etc..
4. libjack receives a success code from jackd
5. libjack sets the scheduling policy on the relevant threads

If at 4., jackd receives an error code, jack_client_open() terminates and
returns an error status.

But maybe that this is too much complication, where setting a global RT
runtime/period is maybe sufficient, and could possibly become the default in
major distributions. Not sure why it's done been done yet though.

--
  Olivier
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Received on Fri Feb 25 20:15:07 2011

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