On Fri, 2010-10-29 at 08:37 +0200, Raistlin wrote:
> Add resource limits for non-root tasks in using the SCHED_DEADLINE
> policy, very similarly to what already exists for RT policies.
>
> In fact, this patch:
> - adds the resource limit RLIMIT_DLDLINE, which is the minimum value
> a user task can use as its own deadline;
> - adds the resource limit RLIMIT_DLRTIME, which is the maximum value
> a user task can use as it own runtime.
>
> Notice that to exploit these, a modified version of the ulimit
> utility and a modified resource.h header file are needed. They
> both will be available on the website of the project.
We might also want to add an additional !SYS_CAP_ADMIN global bandwidth
cap much like the existing sysctl bandwidth cap.
On Thu, 2010-11-11 at 20:57 +0100, Peter Zijlstra wrote:
> > In fact, this patch:
> > - adds the resource limit RLIMIT_DLDLINE, which is the minimum value
> > a user task can use as its own deadline;
> > - adds the resource limit RLIMIT_DLRTIME, which is the maximum value
> > a user task can use as it own runtime.
> >
>
> We might also want to add an additional !SYS_CAP_ADMIN global bandwidth
> cap much like the existing sysctl bandwidth cap.
>
Mmm... I think we've never discussed much about that before, so here I
am. I'm currently asking one to be root to set SCHED_DEADLINE as his
policy. Normal users are allowed to do so, but just under the rlimits
restrictions provided by this patch.
So, first of all, are we cool with this? Or do we want normal users to
be able to give their tasks SCHED_DEADLINE policy by default? Maybe we
want that but up to a certain bandwidth? Is this that you mean here,
having two bandwidth limits, one of which !SYS_ADMINs could not cross?
Sorry for being annoying, but I've never got any feedback on this, while
I think it's something really important.
Thanks,
Dario
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa (Italy)
http://blog.linux.it/raistlin / [email protected] /
[email protected]
On Fri, 2010-11-12 at 22:30 +0100, Raistlin wrote:
> On Thu, 2010-11-11 at 20:57 +0100, Peter Zijlstra wrote:
> > > In fact, this patch:
> > > - adds the resource limit RLIMIT_DLDLINE, which is the minimum value
> > > a user task can use as its own deadline;
> > > - adds the resource limit RLIMIT_DLRTIME, which is the maximum value
> > > a user task can use as it own runtime.
> > >
> >
> > We might also want to add an additional !SYS_CAP_ADMIN global bandwidth
> > cap much like the existing sysctl bandwidth cap.
> >
> Mmm... I think we've never discussed much about that before, so here I
> am. I'm currently asking one to be root to set SCHED_DEADLINE as his
> policy. Normal users are allowed to do so, but just under the rlimits
> restrictions provided by this patch.
>
> So, first of all, are we cool with this? Or do we want normal users to
> be able to give their tasks SCHED_DEADLINE policy by default?
I think so, it would make it much more useful to people.
> Maybe we want that but up to a certain bandwidth?
Exactly.
> Is this that you mean here,
> having two bandwidth limits, one of which !SYS_ADMINs could not cross?
Yep. A bandwidth cap for !SYS_CAP_ADMIN and a these two constraints
already introduced by this patch, a min period to avoid very fast timer
programming and a max runtime to avoid incurring large latencies on the
rest of the system.