Re: [PATCH v3 01/14] sched/core: uclamp: extend sched_setattr to support utilization clamping

Hi Patrick,

On Thursday 09 Aug 2018 at 16:23:13 (+0100), Patrick Bellasi wrote:

On 09-Aug 11:50, Juri Lelli wrote:

quoted

On 09/08/18 10:14, Patrick Bellasi wrote:

quoted

On 07-Aug 14:35, Juri Lelli wrote:

quoted

On 06/08/18 17:39, Patrick Bellasi wrote:

[...]

quoted

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1) make CAP_SYS_NICE protected the clamp groups, with an optional boot
   time parameter to relax this check

It seems to me that this might work well with that the intended usage of
the interface that you depict above. SMS only (or any privileged user)
will be in control of how groups are configured, so no problem for
normal users.

Yes, well... apart normal users still getting a -ENOSPC is they are
requesting one of the not pre-configured clamp values. Which is why
the following bits can be helpful.

So IIUC, normal users would still be free of choosing their clamp values
as long as they choose one in the list of pre-allocated ones ? Is that
correct ?

If yes, that would still let normal users make they tasks look bigger no ?
They could just choose the clamp group with the highest min_clamp or
something. Isn't this a problem too ? I mean, if that can be abused easily,
I'm pretty sure people _will_ abuse it ...

Or maybe I misunderstood something ?

Thanks,
Quentin