linux-kernel - Re: [PATCH v3 01/14] sched/core: uclamp: extend sched

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Message-ID: <20180807123550.GA3062@localhost.localdomain>
Date:   Tue, 7 Aug 2018 14:35:50 +0200
From:   Juri Lelli <juri.lelli@...hat.com>
To:     Patrick Bellasi <patrick.bellasi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tejun Heo <tj@...nel.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Paul Turner <pjt@...gle.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Morten Rasmussen <morten.rasmussen@....com>,
        Todd Kjos <tkjos@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Steve Muckle <smuckle@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>
Subject: Re: [PATCH v3 01/14] sched/core: uclamp: extend sched_setattr to
 support utilization clamping

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

[...]

> @@ -4218,6 +4245,13 @@ static int __sched_setscheduler(struct task_struct *p,
>  			return retval;
>  	}
>  
> +	/* Configure utilization clamps for the task */
> +	if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) {
> +		retval = __setscheduler_uclamp(p, attr);
> +		if (retval)
> +			return retval;
> +	}
> +

IIUC, this is available to root and non-root users. In the latter case,
how do we cope with the fact that some user might occupy all the
available clamping groups configured for the system?

Best,

- Juri