Re: [PATCH v8 06/16] sched/core: uclamp: Extend sched_setattr() to support utilization clamping

From: Patrick Bellasi <patrick.bellasi@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-pm@vger.kernel.org, linux-api@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Paul Turner <pjt@google.com>,
	Quentin Perret <quentin.perret@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Juri Lelli <juri.lelli@redhat.com>, Todd Kjos <tkjos@google.com>,
	Joel Fernandes <joelaf@google.com>,
	Steve Muckle <smuckle@google.com>
Subject: Re: [PATCH v8 06/16] sched/core: uclamp: Extend sched_setattr() to support utilization clamping
Date: Thu, 9 May 2019 10:24:42 +0100	[thread overview]
Message-ID: <20190509092442.3avaelrsxd2l5dfl@e110439-lin> (raw)
In-Reply-To: <20190508194439.GF32547@worktop.programming.kicks-ass.net>

On 08-May 21:44, Peter Zijlstra wrote:
> On Tue, May 07, 2019 at 12:13:47PM +0100, Patrick Bellasi wrote:
> > On 17-Apr 15:26, Suren Baghdasaryan wrote:
> > > On Tue, Apr 2, 2019 at 3:42 AM Patrick Bellasi <patrick.bellasi@arm.com> wrote:
> 
> > > > @@ -1056,6 +1100,13 @@ static void __init init_uclamp(void)
> > > >  #else /* CONFIG_UCLAMP_TASK */
> > > >  static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) { }
> > > >  static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) { }
> > > > +static inline int uclamp_validate(struct task_struct *p,
> > > > +                                 const struct sched_attr *attr)
> > > > +{
> > > > +       return -ENODEV;
> > > 
> > > ENOSYS might be more appropriate?
> > 
> > Yep, agree, thanks!
> 
> No, -ENOSYS (see the comment) is special in that it indicates the whole
> system call is unavailable; that is most certainly not the case!

Yep, noted. Thanks.

-- 
#include <best/regards.h>

Patrick Bellasi