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Date:   Thu, 22 Apr 2021 19:29:29 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Don Hiatt <dhiatt@digitalocean.com>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        "Hyser,Chris" <chris.hyser@oracle.com>,
        Josh Don <joshdon@google.com>, mingo@kernel.org,
        vincent.guittot@linaro.org, valentin.schneider@arm.com,
        mgorman@suse.de, linux-kernel@vger.kernel.org, tglx@linutronix.de
Subject: Re: [PATCH 00/19] sched: Core Scheduling
Message-ID: <YIGyeVBS0qnes/RP@hirez.programming.kicks-ass.net>
References: <20210422120459.447350175@infradead.org>
 <CAOY2WoyMyqjGSWf1JD7tmsBHwKgjpxL7FB3sYjFSge8fBMZv6g@mail.gmail.com>
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On Thu, Apr 22, 2021 at 09:43:59AM -0700, Don Hiatt wrote:
> On Thu, Apr 22, 2021 at 5:37 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > Hai,
> >
> > This is an agressive fold of all the core-scheduling work so far. I've stripped
> > a whole bunch of tags along the way (hopefully not too many, please yell if you
> > feel I made a mistake), including tested-by. Please retest.
> >
> > Changes since the last partial post is dropping all the cgroup stuff and
> > PR_SCHED_CORE_CLEAR as well as that exec() behaviour in order to later resolve
> > the cgroup issue.
> >
> Hi Peter,
> 
> Is there a reason that PR_SCHED_CORE_CLEAR got removed? It's handy to
> be able to clear cookies.

I agree, but if we're forced to do cgroup with cookie inherit, when
CLEAR allows a trivial escape.

Until that whole cgroup thing is sorted, it is easiest to not have
CLEAR, lest we have to change/augment CLEAR semantics in unfortunate
ways, which is always harder once an API is out there.

Also, see the entire previous discussion here:

  https://lore.kernel.org/lkml/20210401131012.395311786@infradead.org/