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From: Josh Don <joshdon@google.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Joel Fernandes" <joel@joelfernandes.org>,
	"Hyser,Chris" <chris.hyser@oracle.com>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Vincent Guittot" <vincent.guittot@linaro.org>,
	"Valentin Schneider" <valentin.schneider@arm.com>,
	"Mel Gorman" <mgorman@suse.de>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Christian Brauner" <christian.brauner@ubuntu.com>,
	"Zefan Li" <lizefan.x@bytedance.com>
Subject: Re: [PATCH 0/9] sched: Core scheduling interfaces
Date: Mon, 19 Apr 2021 18:17:34 -0700	[thread overview]
Message-ID: <CABk29NtahuW6UERvRdK5v8My_MfPsoESDKXUjGdvaQcHOJEMvg@mail.gmail.com> (raw)
In-Reply-To: <YH1pygTubJHh3R9m@slm.duckdns.org>

On Mon, Apr 19, 2021 at 2:01 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Josh, you being on the other Google team, the one that actually uses the
> cgroup interface AFAIU, can you fight the good fight with TJ on this?

A bit of extra context is in
https://lore.kernel.org/lkml/CABk29NtTScu2HO7V9Di+Fh2gv8zu5xiC5iNRwPFCLhpD+DKP0A@mail.gmail.com.

On the management/auditing side, the cgroup interface gives a clear
indication of which tasks share a cookie. It is a bit less attractive
to add a prctl interface for enumerating this.

Also on the management side, I illustrated in the above message how a
thread would potentially group together other threads. One limitation
of the current prctl interface is that the share_{to, from} always
operates on the current thread. Granted we can work around this as
described, and also potentially extend the prctl interface to operate
on two tasks.

So I agree that the cgroup interface here isn't strictly necessary,
though it seems convenient. I will double-check with internal teams
that would be using the interface to see if there are any other
considerations I'm missing.

On Mon, Apr 19, 2021 at 4:30 AM Tejun Heo <tj@kernel.org> wrote:
>
> My suggestion is going ahead with the per-process interface with cgroup
> extension on mind in case actual use cases arise. Also, when planning cgroup
> integration, putting dynamic migration front and center likely isn't a good
> idea.

tasks would not be frequently moved around; I'd expect security
configuration to remain mostly static. Or maybe I'm misunderstanding
your emphasis here?


If you feel the above is not strong enough (ie. there should be a use
case not feasible with prctl), I'd support that we move forward with
the prctl stuff for now, since the cgroup interface is independant.

Thanks,
Josh

      reply	other threads:[~2021-04-20  1:17 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01 13:10 Peter Zijlstra
2021-04-01 13:10 ` [PATCH 1/9] sched: Allow sched_core_put() from atomic context Peter Zijlstra
2021-04-01 13:10 ` [PATCH 2/9] sched: Implement core-sched assertions Peter Zijlstra
2021-04-01 13:10 ` [PATCH 3/9] sched: Trivial core scheduling cookie management Peter Zijlstra
2021-04-01 20:04   ` Josh Don
2021-04-02  7:13     ` Peter Zijlstra
2021-04-01 13:10 ` [PATCH 4/9] sched: Default core-sched policy Peter Zijlstra
2021-04-21 13:33   ` Peter Zijlstra
2021-04-21 14:31     ` Chris Hyser
2021-04-01 13:10 ` [PATCH 5/9] sched: prctl() core-scheduling interface Peter Zijlstra
2021-04-07 17:00   ` Peter Zijlstra
2021-04-18  3:52     ` Joel Fernandes
2021-04-01 13:10 ` [PATCH 6/9] kselftest: Add test for core sched prctl interface Peter Zijlstra
2021-04-01 13:10 ` [PATCH 7/9] sched: Cgroup core-scheduling interface Peter Zijlstra
2021-04-02  0:34   ` Josh Don
2021-04-01 13:10 ` [PATCH 8/9] rbtree: Remove const from the rb_find_add() comparator Peter Zijlstra
2021-04-01 13:10 ` [PATCH 9/9] sched: prctl() and cgroup interaction Peter Zijlstra
2021-04-03  1:30   ` Josh Don
2021-04-06 15:12     ` Peter Zijlstra
2021-04-04 23:39 ` [PATCH 0/9] sched: Core scheduling interfaces Tejun Heo
2021-04-05 18:46   ` Joel Fernandes
2021-04-06 14:16     ` Tejun Heo
2021-04-18  1:35       ` Joel Fernandes
2021-04-19  9:00         ` Peter Zijlstra
2021-04-21 13:35           ` Peter Zijlstra
2021-04-21 14:45             ` Chris Hyser
2021-04-06 15:32   ` Peter Zijlstra
2021-04-06 16:08     ` Tejun Heo
2021-04-07 18:39       ` Peter Zijlstra
2021-04-07 16:50   ` Michal Koutný
2021-04-07 18:34     ` Peter Zijlstra
2021-04-08 13:25       ` Michal Koutný
2021-04-08 15:02         ` Peter Zijlstra
2021-04-09  0:16           ` Josh Don
2021-04-19 11:30       ` Tejun Heo
2021-04-20  1:17         ` Josh Don [this message]

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