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From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Zefan Li <lizefan@huawei.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Cgroups <cgroups@vger.kernel.org>
Subject: Re: [PATCH] sched: Relax a restriction in sched_rt_can_attach()
Date: Mon, 04 May 2015 05:13:56 +0200	[thread overview]
Message-ID: <1430709236.3129.42.camel@gmail.com> (raw)
In-Reply-To: <5546C34C.7050202@huawei.com>

On Mon, 2015-05-04 at 08:54 +0800, Zefan Li wrote:
> It's allowed to promote a task from normal to realtime after it has been
> attached to a non-root cgroup, but it will fail if the attaching happens
> after it has become realtime. I don't see how this restriction is useful.

In the CONFIG_RT_GROUP_SCHED case, promotion will fail is there is no
bandwidth allocated.

> We are moving toward unified hierarchy where all the cgroup controllers
> are bound together, so it would make cgroups easier to use if we have less
> restrictions on attaching tasks between cgroups.

Forcing group scheduling overhead on users if they want cpuset or memory
cgroup functionality would be far from wonderful.  Am I interpreting the
implications of this unification/binding properly?

(I hope not, surely the plan is not to utterly _destroy_ cgroup utility)

	-Mike


  reply	other threads:[~2015-05-04  3:14 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-04  0:54 [PATCH] sched: Relax a restriction in sched_rt_can_attach() Zefan Li
2015-05-04  3:13 ` Mike Galbraith [this message]
2015-05-04  4:39   ` Zefan Li
2015-05-04  5:10     ` Mike Galbraith
2015-05-04  5:39       ` Mike Galbraith
2015-05-04  9:11         ` Zefan Li
2015-05-04 12:08           ` Mike Galbraith
2015-05-04 12:37           ` Peter Zijlstra
2015-05-04 14:09             ` Mike Galbraith
2015-05-05  3:46               ` Zefan Li
2015-05-05  6:02                 ` Mike Galbraith
2015-05-05  3:54             ` Zefan Li
2015-05-05 14:10               ` Peter Zijlstra
2015-05-05 14:18                 ` Tejun Heo
2015-05-05 15:19                   ` Peter Zijlstra
2015-05-05 16:31                     ` Tejun Heo
2015-05-05 19:00                       ` Peter Zijlstra
2015-05-05 19:06                         ` Tejun Heo
2015-05-06  8:49                           ` Peter Zijlstra
2015-05-05 14:41             ` Tejun Heo
2015-05-05 15:11               ` Peter Zijlstra
2015-05-05 16:13                 ` Tejun Heo
2015-05-05 16:50                   ` Peter Zijlstra
2015-05-05 18:29                     ` Thomas Gleixner
2015-05-05 19:00                       ` Tejun Heo
2015-05-06  9:12                         ` Thomas Gleixner
2015-05-05 18:31                     ` Tejun Heo
2015-05-05 14:09         ` Tejun Heo

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