From: Tejun Heo <tj@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Ingo Molnar <mingo@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: Tue, 5 May 2015 15:06:03 -0400 [thread overview]
Message-ID: <20150505190603.GZ1971@htj.duckdns.org> (raw)
In-Reply-To: <20150505190057.GR23123@twins.programming.kicks-ass.net>
Hello, Peter.
On Tue, May 05, 2015 at 09:00:57PM +0200, Peter Zijlstra wrote:
> On Tue, May 05, 2015 at 12:31:12PM -0400, Tejun Heo wrote:
> > What I don't want to happen is controllers failing migrations
> > willy-nilly for random reasons leaving users baffled, which we've
> > actually been doing unfortunately. Maybe we need to deal with this
> > fixed resource arbitration as a separate class and allow them to fail
> > migration w/ -EBUSY.
>
> Ah, _that_ was the problem.
>
> Which is something created by this co-mounting of controllers.
Yeah, partly, but also that it's an extra failure mode which isn't
necessary for most controllers.
> You could of course store the ss-id of the failing operation in
> task_struct and have a file reporting the name of the ss-id.
>
> That way, there is a simple way to find out which controller failed the
> migrate.
Given that the resources which can fail are very limited, I don't
think we need that right now as long as we limit and document the
possible failure cases clearly. Hopefully, this won't devolve into
collection of arbitrary failures.
Thanks.
--
tejun
next prev parent reply other threads:[~2015-05-05 19:06 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
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 [this message]
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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