From: Tejun Heo <tj@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"linux-kernel@vger.kernel.org >> Linux Kernel Mailing List"
<linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>, Oleg Nesterov <oleg@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: regression 4.4: deadlock in with cgroup percpu_rwsem
Date: Wed, 20 Jan 2016 11:04:35 -0500 [thread overview]
Message-ID: <20160120160435.GD5157@mtj.duckdns.org> (raw)
In-Reply-To: <20160120153007.GC5157@mtj.duckdns.org>
On Wed, Jan 20, 2016 at 10:30:07AM -0500, Tejun Heo wrote:
> > So the current place in free_fair_sched_group() is far too late to be
> > calling remove_entity_load_avg(). But I'm not sure where I should put
> > it, it needs to be in a place where we know the group is going to die
> > but its parent is guaranteed to still exist.
> >
> > Would offline be that place?
>
> Hmmm... css_free would be with the following patch.
I thought a bit more about this and I think the right thing to do here
is making both css_offline and css_free follow the ancestry order.
I'll post a patch to do that soon. offline is called at the head of
destruction when the css is made invisble and draining of existing
refs starts. free at the end of that process. Tree ordering
shouldn't be where the two differ.
Thanks.
--
tejun
next prev parent reply other threads:[~2016-01-20 16:04 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 11:19 regression 4.4: deadlock in with cgroup percpu_rwsem Christian Borntraeger
2016-01-14 13:38 ` Christian Borntraeger
2016-01-14 14:04 ` Nikolay Borisov
2016-01-14 14:08 ` Christian Borntraeger
2016-01-14 14:27 ` Nikolay Borisov
2016-01-14 17:15 ` Christian Borntraeger
2016-01-14 19:56 ` Tejun Heo
2016-01-15 7:30 ` Christian Borntraeger
2016-01-15 15:13 ` Christian Borntraeger
2016-01-18 18:32 ` Peter Zijlstra
2016-01-18 18:48 ` Christian Borntraeger
2016-01-19 9:55 ` Heiko Carstens
2016-01-19 19:36 ` Christian Borntraeger
2016-01-19 19:38 ` Tejun Heo
2016-01-20 7:07 ` Heiko Carstens
2016-01-20 10:15 ` Christian Borntraeger
2016-01-20 10:30 ` Peter Zijlstra
2016-01-20 10:47 ` Peter Zijlstra
2016-01-20 15:30 ` Tejun Heo
2016-01-20 16:04 ` Tejun Heo [this message]
2016-01-20 16:49 ` Peter Zijlstra
2016-01-20 16:56 ` Tejun Heo
2016-01-23 2:03 ` Paul E. McKenney
2016-01-25 8:49 ` Christoph Hellwig
2016-01-25 19:38 ` Tejun Heo
2016-01-26 14:51 ` Christoph Hellwig
2016-01-26 15:28 ` Tejun Heo
2016-01-26 16:41 ` Christoph Hellwig
2016-01-20 10:53 ` Peter Zijlstra
2016-01-21 8:23 ` Christian Borntraeger
2016-01-21 9:27 ` Peter Zijlstra
2016-01-15 16:40 ` Tejun Heo
2016-01-19 17:18 ` [PATCH cgroup/for-4.5-fixes] cpuset: make mm migration asynchronous Tejun Heo
2016-01-22 14:24 ` Christian Borntraeger
2016-01-22 15:22 ` Tejun Heo
2016-01-22 15:45 ` Christian Borntraeger
2016-01-22 15:47 ` Tejun Heo
2016-01-22 15:23 ` Tejun Heo
2016-01-21 20:31 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
2016-01-21 20:32 ` [PATCH 2/2] cgroup: make sure a parent css isn't freed " Tejun Heo
2016-01-22 15:45 ` [PATCH v2 " Tejun Heo
2016-01-21 21:24 ` [PATCH 1/2] cgroup: make sure a parent css isn't offlined " Peter Zijlstra
2016-01-21 21:28 ` Tejun Heo
2016-01-22 8:18 ` Christian Borntraeger
2016-02-29 11:13 ` [tip:sched/core] sched/cgroup: Fix cgroup entity load tracking tear-down tip-bot for Peter Zijlstra
2016-01-22 15:45 ` [PATCH v2 1/2] cgroup: make sure a parent css isn't offlined before its children Tejun Heo
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