From: Tejun Heo <tj@kernel.org>
To: Prateek Sood <prsood@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
avagin@gmail.com, mingo@kernel.org, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org, sramana@codeaurora.org
Subject: Re: [PATCH] cgroup/cpuset: fix circular locking dependency
Date: Wed, 13 Dec 2017 08:06:17 -0800 [thread overview]
Message-ID: <20171213160617.GQ3919388@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <cca9aea2-9bff-decf-d669-8f90b928ea18@codeaurora.org>
Hello, Prateek.
On Wed, Dec 13, 2017 at 01:20:46PM +0530, Prateek Sood wrote:
> This change makes the usage of cpuset_hotplug_workfn() from cpu
> hotplug path synchronous. For memory hotplug it still remains
> asynchronous.
Ah, right.
> Memory migration happening from cpuset_hotplug_workfn() is
> already asynchronous by queuing cpuset_migrate_mm_workfn() in
> cpuset_migrate_mm_wq.
>
> cpuset_hotplug_workfn()
> cpuset_hotplug_workfn(()
> cpuset_migrate_mm()
> queue_work(cpuset_migrate_mm_wq)
>
> It seems that memory migration latency might not have
> impact with this change.
>
> Please let me know if you meant something else by cpuset
> migration taking time when memory migration is turned on.
No, I didn't. I was just confused about which part became
synchronous. So, I don't have anything against making the cpu part
synchronous, but let's not do that as the fix to the deadlocks cuz,
while we can avoid them by changing cpuset, I don't think cpuset is
the root cause for them. If there are benefits to making cpuset cpu
migration synchronous, let's do that for those benefits.
Thanks.
--
tejun
next prev parent reply other threads:[~2017-12-13 16:06 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CANaxB-zT+sz=z1FFk5npnwMySdfKCBZDkM+P+=JXDkCXbh=rCw@mail.gmail.com>
2017-11-28 11:35 ` [PATCH] cgroup/cpuset: fix circular locking dependency Prateek Sood
2017-12-04 5:14 ` Prateek Sood
2017-12-04 20:22 ` Tejun Heo
2017-12-04 22:58 ` Tejun Heo
2017-12-04 23:01 ` Peter Zijlstra
2017-12-08 9:40 ` Prateek Sood
2017-12-08 11:45 ` Prateek Sood
2017-12-11 15:32 ` Tejun Heo
2017-12-13 14:28 ` Prateek Sood
2017-12-13 15:40 ` Tejun Heo
2017-12-15 8:54 ` Prateek Sood
2017-12-15 13:22 ` Tejun Heo
2017-12-15 19:06 ` Prateek Sood
2017-12-19 7:26 ` [PATCH] cgroup: Fix deadlock in cpu hotplug path Prateek Sood
2017-12-19 13:39 ` Tejun Heo
2017-12-11 15:20 ` [PATCH] cgroup/cpuset: fix circular locking dependency Tejun Heo
2017-12-13 7:50 ` Prateek Sood
2017-12-13 16:06 ` Tejun Heo [this message]
2017-12-15 19:04 ` Prateek Sood
2017-12-28 20:37 ` Prateek Sood
2018-01-02 16:16 ` Tejun Heo
2018-01-02 17:44 ` Paul E. McKenney
2018-01-02 18:01 ` Paul E. McKenney
2018-01-08 12:28 ` Tejun Heo
2018-01-08 13:47 ` [PATCH wq/for-4.16 1/2] workqueue: separate out init_rescuer() Tejun Heo
2018-01-08 13:47 ` [PATCH wq/for-4.16 2/2] workqueue: allow WQ_MEM_RECLAIM on early init workqueues Tejun Heo
2018-01-08 22:52 ` [PATCH] cgroup/cpuset: fix circular locking dependency Paul E. McKenney
2018-01-09 0:31 ` Paul E. McKenney
2018-01-09 3:42 ` Tejun Heo
2018-01-09 4:20 ` Paul E. McKenney
2018-01-09 13:44 ` Tejun Heo
2018-01-09 15:21 ` Paul E. McKenney
2018-01-09 15:37 ` Tejun Heo
2018-01-09 16:00 ` Paul E. McKenney
2018-01-10 20:08 ` Paul E. McKenney
2018-01-10 21:41 ` Tejun Heo
2018-01-10 22:10 ` Paul E. McKenney
2018-01-15 12:02 ` Prateek Sood
2018-01-16 16:27 ` Tejun Heo
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