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Date:   Wed, 23 May 2018 12:10:44 -0700
From:   "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To:     Tejun Heo <tj@kernel.org>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org,
        Jan Kara <jack@suse.com>,
        Andrew Morton <akpm@linux-foundation.org>, kernel-team@fb.com
Subject: Re: [PATCH] bdi: Move cgroup bdi_writeback to a dedicated low
 concurrency workqueue
Reply-To: paulmck@linux.vnet.ibm.com
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On Wed, May 23, 2018 at 11:51:43AM -0700, Tejun Heo wrote:
> On Wed, May 23, 2018 at 11:39:07AM -0700, Paul E. McKenney wrote:
> > > While this resolves the problem at hand, it might be a good idea to
> > > isolate rcu_exp_work to its own workqueue too as it can be used from
> > > various paths and is prone to this sort of indirect A-A deadlocks.
> > 
> > Commit ad7c946b35ad4 ("rcu: Create RCU-specific workqueues with rescuers")
> > was accepted into mainline this past merge window.  Does that do what
> > you want, or are you looking for something else?
> 
> Ah, that does it.  Sorry, was looking at an older kernel.

No worries -- after all, I must confess that I was a bit slow in getting
to this.

							Thanx, Paul