From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] backing-dev: use synchronize_rcu_expedited instead of
 synchronize_rcu
Date: Thu, 02 Feb 2012 22:59:04 +0100
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To: Mikulas Patocka <mpatocka@redhat.com>
Cc: axboe@kernel.dk, "Alasdair G. Kergon" <agk@redhat.com>, dm-devel@redhat.com, linux-kernel@vger.kernel.org, "Paul E. McKenney" <paulmck@us.ibm.com>
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On Thu, 2012-02-02 at 15:43 -0500, Mikulas Patocka wrote:
> Do you have some measurable use case where the user is removing block 
> devices so heavily that this causes a problem? 

Even one can be a problem, we're having people spend lots of time and
effort to reduce machine wide jitter and interference. Adding it with
such disregard isn't cool.

There's no reason a management cpu adding or removing block devices
should perturb the high-freq trading or industrial laser control running
on the other side of the machine.