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Date:   Wed, 7 Mar 2018 17:23:17 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc:     Lai Jiangshan <jiangshanlai+lkml@gmail.com>,
        Tejun Heo <tj@kernel.org>, torvalds@linux-foundation.org,
        jannh@google.com, bcrl@kvack.org, viro@zeniv.linux.org.uk,
        kent.overstreet@gmail.com, security@kernel.org,
        LKML <linux-kernel@vger.kernel.org>, kernel-team@fb.com
Subject: Re: [PATCH 7/7] RCU, workqueue: Implement rcu_work
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On Wed, Mar 07, 2018 at 06:54:08AM -0800, Paul E. McKenney wrote:
> One downside of allowing RCU callback functions to sleep is that
> one poorly written callback can block a bunch of other ones.

Not to mention that we really want the RCU callbacks to be simple and
short. Needing fancy things in the callback really should be the
exception not the rule.