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Date:   Sat, 14 Jan 2023 11:55:17 -0500
From:   Alan Stern <stern@rowland.harvard.edu>
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     Jonas Oberhauser <jonas.oberhauser@huawei.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "parri.andrea" <parri.andrea@gmail.com>, will <will@kernel.org>,
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        Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Internal vs. external barriers (was: Re: Interesting LKMM litmus
 test)
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On Fri, Jan 13, 2023 at 12:07:06PM -0800, Paul E. McKenney wrote:
> What Alan said!  You could even have distinct partially overlapping
> grace periods, as the Linux kernel actually does have courtesy of normal
> grace periods via synchronize_rcu() and expedited grace periods via
> synchronize_rcu_expedited().

Or just two different CPUs making overlapping calls to
synchronize_rcu().

Alan