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Date:   Fri, 8 Apr 2022 17:27:14 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        Kalesh Singh <kaleshsingh@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        kernel-team <kernel-team@android.com>, Tejun Heo <tj@kernel.org>,
        Tim Murray <timmurray@google.com>, Wei Wang <wvw@google.com>,
        Kyle Lin <kylelin@google.com>,
        Chunwei Lu <chunweilu@google.com>,
        Lulu Wang <luluw@google.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        rcu <rcu@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] EXP rcu: Move expedited grace period (GP) work to RT
 kthread_worker
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On Fri, 8 Apr 2022 08:58:34 -0700
"Paul E. McKenney" <paulmck@kernel.org> wrote:

> > I do not see why PREEMPT_RT is special here. Why was it singled out?  
> 
> Because I didn't see the point of doing kthread_create_worker() to create
> a pair of kthread_worker structuress that were never going to be used
> in PREEMPT_RT kernels.
> 
> Or are PREEMPT_RT kernels no longer booting with rcupdate.rcu_normal?
> Last I knew, they all did this to avoid IPI latencies from expedited
> grace periods.  Has this changed?

Honestly, I don't know. But I guess I can go and find out ;-)

-- Steve