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Date:   Thu, 13 May 2021 07:22:16 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Ingo Molnar <mingo@kernel.org>
Cc:     Paul Gortmaker <paul.gortmaker@windriver.com>,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH] sched/isolation: reconcile rcu_nocbs= and nohz_full=
Message-ID: <20210513142216.GZ975577@paulmck-ThinkPad-P17-Gen-1>
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 <YJ0X6MciAc36TMJc@gmail.com>
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On Thu, May 13, 2021 at 02:13:28PM +0200, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@kernel.org> wrote:
> 
> > On Mon, Apr 19, 2021 at 12:26:59AM -0400, Paul Gortmaker wrote:
> > > We have a mismatch between RCU and isolation -- in relation to what is
> > > considered the maximum valid CPU number.
> > > 
> > > This matters because nohz_full= and rcu_nocbs= are joined at the hip; in
> > > fact the former will enforce the latter.  So we don't want a CPU mask to
> > > be valid for one and denied for the other.
> > > 
> > > The difference 1st appeared as of v4.15; further details are below.
> > 
> > I pulled this into -rcu for testing and further review.
> > 
> > If it should instead go through some other tree:
> > 
> > Acked-by: Paul E. McKenney <paulmck@kernel.org>
> 
> Thanks - added this fix to tip:sched/core.

Very good, I will drop it from -rcu later today, Pacific Time.

							Thanx, Paul