From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>,
josh@joshtriplett.org, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org, peterz@infradead.org,
tglx@linutronix.de, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
joel@joelfernandes.org, rcu@vger.kernel.org
Subject: Re: [PATCH] rcu: Make rcu_normal_after_boot writable on RT
Date: Fri, 6 Aug 2021 10:04:55 +0200 [thread overview]
Message-ID: <20210806080455.wkhlebgt7howjcrk@linutronix.de> (raw)
In-Reply-To: <20210805160337.GI4397@paulmck-ThinkPad-P17-Gen-1>
On 2021-08-05 09:03:37 [-0700], Paul E. McKenney wrote:
> Makes sense to me!
>
> But would another of the -rt people be willing to give an Acked-by?
> For example, maybe they would prefer this kernel boot parameter to be
> exposed only if (!PREEMPT_RT || NO_HZ_FULL). Or are there !NO_HZ_FULL
> situations where rcu_normal_after_boot makes sense?
Julia crafted that "rcu_normal_after_boot = 1" for RT after we had more
and more synchronize_rcu_expedited() users popping up. I would like to
keep that part (default value) since it good to have for most users.
I don't mind removing CONFIG_PREEMPT_RT part here if there are legitimate
use cases for using "rcu_normal_after_boot = 0".
Paul suggested initially to restrict that option for PREEMPT_RT and I
would follow here Paul's guidance to either remove it or restrict it to
NO_HZ_FULL in RT's case (as suggested).
> Thanx, Paul
Sebastian
next prev parent reply other threads:[~2021-08-06 8:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 8:01 [PATCH] rcu: Make rcu_normal_after_boot writable on RT Juri Lelli
2021-08-05 16:03 ` Paul E. McKenney
2021-08-05 21:08 ` Paul E. McKenney
2021-08-06 7:41 ` Juri Lelli
2021-08-06 8:04 ` Sebastian Andrzej Siewior [this message]
2021-08-06 17:44 ` Paul E. McKenney
2021-08-09 8:37 ` Juri Lelli
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