From: Frederic Weisbecker <frederic@kernel.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>,
paulmck@kernel.org, josh@joshtriplett.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
joel@joelfernandes.org, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org, urezki@gmail.com,
boqun.feng@gmail.com
Subject: Re: [PATCH v2] rcu/nocb: Handle concurrent nocb kthreads creation
Date: Mon, 13 Dec 2021 14:14:07 +0100 [thread overview]
Message-ID: <20211213131407.GD782195@lothringen> (raw)
In-Reply-To: <984a63d4c11d04e2ee8a83fc9c61006413bf209e.camel@infradead.org>
On Mon, Dec 13, 2021 at 11:28:45AM +0000, David Woodhouse wrote:
> On Mon, 2021-12-13 at 12:22 +0100, Frederic Weisbecker wrote:
> > I was about to ack the patch but, should we really add code that isn't going to
> > be necessary before a long while?
>
> Yeah, I'm torn on that. In this case it's harmless enough and it makes
> the code reentrant in its own right instead of relying on the fact that
> the cpuhp code won't invoke it multiple times in parallel. So I think
> that's reasonable defensive programming.
>
The thing is that RCU code is already quite complicated. Are we even at least
sure that we'll ever make CPU hotplug allow concurrent CPU onlining/offlining?
This will require much more thoughts and a new hotplug concurrency
infrastructure that we'll need to base RCU on. IMHO it's a bit early to handle
that on hotplug individual callbacks.
But anyway, let's see what Paul thinks about it...
next prev parent reply other threads:[~2021-12-13 13:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-11 17:01 [PATCH v2] rcu/nocb: Handle concurrent nocb kthreads creation Neeraj Upadhyay
2021-12-13 8:18 ` [EXTERNAL] " David Woodhouse
2021-12-13 8:55 ` Neeraj Upadhyay
2021-12-13 11:22 ` Frederic Weisbecker
2021-12-13 11:28 ` David Woodhouse
2021-12-13 13:14 ` Frederic Weisbecker [this message]
2021-12-13 19:00 ` Paul E. McKenney
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