From: Tejun Heo <tj@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
Lai Jiangshan <jiangshanlai@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/2] workqueue: Use normal rcu
Date: Fri, 22 Mar 2019 10:43:34 -0700 [thread overview]
Message-ID: <20190322174334.GC69236@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20190321205935.7ndo5k5zumc77h37@linutronix.de>
Hello,
On Thu, Mar 21, 2019 at 09:59:35PM +0100, Sebastian Andrzej Siewior wrote:
> On 2019-03-13 17:55:47 [+0100], To linux-kernel@vger.kernel.org wrote:
> > From: Thomas Gleixner <tglx@linutronix.de>
> >
> > There is no need for sched_rcu. The undocumented reason why sched_rcu
> > is used is to avoid a few explicit rcu_read_lock()/unlock() pairs by
> > the fact that sched_rcu reader side critical sections are also protected
> > by preempt or irq disabled regions.
> >
> > Replace rcu_read_lock_sched with rcu_read_lock and acquire the RCU lock
> > where it is not yet explicit acquired. Replace local_irq_disable() with
> > rcu_read_lock(). Update asserts.
> >
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > [bigeasy: mangle changelog a little]
> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>
> A gentle ping.
We can switch but it doesn't really say why we'd want to. Can you
please explain why this is better?
Thanks.
--
tejun
next prev parent reply other threads:[~2019-03-22 17:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-13 16:55 [PATCH 0/2] workqueue: use normal RCU and don't depend on the rq lock Sebastian Andrzej Siewior
2019-03-13 16:55 ` [PATCH 1/2] workqueue: Use normal rcu Sebastian Andrzej Siewior
2019-03-21 20:59 ` Sebastian Andrzej Siewior
2019-03-22 17:43 ` Tejun Heo [this message]
2019-03-22 17:59 ` Sebastian Andrzej Siewior
2019-04-05 14:42 ` Sebastian Andrzej Siewior
2019-04-08 15:10 ` Tejun Heo
2019-04-08 19:38 ` Tejun Heo
2019-03-13 16:55 ` [PATCH 2/2] sched: Distangle worker accounting from rq lock Sebastian Andrzej Siewior
2019-04-08 19:45 ` Tejun Heo
2019-04-09 7:33 ` Sebastian Andrzej Siewior
2019-04-09 8:22 ` Peter Zijlstra
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