Re: [PATCH] rcu: per-cpu rcuc kthread are created only when rcutree.use_softirq=0

From: Sebastian Andrzej Siewior
Date: Mon Jan 03 2022 - 08:17:16 EST


On 2022-01-01 08:44:26 [-0800], Paul E. McKenney wrote:
> On Wed, Dec 29, 2021 at 12:05:10AM +0800, Zqiang wrote:
> > In non-RT kernel, if the RCU_BOOST is enabled, the per-cpu rcuc
> > kthread will be created, however under the rcutree.use_softirq=1,
> > the RCU core processing only in softirq context, the rcuc kthread
> > doesn't do anything, so remove RCU_BOOST interference.
> >
> > Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
>
> Looks sane to me, but adding Sebastian on CC for his thoughts.

Yes, it makes sense. invoke_rcu_core_kthread() is only invoked for
!use_softirq so it makes to create the threads based on this condition.

Acked-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

> Thanx, Paul

Sebastian