Re: [PATCH v2 33/35] osnoise: handle quiescent states for PREEMPT_RCU=n, PREEMPTION=y

Daniel Bristot de Oliveira
2024-05-28T13:12:58Z

On 5/28/24 02:35, Ankur Arora wrote:
> To reduce RCU noise for nohz_full configurations, osnoise depends
> on cond_resched() providing quiescent states for PREEMPT_RCU=n
> configurations. And, for PREEMPT_RCU=y configurations does this
> by directly calling rcu_momentary_dyntick_idle().
>
> With PREEMPT_AUTO=y, however, we can have configurations with
> (PREEMPTION=y, PREEMPT_RCU=n), which means neither of the above can
> help.
>
> Handle that by fallback to the explicit quiescent states via
> rcu_momentary_dyntick_idle().
>
> Cc: Paul E. McKenney <paulmck@kernel.org>
> Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Suggested-by: Paul E. McKenney <paulmck@kernel.org>
> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>

Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>

Thanks
-- Daniel