Re: [PATCH 6/7] osnoise: handle quiescent states for PREEMPT_RCU=n, PREEMPTION=y

[Sebastian Andrzej Siewior]

On 2024-10-09 09:54:10 [-0700], 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_eqs().
> 
> With PREEMPT_LAZY=y, however, we can have configurations with
> (PREEMPTION=y, PREEMPT_RCU=n), which means neither of the above
> can help.

PREEMPTION=y, PREEMPT_RCU=n should not be possible.

> Handle that by fallback to the explicit quiescent states via
> rcu_momentary_eqs().

Sebastian