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Date: Tue, 28 May 2024 15:12:52 +0200
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Subject: Re: [PATCH v2 33/35] osnoise: handle quiescent states for
 PREEMPT_RCU=n, PREEMPTION=y
To: Ankur Arora <ankur.a.arora@oracle.com>, linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de, peterz@infradead.org, torvalds@linux-foundation.org,
 paulmck@kernel.org, rostedt@goodmis.org, mark.rutland@arm.com,
 juri.lelli@redhat.com, joel@joelfernandes.org, raghavendra.kt@amd.com,
 sshegde@linux.ibm.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com
References: <20240528003521.979836-1-ankur.a.arora@oracle.com>
 <20240528003521.979836-34-ankur.a.arora@oracle.com>
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From: Daniel Bristot de Oliveira <bristot@kernel.org>
In-Reply-To: <20240528003521.979836-34-ankur.a.arora@oracle.com>
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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