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From: Joel Fernandes <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: rcu@vger.kernel.org, "Paul E. McKenney" <paulmck@linux.ibm.com>,
	frederic@kernel.org
Subject: Re: [PATCH -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI
Date: Thu, 15 Aug 2019 22:57:56 -0400
Message-ID: <20190816025756.GA242309@google.com> (raw)
In-Reply-To: <20190816025311.241257-2-joel@joelfernandes.org>

On Thu, Aug 15, 2019 at 10:53:10PM -0400, Joel Fernandes (Google) wrote:
> Sometimes I see rcu_urgent_qs is not set. This could be when the last
> IPI was a long time ago, however, the grace period just started. Set
> rcu_urgent_qs so the tick can indeed be stopped.
Here I meant:
                                   not be stopped.

I will resend the patch as v2.
thanks,

 - Joel


> 
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> ---
>  kernel/rcu/tree.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 322b1b57967c..856d3c9f1955 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -1091,6 +1091,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
>  	if (tick_nohz_full_cpu(rdp->cpu) &&
>  		   time_after(jiffies,
>  			      READ_ONCE(rdp->last_fqs_resched) + jtsq * 3)) {
> +		WRITE_ONCE(*ruqp, true);
>  		resched_cpu(rdp->cpu);
>  		WRITE_ONCE(rdp->last_fqs_resched, jiffies);
>  	}
> -- 
> 2.23.0.rc1.153.gdeed80330f-goog
> 

  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16  2:53 [PATCH -rcu dev 1/3] rcu/tree: tick_dep_set/clear_cpu should accept bits instead of masks Joel Fernandes (Google)
2019-08-16  2:53 ` [PATCH -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI Joel Fernandes (Google)
2019-08-16  2:57   ` Joel Fernandes [this message]
2019-08-16  2:53 ` [PATCH -rcu dev 3/3] RFC: rcu/tree: Read dynticks_nmi_nesting in advance Joel Fernandes (Google)
2019-08-16 16:24   ` Joel Fernandes
2019-08-16 16:52     ` Paul E. McKenney
2019-08-16 17:07       ` Joel Fernandes
2019-08-16 17:30         ` Paul E. McKenney
2019-08-19 12:59       ` Frederic Weisbecker
2019-08-19 14:22         ` Joel Fernandes
2019-08-19 14:41           ` Paul E. McKenney
2019-08-19 15:46             ` Joel Fernandes
2019-08-19 16:17               ` Paul E. McKenney
2019-08-19 14:40         ` Paul E. McKenney
2019-08-16  2:59 ` [PATCH v2 -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI Joel Fernandes (Google)
2019-08-16 17:04   ` Paul E. McKenney
2019-08-16 17:25 ` [PATCH -rcu dev 1/3] rcu/tree: tick_dep_set/clear_cpu should accept bits instead of masks Paul E. McKenney
2019-08-16 17:35   ` Joel Fernandes
2019-08-19 12:38 ` Frederic Weisbecker
2019-08-19 14:46   ` Paul E. McKenney
2019-08-19 16:32     ` Frederic Weisbecker
2019-08-19 16:44       ` Paul E. McKenney
2019-08-20 12:08         ` Frederic Weisbecker
2019-08-20 14:44           ` Paul E. McKenney

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