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Date:   Sat, 22 Sep 2018 17:36:43 -0700
From:   "Paul E. McKenney" <paulmck@linux.ibm.com>
To:     "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc:     linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
        Josh Triplett <josh@joshtriplett.org>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-doc@vger.kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH RFC 2/3] rcu: tree: Fix comment about gp_seq_needed
Reply-To: paulmck@linux.ibm.com
References: <20180922234127.94970-1-joel@joelfernandes.org>
 <20180922234127.94970-2-joel@joelfernandes.org>
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On Sat, Sep 22, 2018 at 07:41:26PM -0400, Joel Fernandes (Google) wrote:
> rcu_state does not have a gp_seq_needed field. This comment therefore is
> confusing or incorrect. Fix it.
> 
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>

Good eyes, queued and pushed with edits, thank you!

(Yes, I do have a great deal of experience with punched cards.  Why do
you ask?)

							Thanx, Paul

> ---
>  kernel/rcu/tree.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> index 57a937ac51c2..fd2ba3f9eee9 100644
> --- a/kernel/rcu/tree.h
> +++ b/kernel/rcu/tree.h
> @@ -57,7 +57,7 @@ struct rcu_node {
>  					/*  some rcu_state fields as well as */
>  					/*  following. */
>  	unsigned long gp_seq;	/* Track rsp->rcu_gp_seq. */
> -	unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed. */
> +	unsigned long gp_seq_needed; /* Track the furthest future gp request seen */
>  	unsigned long completedqs; /* All QSes done for this node. */
>  	unsigned long qsmask;	/* CPUs or groups that need to switch in */
>  				/*  order for current grace period to proceed.*/
> @@ -163,7 +163,7 @@ union rcu_noqs {
>  struct rcu_data {
>  	/* 1) quiescent-state and grace-period handling : */
>  	unsigned long	gp_seq;		/* Track rsp->rcu_gp_seq counter. */
> -	unsigned long	gp_seq_needed;	/* Track rsp->rcu_gp_seq_needed ctr. */
> +	unsigned long	gp_seq_needed;	/* Track the furthest future gp request seen */
>  	union rcu_noqs	cpu_no_qs;	/* No QSes yet for this CPU. */
>  	bool		core_needs_qs;	/* Core waits for quiesc state. */
>  	bool		beenonline;	/* CPU online at least once. */
> -- 
> 2.19.0.444.g18242da7ef-goog
>