From: Joel Fernandes <joel@joelfernandes.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
rcu <rcu@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 2/2] rcu/tree: Clarify comments about FQS loop reporting quiescent states
Date: Thu, 30 Jul 2020 21:21:52 -0400 [thread overview]
Message-ID: <20200731012152.GC2336096@google.com> (raw)
In-Reply-To: <20200730163520.GA9247@paulmck-ThinkPad-P72>
On Thu, Jul 30, 2020 at 09:35:20AM -0700, Paul E. McKenney wrote:
> On Wed, Jul 29, 2020 at 11:25:19PM -0400, Joel Fernandes wrote:
> > On Wed, Jul 29, 2020 at 11:02 PM Joel Fernandes (Google)
> > <joel@joelfernandes.org> wrote:
> > >
> > > At least since v4.19, the FQS loop no longer reports quiescent states
> >
> > I meant here, "FQS loop no longer reports quiescent states for offline CPUs."
> >
> > Sorry,
>
> You did have me going there for a bit. ;-)
>
> No period (".") at the end though, unless you fix up the following
> to start a new sentence.
Ok.
> > > unless it is a dire situation where an offlined CPU failed to report
> > > a quiescent state. Let us clarify the comment in rcu_gp_init() inorder
> > > to keep the comment current.
>
> How about the following for this last sentence?
>
> "This commit therefore fixes the comment in rcu_gp_init() to match
> the current code."
As per:
https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html
It says:
Describe your changes in imperative mood, e.g. “make xyzzy do frotz” instead
of “[This patch] makes xyzzy do frotz” or “[I] changed xyzzy to do frotz”, as
if you are giving orders to the codebase to change its behaviour.
May be I should make it "Fix the comment in rcu_gp_init() to match the
current code"?
> > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > > ---
> > > kernel/rcu/tree.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > > index 1e51962b565b..929568ff5989 100644
> > > --- a/kernel/rcu/tree.c
> > > +++ b/kernel/rcu/tree.c
> > > @@ -1701,8 +1701,8 @@ static bool rcu_gp_init(void)
> > >
> > > /*
> > > * Apply per-leaf buffered online and offline operations to the
> > > - * rcu_node tree. Note that this new grace period need not wait
> > > - * for subsequent online CPUs, and that quiescent-state forcing
> > > + * rcu_node tree. Note that this new grace period need not wait for
> > > + * subsequent online CPUs, and that RCU hooks in CPU offlining path
> > > * will handle subsequent offline CPUs.
>
> How about something like this?
>
> ... Note that this new grace period ned not wait for subsequent
> online CPUs, and that RCU hooks in the CPU offlining path, when
> combined with checks in this function, will handle CPUs that
> are currently going offline and that go offline later.
Sounds good to me. I think s/and that go/or that go/ though.
I will make these changes and send v3, let me know though if you object.
thanks,
- Joel
> Thanx, Paul
>
> > > */
> > > rcu_state.gp_state = RCU_GP_ONOFF;
> > > --
> > > 2.28.0.rc0.142.g3c755180ce-goog
> > >
next prev parent reply other threads:[~2020-07-31 1:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 3:02 [PATCH 1/2] rcu/tree: Add a warning if CPU being onlined did not report QS already Joel Fernandes (Google)
2020-07-30 3:02 ` [PATCH 2/2] rcu/tree: Clarify comments about FQS loop reporting quiescent states Joel Fernandes (Google)
2020-07-30 3:25 ` Joel Fernandes
2020-07-30 16:35 ` Paul E. McKenney
2020-07-31 1:21 ` Joel Fernandes [this message]
2020-07-31 1:34 ` Paul E. McKenney
2020-07-30 16:21 ` [PATCH 1/2] rcu/tree: Add a warning if CPU being onlined did not report QS already Paul E. McKenney
2020-07-31 1:08 ` Joel Fernandes
2020-07-31 1:42 ` Joel Fernandes
2020-07-31 3:48 ` Paul E. McKenney
2020-08-07 15:37 ` Joel Fernandes
2020-08-07 15:45 ` Joel Fernandes
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