On Thu, Jul 30, 2020 at 09:21:52PM -0400, Joel Fernandes wrote:
> 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@xxxxxxxxxxxxxxxxx> 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"?
What submitting-patches.rst is objecting to is starting the commit
log with "This patch...". I am suggesting something quite different,
namely providing a clear indication of the transition from problem
statement to solution.
> > > > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> > > > ---
> > > > 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.
Good point! Another approach would be s/and that/and those that/
but yours works.
> I will make these changes and send v3, let me know though if you object.
Sounds good!
Thanx, Paul
> thanks,
>
> - Joel
>
>
> > Thanx, Paul
> >
> > > > */
> > > > rcu_state.gp_state = RCU_GP_ONOFF;
> > > > --
> > > > 2.28.0.rc0.142.g3c755180ce-goog
> > > >
