On Wed, Nov 23, 2022 at 04:59:29PM +0100, Frederic Weisbecker wrote:
> On Mon, Nov 21, 2022 at 05:04:10PM -0800, Paul E. McKenney wrote:
> > From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>
> >
> > This consolidates the code a bit and makes it cleaner. Functionally it
> > is the same.
> >
> > Reported-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > ---
> > kernel/rcu/tree_nocb.h | 17 +++++++++--------
> > 1 file changed, 9 insertions(+), 8 deletions(-)
> >
> > diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> > index d6e4c076b0515..213daf81c057f 100644
> > --- a/kernel/rcu/tree_nocb.h
> > +++ b/kernel/rcu/tree_nocb.h
> > @@ -327,10 +327,11 @@ static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype,
> > *
> > * Note that this function always returns true if rhp is NULL.
> > */
> > -static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
> > +static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp_in,
> > unsigned long j, bool lazy)
> > {
> > struct rcu_cblist rcl;
> > + struct rcu_head *rhp = rhp_in;
>
> Why that intermediate rhp_in?
To avoid modifying the formal parameter, should the original value prove
useful, for example, for tracing or debugging.
> > WARN_ON_ONCE(!rcu_rdp_is_offloaded(rdp));
> > rcu_lockdep_assert_cblist_protected(rdp);
> > @@ -345,16 +346,16 @@ static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
> >
> > /*
> > * If the new CB requested was a lazy one, queue it onto the main
> > - * ->cblist so we can take advantage of a sooner grade period.
> > + * ->cblist so that we can take advantage of the grace-period that will
> > + * happen regardless. But queue it onto the bypass list first so that
> > + * the lazy CB is ordered with the existing CBs in the bypass list.
> > */
> > if (lazy && rhp) {
> > - rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, NULL);
> > - rcu_cblist_enqueue(&rcl, rhp);
> > - WRITE_ONCE(rdp->lazy_len, 0);
> > - } else {
> > - rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, rhp);
> > - WRITE_ONCE(rdp->lazy_len, 0);
> > + rcu_cblist_enqueue(&rdp->nocb_bypass, rhp);
> > + rhp = NULL;
> > }
> > + rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, rhp);
> > + WRITE_ONCE(rdp->lazy_len, 0);
>
> Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Thank you! I will apply this on my next rebase.
Thanx, Paul
> Thanks.
>
> >
> > rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rcl);
> > WRITE_ONCE(rdp->nocb_bypass_first, j);
> > --
> > 2.31.1.189.g2e36527f23
> >
