On Fri, Mar 12, 2021 at 01:26:47PM +0100, Frederic Weisbecker wrote:
> On Wed, Mar 03, 2021 at 04:26:30PM -0800, paulmck@xxxxxxxxxx wrote:
> > /**
> > + * start_poll_state_synchronize_rcu - Snapshot and start RCU grace period
> > + *
> > + * Returns a cookie that is used by a later call to cond_synchronize_rcu()
> > + * or poll_state_synchronize_rcu() to determine whether or not a full
> > + * grace period has elapsed in the meantime. If the needed grace period
> > + * is not already slated to start, notifies RCU core of the need for that
> > + * grace period.
> > + *
> > + * Interrupts must be enabled for the case where it is necessary to awaken
> > + * the grace-period kthread.
> > + */
> > +unsigned long start_poll_synchronize_rcu(void)
> > +{
> > + unsigned long flags;
> > + unsigned long gp_seq = get_state_synchronize_rcu();
>
> Ah! It's using rcu_seq_snap() and not rcu_seq_current() and therefore it's
> waiting for a safe future grace period, right?
Exactly! ;-)
Thanx, Paul
> If so, please discard my previous email.
>
> Thanks.
