Re: [PATCH 3/3] rcu/trace: Add name of the source for gp_seq to prevent confusion

Joel Fernandes
2020-06-20T05:36:24Z

On Fri, Jun 19, 2020 at 10:40:01AM -0700, Paul E. McKenney wrote:
> On Thu, Jun 18, 2020 at 10:07:18PM -0400, Joel Fernandes wrote:
> > On Thu, Jun 18, 2020 at 09:36:41PM -0400, Joel Fernandes (Google) wrote:
> > [...]
> > > @@ -2019,7 +2019,7 @@ static int __noreturn rcu_gp_kthread(void *unused)
> > > cond_resched_tasks_rcu_qs();
> > > WRITE_ONCE(rcu_state.gp_activity, jiffies);
> > > WARN_ON(signal_pending(current));
> > > - trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
> > > + trace_rcu_grace_period(rcu_state.name, TPS("rsp"), rcu_state.gp_seq,
> > > TPS("reqwaitsig"));
> > > }
> > >
> > > @@ -2263,7 +2263,7 @@ int rcutree_dying_cpu(unsigned int cpu)
> > > return 0;
> > >
> > > blkd = !!(rnp->qsmask & rdp->grpmask);
> > > - trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
> > > + trace_rcu_grace_period(rcu_state.name, TPS("rsp"), READ_ONCE(rnp->gp_seq),
> >
> > This should be: TPS("rnp") :-(
> >
> > Happy to fix it up and resend if you'd like. Thanks!
>
> I queued and pushed 1/2 and 2/2.

Thanks!

> but again, I am still not at all
> convinced by 3/3. If you want to make RCU trace output human
> readable, post-processing will be needed.

Or I could post-process the code before building it since the pattern seems
easy to parse ;-)

- Joel