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

Paul E. McKenney
2020-06-19T17:40:04Z

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, 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.

Thanx, Paul