On Sat, Mar 18, 2023 at 9:20 AM Zqiang <qiang1.zhang@xxxxxxxxx> wrote:
>
> Currently, the trace string information before and after rcu_wait()
> and schedule_timeout_idle() are reversed, this commit therefore
> switches these strings in order to correctly trace.
I suggest provide more details of how this affects your tracing. One
commit to draw inspiration from could be:
f7f7bac9cb1c ("rcu: Have the RCU tracepoints use the tracepoint_string
infrastructure")
Which also modifies the same code.
>
> Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
> ---
> kernel/rcu/tree_plugin.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index 7b0fe741a088..7b622b5196a8 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -1114,10 +1114,10 @@ static int rcu_boost_kthread(void *arg)
> trace_rcu_utilization(TPS("Start boost kthread@init"));
> for (;;) {
> WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_WAITING);
> - trace_rcu_utilization(TPS("End boost kthread@rcu_wait"));
> + trace_rcu_utilization(TPS("Start boost kthread@rcu_wait"));
Doesn't that look weird because now you will have 2 "Start boost
kthread@" messages in succession (one of them coming before the for
loop) ?
> rcu_wait(READ_ONCE(rnp->boost_tasks) ||
> READ_ONCE(rnp->exp_tasks));
> - trace_rcu_utilization(TPS("Start boost kthread@rcu_wait"));
> + trace_rcu_utilization(TPS("End boost kthread@rcu_wait"));
> WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_RUNNING);
> more2boost = rcu_boost(rnp);
Also, it is weird here that you are calling rcu_boost() right after
printing "End boost kthread".
thanks,
- Joel
> if (more2boost)
> @@ -1126,9 +1126,9 @@ static int rcu_boost_kthread(void *arg)
> spincnt = 0;
> if (spincnt > 10) {
> WRITE_ONCE(rnp->boost_kthread_status, RCU_KTHREAD_YIELDING);
> - trace_rcu_utilization(TPS("End boost kthread@rcu_yield"));
> - schedule_timeout_idle(2);
> trace_rcu_utilization(TPS("Start boost kthread@rcu_yield"));
> + schedule_timeout_idle(2);
> + trace_rcu_utilization(TPS("End boost kthread@rcu_yield"));
> spincnt = 0;
> }
> }
> --
> 2.25.1
>
