On Tue, May 2, 2023 at 9:40 PM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> On Tue, May 02, 2023 at 08:01:41AM +0800, zhouzhouyi@xxxxxxxxx wrote:
> > From: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx>
> >
> > In kfree_rcu_test, kfree_scale_shutdown will be detected as hung task
> > if kfree_loops is too big. Replace wait_event with wait_event_idle
> > to avoid false positive.
> >
> > Tested in the PPC VM of Open Source Lab of Oregon State University.
> >
> > Suggested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Signed-off-by: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx>
>
> Good catch, thank you!
>
> However, this commit beat you to it:
>
> ef1ef3d47677 ("rcuscale: Move shutdown from wait_event() to wait_event_idle()")
You are very welcome ;-) Still, this is a very fruitful learning
process for me ;-)
Cheers
Zhouyi
>
> Thanx, Paul
>
> > ---
> > kernel/rcu/rcuscale.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
> > index 91fb5905a008..d99c586939d1 100644
> > --- a/kernel/rcu/rcuscale.c
> > +++ b/kernel/rcu/rcuscale.c
> > @@ -771,7 +771,7 @@ kfree_scale_cleanup(void)
> > static int
> > kfree_scale_shutdown(void *arg)
> > {
> > - wait_event(shutdown_wq,
> > + wait_event_idle(shutdown_wq,
> > atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
> >
> > smp_mb(); /* Wake before output. */
> > --
> > 2.34.1
> >
