On Thu, 28 Apr 2022 15:00:11 -0300 Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote: > On Thu, Mar 31, 2022 at 03:52:45PM +0200, Borislav Petkov wrote: > > On Thu, Mar 10, 2022 at 10:22:12AM -0300, Marcelo Tosatti wrote: > > > > ... > > > > > Someone pointed me at this: > > > > https://www.phoronix.com/scan.php?page=news_item&px=Linux-518-Stress-NUMA-Goes-Boom > > > > which says this one causes a performance regression with stress-ng's > > NUMA test... > > Michael, > > This is probably do_migrate_pages that is taking too long due to > synchronize_rcu(). > > Switching to synchronize_rcu_expedited() should probably fix it... > Can you give it a try, please? I guess not. Is anyone else able to demonstrate a stress-ng performance regression due to ff042f4a9b0508? And if so, are they able to try Marcelo's one-liner? > diff --git a/mm/swap.c b/mm/swap.c > index bceff0cb559c..04a8bbf9817a 100644 > --- a/mm/swap.c > +++ b/mm/swap.c > @@ -879,7 +879,7 @@ void lru_cache_disable(void) > * lru_disable_count = 0 will have exited the critical > * section when synchronize_rcu() returns. > */ > - synchronize_rcu(); > + synchronize_rcu_expedited(); > #ifdef CONFIG_SMP > __lru_add_drain_all(true); > #else > >
