On Thu, Dec 01, 2016 at 09:10:01PM +0300, Boris Zhmurov wrote: > Michal Hocko 30/11/16 21:25: > > >>> Do I get it right that s@cond_resched_rcu_qs@cond_resched@ didn't help? > >> > >> I didn't try that. I've tried 4 patches from Paul's linux-rcu tree. > >> I can try another portion of patches, no problem :) > > > > Replacing cond_resched_rcu_qs in shrink_node_memcg by cond_resched would > > be really helpful to tell whether we are missing a real scheduling point > > or whether something more serious is going on here. > > Well, I can confirm, that replacing cond_resched_rcu_qs in > shrink_node_memcg by cond_resched also makes dmesg clean from RCU CPU > stall warnings. > > I've attached patch (just modification of Paul's patch), that fixes RCU > stall messages in situations, when all memory is used by > couchbase/memcached + fs cache and linux starts to use swap. > > > -- > Boris Zhmurov > System/Network Administrator > mailto: bb@xxxxxxxxxxxxxx > "wget http://kernelpanic.ru/bb_public_key.pgp -O - | gpg --import" > --- a/mm/vmscan.c.orig 2016-11-30 21:52:58.314895320 +0300 > +++ b/mm/vmscan.c 2016-11-30 21:53:29.502895320 +0300 > @@ -2352,6 +2352,7 @@ > nr_reclaimed += shrink_list(lru, nr_to_scan, > lruvec, sc); > } > + cond_resched(); > } > > if (nr_reclaimed < nr_to_reclaim || scan_adjusted) Nice! Just to double-check, could you please also test your patch above with these two commits from -rcu? d2db185bfee8 ("rcu: Remove short-term CPU kicking") f8f127e738e3 ("rcu: Add long-term CPU kicking") Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>