On Thu 26-11-15 10:56:12, Joonsoo Kim wrote: > On Wed, Nov 25, 2015 at 01:00:22PM +0100, Michal Hocko wrote: > > On Tue 24-11-15 15:22:03, Joonsoo Kim wrote: > > > When I tested compaction in low memory condition, I found that > > > my benchmark is stuck in congestion_wait() at shrink_inactive_list(). > > > This stuck last for 1 sec and after then it can escape. More investigation > > > shows that it is due to stale vmstat value. vmstat is updated every 1 sec > > > so it is stuck for 1 sec. > > > > Wouldn't it be sufficient to use zone_page_state_snapshot in > > too_many_isolated? > > Yes, it would work in this case. But, I prefer this patch because > all zone_page_state() users get this benefit. Just to make it clear, I am not against your patch in general. I am just not sure it would help for too_many_isolated case where a significant drift might occur on remote cpus as well so I am not really sure that is appropriate for the issue you are seeing. -- Michal Hocko SUSE Labs -- 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>