On Wed 17-08-16 17:48:25, Michal Hocko wrote: [...] > I will try to catch up with the rest of the email thread but from a > quick glance it just feels like we are doing more more work under the > lock.
Hmm, so it doesn't seem to be more work in __remove_mapping as pointed out in http://lkml.kernel.org/r/20160816220250.GI16044@dastard As Mel already pointed out the LRU will be basically single mapping for this workload so any subtle change in timing might make a difference. I was looking through 4.6..4.7 and one thing that has changed is the inactive vs. active LRU size ratio. See 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list"). The machine has quite a lot of memory and so the LRUs will be large as well so I guess this could have change the timing somehow, but it feels like a wild guess so I would be careful to blame this commit... -- Michal Hocko SUSE Labs
