On Fri, Nov 17, 2023 at 10:07:45AM +0000, Mel Gorman wrote: > This leads into a generic problem with large anything with NUMA > balancing -- false sharing. As it stands, THP can be false shared by > threads if thread-local data is split within a THP range. In this case, > the ideal would be the THP is migrated to the hottest node but such > support doesn't exist. The same applies for folios. If not handled > properly, a large folio of any type can ping-pong between nodes so just > migrating because we can is not necessarily a good idea. The patch > should cover a realistic case why this matters, why splitting the folio > is not better and supporting data. Would it make sense to have THP merging conditional on all (most?) pages having the same node?
