On Tue, Mar 26, 2019 at 08:41:15PM -0700, Yang Shi wrote: > On 3/26/19 5:35 PM, Keith Busch wrote: > > migration nodes have higher free capacity than source nodes. And since > > your attempting THP's without ever splitting them, that also requires > > lower fragmentation for a successful migration. > > Yes, it is possible. However, migrate_pages() already has logic to > handle such case. If the target node has not enough space for migrating > THP in a whole, it would split THP then retry with base pages.
Oh, you're right, my mistake on splitting. So you have a good best effort migrate, but I still think it can fail for legitimate reasons that should have a swap fallback.
