On Wed, Feb 03, 2021 at 01:22:18PM +0000, Joao Martins wrote: > With this, longterm gup will 'regress' for hugetlbfs e.g. from ~6k -> 32k usecs when > pinning a 16G hugetlb file. Yes, but correctness demands it. The solution is to track these pages as we discover them so we know if a PMD/PUD points and can directly skip the duplicated work > Splitting can only occur on THP right? If so, perhaps we could > retain the @step increment for compound pages but when > !is_transparent_hugepage(head) or just PageHuge(head) like: Honestly I'd rather see it fixed properly which will give even bigger performance gains - avoiding the entire rescan of the page list will be a win Jason
