On Tue 04-01-22 13:22:24, Yu Zhao wrote: > To exploit spatial locality, the aging prefers to walk page tables to > search for young PTEs. And this patch paves the way for that. > > An mm_struct list is maintained for each memcg, and an mm_struct > follows its owner task to the new memcg when this task is migrated. How does this work actually for the memcg reclaim? I can see you lru_gen_migrate_mm on the task migration. My concern is, though, that such a task leaves all the memory behind in the previous memcg (in cgroup v2, in v1 you can opt in for charge migration). If you move the mm to a new memcg then you age it somewhere where the memory is not really consumed. -- Michal Hocko SUSE Labs