[PATCH v6 5/9] mm: multigenerational lru: mm_struct list

[Michal Hocko]

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