Re: [PATCH 1/1] mm/khugepaged: bypassing unnecessary scans with MMF_DISABLE_THP check

[Michal Hocko]

On Mon 29-01-24 13:45:51, Lance Yang wrote:
> khugepaged scans the entire address space in the
> background for each given mm, looking for
> opportunities to merge sequences of basic pages
> into huge pages. However, when an mm is inserted
> to the mm_slots list, and the MMF_DISABLE_THP flag
> is set later, this scanning process becomes
> unnecessary for that mm and can be skipped to avoid
> redundant operations, especially in scenarios with
> a large address space.

Is this a real problem? I thought that the prctl is called
on the parent before fork/exec. Or are you aware of any
applications which do call prctl late enough that the race
would be actually observable?
-- 
Michal Hocko
SUSE Labs