Re: [PATCH v1] mm: consider non-anonymous thp as unmovable page

[Michal Hocko]

On Tue 03-04-18 13:46:28, Naoya Horiguchi wrote:
> My testing for the latest kernel supporting thp migration found out an
> infinite loop in offlining the memory block that is filled with shmem
> thps.  We can get out of the loop with a signal, but kernel should
> return with failure in this case.
> 
> What happens in the loop is that scan_movable_pages() repeats returning
> the same pfn without any progress. That's because page migration always
> fails for shmem thps.

Why does it fail? Shmem pages should be movable without any issues.

-- 
Michal Hocko
SUSE Labs