Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

From: Michal Hocko
Date: Wed Sep 05 2018 - 02:57:54 EST


On Tue 04-09-18 10:00:36, Jerome Glisse wrote:
> On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote:
[...]
> > And THP migration is still a problem with 4.4 AFAICS. All other cases
> > simply split the huge page but THP migration keeps it in one piece and
> > as such it is theoretically broken as you have explained. So I would
> > stick with what I posted with some more clarifications in the changelog
> > if you think it is appropriate (suggestions welcome).
>
> Reading code there is no THP migration in 4.4 only huge tlb migration.

Meh, you are right. For some reason I misread unmap_and_move_huge_page
to be also for THP. Sorry for the conusion. My fault!

Then it would be indeed safer to use your backport.
--
Michal Hocko
SUSE Labs