Re: [PATCH -next v2] mm/hotplug: silence a lockdep splat with printk()

From: Michal Hocko
Date: Wed Jan 15 2020 - 09:46:34 EST


On Wed 15-01-20 07:35:45, Qian Cai wrote:
>
>
> > On Jan 15, 2020, at 4:22 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> >
> > Is this correct? CMA pages cannot be comound?
>
> I never saw a CMA page also a compound page. Also, in
> alloc_contig_range(), it calls migrate_pages()â>
> unmap_and_move_huge_page() which will free the old huge page, so I
> think that will clear pageCompound.

This sounds like the implementation detail. I do not think you want to
depend on that. Anyway, see my other response. If you rebase on top of
Vlastimil's patch you do not really have to care.
--
Michal Hocko
SUSE Labs