Re: [PATCH 4/7] mm/hmm: properly handle migration pmd

[Michal Hocko]

On Fri 24-08-18 20:05:46, Zi Yan wrote:
[...]
> > +	if (!pmd_present(pmd)) {
> > +		swp_entry_t entry = pmd_to_swp_entry(pmd);
> > +
> > +		if (is_migration_entry(entry)) {
> 
> I think you should check thp_migration_supported() here, since PMD migration is only enabled in x86_64 systems.
> Other architectures should treat PMD migration entries as bad.

How can we have a migration pmd entry when the migration is not
supported?

-- 
Michal Hocko
SUSE Labs