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