I know a bit about device private pages but not so much other variants. try_to_migrate_one() will work with private pages so in general that check still looks good. Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx> On Thursday, 8 July 2021 6:13:33 AM AEST Hugh Dickins wrote: > I know nothing about zone_device pages and !device_private pages; but > if try_to_migrate_one() will do nothing for them, then it's better that > try_to_migrate() filter them first, than trawl through all their vmas. > > Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> > --- > mm/rmap.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 1235368f0628..795f9d5f8386 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1703,9 +1703,6 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, > struct mmu_notifier_range range; > enum ttu_flags flags = (enum ttu_flags)(long)arg; > > - if (is_zone_device_page(page) && !is_device_private_page(page)) > - return true; > - > /* > * When racing against e.g. zap_pte_range() on another cpu, > * in between its ptep_get_and_clear_full() and page_remove_rmap(), > @@ -1944,6 +1941,9 @@ void try_to_migrate(struct page *page, enum ttu_flags flags) > TTU_SYNC))) > return; > > + if (is_zone_device_page(page) && !is_device_private_page(page)) > + return; > + > /* > * During exec, a temporary VMA is setup and later moved. > * The VMA is moved under the anon_vma lock but not the >
