Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> writes:
> The page for migrate_device_unmap() already has a reference, so it is
> safe to convert the page to folio to save a few calls to compound_head(),
> which removes the last isolate_lru_page() call.
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: Alistair Popple <apopple@xxxxxxxxxx>
> ---
> mm/migrate_device.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/mm/migrate_device.c b/mm/migrate_device.c
> index 66db28b89f9b..b49f4956617a 100644
> --- a/mm/migrate_device.c
> +++ b/mm/migrate_device.c
> @@ -379,33 +379,33 @@ static unsigned long migrate_device_unmap(unsigned long *src_pfns,
> continue;
> }
>
> - /* ZONE_DEVICE pages are not on LRU */
> - if (!is_zone_device_page(page)) {
> - if (!PageLRU(page) && allow_drain) {
> + folio = page_folio(page);
> + /* ZONE_DEVICE folios are not on LRU */
> + if (!folio_is_zone_device(folio)) {
> + if (!folio_test_lru(folio) && allow_drain) {
> /* Drain CPU's lru cache */
> lru_add_drain_all();
> allow_drain = false;
> }
>
> - if (!isolate_lru_page(page)) {
> + if (!folio_isolate_lru(folio)) {
> src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
> restore++;
> continue;
> }
>
> /* Drop the reference we took in collect */
> - put_page(page);
> + folio_put(folio);
> }
>
> - folio = page_folio(page);
> if (folio_mapped(folio))
> try_to_migrate(folio, 0);
>
> - if (page_mapped(page) ||
> + if (folio_mapped(folio) ||
> !migrate_vma_check_page(page, fault_page)) {
> - if (!is_zone_device_page(page)) {
> - get_page(page);
> - putback_lru_page(page);
> + if (!folio_is_zone_device(folio)) {
> + folio_get(folio);
> + folio_putback_lru(folio);
> }
>
> src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
