On Sat, Apr 09, 2022 at 05:34:53PM +0800, Miaohe Lin wrote:
> We don't need to check can_split_folio() because folio_maybe_dma_pinned()
> is checked before. It will avoid the long term pinned pages to be swapped
> out. And we can live with short term pinned pages. Without can_split_folio
> checking we can simplify the code. Also activate_locked can be changed to
> keep_locked as it's just short term pinning.
>
> Suggested-by: Huang, Ying <ying.huang@xxxxxxxxx>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/vmscan.c | 22 ++++++++--------------
> 1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 4a76be47bed1..01f5db75a507 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1711,20 +1711,14 @@ static unsigned int shrink_page_list(struct list_head *page_list,
> goto keep_locked;
> if (folio_maybe_dma_pinned(folio))
> goto keep_locked;
> - if (PageTransHuge(page)) {
> - /* cannot split THP, skip it */
> - if (!can_split_folio(folio, NULL))
> - goto activate_locked;
> - /*
> - * Split pages without a PMD map right
> - * away. Chances are some or all of the
> - * tail pages can be freed without IO.
> - */
> - if (!folio_entire_mapcount(folio) &&
> - split_folio_to_list(folio,
> - page_list))
> - goto activate_locked;
> - }
> + /*
> + * Split pages without a PMD map right
> + * away. Chances are some or all of the
> + * tail pages can be freed without IO.
> + */
This could use more of the line length and be more readable:
/*
* Split pages without a PMD map right away.
* Chances are some or all of the tail pages
* can be freed without IO.
*/
> + if (PageTransHuge(page) && !folio_entire_mapcount(folio) &&
Please put the folio_entire_mapcoun ont a separate line to make this a
bit more redable.
