On Sat, 2022-04-09 at 17:34 +0800, Miaohe Lin wrote:
> The MADV_FREE pages check in folio_check_dirty_writeback is a bit hard to
> follow. Add a comment to make the code clear.
>
> Suggested-by: Huang, Ying <ying.huang@xxxxxxxxx>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/vmscan.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index c77d5052f230..4a76be47bed1 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1436,6 +1436,9 @@ static void folio_check_dirty_writeback(struct folio
> *folio,
> /*
> * Anonymous pages are not handled by flushers and must be written
> * from reclaim context. Do not stall reclaim based on them
> + * MADV_FREE anonymous pages are put into inactive file list too.
> + * They could be mistakenly treated as file lru. So further anon
> + * test is needed.
> */
How about something as follows,
/*
* Anonymous pages (including MADV_FREE ones) are not handled
by * flushers and must be written from reclaim context. Do not stall
* reclaim based on them
*/.
Best Regards,
Huang, Ying
> if (!folio_is_file_lru(folio) ||
> (folio_test_anon(folio) && !folio_test_swapbacked(folio))) {
