Re: [PATCH 5/5] mm/vmscan: fix misleading comment in isolate_lru_pages()

From: Michal Hocko
Date: Mon Jul 12 2021 - 04:09:11 EST


On Sat 10-07-21 18:03:29, Miaohe Lin wrote:
> We couldn't know whether the page is being freed elsewhere until we failed
> to increase the page count.

This is moving a hard to understand comment from one place to another.
If anything this would benefit from what that elsewhere might be
typically or simply drop the comment altogether.

>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/vmscan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index a74760c48bd8..6e26b3c93242 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1891,7 +1891,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> */
> scan += nr_pages;
> if (!__isolate_lru_page_prepare(page, mode)) {
> - /* It is being freed elsewhere */
> list_move(&page->lru, src);
> continue;
> }
> @@ -1901,6 +1900,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
> * page release code relies on it.
> */
> if (unlikely(!get_page_unless_zero(page))) {
> + /* It is being freed elsewhere. */
> list_move(&page->lru, src);
> continue;
> }
> --
> 2.23.0

--
Michal Hocko
SUSE Labs