Re: [PATCH] mm: replace list_move_tail() with add_page_to_lru_list_tail()

[Andrew Morton]

On Tue, 16 Jul 2019 15:24:36 -0600 Yu Zhao <yuz...@google.com> wrote:

> This is a cleanup patch that replaces two historical uses of
> list_move_tail() with relatively recent add_page_to_lru_list_tail().
> 

Looks OK to me.

> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -515,7 +515,6 @@ static void lru_deactivate_file_fn(struct page *page, 
> struct lruvec *lruvec,
>       del_page_from_lru_list(page, lruvec, lru + active);
>       ClearPageActive(page);
>       ClearPageReferenced(page);
> -     add_page_to_lru_list(page, lruvec, lru);
>  
>       if (PageWriteback(page) || PageDirty(page)) {
>               /*
> @@ -523,13 +522,14 @@ static void lru_deactivate_file_fn(struct page *page, 
> struct lruvec *lruvec,
>                * It can make readahead confusing.  But race window
>                * is _really_ small and  it's non-critical problem.
>                */
> +             add_page_to_lru_list(page, lruvec, lru);
>               SetPageReclaim(page);
>       } else {
>               /*
>                * The page's writeback ends up during pagevec
>                * We moves tha page into tail of inactive.
>                */

That comment is really hard to follow.  Minchan, can you please explain
the first sentence?

The second sentence can simply be removed.

> -             list_move_tail(&page->lru, &lruvec->lists[lru]);
> +             add_page_to_lru_list_tail(page, lruvec, lru);
>               __count_vm_event(PGROTATED);
>       }