On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
> This is a trivial but worth having clean-up patch. There should be
> no side effects except page->lru is temporarily poisoned after it's
> deleted but before it's added to the new list in move_pages_to_lru()
> (which is not a problem).
> 
> Signed-off-by: Yu Zhao <yuz...@google.com>

Hi Alex, I just realized your
  [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
at
  https://patchwork.kernel.org/patch/11733123/
also touches move_pages_to_lru(). I agree it's better not to add
a page we are going to free to the list in the first place. The
rest in this patch would be too trivial to be a separate one (on
top of yours).

So would you mind taking of the clean-up too in your series? I'll
drop this one then. Thanks.

> ---
>  mm/swap.c   |  4 +---
>  mm/vmscan.c | 14 ++++----------
>  2 files changed, 5 insertions(+), 13 deletions(-)
> 
> diff --git a/mm/swap.c b/mm/swap.c
> index 40bf20a75278..2735ecf0f566 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct 
> lruvec *lruvec,
>  {
>       if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
>           !PageSwapCache(page) && !PageUnevictable(page)) {
> -             bool active = PageActive(page);
>               int nr_pages = thp_nr_pages(page);
>  
> -             del_page_from_lru_list(page, lruvec,
> -                                    LRU_INACTIVE_ANON + active);
> +             del_page_from_lru_list(page, lruvec, page_lru(page));
>               ClearPageActive(page);
>               ClearPageReferenced(page);
>               /*
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 99e1796eb833..b479ced26cd3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack 
> move_pages_to_lru(struct lruvec *lruvec,
>       int nr_pages, nr_moved = 0;
>       LIST_HEAD(pages_to_free);
>       struct page *page;
> -     enum lru_list lru;
>  
>       while (!list_empty(list)) {
>               page = lru_to_page(list);
>               VM_BUG_ON_PAGE(PageLRU(page), page);
> +             list_del(&page->lru);
>               if (unlikely(!page_evictable(page))) {
> -                     list_del(&page->lru);
>                       spin_unlock_irq(&pgdat->lru_lock);
>                       putback_lru_page(page);
>                       spin_lock_irq(&pgdat->lru_lock);
> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack 
> move_pages_to_lru(struct lruvec *lruvec,
>               lruvec = mem_cgroup_page_lruvec(page, pgdat);
>  
>               SetPageLRU(page);
> -             lru = page_lru(page);
> -
> -             nr_pages = thp_nr_pages(page);
> -             update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
> -             list_move(&page->lru, &lruvec->lists[lru]);
> +             add_page_to_lru_list(page, lruvec, page_lru(page));
>  
>               if (put_page_testzero(page)) {
> -                     __ClearPageLRU(page);
> -                     __ClearPageActive(page);
> -                     del_page_from_lru_list(page, lruvec, lru);
> +                     del_page_from_lru_list(page, lruvec, 
> page_off_lru(page));
>  
>                       if (unlikely(PageCompound(page))) {
>                               spin_unlock_irq(&pgdat->lru_lock);
> @@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack 
> move_pages_to_lru(struct lruvec *lruvec,
>                       } else
>                               list_add(&page->lru, &pages_to_free);
>               } else {
> +                     nr_pages = thp_nr_pages(page);
>                       nr_moved += nr_pages;
>                       if (PageActive(page))
>                               workingset_age_nonresident(lruvec, nr_pages);
> -- 
> 2.28.0.402.g5ffc5be6b7-goog
> 

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