[PATCH 01/13] mm: use add_page_to_lru_list()

[Yu Zhao]

This patch replaces the only open-coded lru list addition with
add_page_to_lru_list().

Before this patch, we have:
        update_lru_size()
        list_move()

After this patch, we have:
        list_del()
        add_page_to_lru_list()
                update_lru_size()
                list_add()

The only side effect is that page->lru is temporarily poisoned
after a page is deleted from its old list, which shouldn't be a
problem.

Signed-off-by: Yu Zhao <yuz...@google.com>
---
 mm/vmscan.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9727dd8e2581..503fc5e1fe32 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1850,8 +1850,8 @@ static unsigned noinline_for_stack 
move_pages_to_lru(struct lruvec *lruvec,
        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);
@@ -1862,9 +1862,7 @@ static unsigned noinline_for_stack 
move_pages_to_lru(struct lruvec *lruvec,
                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, lru);
 
                if (put_page_testzero(page)) {
                        __ClearPageLRU(page);
@@ -1878,6 +1876,7 @@ 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);
-- 
2.28.0.681.g6f77f65b4e-goog