[PATCH 10/13] mm: VM_BUG_ON lru page flags

[Yu Zhao]

Move scattered VM_BUG_ONs to two essential places that cover all
lru list additions and deletions.

Signed-off-by: Yu Zhao <yuz...@google.com>
---
 include/linux/mm_inline.h | 4 ++++
 mm/swap.c                 | 2 --
 mm/vmscan.c               | 1 -
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 07d9a0286635..7183c7a03f09 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -51,6 +51,8 @@ static __always_inline void update_lru_size(struct lruvec 
*lruvec,
  */
 static __always_inline void __clear_page_lru_flags(struct page *page)
 {
+       VM_BUG_ON_PAGE(!PageLRU(page), page);
+
        __ClearPageLRU(page);
 
        /* this shouldn't happen, so leave the flags to bad_page() */
@@ -72,6 +74,8 @@ static __always_inline enum lru_list page_lru(struct page 
*page)
 {
        enum lru_list lru;
 
+       VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
+
        if (PageUnevictable(page))
                return LRU_UNEVICTABLE;
 
diff --git a/mm/swap.c b/mm/swap.c
index b252f3593c57..4daa46907dd5 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -85,7 +85,6 @@ static void __page_cache_release(struct page *page)
 
                spin_lock_irqsave(&pgdat->lru_lock, flags);
                lruvec = mem_cgroup_page_lruvec(page, pgdat);
-               VM_BUG_ON_PAGE(!PageLRU(page), page);
                del_page_from_lru_list(page, lruvec);
                __clear_page_lru_flags(page);
                spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -885,7 +884,6 @@ void release_pages(struct page **pages, int nr)
                        }
 
                        lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
-                       VM_BUG_ON_PAGE(!PageLRU(page), page);
                        del_page_from_lru_list(page, lruvec);
                        __clear_page_lru_flags(page);
                }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d93033407200..4688e495c242 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4276,7 +4276,6 @@ void check_move_unevictable_pages(struct pagevec *pvec)
                        continue;
 
                if (page_evictable(page)) {
-                       VM_BUG_ON_PAGE(PageActive(page), page);
                        del_page_from_lru_list(page, lruvec);
                        ClearPageUnevictable(page);
                        add_page_to_lru_list(page, lruvec);
-- 
2.28.0.681.g6f77f65b4e-goog