[PATCH 07/11] mm: VM_BUG_ON lru page flags

Yu Zhao
2020-12-07T22:11:43Z

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

Signed-off-by: Yu Zhao <yuzhao@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 ef3fd79222e5..6d907a4dd6ad 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -66,6 +66,8 @@ static inline enum lru_list page_lru_base_type(struct page *page)
*/
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() */
@@ -87,6 +89,8 @@ 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))
lru = LRU_UNEVICTABLE;
else {
diff --git a/mm/swap.c b/mm/swap.c
index a37c896a32b0..09c4a48e0bcd 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -83,7 +83,6 @@ static void __page_cache_release(struct page *page)
unsigned long flags;

lruvec = lock_page_lruvec_irqsave(page, &flags);
- VM_BUG_ON_PAGE(!PageLRU(page), page);
del_page_from_lru_list(page, lruvec);
__clear_page_lru_flags(page);
unlock_page_lruvec_irqrestore(lruvec, flags);
@@ -909,7 +908,6 @@ void release_pages(struct page **pages, int nr)
if (prev_lruvec != lruvec)
lock_batch = 0;

- 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 e6bdfdfa2da1..95e581c9d9af 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4279,7 +4279,6 @@ void check_move_unevictable_pages(struct pagevec *pvec)

lruvec = relock_page_lruvec_irq(page, lruvec);
if (page_evictable(page) && PageUnevictable(page)) {
- VM_BUG_ON_PAGE(PageActive(page), page);
del_page_from_lru_list(page, lruvec);
ClearPageUnevictable(page);
add_page_to_lru_list(page, lruvec);
--
2.29.2.576.ga3fc446d84-goog