2022-05-30 13:38:14

by Muchun Song

Subject: [PATCH v5 10/11] mm: lru: add VM_BUG_ON_FOLIO to lru maintenance function

We need to make sure that the page is deleted from or added to the
correct lruvec list. So add a VM_WARN_ON_ONCE_FOLIO() to catch
invalid users. Then the VM_BUG_ON_PAGE() in move_pages_to_lru()
could be removed since add_page_to_lru_list() will check that.

Signed-off-by: Muchun Song <[email protected]>
---
include/linux/mm_inline.h | 6 ++++++
mm/vmscan.c | 1 -
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index ac32125745ab..e13e56c7fdbd 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -97,6 +97,8 @@ void lruvec_add_folio(struct lruvec *lruvec, struct folio *folio)
{
enum lru_list lru = folio_lru_list(folio);

+ VM_WARN_ON_ONCE_FOLIO(!folio_matches_lruvec(folio, lruvec), folio);
+
update_lru_size(lruvec, lru, folio_zonenum(folio),
folio_nr_pages(folio));
if (lru != LRU_UNEVICTABLE)
@@ -114,6 +116,8 @@ void lruvec_add_folio_tail(struct lruvec *lruvec, struct folio *folio)
{
enum lru_list lru = folio_lru_list(folio);

+ VM_WARN_ON_ONCE_FOLIO(!folio_matches_lruvec(folio, lruvec), folio);
+
update_lru_size(lruvec, lru, folio_zonenum(folio),
folio_nr_pages(folio));
/* This is not expected to be used on LRU_UNEVICTABLE */
@@ -131,6 +135,8 @@ void lruvec_del_folio(struct lruvec *lruvec, struct folio *folio)
{
enum lru_list lru = folio_lru_list(folio);

+ VM_WARN_ON_ONCE_FOLIO(!folio_matches_lruvec(folio, lruvec), folio);
+
if (lru != LRU_UNEVICTABLE)
list_del(&folio->lru);
update_lru_size(lruvec, lru, folio_zonenum(folio),
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 67f1462b150d..51853d6df7b4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2277,7 +2277,6 @@ static unsigned int move_pages_to_lru(struct list_head *list)
continue;
}

- VM_BUG_ON_PAGE(!folio_matches_lruvec(folio, lruvec), page);
add_page_to_lru_list(page, lruvec);
nr_pages = thp_nr_pages(page);
nr_moved += nr_pages;
--
2.11.0

2022-06-19 20:15:48

by Roman Gushchin

Subject: Re: [PATCH v5 10/11] mm: lru: add VM_BUG_ON_FOLIO to lru maintenance function

On Mon, May 30, 2022 at 03:49:18PM +0800, Muchun Song wrote:
> We need to make sure that the page is deleted from or added to the
> correct lruvec list. So add a VM_WARN_ON_ONCE_FOLIO() to catch
> invalid users. Then the VM_BUG_ON_PAGE() in move_pages_to_lru()
> could be removed since add_page_to_lru_list() will check that.
>
> Signed-off-by: Muchun Song <[email protected]>

Acked-by: Roman Gushchin <[email protected]>