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From:   Muchun Song <songmuchun@bytedance.com>
To:     akpm@linux-foundation.org, hannes@cmpxchg.org, longman@redhat.com,
        mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com
Cc:     cgroups@vger.kernel.org, duanxiongchun@bytedance.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH v6 10/11] mm: lru: add VM_WARN_ON_ONCE_FOLIO to lru maintenance function
Date:   Tue, 21 Jun 2022 20:56:57 +0800
Message-Id: <20220621125658.64935-11-songmuchun@bytedance.com>
In-Reply-To: <20220621125658.64935-1-songmuchun@bytedance.com>
References: <20220621125658.64935-1-songmuchun@bytedance.com>
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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 <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
---
 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 7b25b53c474a..6585198b19e2 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -99,6 +99,8 @@ 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)
@@ -116,6 +118,8 @@ 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 */
@@ -133,6 +137,8 @@ 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 697656151431..51b1607c81e4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2361,7 +2361,6 @@ static unsigned int move_pages_to_lru(struct list_head *list)
 			continue;
 		}
 
-		VM_BUG_ON_FOLIO(!folio_matches_lruvec(folio, lruvec), folio);
 		lruvec_add_folio(lruvec, folio);
 		nr_pages = folio_nr_pages(folio);
 		nr_moved += nr_pages;
-- 
2.11.0