[PATCH v1] mm/vmscan: check the return value of migrate_pages()

[Li Zhong]

Check the return value of migrate_pages() to check error exeuction.

Signed-off-by: Li Zhong <floridsleeves@xxxxxxxxx>
---
 mm/vmscan.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b2b1431352dc..50aaaa9377e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1547,6 +1547,7 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
 {
 	int target_nid = next_demotion_node(pgdat->node_id);
 	unsigned int nr_succeeded;
+	int ret;
 
 	if (list_empty(demote_pages))
 		return 0;
@@ -1555,10 +1556,13 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
 		return 0;
 
 	/* Demotion ignores all cpuset and mempolicy settings */
-	migrate_pages(demote_pages, alloc_demote_page, NULL,
+	ret = migrate_pages(demote_pages, alloc_demote_page, NULL,
 			    target_nid, MIGRATE_ASYNC, MR_DEMOTION,
 			    &nr_succeeded);
 
+	if (ret)
+		putback_movable_pages(&pagelist);
+
 	if (current_is_kswapd())
 		__count_vm_events(PGDEMOTE_KSWAPD, nr_succeeded);
 	else
-- 
2.25.1