[PATCH] mm: page_alloc: dump migrate-failed pages only at -EBUSY

[Minchan Kim]

alloc_contig_dump_pages aims for helping debugging page migration
failure by elevated page refcount compared to expected_count.
(for the detail, please look at migrate_page_move_mapping)

However, -ENOMEM is just the case that system is under memory
pressure state, not relevant with page refcount at all. Thus,
the dumping page list is not helpful for the debugging point of view.

Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
 mm/page_alloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3100fcb08500..c0a2971dc755 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8760,7 +8760,8 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
 
 	lru_cache_enable();
 	if (ret < 0) {
-		alloc_contig_dump_pages(&cc->migratepages);
+		if (ret == -EBUSY)
+			alloc_contig_dump_pages(&cc->migratepages);
 		putback_movable_pages(&cc->migratepages);
 		return ret;
 	}
-- 
2.31.1.818.g46aad6cb9e-goog