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

From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Suren Baghdasaryan <surenb@google.com>,
	John Dias <joaodias@google.com>, Michal Hocko <mhocko@suse.com>,
	David Hildenbrand <david@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>, Minchan Kim <minchan@kernel.org>
Subject: [PATCH] mm: page_alloc: dump migrate-failed pages only at -EBUSY
Date: Wed, 19 May 2021 14:33:41 -0700	[thread overview]
Message-ID: <20210519213341.2620708-1-minchan@kernel.org> (raw)

alloc_contig_dump_pages aims for helping debugging page migration
failure by page refcount mismatch or something else of page itself
from migration handler function. However, in -ENOMEM case, there is
nothing to get clue from page descriptor information so just
dump pages only when -EBUSY happens.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 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;
 	}
-- 
2.31.1.751.gd2f1c929bd-goog

