[PATCH] mm, migrate: count pages failing all retries in vmstat and tracepoint

From: Vlastimil Babka
Date: Thu Aug 27 2015 - 10:21:05 EST

Migration tries up to 10 times to migrate pages that return -EAGAIN until it
gives up. If some pages fail all retries, they are counted towards the number
of failed pages that migrate_pages() returns. They should also be counted in
the /proc/vmstat pgmigrate_fail and in the mm_migrate_pages tracepoint.

Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
mm/migrate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index eb42671..e705324 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1152,7 +1152,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
- rc = nr_failed + retry;
+ nr_failed += retry;
+ rc = nr_failed;
if (nr_succeeded)
count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);

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