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

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@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index 842ecd7..94961f4 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1169,7 +1169,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
                        }
                }
        }
-       rc = nr_failed + retry;
+       nr_failed += retry;
+       rc = nr_failed;
 out:
        if (nr_succeeded)
                count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);