migrate_pages(): fix failure counting for THP subpages retrying

If THP is failed to be migrated for -ENOSYS and -ENOMEM, the THP will be
split into thp_split_pages, and after other pages are migrated, pages in
thp_split_pages will be migrated with no_subpage_counting == true, because
its failure have been counted already.  If some pages in thp_split_pages
are retried during migration, we should not count their failure if
no_subpage_counting == true too.  This is done this patch to fix the
failure counting for THP subpages retrying.

Link: https://lkml.kernel.org/r/20220817081408.513338-5-ying.huang@intel.com
Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index ae55f08e72cecb956ae74dff1da6a04f5106943b..0018b5191799e772cd2dd98c98acf15d0ab66dff 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1545,7 +1545,8 @@ retry:
                        }
                }
        }
-       nr_failed += retry;
+       if (!no_subpage_counting)
+               nr_failed += retry;
        nr_thp_failed += thp_retry;
        /*
         * Try to migrate subpages of fail-to-migrate THPs, no nr_failed