From: Zi Yan <ziy@xxxxxxxxxx> As Ying pointed out in [1], stats->nr_thp_failed needs to be updated to avoid stats inconsistency between MIGRATE_SYNC and MIGRATE_ASYNC when calling migrate_pages_batch(). Because if not, when migrate_pages_batch() is called via migrate_pages(MIGRATE_ASYNC), nr_thp_failed will not be increased and when migrate_pages_batch() is called via migrate_pages(MIGRATE_SYNC*), nr_thp_failed will be increase in migrate_pages_sync() by stats->nr_thp_failed += astats.nr_thp_split. [1] https://lore.kernel.org/linux-mm/87msnq7key.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Suggested-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx> --- mm/migrate.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 66c74b89d3de..781979567f64 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1645,6 +1645,10 @@ static int migrate_pages_batch(struct list_head *from, * migrate_pages() may report success with (split but * unmigrated) pages still on its fromlist; whereas it * always reports success when its fromlist is empty. + * stats->nr_thp_failed should be increased too, + * otherwise stats inconsistency will happen when + * migrate_pages_batch is called via migrate_pages() + * with MIGRATE_SYNC and MIGRATE_ASYNC. * * Only check it without removing it from the list. * Since the folio can be on deferred_split_scan() @@ -1661,6 +1665,7 @@ static int migrate_pages_batch(struct list_head *from, !list_empty(&folio->_deferred_list)) { if (try_split_folio(folio, split_folios) == 0) { nr_failed++; + stats->nr_thp_failed += is_thp; stats->nr_thp_split += is_thp; stats->nr_split++; continue; base-commit: 7c4c5a2ebbcea9031dbb130bb529c8eba025b16a -- 2.43.0
