Zi Yan <zi.yan@xxxxxxxx> writes: > 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> LGTM, Thanks! Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > --- > 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
