The migrate_pages() will return the number of {normal page, THP, hugetlb}
that were not migrated, or an error code. That means it can still return
the number of failure count, though the pages have been migrated
successfully with several times re-try.
So we should not use the return value of migrate_pages() to determin
if there are pages are failed to migrate. Instead we can validate the
'movable_page_list' to see if there are pages remained in the list,
which are failed to migrate. That can mitigate the failure of longterm
pinning.
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
mm/gup.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 5182aba..bd8cfcd 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1914,9 +1914,10 @@ static int migrate_longterm_unpinnable_pages(
.gfp_mask = GFP_USER | __GFP_NOWARN,
};
- if (migrate_pages(movable_page_list, alloc_migration_target,
- NULL, (unsigned long)&mtc, MIGRATE_SYNC,
- MR_LONGTERM_PIN, NULL)) {
+ ret = migrate_pages(movable_page_list, alloc_migration_target,
+ NULL, (unsigned long)&mtc, MIGRATE_SYNC,
+ MR_LONGTERM_PIN, NULL);
+ if (ret < 0 || !list_empty(movable_page_list)) {
ret = -ENOMEM;
goto err;
}
--
1.8.3.1
