Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | David Hildenbrand <> | Subject | [PATCH v1 11/18] mm/migrate: use folio_likely_mapped_shared() in add_page_for_migration() | Date | Tue, 9 Apr 2024 21:22:54 +0200 |
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We want to limit the use of page_mapcount() to the places where it is absolutely necessary. In add_page_for_migration(), we actually want to check if the folio is mapped shared, to reject such folios. So let's use folio_likely_mapped_shared() instead.
For small folios, fully mapped THP, and hugetlb folios, there is no change. For partially mapped, shared THP, we should now do a better job at rejecting such folios.
Signed-off-by: David Hildenbrand <david@redhat.com> --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/migrate.c b/mm/migrate.c index 285072bca29c..d87ce32645d4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2140,7 +2140,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, goto out_putfolio; err = -EACCES; - if (page_mapcount(page) > 1 && !migrate_all) + if (folio_likely_mapped_shared(folio) && !migrate_all) goto out_putfolio; err = -EBUSY; -- 2.44.0
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