From: Luis Chamberlain <mcgrof@xxxxxxxxxx>
When we truncate we always check if we can split a large folio, we do
this by checking the userspace mapped pages match folio_nr_pages() - 1,
but if we are using a filesystem or a block device which has a min order
it must be respected and we should only split rounding down to the
min order page requirements.
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
mm/huge_memory.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f899b3500419..e608a805c79f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2617,16 +2617,24 @@ static void __split_huge_page(struct page *page, struct list_head *list,
bool can_split_folio(struct folio *folio, int *pextra_pins)
{
int extra_pins;
+ unsigned int min_order = 0;
+ unsigned int nrpages;
/* Additional pins from page cache */
- if (folio_test_anon(folio))
+ if (folio_test_anon(folio)) {
extra_pins = folio_test_swapcache(folio) ?
folio_nr_pages(folio) : 0;
- else
+ } else {
extra_pins = folio_nr_pages(folio);
+ if (folio->mapping)
+ min_order = mapping_min_folio_order(folio->mapping);
+ }
+
+ nrpages = 1UL << min_order;
+
if (pextra_pins)
*pextra_pins = extra_pins;
- return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - 1;
+ return folio_mapcount(folio) == folio_ref_count(folio) - extra_pins - nrpages;
}
/*
--
2.40.1
