[PATCH] mm: huge_memory: add the missing folio_test_pmd_mappable() for THP split statistics

[Baolin Wang]

Now the mTHP can also be split or added into the deferred list, so add
folio_test_pmd_mappable() validation for PMD mapped THP, to avoid confusion
with PMD mapped THP related statistics.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 mm/huge_memory.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1683de78c313..3ca9282a0dc9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3109,7 +3109,8 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 		i_mmap_unlock_read(mapping);
 out:
 	xas_destroy(&xas);
-	count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
+	if (folio_test_pmd_mappable(folio))
+		count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
 	return ret;
 }
 
@@ -3171,7 +3172,8 @@ void deferred_split_folio(struct folio *folio)
 
 	spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
 	if (list_empty(&folio->_deferred_list)) {
-		count_vm_event(THP_DEFERRED_SPLIT_PAGE);
+		if (folio_test_pmd_mappable(folio))
+			count_vm_event(THP_DEFERRED_SPLIT_PAGE);
 		list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
 		ds_queue->split_queue_len++;
 #ifdef CONFIG_MEMCG
-- 
2.39.3