[Patch v3 1/4] mm/huge_memory: avoid reinvoking folio_test_anon()

[Wei Yang <richard.weiyang@gmail.com>]

During the execution of __split_unmapped_folio(), the folio's anon/!anon
attribute is invariant (not expected to change).

Therefore, it is safe and more efficient to retrieve this attribute once
at the start and reuse it throughout the function.

Link: https://lkml.kernel.org/r/20251016004613.514-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20251016004613.514-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: wang lian <lianux.mm@gmail.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>

---
v3:
  * adjust subject
  * add const to variable is_anon
---
 mm/huge_memory.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 370ecfd6a182..6d82df4a88dc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3595,6 +3595,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 		struct page *split_at, struct xa_state *xas,
 		struct address_space *mapping, bool uniform_split)
 {
+	const bool is_anon = folio_test_anon(folio);
 	int order = folio_order(folio);
 	int start_order = uniform_split ? new_order : order - 1;
 	bool stop_split = false;
@@ -3602,7 +3603,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 	int split_order;
 	int ret = 0;
 
-	if (folio_test_anon(folio))
+	if (is_anon)
 		mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1);
 
 	folio_clear_has_hwpoisoned(folio);
@@ -3619,7 +3620,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 		struct folio *new_folio;
 
 		/* order-1 anonymous folio is not supported */
-		if (folio_test_anon(folio) && split_order == 1)
+		if (is_anon && split_order == 1)
 			continue;
 		if (uniform_split && split_order != new_order)
 			continue;
@@ -3671,7 +3672,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
 				if (split_order != new_order && !stop_split)
 					continue;
 			}
-			if (folio_test_anon(new_folio))
+			if (is_anon)
 				mod_mthp_stat(folio_order(new_folio),
 					      MTHP_STAT_NR_ANON, 1);
 		}
-- 
2.34.1