+ mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch added to mm-new branch

+ mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/huge_memory: use folio_expected_ref_count() to calculate ref_count.
has been added to the -mm mm-new branch.  Its filename is
     mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/huge_memory: use folio_expected_ref_count() to calculate ref_count.
Date: Fri, 11 Jul 2025 14:23:55 -0400

Instead of open coding the ref_count calculation, use
folio_expected_ref_count().

Link: https://lkml.kernel.org/r/20250711182355.3592618-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <k.shutemov@gmail.com>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |   12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count
+++ a/mm/huge_memory.c
@@ -3728,6 +3728,7 @@ static int __folio_split(struct folio *f
 	if (folio_ref_freeze(folio, 1 + extra_pins)) {
 		struct address_space *swap_cache = NULL;
 		struct lruvec *lruvec;
+		int expected_refs;
 
 		if (folio_order(folio) > 1 &&
 		    !list_empty(&folio->_deferred_list)) {
@@ -3798,11 +3799,8 @@ static int __folio_split(struct folio *f
 		     new_folio = next) {
 			next = folio_next(new_folio);
 
-			folio_ref_unfreeze(
-				new_folio,
-				1 + ((mapping || swap_cache) ?
-					     folio_nr_pages(new_folio) :
-					     0));
+			expected_refs = folio_expected_ref_count(new_folio) + 1;
+			folio_ref_unfreeze(new_folio, expected_refs);
 
 			lru_add_split_folio(folio, new_folio, lruvec, list);
 
@@ -3832,8 +3830,8 @@ static int __folio_split(struct folio *f
 		 * Otherwise, a parallel folio_try_get() can grab origin_folio
 		 * and its caller can see stale page cache entries.
 		 */
-		folio_ref_unfreeze(folio, 1 +
-			((mapping || swap_cache) ? folio_nr_pages(folio) : 0));
+		expected_refs = folio_expected_ref_count(folio) + 1;
+		folio_ref_unfreeze(folio, expected_refs);
 
 		unlock_page_lruvec(lruvec);
 
_

Patches currently in -mm which might be from ziy@nvidia.com are

selftests-mm-fix-split_huge_page_test-for-folio_split-tests.patch
mm-page_alloc-pageblock-flags-functions-clean-up.patch
mm-page_isolation-make-page-isolation-a-standalone-bit.patch
mm-page_alloc-add-support-for-initializing-pageblock-as-isolated.patch
mm-page_isolation-remove-migratetype-from-move_freepages_block_isolate.patch
mm-page_isolation-remove-migratetype-from-undo_isolate_page_range.patch
mm-page_isolation-remove-migratetype-parameter-from-more-functions.patch
mm-huge_memory-move-unrelated-code-out-of-__split_unmapped_folio.patch
mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch