[merged mm-stable] mm-skip-mlocked-thps-that-are-underused-early-in-deferred_split_scan.patch removed from -mm tree

[merged mm-stable] mm-skip-mlocked-thps-that-are-underused-early-in-deferred_split_scan.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: skip mlocked THPs that are underused early in deferred_split_scan()
has been removed from the -mm tree.  Its filename was
     mm-skip-mlocked-thps-that-are-underused-early-in-deferred_split_scan.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Lance Yang <lance.yang@linux.dev>
Subject: mm: skip mlocked THPs that are underused early in deferred_split_scan()
Date: Mon, 8 Sep 2025 17:07:41 +0800

When we stumble over a fully-mapped mlocked THP in the deferred shrinker,
it does not make sense to try to detect whether it is underused, because
try_to_map_unused_to_zeropage(), called while splitting the folio, will
not actually replace any zeroed pages by the shared zeropage.

Splitting the folio in that case does not make any sense, so let's not
even scan to check if the folio is underused.

Link: https://lkml.kernel.org/r/20250908090741.61519-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Kiryl Shutsemau <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/mm/huge_memory.c~mm-skip-mlocked-thps-that-are-underused-early-in-deferred_split_scan
+++ a/mm/huge_memory.c
@@ -4175,6 +4175,13 @@ static unsigned long deferred_split_scan
 		bool underused = false;
 
 		if (!folio_test_partially_mapped(folio)) {
+			/*
+			 * See try_to_map_unused_to_zeropage(): we cannot
+			 * optimize zero-filled pages after splitting an
+			 * mlocked folio.
+			 */
+			if (folio_test_mlocked(folio))
+				goto next;
 			underused = thp_underused(folio);
 			if (!underused)
 				goto next;
_

Patches currently in -mm which might be from lance.yang@linux.dev are

hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch
selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled.patch