+ mm-huge_memory-use-folio_can_map_prot_numa-for-pmd-folio.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: huge_memory: use folio_can_map_prot_numa() for pmd folio
has been added to the -mm mm-unstable branch.  Its filename is
     mm-huge_memory-use-folio_can_map_prot_numa-for-pmd-folio.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_can_map_prot_numa-for-pmd-folio.patch

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

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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: mm: huge_memory: use folio_can_map_prot_numa() for pmd folio
Date: Thu, 23 Oct 2025 19:37:37 +0800

The folio_can_map_prot_numa() checks whether the folio can map prot numa,
which skips unsuitable folio, i.e.  zone device, shared folios (KSM, CoW),
non-movable dma pinned, dirty file folio and folios that already have the
expected node affinity.  Although the ksm only applies to small folios, an
extra test was added for large folios, but the other policies should be
applied to pmd folio, which helps to avoid unnecessary pmd change and
folio migration attempts.

Link: https://lkml.kernel.org/r/20251023113737.3572790-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: 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: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |   17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-use-folio_can_map_prot_numa-for-pmd-folio
+++ a/mm/huge_memory.c
@@ -2477,8 +2477,7 @@ int change_huge_pmd(struct mmu_gather *t
 #endif
 
 	if (prot_numa) {
-		struct folio *folio;
-		bool toptier;
+
 		/*
 		 * Avoid trapping faults against the zero page. The read-only
 		 * data is likely to be read-cached on the local CPU and
@@ -2490,19 +2489,9 @@ int change_huge_pmd(struct mmu_gather *t
 		if (pmd_protnone(*pmd))
 			goto unlock;
 
-		folio = pmd_folio(*pmd);
-		toptier = node_is_toptier(folio_nid(folio));
-		/*
-		 * Skip scanning top tier node if normal numa
-		 * balancing is disabled
-		 */
-		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
-		    toptier)
+		if (!folio_can_map_prot_numa(pmd_folio(*pmd), vma,
+					     vma_is_single_threaded_private(vma)))
 			goto unlock;
-
-		if (folio_use_access_time(folio))
-			folio_xchg_access_time(folio,
-					       jiffies_to_msecs(jiffies));
 	}
 	/*
 	 * In case prot_numa, we are under mmap_read_lock(mm). It's critical
_

Patches currently in -mm which might be from wangkefeng.wang@huawei.com are

mm-mprotect-always-skip-dma-pinned-folio-in-prot_numa_skip.patch
mm-mprotect-avoid-unnecessary-struct-page-accessing-if-pte_protnone.patch
mm-mprotect-convert-to-folio_can_map_prot_numa.patch
mm-huge_memory-use-folio_can_map_prot_numa-for-pmd-folio.patch
mm-debug_vm_pgtable-add-debug_vm_pgtable_free_huge_page.patch
mm-page_alloc-add-__split_page.patch
mm-cma-add-__cma_release.patch
mm-page_alloc-add-alloc_contig_frozen_rangepages.patch
mm-cma-add-cma_alloc_frozen_compound.patch
mm-hugetlb-allocate-frozen-pages-in-alloc_gigantic_folio.patch