+ mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch added to mm-new branch

+ mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/madvise: skip zone device folios in cold/pageout PMD range
has been added to the -mm mm-new branch.  Its filename is
     mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.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
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Gregory Price <gourry@gourry.net>
Subject: mm/madvise: skip zone device folios in cold/pageout PMD range
Date: Mon, 17 Aug 2026 18:08:09 -0400

madvise_cold_or_pageout_pte_range() resolves the folio backing a PMD via
pmd_folio() and ages or reclaims it without checking for zone device
memory.

The surrounding guards do not cover every zone device case:

  - can_madv_lru_vma() excludes VM_PFNMAP and VM_HUGETLB VMAs
    (so device DAX is filtered)

  - !pmd_present() branch above rejects device-private and
    migration entries, which are non-present.

  - A present zone device PMD - e.g. a device-coherent THP - is
    not filtered by any of these, nor by pmd_folio() (unlike
    vm_normal_page_pmd(), it performs no special/pfnmap check),
    and would be aged or paged out here.

Skip ZONE_DEVICE folios explicitly during MADV_COLD/PAGEOUT.

Link: https://lore.kernel.org/20260817220810.1175596-3-gourry@gourry.net
Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
Signed-off-by: Gregory Price (Meta) <gourry@gourry.net>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Tested-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/madvise.c~mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range
+++ a/mm/madvise.c
@@ -404,6 +404,9 @@ static int madvise_cold_or_pageout_pte_r
 
 		folio = pmd_folio(orig_pmd);
 
+		if (folio_is_zone_device(folio))
+			goto huge_unlock;
+
 		/* Do not interfere with other mappings of this folio */
 		if (folio_maybe_mapped_shared(folio))
 			goto huge_unlock;
_

Patches currently in -mm which might be from gourry@gourry.net are

mm-mempolicy-take-a-cpuset-cookie-for-the-interleave-node-count.patch
mm-mempolicy-use-srcu-for-the-weighted-interleave-state.patch
mm-mempolicy-stop-copying-the-nodemask-in-the-interleave-paths.patch
mm-huge_memory-skip-zone-device-folios-in-madvise_free_huge_pmd.patch
mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch
mm-mempolicy-skip-zone-device-folios-when-queueing-folios.patch