[to-be-updated] mm-khugepaged-extract-young-page-check-into-pte_is_referenced-helper.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm/khugepaged: extract young page check into pte_is_referenced() helper
has been removed from the -mm tree.  Its filename was
     mm-khugepaged-extract-young-page-check-into-pte_is_referenced-helper.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: "Nico Pache (Red Hat)" <nico.pache@linux.dev>
Subject: mm/khugepaged: extract young page check into pte_is_referenced() helper
Date: Tue, 04 Aug 2026 13:25:00 -0600

This change deduplicates the "is this PTE/folio referenced enough to be
considered for a collapse" condition that was repeated in both
__collapse_huge_page_isolate() and collapse_scan_pmd(), extracting it into
a single inline helper function.

Also move the comment and use it as the function header.  While we are at
it, updated the comment to clarify that a young pte is a recently accessed
one.

Link: https://lore.kernel.org/20260804-khugepaged_pte_refactor-v3-2-0364cad642a0@linux.dev
Signed-off-by: Nico Pache (Red Hat) <nico.pache@linux.dev>
Acked-by: Usama Arif <usama.arif@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/khugepaged.c |   35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

--- a/mm/khugepaged.c~mm-khugepaged-extract-young-page-check-into-pte_is_referenced-helper
+++ a/mm/khugepaged.c
@@ -672,6 +672,23 @@ static void release_pte_pages(pte_t *pte
 	}
 }
 
+/*
+ * pte_is_referenced() - Check for enough referenced PTEs to justify collapsing
+ *
+ * If collapse was initiated by khugepaged, check that the page has been
+ * recently accessed (young pte) to justify collapsing the page.
+ *
+ * Return: true if the page has been recently accessed.
+ */
+static inline bool pte_is_referenced(struct collapse_control *cc, pte_t pteval,
+	struct folio *folio, struct vm_area_struct *vma, unsigned long addr)
+{
+	return cc->is_khugepaged &&
+	       (pte_young(pteval) || folio_test_young(folio) ||
+		folio_test_referenced(folio) ||
+		mmu_notifier_test_young(vma->vm_mm, addr));
+}
+
 static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
 		unsigned long start_addr, pte_t *pte, struct collapse_control *cc,
 		unsigned int order, struct list_head *compound_pagelist)
@@ -810,14 +827,7 @@ static enum scan_result __collapse_huge_
 		if (folio_test_large(folio))
 			list_add_tail(&folio->lru, compound_pagelist);
 next:
-		/*
-		 * If collapse was initiated by khugepaged, check that there is
-		 * enough young pte to justify collapsing the page
-		 */
-		if (cc->is_khugepaged &&
-		    (pte_young(pteval) || folio_test_young(folio) ||
-		     folio_test_referenced(folio) ||
-		     mmu_notifier_test_young(vma->vm_mm, addr)))
+		if (pte_is_referenced(cc, pteval, folio, vma, addr))
 			referenced++;
 	}
 
@@ -1766,14 +1776,7 @@ static enum scan_result collapse_scan_pm
 			goto out_unmap;
 		}
 
-		/*
-		 * If collapse was initiated by khugepaged, check that there is
-		 * enough young pte to justify collapsing the page
-		 */
-		if (cc->is_khugepaged &&
-		    (pte_young(pteval) || folio_test_young(folio) ||
-		     folio_test_referenced(folio) ||
-		     mmu_notifier_test_young(vma->vm_mm, addr)))
+		if (pte_is_referenced(cc, pteval, folio, vma, addr))
 			referenced++;
 	}
 	if (cc->is_khugepaged &&
_

Patches currently in -mm which might be from nico.pache@linux.dev are

mm-khugepaged-introduce-a-count_collapse_event-helper.patch
mm-khugepaged-fix-outdated-comments.patch
mm-khugepaged-refactor-the-pte-state-checks-into-a-helper.patch
mm-khugepaged-unmap-pte-before-releasing-vma-write-lock.patch
mm-documentation-clarify-where-the-mthp-stats-live.patch