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From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,muchun.song@linux.dev,akpm@linux-foundation.org
Subject: [to-be-updated] mm-hugetlb_vmemmap-make-vmemmap-pte-conversion-folio-oriented.patch removed from -mm tree
Date: Fri, 06 Nov 2026 19:49:58 -0800	[thread overview]
Message-ID: <20261107034958.8A55C1F0089F@smtp.kernel.org> (raw)


The quilt patch titled
     Subject: mm: hugetlb_vmemmap: make vmemmap PTE conversion folio-oriented
has been removed from the -mm tree.  Its filename was
     mm-hugetlb_vmemmap-make-vmemmap-pte-conversion-folio-oriented.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Muchun Song <muchun.song@linux.dev>
Subject: mm: hugetlb_vmemmap: make vmemmap PTE conversion folio-oriented
Date: Wed, 04 Nov 2026 10:35:10 +0800

Converting a folio's vmemmap mappings from PMDs to PTEs is a per-folio
operation, but the current interface exposes a raw address range and
hardcodes deferred TLB flushing.  This splits the common mechanism across
layers and couples it to the HugeTLB batching policy.

Make the folio the unit of PTE conversion and let callers select the TLB
flush policy through the folio-oriented interface.  This keeps
HugeTLB-specific eligibility and batching outside the common operation.

No functional change intended.

Link: https://lore.kernel.org/20261104023510.260766-13-songmuchun@bytedance.com
Signed-off-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Andrew Morton <akpm@linux-foundation.org>
  Link: https://lore.kernel.org/20261103224659.2865b9ff27d09994949edd78@linux-foundation.org
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: James Houghton <jthoughton@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
---

 mm/hugetlb_vmemmap.c |   40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-make-vmemmap-pte-conversion-folio-oriented
+++ a/mm/hugetlb_vmemmap.c
@@ -300,20 +300,26 @@ static inline int vmemmap_restore_range(
 }
 
 /**
- * vmemmap_remap_split - split the vmemmap virtual address range [@start, @end)
- *                      backing PMDs of the directmap into PTEs
- * @start:     start address of the vmemmap virtual address range that we want
- *             to remap.
- * @end:       end address of the vmemmap virtual address range that we want to
- *             remap.
+ * vmemmap_pteify_folio - convert the vmemmap backing of a folio to PTE mappings
+ * @folio:	folio whose vmemmap range should be converted to PTE mappings.
+ * @flags:	vmemmap remap control flags passed to vmemmap_remap_walk.
+ *
+ * Convert mappings covering @folio's vmemmap into PTE mappings. If TLB flushing
+ * is skipped, the caller must flush TLBs after all pteify operations are complete
+ * before remapping the folio's vmemmap pages.
+ *
  * Return: %0 on success, negative error code otherwise.
  */
-static int vmemmap_remap_split(unsigned long start, unsigned long end)
+static int vmemmap_pteify_folio(const struct folio *folio, unsigned long flags)
 {
 	struct vmemmap_remap_walk walk = {
-		.remap_pte	= NULL,
-		.flags		= VMEMMAP_DEFER_TLB_FLUSH,
+		.flags		= flags,
 	};
+	unsigned long start = (unsigned long)folio_page(folio, 0);
+	unsigned long end = start + folio_vmemmap_size(folio);
+
+	if (!vmemmap_optimizable_order(folio_order(folio)))
+		return -EOPNOTSUPP;
 
 	return vmemmap_remap_range(start, end, &walk);
 }
@@ -532,21 +538,13 @@ void hugetlb_vmemmap_optimize_folio(cons
 	free_vmemmap_page_list(&vmemmap_pages);
 }
 
-static int hugetlb_vmemmap_split_folio(const struct hstate *h, struct folio *folio)
+static int hugetlb_vmemmap_pteify_folio(const struct hstate *h, struct folio *folio,
+		unsigned long flags)
 {
-	unsigned long vmemmap_start, vmemmap_end;
-
 	if (!vmemmap_should_optimize_folio(h, folio))
 		return 0;
 
-	vmemmap_start	= (unsigned long)&folio->page;
-	vmemmap_end	= vmemmap_start + hugetlb_vmemmap_size(h);
-
-	/*
-	 * Split PMDs on the vmemmap virtual address range [@vmemmap_start,
-	 * @vmemmap_end]
-	 */
-	return vmemmap_remap_split(vmemmap_start, vmemmap_end);
+	return vmemmap_pteify_folio(folio, flags);
 }
 
 void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)
@@ -571,7 +569,7 @@ void hugetlb_vmemmap_optimize_folios(str
 
 		nr_to_optimize++;
 
-		ret = hugetlb_vmemmap_split_folio(h, folio);
+		ret = hugetlb_vmemmap_pteify_folio(h, folio, flags);
 
 		/*
 		 * Splitting the PMD requires allocating a page, thus let's fail
_

Patches currently in -mm which might be from muchun.song@linux.dev are

mm-fix-missing-page-table-destructor-in-pagetable_free.patch
riscv-mm-fix-hotplug-page-table-destructor-handling.patch
riscv-mm-fix-missing-destructor-for-hotplug-pud-tables.patch
arm64-mm-fix-destructor-for-unconstructed-hotplug-page-tables.patch
mm-sparse-vmemmap-map-shared-vmemmap-tail-pages-as-read-only.patch
powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only.patch
mm-hugetlb_vmemmap-remove-vmemmap_wrprotect_hvo.patch
mm-hugetlb_vmemmap-remove-hugetlb_vmemmap_optimize_bootmem_folios.patch
mm-generalize-kernel-pte-table-allocation.patch
mm-generalize-pmd-page-table-allocation.patch
mm-generalize-pud-page-table-allocation.patch
mm-remove-pagetable_dtor_free.patch
mm-remove-redundant-pagetable_dtor-calls.patch
mm-hugetlb-fix-validation-of-unsupported-hugetlb-orders.patch


                 reply	other threads:[~2026-11-07  3:49 UTC|newest]

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