[to-be-updated] mm-hugetlb_vmemmap-generalize-vmemmap-page-allocation.patch removed from -mm tree

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

The quilt patch titled
     Subject: mm: hugetlb_vmemmap: generalize vmemmap page allocation
has been removed from the -mm tree.  Its filename was
     mm-hugetlb_vmemmap-generalize-vmemmap-page-allocation.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Muchun Song <muchun.song@linux.dev>
Subject: mm: hugetlb_vmemmap: generalize vmemmap page allocation
Date: Wed, 04 Nov 2026 10:35:02 +0800

Vmemmap page allocation is currently tied to restoring a virtual range and
assumes an empty destination list.  These constraints prevent it from
being reused when pages are requested independently of a vmemmap range or
appended to an existing list.

Generalize the allocator and give it an all-or-nothing list contract so
the restore and optimization paths can share the same allocation policy. 
This also allows HVO head-page allocation to fail gracefully under memory
pressure without triggering the OOM killer.

Link: https://lore.kernel.org/20261104023510.260766-5-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>
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>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: James Houghton <jthoughton@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
---

 mm/hugetlb_vmemmap.c |   31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-generalize-vmemmap-page-allocation
+++ a/mm/hugetlb_vmemmap.c
@@ -334,26 +334,24 @@ static int vmemmap_remap_free(unsigned l
 	return ret;
 }
 
-static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
-				   struct list_head *list)
+static int alloc_vmemmap_page_list(struct list_head *head,
+		unsigned int nr_pages, int nid)
 {
-	gfp_t gfp_mask = GFP_KERNEL | __GFP_RETRY_MAYFAIL;
-	unsigned long nr_pages = (end - start) >> PAGE_SHIFT;
-	int nid = page_to_nid((struct page *)start);
+	LIST_HEAD(new_pages);
 	struct page *page, *next;
-	int i;
 
-	for (i = 0; i < nr_pages; i++) {
-		page = alloc_pages_node(nid, gfp_mask, 0);
+	for (unsigned int i = 0; i < nr_pages; i++) {
+		page = alloc_pages_node(nid, GFP_KERNEL | __GFP_RETRY_MAYFAIL, 0);
 		if (!page)
-			goto out;
-		list_add(&page->lru, list);
+			goto free_pages;
+		list_add(&page->lru, &new_pages);
 	}
+	list_splice(&new_pages, head);
 	memmap_pages_add(nr_pages);
 
 	return 0;
-out:
-	list_for_each_entry_safe(page, next, list, lru)
+free_pages:
+	list_for_each_entry_safe(page, next, &new_pages, lru)
 		__free_page(page);
 	return -ENOMEM;
 }
@@ -374,13 +372,14 @@ static int vmemmap_remap_alloc(unsigned
 			       unsigned long flags)
 {
 	LIST_HEAD(vmemmap_pages);
+	int nid = page_to_nid((struct page *)start);
 	struct vmemmap_remap_walk walk = {
 		.remap_pte	= vmemmap_restore_pte,
 		.vmemmap_pages	= &vmemmap_pages,
 		.flags		= flags,
 	};
 
-	if (alloc_vmemmap_page_list(start, end, &vmemmap_pages))
+	if (alloc_vmemmap_page_list(&vmemmap_pages, (end - start) / PAGE_SIZE, nid))
 		return -ENOMEM;
 
 	return vmemmap_remap_range(start, end, &walk);
@@ -527,15 +526,13 @@ static int __hugetlb_vmemmap_optimize_fo
 	 */
 	folio_set_hugetlb_vmemmap_optimized(folio);
 
-	vmemmap_head = alloc_pages_node(nid, GFP_KERNEL, 0);
-	if (!vmemmap_head) {
+	if (alloc_vmemmap_page_list(vmemmap_pages, VMEMMAP_OPTIMIZATION_PAGES, nid)) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	vmemmap_head = list_first_entry(vmemmap_pages, struct page, lru);
 	copy_page(page_to_virt(vmemmap_head), folio);
-	list_add(&vmemmap_head->lru, vmemmap_pages);
-	memmap_pages_add(1);
 
 	vmemmap_start	= (unsigned long)&folio->page;
 	vmemmap_end	= vmemmap_start + hugetlb_vmemmap_size(h);
_

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_vmemmap-unify-writable-vmemmap-page-preparation.patch
mm-hugetlb_vmemmap-rename-vmemmap_remap_pte-to-vmemmap_optimize_pte.patch
mm-hugetlb_vmemmap-simplify-shared-tail-page-handling.patch
mm-hugetlb_vmemmap-move-alloc_vmemmap_page_list-next-to-its-free-helper.patch
mm-hugetlb_vmemmap-make-vmemmap-optimization-folio-oriented.patch
mm-hugetlb_vmemmap-make-vmemmap-restoration-folio-oriented.patch
mm-hugetlb_vmemmap-unify-vmemmap-range-restoration.patch
mm-hugetlb_vmemmap-make-vmemmap-pte-conversion-folio-oriented.patch
mm-hugetlb-fix-validation-of-unsupported-hugetlb-orders.patch