[merged mm-stable] mm-sparse-vmemmap-initialize-shared-tail-vmemmap-pages-on-allocation.patch removed from -mm tree

[merged mm-stable] mm-sparse-vmemmap-initialize-shared-tail-vmemmap-pages-on-allocation.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/sparse-vmemmap: initialize shared tail vmemmap pages on allocation
has been removed from the -mm tree.  Its filename was
     mm-sparse-vmemmap-initialize-shared-tail-vmemmap-pages-on-allocation.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/sparse-vmemmap: initialize shared tail vmemmap pages on allocation
Date: Thu, 10 Sep 2026 14:32:43 +0800

The shared tail vmemmap page allocated in vmemmap_get_tail() used to be
left uninitialized, because memmap_init_range() would later overwrite it. 
That forced users such as HugeTLB to defer the initialization to their own
setup paths.

Now that memmap_init_range() skips shared tail vmemmap pages, initialize
them immediately in vmemmap_get_tail() with init_compound_tail() instead.

This adds initialization at the point where the shared tail page is
allocated.  The existing HugeTLB initialization remains necessary until
the compound page order is set and memmap_init_range() starts skipping
shared tails.  It is removed when HugeTLB switches to the section-based
mechanism.

Link: https://lore.kernel.org/20260910063256.64386-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Qi Zheng <qi.zheng@linux.dev>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
---

 mm/sparse-vmemmap.c |   12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

--- a/mm/sparse-vmemmap.c~mm-sparse-vmemmap-initialize-shared-tail-vmemmap-pages-on-allocation
+++ a/mm/sparse-vmemmap.c
@@ -338,19 +338,11 @@ static __meminit struct page *vmemmap_ge
 	tail = zone->vmemmap_tails[idx];
 	if (tail)
 		return tail;
-
-	/*
-	 * Only allocate the page, but do not initialize it.
-	 *
-	 * Any initialization done here will be overwritten by memmap_init().
-	 *
-	 * hugetlb_bootmem_struct_page_init() will take care of initialization
-	 * after memmap_init().
-	 */
-
 	p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
 	if (!p)
 		return NULL;
+	for (int i = 0; i < PAGE_SIZE / sizeof(struct page); i++)
+		init_compound_tail(p + i, NULL, order, zone);
 
 	tail = virt_to_page(p);
 	zone->vmemmap_tails[idx] = tail;
_

Patches currently in -mm which might be from songmuchun@bytedance.com are