[merged mm-stable] mm-provide-free_reserved_pages-removing-x86-variant.patch removed from -mm tree

The quilt patch titled
     Subject: mm: provide free_reserved_pages(), removing x86 variant
has been removed from the -mm tree.  Its filename was
     mm-provide-free_reserved_pages-removing-x86-variant.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: "David Hildenbrand (Arm)" <[email protected]>
Subject: mm: provide free_reserved_pages(), removing x86 variant
Date: Thu, 16 Jul 2026 16:51:01 +0200

Let's extend free_reserved_page() in page_alloc.c to
free_reserved_pages(), dropping the custom x86 variant.  The common-code
variant will consume an order, so adjust the x86 callers accordingly.

Make free_reserved_pages() assume that we are freeing ordinary high-order
pages, just with the special "reserved" flavor.  The target use case for
now is freeing vmemmap PMD pages.

Set the refcount directly to 0 (instead of 1) and call
__free_frozen_pages().  Set the page count to 0 before clearing
PG_reserved, so someone checking PG_reserved (and not finding it set) to
then try grabbing a ref would not suddenly have that ref be dropped.  That
is arguably cleaner and safer than the old way of doing it.

Add some kerneldoc.  Use a single adjust_managed_page_count() call.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: David Hildenbrand (Arm) <[email protected]>
Reviewed-by: Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Reviewed-by: Dave Hansen <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: "Borislav Petkov (AMD)" <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 arch/x86/mm/init_64.c |    8 +-------
 include/linux/mm.h    |    8 ++++++--
 mm/page_alloc.c       |   33 ++++++++++++++++++++++++++-------
 3 files changed, 33 insertions(+), 16 deletions(-)

--- a/arch/x86/mm/init_64.c~mm-provide-free_reserved_pages-removing-x86-variant
+++ a/arch/x86/mm/init_64.c
@@ -1000,12 +1000,6 @@ int arch_add_memory(int nid, u64 start,
 	return add_pages(nid, start_pfn, nr_pages, params);
 }
 
-static void free_reserved_pages(struct page *page, unsigned long nr_pages)
-{
-	while (nr_pages--)
-		free_reserved_page(page++);
-}
-
 static void __meminit free_pagetable(struct page *page)
 {
 	/* bootmem page has reserved flag */
@@ -1038,7 +1032,7 @@ static void __meminit free_vmemmap_pages
 			while (nr_pages--)
 				put_page_bootmem(page++);
 		} else {
-			free_reserved_pages(page, nr_pages);
+			free_reserved_pages(page, order);
 		}
 	} else {
 		__free_pages(page, order);
--- a/include/linux/mm.h~mm-provide-free_reserved_pages-removing-x86-variant
+++ a/include/linux/mm.h
@@ -3996,8 +3996,12 @@ extern unsigned long free_reserved_area(
 
 extern void adjust_managed_page_count(struct page *page, long count);
 
-/* Free the reserved page into the buddy system, so it gets managed. */
-void free_reserved_page(struct page *page);
+void free_reserved_pages(struct page *page, unsigned int order);
+
+static inline void free_reserved_page(struct page *page)
+{
+	free_reserved_pages(page, 0);
+}
 
 static inline void mark_page_reserved(struct page *page)
 {
--- a/mm/page_alloc.c~mm-provide-free_reserved_pages-removing-x86-variant
+++ a/mm/page_alloc.c
@@ -6389,15 +6389,34 @@ void adjust_managed_page_count(struct pa
 }
 EXPORT_SYMBOL(adjust_managed_page_count);
 
-void free_reserved_page(struct page *page)
+/**
+ * free_reserved_pages - free reserved pages
+ * @page: First page to free.
+ * @order: The page order to free.
+ *
+ * Free pages allocated through memblock during boot, letting the buddy
+ * manage them from now on.
+ *
+ * @page must be naturally aligned to the order and the order must not
+ * exceed MAX_PAGE_ORDER. All pages must be reserved.
+ */
+void free_reserved_pages(struct page *page, unsigned int order)
 {
-	clear_page_tag_ref(page);
-	ClearPageReserved(page);
-	init_page_count(page);
-	__free_page(page);
-	adjust_managed_page_count(page, 1);
+	const unsigned long nr_pages = 1UL << order;
+	int i;
+
+	VM_WARN_ON_ONCE(!IS_ALIGNED(page_to_pfn(page), nr_pages));
+	VM_WARN_ON_ONCE(order > MAX_PAGE_ORDER);
+
+	for (i = 0; i < nr_pages; i++) {
+		clear_page_tag_ref(page + i);
+		set_page_count(page + i, 0);
+		ClearPageReserved(page + i);
+	}
+	adjust_managed_page_count(page, nr_pages);
+	__free_frozen_pages(page, order, FPI_NONE);
 }
-EXPORT_SYMBOL(free_reserved_page);
+EXPORT_SYMBOL(free_reserved_pages);
 
 static int page_alloc_cpu_dead(unsigned int cpu)
 {
_

Patches currently in -mm which might be from [email protected] are

mm-standardize-printing-for-pgtable-entries.patch
mm-gup-fix-always-draining-lru-caches-in-collect_longterm_unpinnable_folios.patch