Merge tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

torvalds · torvalds · commit 2516a8715318 · 2025-12-13T20:35:41.000+12:00
Pull more MM updates from Andrew Morton:

 - "powerpc/pseries/cmm: two smaller fixes" (David Hildenbrand)
   fixes a couple of minor things in ppc land

 - "Improve folio split related functions" (Zi Yan)
   some cleanups and minorish fixes in the folio splitting code

* tag 'mm-stable-2025-12-11-11-39' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/damon/tests/core-kunit: avoid damos_test_commit stack warning
  mm: vmscan: correct nr_requested tracing in scan_folios
  MAINTAINERS: add idr core-api doc file to XARRAY
  mm/hugetlb: fix incorrect error return from hugetlb_reserve_pages()
  mm: fix CONFIG_STACK_GROWSUP typo in mm.h
  mm/huge_memory: fix folio split stats counting
  mm/huge_memory: make min_order_for_split() always return an order
  mm/huge_memory: replace can_split_folio() with direct refcount calculation
  mm/huge_memory: change folio_split_supported() to folio_check_splittable()
  mm/sparse: fix sparse_vmemmap_init_nid_early definition without CONFIG_SPARSEMEM
  powerpc/pseries/cmm: adjust BALLOON_MIGRATE when migrating pages
  powerpc/pseries/cmm: call balloon_devinfo_init() also without CONFIG_BALLOON_COMPACTION
diff --git a/MAINTAINERS b/MAINTAINERS
@@ -28321,6 +28321,7 @@ M:	Matthew Wilcox <willy@infradead.org>
 L:	linux-fsdevel@vger.kernel.org
 L:	linux-mm@kvack.org
 S:	Supported
+F:	Documentation/core-api/idr.rst
 F:	Documentation/core-api/xarray.rst
 F:	include/linux/idr.h
 F:	include/linux/xarray.h
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
@@ -532,6 +532,7 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
 
 	spin_lock_irqsave(&b_dev_info->pages_lock, flags);
 	balloon_page_insert(b_dev_info, newpage);
+	__count_vm_event(BALLOON_MIGRATE);
 	b_dev_info->isolated_pages--;
 	spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
 
@@ -550,7 +551,6 @@ static int cmm_migratepage(struct balloon_dev_info *b_dev_info,
 
 static void cmm_balloon_compaction_init(void)
 {
-	balloon_devinfo_init(&b_dev_info);
 	b_dev_info.migratepage = cmm_migratepage;
 }
 #else /* CONFIG_BALLOON_COMPACTION */
@@ -572,6 +572,7 @@ static int cmm_init(void)
 	if (!firmware_has_feature(FW_FEATURE_CMO) && !simulate)
 		return -EOPNOTSUPP;
 
+	balloon_devinfo_init(&b_dev_info);
 	cmm_balloon_compaction_init();
 
 	rc = register_oom_notifier(&cmm_oom_nb);
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
@@ -369,14 +369,13 @@ enum split_type {
 	SPLIT_TYPE_NON_UNIFORM,
 };
 
-bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins);
 int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 		unsigned int new_order);
 int folio_split_unmapped(struct folio *folio, unsigned int new_order);
-int min_order_for_split(struct folio *folio);
+unsigned int min_order_for_split(struct folio *folio);
 int split_folio_to_list(struct folio *folio, struct list_head *list);
-bool folio_split_supported(struct folio *folio, unsigned int new_order,
-		enum split_type split_type, bool warns);
+int folio_check_splittable(struct folio *folio, unsigned int new_order,
+			   enum split_type split_type);
 int folio_split(struct folio *folio, unsigned int new_order, struct page *page,
 		struct list_head *list);
 
@@ -407,7 +406,7 @@ static inline int split_huge_page_to_order(struct page *page, unsigned int new_o
 static inline int try_folio_split_to_order(struct folio *folio,
 		struct page *page, unsigned int new_order)
 {
-	if (!folio_split_supported(folio, new_order, SPLIT_TYPE_NON_UNIFORM, /* warns= */ false))
+	if (folio_check_splittable(folio, new_order, SPLIT_TYPE_NON_UNIFORM))
 		return split_huge_page_to_order(&folio->page, new_order);
 	return folio_split(folio, new_order, page, NULL);
 }
@@ -631,10 +630,10 @@ static inline int split_huge_page(struct page *page)
 	return -EINVAL;
 }
 
-static inline int min_order_for_split(struct folio *folio)
+static inline unsigned int min_order_for_split(struct folio *folio)
 {
 	VM_WARN_ON_ONCE_FOLIO(1, folio);
-	return -EINVAL;
+	return 0;
 }
 
 static inline int split_folio_to_list(struct folio *folio, struct list_head *list)
diff --git a/include/linux/mm.h b/include/linux/mm.h
@@ -438,7 +438,7 @@ enum {
 #define VM_NOHUGEPAGE	INIT_VM_FLAG(NOHUGEPAGE)
 #define VM_MERGEABLE	INIT_VM_FLAG(MERGEABLE)
 #define VM_STACK	INIT_VM_FLAG(STACK)
-#ifdef CONFIG_STACK_GROWS_UP
+#ifdef CONFIG_STACK_GROWSUP
 #define VM_STACK_EARLY	INIT_VM_FLAG(STACK_EARLY)
 #else
 #define VM_STACK_EARLY	VM_NONE
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
@@ -2289,7 +2289,7 @@ void sparse_init(void);
 #else
 #define sparse_init()	do {} while (0)
 #define sparse_index_init(_sec, _nid)  do {} while (0)
-#define sparse_vmemmap_init_nid_early(_nid, _use) do {} while (0)
+#define sparse_vmemmap_init_nid_early(_nid) do {} while (0)
 #define sparse_vmemmap_init_nid_late(_nid) do {} while (0)
 #define pfn_in_present_section pfn_valid
 #define subsection_map_init(_pfn, _nr_pages) do {} while (0)
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
@@ -924,7 +924,7 @@ static void damos_test_commit_for(struct kunit *test, struct damos *dst,
 	}
 }
 
-static void damos_test_commit(struct kunit *test)
+static void damos_test_commit_pageout(struct kunit *test)
 {
 	damos_test_commit_for(test,
 			&(struct damos){
@@ -945,6 +945,10 @@ static void damos_test_commit(struct kunit *test)
 					DAMOS_WMARK_FREE_MEM_RATE,
 					800, 50, 30},
 			});
+}
+
+static void damos_test_commit_migrate_hot(struct kunit *test)
+{
 	damos_test_commit_for(test,
 			&(struct damos){
 				.pattern = (struct damos_access_pattern){
@@ -1230,7 +1234,8 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damos_test_commit_quota),
 	KUNIT_CASE(damos_test_commit_dests),
 	KUNIT_CASE(damos_test_commit_filter),
-	KUNIT_CASE(damos_test_commit),
+	KUNIT_CASE(damos_test_commit_pageout),
+	KUNIT_CASE(damos_test_commit_migrate_hot),
 	KUNIT_CASE(damon_test_commit_target_regions),
 	KUNIT_CASE(damos_test_filter_out),
 	KUNIT_CASE(damon_test_feed_loop_next_input),
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
diff --git a/mm/vmscan.c b/mm/vmscan.c
