Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "maple_tree: Replace big node with maple copy" (Liam Howlett)

   Mainly prepararatory work for ongoing development but it does reduce
   stack usage and is an improvement.

 - "mm, swap: swap table phase III: remove swap_map" (Kairui Song)

   Offers memory savings by removing the static swap_map. It also yields
   some CPU savings and implements several cleanups.

 - "mm: memfd_luo: preserve file seals" (Pratyush Yadav)

   File seal preservation to LUO's memfd code

 - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan
   Chen)

   Additional userspace stats reportng to zswap

 - "arch, mm: consolidate empty_zero_page" (Mike Rapoport)

   Some cleanups for our handling of ZERO_PAGE() and zero_pfn

 - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu
   Han)

   A robustness improvement and some cleanups in the kmemleak code

 - "Improve khugepaged scan logic" (Vernon Yang)

   Improve khugepaged scan logic and reduce CPU consumption by
   prioritizing scanning tasks that access memory frequently

 - "Make KHO Stateless" (Jason Miu)

   Simplify Kexec Handover by transitioning KHO from an xarray-based
   metadata tracking system with serialization to a radix tree data
   structure that can be passed directly to the next kernel

 - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas
   Ballasi and Steven Rostedt)

   Enhance vmscan's tracepointing

 - "mm: arch/shstk: Common shadow stack mapping helper and
   VM_NOHUGEPAGE" (Catalin Marinas)

   Cleanup for the shadow stack code: remove per-arch code in favour of
   a generic implementation

 - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin)

   Fix a WARN() which can be emitted the KHO restores a vmalloc area

 - "mm: Remove stray references to pagevec" (Tal Zussman)

   Several cleanups, mainly udpating references to "struct pagevec",
   which became folio_batch three years ago

 - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl
   Shutsemau)

   Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail
   pages encode their relationship to the head page

 - "mm/damon/core: improve DAMOS quota efficiency for core layer
   filters" (SeongJae Park)

   Improve two problematic behaviors of DAMOS that makes it less
   efficient when core layer filters are used

 - "mm/damon: strictly respect min_nr_regions" (SeongJae Park)

   Improve DAMON usability by extending the treatment of the
   min_nr_regions user-settable parameter

 - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka)

   The proper fix for a previously hotfixed SMP=n issue. Code
   simplifications and cleanups ensued

 - "mm: cleanups around unmapping / zapping" (David Hildenbrand)

   A bunch of cleanups around unmapping and zapping. Mostly
   simplifications, code movements, documentation and renaming of
   zapping functions

 - "support batched checking of the young flag for MGLRU" (Baolin Wang)

   Batched checking of the young flag for MGLRU. It's part cleanups; one
   benchmark shows large performance benefits for arm64

 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner)

   memcg cleanup and robustness improvements

 - "Allow order zero pages in page reporting" (Yuvraj Sakshith)

   Enhance free page reporting - it is presently and undesirably order-0
   pages when reporting free memory.

 - "mm: vma flag tweaks" (Lorenzo Stoakes)

   Cleanup work following from the recent conversion of the VMA flags to
   a bitmap

 - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae
   Park)

   Add some more developer-facing debug checks into DAMON core

 - "mm/damon: test and document power-of-2 min_region_sz requirement"
   (SeongJae Park)

   An additional DAMON kunit test and makes some adjustments to the
   addr_unit parameter handling

 - "mm/damon/core: make passed_sample_intervals comparisons
   overflow-safe" (SeongJae Park)

   Fix a hard-to-hit time overflow issue in DAMON core

 - "mm/damon: improve/fixup/update ratio calculation, test and
   documentation" (SeongJae Park)

   A batch of misc/minor improvements and fixups for DAMON

 - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David
   Hildenbrand)

   Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code
   movement was required.

 - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky)

   A somewhat random mix of fixups, recompression cleanups and
   improvements in the zram code

 - "mm/damon: support multiple goal-based quota tuning algorithms"
   (SeongJae Park)

   Extend DAMOS quotas goal auto-tuning to support multiple tuning
   algorithms that users can select

 - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao)

   Fix the khugpaged sysfs handling so we no longer spam the logs with
   reams of junk when starting/stopping khugepaged

 - "mm: improve map count checks" (Lorenzo Stoakes)

   Provide some cleanups and slight fixes in the mremap, mmap and vma
   code

 - "mm/damon: support addr_unit on default monitoring targets for
   modules" (SeongJae Park)

   Extend the use of DAMON core's addr_unit tunable

 - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache)

   Cleanups to khugepaged and is a base for Nico's planned khugepaged
   mTHP support

 - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand)

   Code movement and cleanups in the memhotplug and sparsemem code

 - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup
   CONFIG_MIGRATION" (David Hildenbrand)

   Rationalize some memhotplug Kconfig support

 - "change young flag check functions to return bool" (Baolin Wang)

   Cleanups to change all young flag check functions to return bool

 - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh
   Law and SeongJae Park)

   Fix a few potential DAMON bugs

 - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo
   Stoakes)

   Convert a lot of the existing use of the legacy vm_flags_t data type
   to the new vma_flags_t type which replaces it. Mainly in the vma
   code.

 - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes)

   Expand the mmap_prepare functionality, which is intended to replace
   the deprecated f_op->mmap hook which has been the source of bugs and
   security issues for some time. Cleanups, documentation, extension of
   mmap_prepare into filesystem drivers

 - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes)

   Simplify and clean up zap_huge_pmd(). Additional cleanups around
   vm_normal_folio_pmd() and the softleaf functionality are performed.

* tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
  mm: fix deferred split queue races during migration
  mm/khugepaged: fix issue with tracking lock
  mm/huge_memory: add and use has_deposited_pgtable()
  mm/huge_memory: add and use normal_or_softleaf_folio_pmd()
  mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio()
  mm/huge_memory: separate out the folio part of zap_huge_pmd()
  mm/huge_memory: use mm instead of tlb->mm
  mm/huge_memory: remove unnecessary sanity checks
  mm/huge_memory: deduplicate zap deposited table call
  mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE()
  mm/huge_memory: add a common exit path to zap_huge_pmd()
  mm/huge_memory: handle buggy PMD entry in zap_huge_pmd()
  mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc
  mm/huge: avoid big else branch in zap_huge_pmd()
  mm/huge_memory: simplify vma_is_specal_huge()
  mm: on remap assert that input range within the proposed VMA
  mm: add mmap_action_map_kernel_pages[_full]()
  uio: replace deprecated mmap hook with mmap_prepare in uio_info
  drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare
  mm: allow handling of stacked mmap_prepare hooks in more drivers
  ...

1 files changed, 26 insertions, 24 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index bda71ae609ff..7d5b76478f0b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -735,21 +735,24 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr,
 	return (ret & VM_FAULT_OOM) ? -ENOMEM : 0;
 }
 
-static bool ksm_compatible(const struct file *file, vm_flags_t vm_flags)
+static bool ksm_compatible(const struct file *file, vma_flags_t vma_flags)
 {
-	if (vm_flags & (VM_SHARED  | VM_MAYSHARE | VM_SPECIAL |
-			VM_HUGETLB | VM_DROPPABLE))
-		return false;		/* just ignore the advice */
-
+	/* Just ignore the advice. */
+	if (vma_flags_test_any(&vma_flags, VMA_SHARED_BIT, VMA_MAYSHARE_BIT,
+			       VMA_HUGETLB_BIT))
+		return false;
+	if (vma_flags_test_single_mask(&vma_flags, VMA_DROPPABLE))
+		return false;
+	if (vma_flags_test_any_mask(&vma_flags, VMA_SPECIAL_FLAGS))
+		return false;
 	if (file_is_dax(file))
 		return false;
-
 #ifdef VM_SAO
-	if (vm_flags & VM_SAO)
+	if (vma_flags_test(&vma_flags, VMA_SAO_BIT))
 		return false;
 #endif
 #ifdef VM_SPARC_ADI
-	if (vm_flags & VM_SPARC_ADI)
+	if (vma_flags_test(&vma_flags, VMA_SPARC_ADI_BIT))
 		return false;
 #endif
 
@@ -758,7 +761,7 @@ static bool ksm_compatible(const struct file *file, vm_flags_t vm_flags)
 
 static bool vma_ksm_compatible(struct vm_area_struct *vma)
 {
-	return ksm_compatible(vma->vm_file, vma->vm_flags);
+	return ksm_compatible(vma->vm_file, vma->flags);
 }
 
 static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
@@ -2825,17 +2828,17 @@ static int ksm_scan_thread(void *nothing)
 	return 0;
 }
 
-static bool __ksm_should_add_vma(const struct file *file, vm_flags_t vm_flags)
+static bool __ksm_should_add_vma(const struct file *file, vma_flags_t vma_flags)
 {
-	if (vm_flags & VM_MERGEABLE)
+	if (vma_flags_test(&vma_flags, VMA_MERGEABLE_BIT))
 		return false;
 
-	return ksm_compatible(file, vm_flags);
+	return ksm_compatible(file, vma_flags);
 }
 
 static void __ksm_add_vma(struct vm_area_struct *vma)
 {
-	if (__ksm_should_add_vma(vma->vm_file, vma->vm_flags))
+	if (__ksm_should_add_vma(vma->vm_file, vma->flags))
 		vm_flags_set(vma, VM_MERGEABLE);
 }
 
@@ -2860,16 +2863,16 @@ static int __ksm_del_vma(struct vm_area_struct *vma)
  *
  * @mm:       Proposed VMA's mm_struct
  * @file:     Proposed VMA's file-backed mapping, if any.
- * @vm_flags: Proposed VMA"s flags.
+ * @vma_flags: Proposed VMA"s flags.
  *
- * Returns: @vm_flags possibly updated to mark mergeable.
+ * Returns: @vma_flags possibly updated to mark mergeable.
  */
-vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file,
-			 vm_flags_t vm_flags)
+vma_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file,
+			  vma_flags_t vma_flags)
 {
 	if (mm_flags_test(MMF_VM_MERGE_ANY, mm) &&
-	    __ksm_should_add_vma(file, vm_flags)) {
-		vm_flags |= VM_MERGEABLE;
+	    __ksm_should_add_vma(file, vma_flags)) {
+		vma_flags_set(&vma_flags, VMA_MERGEABLE_BIT);
 		/*
 		 * Generally, the flags here always include MMF_VM_MERGEABLE.
 		 * However, in rare cases, this flag may be cleared by ksmd who
@@ -2879,7 +2882,7 @@ vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file,
 			__ksm_enter(mm);
 	}
 
-	return vm_flags;
+	return vma_flags;
 }
 
 static void ksm_add_vmas(struct mm_struct *mm)
@@ -3168,6 +3171,8 @@ void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
 		return;
 again:
 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
+		/* Ignore the stable/unstable/sqnr flags */
+		const unsigned long addr = rmap_item->address & PAGE_MASK;
 		struct anon_vma *anon_vma = rmap_item->anon_vma;
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
@@ -3180,16 +3185,13 @@ again:
 			}
 			anon_vma_lock_read(anon_vma);
 		}
+
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
-			unsigned long addr;
 
 			cond_resched();
 			vma = vmac->vma;
 
-			/* Ignore the stable/unstable/sqnr flags */
-			addr = rmap_item->address & PAGE_MASK;
-
 			if (addr < vma->vm_start || addr >= vma->vm_end)
 				continue;
 			/*