Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "mm, swap: improve cluster scan strategy" from Kairui Song improves
   performance and reduces the failure rate of swap cluster allocation

 - "support large align and nid in Rust allocators" from Vitaly Wool
   permits Rust allocators to set NUMA node and large alignment when
   perforning slub and vmalloc reallocs

 - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend
   DAMOS_STAT's handling of the DAMON operations sets for virtual
   address spaces for ops-level DAMOS filters

 - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren
   Baghdasaryan reduces mmap_lock contention during reads of
   /proc/pid/maps

 - "mm/mincore: minor clean up for swap cache checking" from Kairui Song
   performs some cleanup in the swap code

 - "mm: vm_normal_page*() improvements" from David Hildenbrand provides
   code cleanup in the pagemap code

 - "add persistent huge zero folio support" from Pankaj Raghav provides
   a block layer speedup by optionalls making the
   huge_zero_pagepersistent, instead of releasing it when its refcount
   falls to zero

 - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to
   the recently added Kexec Handover feature

 - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo
   Stoakes turns mm_struct.flags into a bitmap. To end the constant
   struggle with space shortage on 32-bit conflicting with 64-bit's
   needs

 - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap
   code

 - "selftests/mm: Fix false positives and skip unsupported tests" from
   Donet Tom fixes a few things in our selftests code

 - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised"
   from David Hildenbrand "allows individual processes to opt-out of
   THP=always into THP=madvise, without affecting other workloads on the
   system".

   It's a long story - the [1/N] changelog spells out the considerations

 - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on
   the memdesc project. Please see

      https://kernelnewbies.org/MatthewWilcox/Memdescs and
      https://blogs.oracle.com/linux/post/introducing-memdesc

 - "Tiny optimization for large read operations" from Chi Zhiling
   improves the efficiency of the pagecache read path

 - "Better split_huge_page_test result check" from Zi Yan improves our
   folio splitting selftest code

 - "test that rmap behaves as expected" from Wei Yang adds some rmap
   selftests

 - "remove write_cache_pages()" from Christoph Hellwig removes that
   function and converts its two remaining callers

 - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD
   selftests issues

 - "introduce kernel file mapped folios" from Boris Burkov introduces
   the concept of "kernel file pages". Using these permits btrfs to
   account its metadata pages to the root cgroup, rather than to the
   cgroups of random inappropriate tasks

 - "mm/pageblock: improve readability of some pageblock handling" from
   Wei Yang provides some readability improvements to the page allocator
   code

 - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON
   to understand arm32 highmem

 - "tools: testing: Use existing atomic.h for vma/maple tests" from
   Brendan Jackman performs some code cleanups and deduplication under
   tools/testing/

 - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes
   a couple of 32-bit issues in tools/testing/radix-tree.c

 - "kasan: unify kasan_enabled() and remove arch-specific
   implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific
   initialization code into a common arch-neutral implementation

 - "mm: remove zpool" from Johannes Weiner removes zspool - an
   indirection layer which now only redirects to a single thing
   (zsmalloc)

 - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a
   couple of cleanups in the fork code

 - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of
   adjustments at various nth_page() callsites, eventually permitting
   the removal of that undesirable helper function

 - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun
   creates a KASAN read-only mode for ARM, using that architecture's
   memory tagging feature. It is felt that a read-only mode KASAN is
   suitable for use in production systems rather than debug-only

 - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does
   some tidying in the hugetlb folio allocation code

 - "mm: establish const-correctness for pointer parameters" from Max
   Kellermann makes quite a number of the MM API functions more accurate
   about the constness of their arguments. This was getting in the way
   of subsystems (in this case CEPH) when they attempt to improving
   their own const/non-const accuracy

 - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of
   code sites which were confused over when to use free_pages() vs
   __free_pages()

 - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the
   mapletree code accessible to Rust. Required by nouveau and by its
   forthcoming successor: the new Rust Nova driver

 - "selftests/mm: split_huge_page_test: split_pte_mapped_thp
   improvements" from David Hildenbrand adds a fix and some cleanups to
   the thp selftesting code

 - "mm, swap: introduce swap table as swap cache (phase I)" from Chris
   Li and Kairui Song is the first step along the path to implementing
   "swap tables" - a new approach to swap allocation and state tracking
   which is expected to yield speed and space improvements. This
   patchset itself yields a 5-20% performance benefit in some situations

 - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc
   layer to clean up the ptdesc code a little

 - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some
   issues in our 5-level pagetable selftesting code

 - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan
   addresses a couple of minor issues in relatively new memory
   allocation profiling feature

 - "Small cleanups" from Matthew Wilcox has a few cleanups in
   preparation for more memdesc work

 - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from
   Quanmin Yan makes some changes to DAMON in furtherance of supporting
   arm highmem

 - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad
   Anjum adds that compiler check to selftests code and fixes the
   fallout, by removing dead code

 - "Improvements to Victim Process Thawing and OOM Reaper Traversal
   Order" from zhongjinji makes a number of improvements in the OOM
   killer: mainly thawing a more appropriate group of victim threads so
   they can release resources

 - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park
   is a bunch of small and unrelated fixups for DAMON

 - "mm/damon: define and use DAMON initialization check function" from
   SeongJae Park implement reliability and maintainability improvements
   to a recently-added bug fix

 - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from
   SeongJae Park provides additional transparency to userspace clients
   of the DAMON_STAT information

 - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes
   some constraints on khubepaged's collapsing of anon VMAs. It also
   increases the success rate of MADV_COLLAPSE against an anon vma

 - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()"
   from Lorenzo Stoakes moves us further towards removal of
   file_operations.mmap(). This patchset concentrates upon clearing up
   the treatment of stacked filesystems

 - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau
   provides some fixes and improvements to mlock's tracking of large
   folios. /proc/meminfo's "Mlocked" field became more accurate

 - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from
   Donet Tom fixes several user-visible KSM stats inaccuracies across
   forks and adds selftest code to verify these counters

 - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses
   some potential but presently benign issues in KSM's mm_slot handling

* tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits)
  mm: swap: check for stable address space before operating on the VMA
  mm: convert folio_page() back to a macro
  mm/khugepaged: use start_addr/addr for improved readability
  hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list
  alloc_tag: fix boot failure due to NULL pointer dereference
  mm: silence data-race in update_hiwater_rss
  mm/memory-failure: don't select MEMORY_ISOLATION
  mm/khugepaged: remove definition of struct khugepaged_mm_slot
  mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL
  hugetlb: increase number of reserving hugepages via cmdline
  selftests/mm: add fork inheritance test for ksm_merging_pages counter
  mm/ksm: fix incorrect KSM counter handling in mm_struct during fork
  drivers/base/node: fix double free in register_one_node()
  mm: remove PMD alignment constraint in execmem_vmalloc()
  mm/memory_hotplug: fix typo 'esecially' -> 'especially'
  mm/rmap: improve mlock tracking for large folios
  mm/filemap: map entire large folio faultaround
  mm/fault: try to map the entire file folio in finish_fault()
  mm/rmap: mlock large folios in try_to_unmap_one()
  mm/rmap: fix a mlock race condition in folio_referenced_one()
  ...

90 files changed, 3835 insertions, 2730 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 202e044f2b4d..0e26f4fc8717 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -9,9 +9,6 @@ menu "Memory Management options"
 config ARCH_NO_SWAP
 	bool
 
-config ZPOOL
-	bool
-
 menuconfig SWAP
 	bool "Support for paging of anonymous memory (swap)"
 	depends on MMU && BLOCK && !ARCH_NO_SWAP
@@ -26,7 +23,7 @@ config ZSWAP
 	bool "Compressed cache for swap pages"
 	depends on SWAP
 	select CRYPTO
-	select ZPOOL
+	select ZSMALLOC
 	help
 	  A lightweight compressed cache for swap pages.  It takes
 	  pages that are in the process of being swapped out and attempts to
@@ -125,45 +122,18 @@ config ZSWAP_COMPRESSOR_DEFAULT
        default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD
        default ""
 
-choice
-	prompt "Default allocator"
-	depends on ZSWAP
-	default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC if MMU
-	help
-	  Selects the default allocator for the compressed cache for
-	  swap pages.
-	  The default is 'zbud' for compatibility, however please do
-	  read the description of each of the allocators below before
-	  making a right choice.
+config ZSMALLOC
+	tristate
 
-	  The selection made here can be overridden by using the kernel
-	  command line 'zswap.zpool=' option.
+if ZSMALLOC
 
-config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
-	bool "zsmalloc"
-	select ZSMALLOC
-	help
-	  Use the zsmalloc allocator as the default allocator.
-endchoice
+menu "Zsmalloc allocator options"
+	depends on ZSMALLOC
 
-config ZSWAP_ZPOOL_DEFAULT
-       string
-       depends on ZSWAP
-       default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
-       default ""
-
-config ZSMALLOC
-	tristate
-	prompt "N:1 compression allocator (zsmalloc)" if (ZSWAP || ZRAM)
-	depends on MMU
-	help
-	  zsmalloc is a slab-based memory allocator designed to store
-	  pages of various compression levels efficiently. It achieves
-	  the highest storage density with the least amount of fragmentation.
+comment "Zsmalloc is a common backend allocator for zswap & zram"
 
 config ZSMALLOC_STAT
 	bool "Export zsmalloc statistics"
-	depends on ZSMALLOC
 	select DEBUG_FS
 	help
 	  This option enables code in the zsmalloc to collect various
@@ -175,7 +145,6 @@ config ZSMALLOC_CHAIN_SIZE
 	int "Maximum number of physical pages per-zspage"
 	default 8
 	range 4 16
-	depends on ZSMALLOC
 	help
 	  This option sets the upper limit on the number of physical pages
 	  that a zmalloc page (zspage) can consist of. The optimal zspage
@@ -190,6 +159,10 @@ config ZSMALLOC_CHAIN_SIZE
 
 	  For more information, see zsmalloc documentation.
 
+endmenu
+
+endif
+
 menu "Slab allocator options"
 
 config SLUB
@@ -440,9 +413,8 @@ config SPARSEMEM_VMEMMAP_ENABLE
 	bool
 
 config SPARSEMEM_VMEMMAP
-	bool "Sparse Memory virtual memmap"
+	def_bool y
 	depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
-	default y
 	help
 	  SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
 	  pfn_to_page and page_to_pfn operations.  This is the most
@@ -777,7 +749,6 @@ config MEMORY_FAILURE
 	depends on MMU
 	depends on ARCH_SUPPORTS_MEMORY_FAILURE
 	bool "Enable recovery from hardware memory errors"
-	select MEMORY_ISOLATION
 	select RAS
 	help
 	  Enables code to recover from some memory failures on systems
@@ -824,6 +795,22 @@ config ARCH_WANT_GENERAL_HUGETLB
 config ARCH_WANTS_THP_SWAP
 	def_bool n
 
+config PERSISTENT_HUGE_ZERO_FOLIO
+	bool "Allocate a PMD sized folio for zeroing"
+	depends on TRANSPARENT_HUGEPAGE
+	help
+	  Enable this option to reduce the runtime refcounting overhead
+	  of the huge zero folio and expand the places in the kernel
+	  that can use huge zero folios. For instance, block I/O benefits
+	  from access to large folios for zeroing memory.
+
+	  With this option enabled, the huge zero folio is allocated
+	  once and never freed. One full huge page's worth of memory shall
+	  be used.
+
+	  Say Y if your system has lots of memory. Say N if you are
+	  memory constrained.
+
 config MM_ID
 	def_bool n
 
@@ -1382,6 +1369,8 @@ config PT_RECLAIM
 
 	  Note: now only empty user PTE page table pages will be reclaimed.
 
+config FIND_NORMAL_PAGE
+	def_bool n
 
 source "mm/damon/Kconfig"
 
diff --git a/mm/Makefile b/mm/Makefile
index ef54aa615d9d..21abb3353550 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -115,7 +115,6 @@ obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o
 obj-$(CONFIG_DEBUG_VM_PGTABLE) += debug_vm_pgtable.o
 obj-$(CONFIG_PAGE_OWNER) += page_owner.o
 obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
-obj-$(CONFIG_ZPOOL)	+= zpool.o
 obj-$(CONFIG_ZSMALLOC)	+= zsmalloc.o
 obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
 obj-$(CONFIG_CMA)	+= cma.o
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 0beaca6bacf7..128b525b8811 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -510,7 +510,7 @@ static void wb_update_bandwidth_workfn(struct work_struct *work)
 /*
  * Initial write bandwidth: 100 MB/s
  */
-#define INIT_BW		(100 << (20 - PAGE_SHIFT))
+#define INIT_BW		MB_TO_PAGES(100)
 
 static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
 		   gfp_t gfp)
diff --git a/mm/cma.c b/mm/cma.c
index 2ffa4befb99a..813e6dc7b095 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -780,10 +780,8 @@ static int cma_range_alloc(struct cma *cma, struct cma_memrange *cmr,
 				unsigned long count, unsigned int align,
 				struct page **pagep, gfp_t gfp)
 {
-	unsigned long mask, offset;
-	unsigned long pfn = -1;
-	unsigned long start = 0;
 	unsigned lon