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()
  ...

Author: torvalds

Documentation/ABI/testing/sysfs-kernel-mm-damon

@@ -77,6 +77,13 @@ Description:	Writing a keyword for a monitoring operations set ('vaddr' for
 		Note that only the operations sets that listed in
 		'avail_operations' file are valid inputs.
 
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/addr_unit
+Date:		Aug 2025
+Contact:	SeongJae Park <[email protected]>
+Description:	Writing an integer to this file sets the 'address unit'
+		parameter of the given operations set of the context.  Reading
+		the file returns the last-written 'address unit' value.
+
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/monitoring_attrs/intervals/sample_us
 Date:		Mar 2022
 Contact:	SeongJae Park <[email protected]>

Documentation/admin-guide/mm/damon/start.rst

@@ -175,4 +175,4 @@ Below command makes every memory region of size >=4K that has not accessed for
 
     $ sudo damo start --damos_access_rate 0 0 --damos_sz_region 4K max \
                       --damos_age 60s max --damos_action pageout \
-                      <pid of your workload>
+                      --target_pid <pid of your workload>

Documentation/admin-guide/mm/damon/usage.rst

@@ -61,7 +61,7 @@ comma (",").
     │ :ref:`kdamonds <sysfs_kdamonds>`/nr_kdamonds
     │ │ :ref:`0 <sysfs_kdamond>`/state,pid,refresh_ms
     │ │ │ :ref:`contexts <sysfs_contexts>`/nr_contexts
-    │ │ │ │ :ref:`0 <sysfs_context>`/avail_operations,operations
+    │ │ │ │ :ref:`0 <sysfs_context>`/avail_operations,operations,addr_unit
     │ │ │ │ │ :ref:`monitoring_attrs <sysfs_monitoring_attrs>`/
     │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us
     │ │ │ │ │ │ │ intervals_goal/access_bp,aggrs,min_sample_us,max_sample_us
@@ -188,9 +188,9 @@ details).  At the moment, only one context per kdamond is supported, so only
 contexts/<N>/
 -------------
 
-In each context directory, two files (``avail_operations`` and ``operations``)
-and three directories (``monitoring_attrs``, ``targets``, and ``schemes``)
-exist.
+In each context directory, three files (``avail_operations``, ``operations``
+and ``addr_unit``) and three directories (``monitoring_attrs``, ``targets``,
+and ``schemes``) exist.
 
 DAMON supports multiple types of :ref:`monitoring operations
 <damon_design_configurable_operations_set>`, including those for virtual address
@@ -205,6 +205,9 @@ You can set and get what type of monitoring operations DAMON will use for the
 context by writing one of the keywords listed in ``avail_operations`` file and
 reading from the ``operations`` file.
 
+``addr_unit`` file is for setting and getting the :ref:`address unit
+<damon_design_addr_unit>` parameter of the operations set.
+
 .. _sysfs_monitoring_attrs:
 
 contexts/<N>/monitoring_attrs/

Documentation/admin-guide/mm/transhuge.rst

@@ -225,6 +225,42 @@ to "always" or "madvise"), and it'll be automatically shutdown when
 PMD-sized THP is disabled (when both the per-size anon control and the
 top-level control are "never")
 
+process THP controls
+--------------------
+
+A process can control its own THP behaviour using the ``PR_SET_THP_DISABLE``
+and ``PR_GET_THP_DISABLE`` pair of prctl(2) calls. The THP behaviour set using
+``PR_SET_THP_DISABLE`` is inherited across fork(2) and execve(2). These calls
+support the following arguments::
+
+	prctl(PR_SET_THP_DISABLE, 1, 0, 0, 0):
+		This will disable THPs completely for the process, irrespective
+		of global THP controls or madvise(..., MADV_COLLAPSE) being used.
+
+	prctl(PR_SET_THP_DISABLE, 1, PR_THP_DISABLE_EXCEPT_ADVISED, 0, 0):
+		This will disable THPs for the process except when the usage of THPs is
+		advised. Consequently, THPs will only be used when:
+		- Global THP controls are set to "always" or "madvise" and
+		  madvise(..., MADV_HUGEPAGE) or madvise(..., MADV_COLLAPSE) is used.
+		- Global THP controls are set to "never" and madvise(..., MADV_COLLAPSE)
+		  is used. This is the same behavior as if THPs would not be disabled on
+		  a process level.
+		Note that MADV_COLLAPSE is currently always rejected if
+		madvise(..., MADV_NOHUGEPAGE) is set on an area.
+
+	prctl(PR_SET_THP_DISABLE, 0, 0, 0, 0):
+		This will re-enable THPs for the process, as if they were never disabled.
+		Whether THPs will actually be used depends on global THP controls and
+		madvise() calls.
+
+	prctl(PR_GET_THP_DISABLE, 0, 0, 0, 0):
+		This returns a value whose bits indicate how THP-disable is configured:
+		Bits
+		 1 0  Value  Description
+		|0|0|   0    No THP-disable behaviour specified.
+		|0|1|   1    THP is entirely disabled for this process.
+		|1|1|   3    THP-except-advised mode is set for this process.
+
 Khugepaged controls
 -------------------
 
@@ -383,14 +419,18 @@ option: ``huge=``. It can have following values:
 
 always
     Attempt to allocate huge pages every time we need a new page;
+    Always try PMD-sized huge pages first, and fall back to smaller-sized
+    huge pages if the PMD-sized huge page allocation fails;
 
 never
     Do not allocate huge pages. Note that ``madvise(..., MADV_COLLAPSE)``
     can still cause transparent huge pages to be obtained even if this mode
     is specified everywhere;
 
 within_size
-    Only allocate huge page if it will be fully within i_size.
+    Only allocate huge page if it will be fully within i_size;
+    Always try PMD-sized huge pages first, and fall back to smaller-sized
+    huge pages if the PMD-sized huge page allocation fails;
     Also respect madvise() hints;
 
 advise

Documentation/admin-guide/mm/zswap.rst

@@ -53,26 +53,17 @@ Zswap receives pages for compression from the swap subsystem and is able to
 evict pages from its own compressed pool on an LRU basis and write them back to
 the backing swap device in the case that the compressed pool is full.
 
-Zswap makes use of zpool for the managing the compressed memory pool.  Each
-allocation in zpool is not directly accessible by address.  Rather, a handle is
+Zswap makes use of zsmalloc for the managing the compressed memory pool.  Each
+allocation in zsmalloc is not directly accessible by address.  Rather, a handle is
 returned by the allocation routine and that handle must be mapped before being
 accessed.  The compressed memory pool grows on demand and shrinks as compressed
-pages are freed.  The pool is not preallocated.  By default, a zpool
-of type selected in ``CONFIG_ZSWAP_ZPOOL_DEFAULT`` Kconfig option is created,
-but it can be overridden at boot time by setting the ``zpool`` attribute,
-e.g. ``zswap.zpool=zsmalloc``. It can also be changed at runtime using the sysfs
-``zpool`` attribute, e.g.::
-
-	echo zsmalloc > /sys/module/zswap/parameters/zpool
-
-The zsmalloc type zpool has a complex compressed page storage method, and it
-can achieve great storage densities.
+pages are freed.  The pool is not preallocated.
 
 When a swap page is passed from swapout to zswap, zswap maintains a mapping
-of the swap entry, a combination of the swap type and swap offset, to the zpool
-handle that references that compressed swap page.  This mapping is achieved
-with a red-black tree per swap type.  The swap offset is the search key for the
-tree nodes.
+of the swap entry, a combination of the swap type and swap offset, to the
+zsmalloc handle that references that compressed swap page.  This mapping is
+achieved with a red-black tree per swap type.  The swap offset is the search
+key for the tree nodes.
 
 During a page fault on a PTE that is a swap entry, the swapin code calls the
 zswap load function to decompress the page into the page allocated by the page
@@ -96,11 +87,11 @@ attribute, e.g.::
 
 	echo lzo > /sys/module/zswap/parameters/compressor
 
-When the zpool and/or compressor parameter is changed at runtime, any existing
-compressed pages are not modified; they are left in their own zpool.  When a
-request is made for a page in an old zpool, it is uncompressed using its
-original compressor.  Once all pages are removed from an old zpool, the zpool
-and its compressor are freed.
+When the compressor parameter is changed at runtime, any existing compressed
+pages are not modified; they are left in their own pool.  When a request is
+made for a page in an old pool, it is uncompressed using its original
+compressor.  Once all pages are removed from an old pool, the pool and its
+compressor are freed.
 
 Some of the pages in zswap are same-value filled pages (i.e. contents of the
 page have same value or repetitive pattern). These pages include zero-filled

Documentation/core-api/mm-api.rst

@@ -118,7 +118,6 @@ More Memory Management Functions
 .. kernel-doc:: mm/memremap.c
 .. kernel-doc:: mm/hugetlb.c
 .. kernel-doc:: mm/swap.c
-.. kernel-doc:: mm/zpool.c
 .. kernel-doc:: mm/memcontrol.c
 .. #kernel-doc:: mm/memory-tiers.c (build warnings)
 .. kernel-doc:: mm/shmem.c

Documentation/dev-tools/kasan.rst

@@ -143,6 +143,9 @@ disabling KASAN altogether or controlling its features:
   Asymmetric mode: a bad access is detected synchronously on reads and
   asynchronously on writes.
 
+- ``kasan.write_only=off`` or ``kasan.write_only=on`` controls whether KASAN
+  checks the write (store) accesses only or all accesses (default: ``off``).
+
 - ``kasan.vmalloc=off`` or ``=on`` disables or enables tagging of vmalloc
   allocations (default: ``on``).
 

Documentation/driver-api/crypto/iaa/iaa-crypto.rst

@@ -476,7 +476,6 @@ Use the following commands to enable zswap::
   # echo 0 > /sys/module/zswap/parameters/enabled
   # echo 50 > /sys/module/zswap/parameters/max_pool_percent
   # echo deflate-iaa > /sys/module/zswap/parameters/compressor
-  # echo zsmalloc > /sys/module/zswap/parameters/zpool
   # echo 1 > /sys/module/zswap/parameters/enabled
   # echo 100 > /proc/sys/vm/swappiness
   # echo never > /sys/kernel/mm/transparent_hugepage/enabled
@@ -625,7 +624,6 @@ the 'fixed' compression mode::
   echo 0 > /sys/module/zswap/parameters/enabled
   echo 50 > /sys/module/zswap/parameters/max_pool_percent
   echo deflate-iaa > /sys/module/zswap/parameters/compressor
-  echo zsmalloc > /sys/module/zswap/parameters/zpool
   echo 1 > /sys/module/zswap/parameters/enabled
 
   echo 100 > /proc/sys/vm/swappiness

Documentation/filesystems/proc.rst

@@ -291,8 +291,9 @@ It's slow but very precise.
  HugetlbPages                size of hugetlb memory portions
  CoreDumping                 process's memory is currently being dumped
                              (killing the process may lead to a corrupted core)
- THP_enabled		     process is allowed to use THP (returns 0 when
-			     PR_SET_THP_DISABLE is set on the process
+ THP_enabled                 process is allowed to use THP (returns 0 when
+                             PR_SET_THP_DISABLE is set on the process to disable
+                             THP completely, not just partially)
  Threads                     number of threads
  SigQ                        number of signals queued/max. number for queue
  SigPnd                      bitmap of pending signals for the thread
@@ -1008,6 +1009,19 @@ number, module (if originates from a loadable module) and the function calling
 the allocation. The number of bytes allocated and number of calls at each
 location are reported. The first line indicates the version of the file, the
 second line is the header listing fields in the file.
+If file version is 2.0 or higher then each line may contain additional
+<key>:<value> pairs representing extra information about the call site.
+For example if the counters are not accurate, the line will be appended with
+"accurate:no" pair.
+
+Supported markers in v2:
+accurate:no
+
+              Absolute values of the counters in this line are not accurate
+              because of the failure to allocate memory to track some of the
+              allocations made at this location.  Deltas in these counters are
+              accurate, therefore counters can be used to track allocation size
+              and count changes.
 
 Example output.
 

Documentation/mm/damon/design.rst

@@ -67,7 +67,7 @@ processes, NUMA nodes, files, and backing memory devices would be supportable.
 Also, if some architectures or devices support special optimized access check
 features, those will be easily configurable.
 
-DAMON currently provides below three operation sets.  Below two subsections
+DAMON currently provides below three operation sets.  Below three subsections
 describe how those work.
 
  - vaddr: Monitor virtual address spaces of specific processes
@@ -135,6 +135,20 @@ the interference is the responsibility of sysadmins.  However, it solves the
 conflict with the reclaim logic using ``PG_idle`` and ``PG_young`` page flags,
 as Idle page tracking does.
 
+.. _damon_design_addr_unit:
+
+Address Unit
+------------
+
+DAMON core layer uses ``unsinged long`` type for monitoring target address
+ranges.  In some cases, the address space for a given operations set could be
+too large to be handled with the type.  ARM (32-bit) with large physical
+address extension is an example.  For such cases, a per-operations set
+parameter called ``address unit`` is provided.  It represents the scale factor
+that need to be multiplied to the core layer's address for calculating real
+address on the given address space.  Support of ``address unit`` parameter is
+up to each operations set implementation.  ``paddr`` is the only operations set
+implementation that supports the parameter.
 
 .. _damon_core_logic:
 
@@ -689,7 +703,7 @@ DAMOS accounts below statistics for each scheme, from the beginning of the
 scheme's execution.
 
 - ``nr_tried``: Total number of regions that the scheme is tried to be applied.
-- ``sz_trtied``: Total size of regions that the scheme is tried to be applied.
+- ``sz_tried``: Total size of regions that the scheme is tried to be applied.
 - ``sz_ops_filter_passed``: Total bytes that passed operations set
   layer-handled DAMOS filters.
 - ``nr_applied``: Total number of regions that the scheme is applied.