Merge tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - More userfaultfs work from Peter Xu

 - Several convert-to-folios series from Sidhartha Kumar and Huang Ying

 - Some filemap cleanups from Vishal Moola

 - David Hildenbrand added the ability to selftest anon memory COW
   handling

 - Some cpuset simplifications from Liu Shixin

 - Addition of vmalloc tracing support by Uladzislau Rezki

 - Some pagecache folioifications and simplifications from Matthew
   Wilcox

 - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use
   it

 - Miguel Ojeda contributed some cleanups for our use of the
   __no_sanitize_thread__ gcc keyword.

   This series should have been in the non-MM tree, my bad

 - Naoya Horiguchi improved the interaction between memory poisoning and
   memory section removal for huge pages

 - DAMON cleanups and tuneups from SeongJae Park

 - Tony Luck fixed the handling of COW faults against poisoned pages

 - Peter Xu utilized the PTE marker code for handling swapin errors

 - Hugh Dickins reworked compound page mapcount handling, simplifying it
   and making it more efficient

 - Removal of the autonuma savedwrite infrastructure from Nadav Amit and
   David Hildenbrand

 - zram support for multiple compression streams from Sergey Senozhatsky

 - David Hildenbrand reworked the GUP code's R/O long-term pinning so
   that drivers no longer need to use the FOLL_FORCE workaround which
   didn't work very well anyway

 - Mel Gorman altered the page allocator so that local IRQs can remnain
   enabled during per-cpu page allocations

 - Vishal Moola removed the try_to_release_page() wrapper

 - Stefan Roesch added some per-BDI sysfs tunables which are used to
   prevent network block devices from dirtying excessive amounts of
   pagecache

 - David Hildenbrand did some cleanup and repair work on KSM COW
   breaking

 - Nhat Pham and Johannes Weiner have implemented writeback in zswap's
   zsmalloc backend

 - Brian Foster has fixed a longstanding corner-case oddity in
   file[map]_write_and_wait_range()

 - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
   Chen

 - Shiyang Ruan has done some work on fsdax, to make its reflink mode
   work better under xfstests. Better, but still not perfect

 - Christoph Hellwig has removed the .writepage() method from several
   filesystems. They only need .writepages()

 - Yosry Ahmed wrote a series which fixes the memcg reclaim target
   beancounting

 - David Hildenbrand has fixed some of our MM selftests for 32-bit
   machines

 - Many singleton patches, as usual

* tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits)
  mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio
  mm: mmu_gather: allow more than one batch of delayed rmaps
  mm: fix typo in struct pglist_data code comment
  kmsan: fix memcpy tests
  mm: add cond_resched() in swapin_walk_pmd_entry()
  mm: do not show fs mm pc for VM_LOCKONFAULT pages
  selftests/vm: ksm_functional_tests: fixes for 32bit
  selftests/vm: cow: fix compile warning on 32bit
  selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions
  mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem
  mm,thp,rmap: fix races between updates of subpages_mapcount
  mm: memcg: fix swapcached stat accounting
  mm: add nodes= arg to memory.reclaim
  mm: disable top-tier fallback to reclaim on proactive reclaim
  selftests: cgroup: make sure reclaim target memcg is unprotected
  selftests: cgroup: refactor proactive reclaim code to reclaim_until()
  mm: memcg: fix stale protection of reclaim target memcg
  mm/mmap: properly unaccount memory on mas_preallocate() failure
  omfs: remove ->writepage
  jfs: remove ->writepage
  ...

10 files changed, 293 insertions, 48 deletions

diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index 14b2bf2e5105..628a00fb20a9 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -137,3 +137,17 @@ Description:
 		The writeback_limit file is read-write and specifies the maximum
 		amount of writeback ZRAM can do. The limit could be changed
 		in run time.
+
+What:		/sys/block/zram<id>/recomp_algorithm
+Date:		November 2022
+Contact:	Sergey Senozhatsky <senozhatsky@chromium.org>
+Description:
+		The recomp_algorithm file is read-write and allows to set
+		or show secondary compression algorithms.
+
+What:		/sys/block/zram<id>/recompress
+Date:		November 2022
+Contact:	Sergey Senozhatsky <senozhatsky@chromium.org>
+Description:
+		The recompress file is write-only and triggers re-compression
+		with secondary compression algorithms.
diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi
index 6d2a2fc189dd..0d2abd88a18c 100644
--- a/Documentation/ABI/testing/sysfs-class-bdi
+++ b/Documentation/ABI/testing/sysfs-class-bdi
@@ -44,6 +44,21 @@ Description:
 
 	(read-write)
 
+What:		/sys/class/bdi/<bdi>/min_ratio_fine
+Date:		November 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Under normal circumstances each device is given a part of the
+	total write-back cache that relates to its current average
+	writeout speed in relation to the other devices.
+
+	The 'min_ratio_fine' parameter allows assigning a minimum reserve
+	of the write-back cache to a particular device. The value is
+	expressed as part of 1 million. For example, this is useful for
+	providing a minimum QoS.
+
+	(read-write)
+
 What:		/sys/class/bdi/<bdi>/max_ratio
 Date:		January 2008
 Contact:	Peter Zijlstra <a.p.zijlstra@chello.nl>
@@ -56,6 +71,59 @@ Description:
 	be trusted to play fair.
 
 	(read-write)
+
+What:		/sys/class/bdi/<bdi>/max_ratio_fine
+Date:		November 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Allows limiting a particular device to use not more than the
+	given value of the write-back cache.  The value is given as part
+	of 1 million. This is useful in situations where we want to avoid
+	one device taking all or most of the write-back cache.  For example
+	in case of an NFS mount that is prone to get stuck, or a FUSE mount
+	which cannot be trusted to play fair.
+
+	(read-write)
+
+What:		/sys/class/bdi/<bdi>/min_bytes
+Date:		October 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Under normal circumstances each device is given a part of the
+	total write-back cache that relates to its current average
+	writeout speed in relation to the other devices.
+
+	The 'min_bytes' parameter allows assigning a minimum
+	percentage of the write-back cache to a particular device
+	expressed in bytes.
+	For example, this is useful for providing a minimum QoS.
+
+	(read-write)
+
+What:		/sys/class/bdi/<bdi>/max_bytes
+Date:		October 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Allows limiting a particular device to use not more than the
+	given 'max_bytes' of the write-back cache.  This is useful in
+	situations where we want to avoid one device taking all or
+	most of the write-back cache.  For example in case of an NFS
+	mount that is prone to get stuck, a FUSE mount which cannot be
+	trusted to play fair, or a nbd device.
+
+	(read-write)
+
+What:		/sys/class/bdi/<bdi>/strict_limit
+Date:		October 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Forces per-BDI checks for the share of given device in the write-back
+	cache even before the global background dirty limit is reached. This
+	is useful in situations where the global limit is much higher than
+	affordable for given relatively slow (or untrusted) device. Turning
+	strictlimit on has no visible effect if max_ratio is equal to 100%.
+
+	(read-write)
 What:		/sys/class/bdi/<bdi>/stable_pages_required
 Date:		January 2008
 Contact:	Peter Zijlstra <a.p.zijlstra@chello.nl>
diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
index 08b9df323560..13397b853692 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
@@ -27,6 +27,10 @@ Description:	Writing 'on' or 'off' to this file makes the kdamond starts or
 		makes the kdamond reads the user inputs in the sysfs files
 		except 'state' again.  Writing 'update_schemes_stats' to the
 		file updates contents of schemes stats files of the kdamond.
+		Writing 'update_schemes_tried_regions' to the file updates
+		contents of 'tried_regions' directory of every scheme directory
+		of this kdamond.  Writing 'clear_schemes_tried_regions' to the
+		file removes contents of the 'tried_regions' directory.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/pid
 Date:		Mar 2022
@@ -283,3 +287,31 @@ Date:		Mar 2022
 Contact:	SeongJae Park <sj@kernel.org>
 Description:	Reading this file returns the number of the exceed events of
 		the scheme's quotas.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/start
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the start address of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/end
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the end address of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/nr_accesses
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the 'nr_accesses' of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/age
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the 'age' of a memory region that
+		corresponding DAMON-based Operation Scheme's action has tried
+		to be applied.
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index c73b16930449..e4551579cb12 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -348,8 +348,13 @@ this can be accomplished with::
 
         echo huge_idle > /sys/block/zramX/writeback
 
+If a user chooses to writeback only incompressible pages (pages that none of
+algorithms can compress) this can be accomplished with::
+
+	echo incompressible > /sys/block/zramX/writeback
+
 If an admin wants to write a specific page in zram device to the backing device,
-they could write a page index into the interface.
+they could write a page index into the interface::
 
 	echo "page_index=1251" > /sys/block/zramX/writeback
 
@@ -401,6 +406,87 @@ budget in next setting is user's job.
 If admin wants to measure writeback count in a certain period, they could
 know it via /sys/block/zram0/bd_stat's 3rd column.
 
+recompression
+-------------
+
+With CONFIG_ZRAM_MULTI_COMP, zram can recompress pages using alternative
+(secondary) compression algorithms. The basic idea is that alternative
+compression algorithm can provide better compression ratio at a price of
+(potentially) slower compression/decompression speeds. Alternative compression
+algorithm can, for example, be more successful compressing huge pages (those
+that default algorithm failed to compress). Another application is idle pages
+recompression - pages that are cold and sit in the memory can be recompressed
+using more effective algorithm and, hence, reduce zsmalloc memory usage.
+
+With CONFIG_ZRAM_MULTI_COMP, zram supports up to 4 compression algorithms:
+one primary and up to 3 secondary ones. Primary zram compressor is explained
+in "3) Select compression algorithm", secondary algorithms are configured
+using recomp_algorithm device attribute.
+
+Example:::
+
+	#show supported recompression algorithms
+	cat /sys/block/zramX/recomp_algorithm
+	#1: lzo lzo-rle lz4 lz4hc [zstd]
+	#2: lzo lzo-rle lz4 [lz4hc] zstd
+
+Alternative compression algorithms are sorted by priority. In the example
+above, zstd is used as the first alternative algorithm, which has priority
+of 1, while lz4hc is configured as a compression algorithm with priority 2.
+Alternative compression algorithm's priority is provided during algorithms
+configuration:::
+
+	#select zstd recompression algorithm, priority 1
+	echo "algo=zstd priority=1" > /sys/block/zramX/recomp_algorithm
+
+	#select deflate recompression algorithm, priority 2
+	echo "algo=deflate priority=2" > /sys/block/zramX/recomp_algorithm
+
+Another device attribute that CONFIG_ZRAM_MULTI_COMP enables is recompress,
+which controls recompression.
+
+Examples:::
+
+	#IDLE pages recompression is activated by `idle` mode
+	echo "type=idle" > /sys/block/zramX/recompress
+
+	#HUGE pages recompression is activated by `huge` mode
+	echo "type=huge" > /sys/block/zram0/recompress
+
+	#HUGE_IDLE pages recompression is activated by `huge_idle` mode
+	echo "type=huge_idle" > /sys/block/zramX/recompress
+
+The number of idle pages can be significant, so user-space can pass a size
+threshold (in bytes) to the recompress knob: zram will recompress only pages
+of equal or greater size:::
+
+	#recompress all pages larger than 3000 bytes
+	echo "threshold=3000" > /sys/block/zramX/recompress
+
+	#recompress idle pages larger than 2000 bytes
+	echo "type=idle threshold=2000" > /sys/block/zramX/recompress
+
+Recompression of idle pages requires memory tracking.
+
+During re-compression for every page, that matches re-compression criteria,
+ZRAM iterates the list of registered alternative compression algorithms in
+order of their priorities. ZRAM stops either when re-compression was
+successful (re-compressed object is smaller in size than the original one)
+and matches re-compression criteria (e.g. size threshold) or when there are
+no secondary algorithms left to try. If none of the secondary algorithms can
+successfully re-compressed the page such a page is marked as incompressible,
+so ZRAM will not attempt to re-compress it in the future.
+
+This re-compression behaviour, when it iterates through the list of
+registered compression algorithms, increases our chances of finding the
+algorithm that successfully compresses a particular page. Sometimes, however,
+it is convenient (and sometimes even necessary) to limit recompression to
+only one particular algorithm so that it will not try any other algorithms.
+This can be achieved by providing a algo=NAME parameter:::
+
+	#use zstd algorithm only (if registered)
+	echo "type=huge algo=zstd" > /sys/block/zramX/recompress
+
 memory tracking
 ===============
 
@@ -411,9 +497,11 @@ pages of the process with*pagemap.
 If you enable the feature, you could see block state via
 /sys/kernel/debug/zram/zram0/block_state". The output is as follows::
 
-	  300    75.033841 .wh.
-	  301    63.806904 s...
-	  302    63.806919 ..hi
+	  300    75.033841 .wh...
+	  301    63.806904 s.....
+	  302    63.806919 ..hi..
+	  303    62.801919 ....r.
+	  304   146.781902 ..hi.n
 
 First column
 	zram's block index.
@@ -430,6 +518,10 @@ Third column
 		huge page
 	i:
 		idle page
+	r:
+		recompressed page (secondary compression algorithm)
+	n:
+		none (including secondary) of algorithms could compress it
 
 First line of above example says 300th block is accessed at 75.033841sec
 and the block's state is huge so it is written back to the backing
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index 5b86245450bd..60370f2c67b9 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -543,7 +543,8 @@ inactive_anon	# of bytes of anonymous and swap cache memory on inactive
 		LRU list.
 active_anon	# of bytes of anonymous and swap cache memory on active
 		LRU list.
-inactive_file	# of bytes of file-backed memory on inactive LRU list.
+inactive_file	# of bytes of file-backed memory and MADV_FREE anonymous memory(
+                LazyFree pages) on inactive LRU list.
 active_file	# of bytes of file-backed memory on active LRU list.
 unevictable	# of bytes of memory that cannot be reclaimed (mlocked etc).
 =============== ===============================================================
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index dc254a3cb956..c8ae7c897f14 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1245,17 +1245,13 @@ PAGE_SIZE multiple when read back.
 	This is a simple interface to trigger memory reclaim in the
 	target cgroup.
 
-	This file accepts a single key, the number of bytes to reclaim.
-	No nested keys are currently supported.
+	This file accepts a string which contains the number of bytes to
+	reclaim.
 
 	Example::
 
 	  echo "1G" > memory.reclaim
 
-	The interface can be later extended with nested keys to
-	configure the reclaim behavior. For example, specify the
-	type of memory to reclaim from (anon, file, ..).
-
 	Please note that the kernel can over or under reclaim from
 	the target cgroup. If less bytes are reclaimed than the
 	specified amount, -EAGAIN is returned.
@@ -1267,6 +1263,13 @@ PAGE_SIZE multiple when read back.
 	This means that the networking layer will not adapt based on
 	reclaim induced by memory.reclaim.
 
+	This file also allows the user to specify the nodes to reclaim from,
+	via the 'nodes=' key, for example::
+
+	  echo "1G nodes=0,1" > memory.reclaim
+
+	The above instructs the kernel to reclaim memory from nodes 0,1.
+
   memory.peak
 	A read-only single value file which exists on non-root
 	cgroups.
@@ -1488,12 +1491,18 @@ PAGE_SIZE multiple when read back.
 	  pgscan_direct (npn)
 		Amount of scanned pages directly  (in an inactive LRU list)
 
+	  pgscan_khugepaged (npn)
+		Amount of scanned pages by khugepaged  (in an inactive LRU list)
+
 	  pgsteal_kswapd (npn)
 		Amount of reclaimed pages by kswapd
 
 	  pgsteal_direct (npn)
 		Amount of reclaimed pages directly
 
+	  pgsteal_khugepaged (npn)
+		Amount of reclaimed pages by khugepaged
+
 	  pgfault (npn)
 		Total number of page faults incurred
 
diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index b47b0cbbd491..1a5b6b71efa1 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -88,6 +88,9 @@ comma (","). ::
     │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
     │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
     │ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds
+    │ │ │ │ │ │ │ tried_regions/
+    │ │ │ │ │ │ │ │ 0/start,end,nr_accesses,age
+    │ │ │ │ │ │ │ │ ...
     │ │ │ │ │ │ ...
     │ │ │ │ ...
     │ │ ...
@@ -125,7 +128,14 @@ in the state.  Writing ``commit`` to the ``state`` file makes kdamond reads the
 user inputs in the sysfs files except ``state`` file again.  Writing
 ``update_schemes_stats`` to ``state`` file updates the contents of stats files
 for each DAMON-based operation scheme of the kdamond.  For details of the
-stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.
+stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.  Writing
+``update_schemes_tried_regions`` to ``state`` file updates the DAMON-based
+operation scheme action tried regions directory for each DAMON-based operation
+scheme of the kdamond.  Writing ``clear_schemes_tried_regions`` to ``state``
+file clears the DAMON-based operating scheme action tried regions directory for
+each DAMON-based operation scheme of the kdamond.  For details of the
+DAMON-based operation scheme action tried regions directory, please refer to
+:ref:tried_regions section <sysfs_schemes_tried_regions>`.
 
 If the state is ``on``, reading ``pid`` shows the pid of the kdamond thread.
 
@@ -166,6 +176,8 @@ 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.
 
+.. _sysfs_monitoring_attrs:
+
 contexts/<N>/monitoring_attrs/
 ------------------------------
 
@@ -235,6 +247,9 @@ In each region directory, you will find two files (``start`` and ``end``).  You
 can set and get the start and end addresses of the initial monitoring target
 region by writing to and reading from the files, respectively.
 
+Each region should not overlap with others.  ``end`` of directory ``N`` should
+be equal or smaller than ``start`` of directory ``N+1``.
+
 contexts/<N>/schemes/
 ---------------------
 
@@ -252,8 +267,9 @@ to ``N-1``.  Each directory represents each DAMON-based operation scheme.
 schemes/<N>/
 ------------
 
-In each scheme directory, four directories (``access_pattern``, ``quotas``,
-``watermarks``, and ``stats``) and one file (``action``) exist.
+In each scheme directory, five directories (``access_pattern``, ``quotas``,
+``watermarks``, ``stats``, and ``tried_regions``) and one file (``action``)
+exist.
 
 The ``action`` file is for setting and getting what action you want to apply to
 memory regions having specific access pattern of the interest.  The keywords
@@ -348,6 +364,32 @@ should ask DAMON sysfs interface to updte the content of the files for the
 stats by writing a special keyword, ``update_schemes_stats`` to the relevant
 ``kdamonds/<N>/state`` file.
 
+.. _sysfs_schemes_tried_regions:
+
+schemes/<N>/tried_regions/
+--------------------------
+
+When a special keyword, ``update_schemes_tried_regions``, is written to the
+relevant ``kdamonds/<N>/state`` file, DAMON creates directories named integer
+starting from ``0`` under this directory.  Each directory contains files
+exposing detailed information about each of the memory region that the
+corresponding scheme's ``action`` has tried to be applied under this directory,
+during next :ref:`aggregation interval <sysfs_monitoring_attrs>`.  The
+information includes address range, ``nr_accesses``, , and ``age`` of the
+region.
+
+The directories will be removed when another special keyword,
+``clear_schemes_tried_regions``, is written to the relevant
+``kdamonds/<N>/state`` file.
+
+tried_regions/<N>/
+------------------
+
+In each region directory, you will find four files (``start``, ``end``,
+``nr_accesses``, and ``age``).  Reading the files will show the start and end
+addresses, ``nr_accesses``, and ``age`` of the region that corresponding
+DAMON-based operation scheme ``action`` has tried to be applied.
+
 Example
 ~~~~~~~
 
@@ -465,8 +507,9 @@ regions in case of physical memory monitoring.  Therefore, users should set the
 monitoring target regions by themselves.
 
 In such cases, users can explicitly set the initial monitoring target regions
-as they want, by writing proper values to the ``init_regions`` file.  Each line
-of the input should represent one region in below form.::
+as they want, by writing proper values to the ``init_regions`` file.  The input
+should be a sequence of three integers separated by white spaces that represent
+one region in below form.::
 
     <target idx> <start address> <end address>
 
@@ -481,9 +524,9 @@ ranges, ``20-40`` and ``50-100`` as that of pid 4242, which is the second one
     # cd <debugfs>/damon
     # cat target_ids
     42 4242
-    # echo "0   1       100
-            0   100     200
-            1   20      40
+    # echo "0   1       100 \
+            0   100     200 \
+            1   20      40  \
             1   50      100" > init_regions
 
 Note that this sets the initial monitoring target regions only.  In case of
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index f4ee84d7b351..e224b6d5b642 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -428,14 +428,16 @@ with the memory region, as the case would be with BSS (uninitialized data).
 The "pathname" shows the name associated file for this mapping.  If the mapping
 is not associated with a file:
 
- =============              ====================================
+ ===================        ===========================================
  [heap]                     the heap of the program
  [stack]                    the stack of the main process
  [vdso]                     the "virtual dynamic shared object",
                             the kernel system call handler
- [anon:<name>]              an anonymous mapping that has been
+ [anon:<name>]              a private anonymous mapping that has been
                             named by userspace
- =============              ====================================
+ [anon_shmem:<name>]        an anonymous shared memory mapping that has
+                            been named by userspace
+ ===================        ===========================================
 
  or if empty, the mapping is anonymous.
 
diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst
index cbaee9e59241..fd2a19df884e 100644
--- a/Documentation/mm/arch_pgtable_helpers.rst
+++ b/Documentation/mm/arch_pgtable_helpers.rst
@@ -94,7 +94,7 @@ PMD Page Table Helpers
 +---------------------------+--------------------------------------------------+
 | pmd_trans_huge            | Tests a Transparent Huge Page (THP) at PMD       |
 +---------------------------+--------------------------------------------------+
-| pmd_present               | Tests a valid mapped PMD                         |
+| pmd_present               | Tests whether pmd_page() points to valid memory  |
 +---------------------------+--------------------------------------------------+
 | pmd_young                 | Tests a young PMD                                |
 +---------------------------+--------------------------------------------------+
diff --git a/Documentation/mm/transhuge.rst b/Documentation/mm/transhuge.rst
index 216db1d67d04..ec3dc5b04226 100644
--- a/Documentation/mm/transhuge.rst
+++ b/Documentation/mm/transhuge.rst
@@ -117,31 +117,15 @@ pages:
   - ->_refcount in tail pages is always zero: get_page_unless_zero() never
     succeeds on tail pages.
 
-  - map/unmap of the pages with PTE entry increment/decrement ->_mapcount
-    on relevant sub-page of the compound page.
-
-  - map/unmap of the whole compound page is accounted for in compound_mapcount
-    (stored in first tail page). For file huge pages, we also increment
-    ->_mapcount of all sub-pages in order to have race-free detection of
-    last unmap of subpages.
-
-PageDoubleMap() indicates that the page is *possibly* mapped with PTEs.
-
-For anonymous pages, PageDoubleMap() also indicates ->_mapcount in all
-subpages is offset up by one. This additional reference is required to
-get race-free detection of unmap of subpages when we have them mapped with
-both PMDs and PTEs.
-
-This optimization is required to lower the overhead of per-subpage mapcount
-tracking. The alternative is to alter ->_mapcount in all subpages on each
-map/unmap of the whole compound page.
-
-For anonymous pages, we set PG_double_map when a PMD of the page is split
-for the first time, but still have a PMD mapping. The additional references
-go away with the last compound_mapcount.
-
-File pages get PG_double_map set on the first map of the page with PTE and
-goes away when the page gets evicted from the page cache.
+  - map/unmap of PMD entry for the whole compound page increment/decrement
+    ->compound_mapcount, stored in the first tail page of the compound page;
+    and also increment/decrement ->subpages_mapcount (also in the first tail)
+    by COMPOUND_MAPPED when compound_mapcount goes from -1 to 0 or 0 to -1.
+
+  - map/unmap of sub-pages with PTE entry increment/decrement ->_mapcount
+    on relevant sub-page of the compound page, and also increment/decrement
+    ->subpages_mapcount, stored in first tail page of the compound page, when
+    _mapcount goes from -1 to 0 or 0 to -1: counting sub-pages mapped by PTE.
 
 split_huge_page internally has to distribute the refcounts in the head
 page to the tail pages before clearing all PG_head/tail bits from the page