Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton <[email protected]>: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...

Documentation/admin-guide/blockdev/zram.rst

@@ -266,6 +266,7 @@ line of text and contains the following stats separated by whitespace:
                   No memory is allocated for such pages.
  pages_compacted  the number of pages freed during compaction
  huge_pages	  the number of incompressible pages
+ huge_pages_since the number of incompressible pages since zram set up
  ================ =============================================================
 
 File /sys/block/zram<id>/bd_stat
@@ -334,6 +335,11 @@ Admin can request writeback of those idle pages at right timing via::
 
 With the command, zram writeback idle pages from memory to the storage.
 
+If admin want to write a specific page in zram device to backing device,
+they could write a page index into the interface.
+
+	echo "page_index=1251" > /sys/block/zramX/writeback
+
 If there are lots of write IO with flash device, potentially, it has
 flash wearout problem so that admin needs to design write limitation
 to guarantee storage health for entire product life.

Documentation/admin-guide/cgroup-v1/memcg_test.rst

@@ -219,13 +219,11 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
 
 	This is an easy way to test page migration, too.
 
-9.5 mkdir/rmdir
----------------
+9.5 nested cgroups
+------------------
 
-	When using hierarchy, mkdir/rmdir test should be done.
-	Use tests like the following::
+	Use tests like the following for testing nested cgroups::
 
-		echo 1 >/opt/cgroup/01/memory/use_hierarchy
 		mkdir /opt/cgroup/01/child_a
 		mkdir /opt/cgroup/01/child_b
 

Documentation/admin-guide/cgroup-v1/memory.rst

@@ -77,6 +77,8 @@ Brief summary of control files.
  memory.soft_limit_in_bytes	     set/show soft limit of memory usage
  memory.stat			     show various statistics
  memory.use_hierarchy		     set/show hierarchical account enabled
+                                     This knob is deprecated and shouldn't be
+                                     used.
  memory.force_empty		     trigger forced page reclaim
  memory.pressure_level		     set memory pressure notifications
  memory.swappiness		     set/show swappiness parameter of vmscan
@@ -495,16 +497,13 @@ cgroup might have some charge associated with it, even though all
 tasks have migrated away from it. (because we charge against pages, not
 against tasks.)
 
-We move the stats to root (if use_hierarchy==0) or parent (if
-use_hierarchy==1), and no change on the charge except uncharging
+We move the stats to parent, and no change on the charge except uncharging
 from the child.
 
 Charges recorded in swap information is not updated at removal of cgroup.
 Recorded information is discarded and a cgroup which uses swap (swapcache)
 will be charged as a new owner of it.
 
-About use_hierarchy, see Section 6.
-
 5. Misc. interfaces
 ===================
 
@@ -527,8 +526,6 @@ About use_hierarchy, see Section 6.
   write will still return success. In this case, it is expected that
   memory.kmem.usage_in_bytes == memory.usage_in_bytes.
 
-  About use_hierarchy, see Section 6.
-
 5.2 stat file
 -------------
 
@@ -675,31 +672,20 @@ hierarchy::
 		      d   e
 
 In the diagram above, with hierarchical accounting enabled, all memory
-usage of e, is accounted to its ancestors up until the root (i.e, c and root),
-that has memory.use_hierarchy enabled. If one of the ancestors goes over its
-limit, the reclaim algorithm reclaims from the tasks in the ancestor and the
-children of the ancestor.
-
-6.1 Enabling hierarchical accounting and reclaim
-------------------------------------------------
-
-A memory cgroup by default disables the hierarchy feature. Support
-can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup::
+usage of e, is accounted to its ancestors up until the root (i.e, c and root).
+If one of the ancestors goes over its limit, the reclaim algorithm reclaims
+from the tasks in the ancestor and the children of the ancestor.
 
-	# echo 1 > memory.use_hierarchy
-
-The feature can be disabled by::
+6.1 Hierarchical accounting and reclaim
+---------------------------------------
 
-	# echo 0 > memory.use_hierarchy
+Hierarchical accounting is enabled by default. Disabling the hierarchical
+accounting is deprecated. An attempt to do it will result in a failure
+and a warning printed to dmesg.
 
-NOTE1:
-       Enabling/disabling will fail if either the cgroup already has other
-       cgroups created below it, or if the parent cgroup has use_hierarchy
-       enabled.
+For compatibility reasons writing 1 to memory.use_hierarchy will always pass::
 
-NOTE2:
-       When panic_on_oom is set to "2", the whole system will panic in
-       case of an OOM event in any cgroup.
+	# echo 1 > memory.use_hierarchy
 
 7. Soft limits
 ==============

Documentation/admin-guide/cgroup-v2.rst

@@ -1274,6 +1274,9 @@ PAGE_SIZE multiple when read back.
 	  kernel_stack
 		Amount of memory allocated to kernel stacks.
 
+	  pagetables
+                Amount of memory allocated for page tables.
+
 	  percpu(npn)
 		Amount of memory used for storing per-cpu kernel
 		data structures.
@@ -1300,6 +1303,14 @@ PAGE_SIZE multiple when read back.
 		Amount of memory used in anonymous mappings backed by
 		transparent hugepages
 
+	  file_thp
+		Amount of cached filesystem data backed by transparent
+		hugepages
+
+	  shmem_thp
+		Amount of shm, tmpfs, shared anonymous mmap()s backed by
+		transparent hugepages
+
 	  inactive_anon, active_anon, inactive_file, active_file, unevictable
 		Amount of memory, swap-backed and filesystem-backed,
 		on the internal memory management lists used by the

Documentation/admin-guide/mm/transhuge.rst

@@ -401,21 +401,6 @@ compact_fail
 	is incremented if the system tries to compact memory
 	but failed.
 
-compact_pages_moved
-	is incremented each time a page is moved. If
-	this value is increasing rapidly, it implies that the system
-	is copying a lot of data to satisfy the huge page allocation.
-	It is possible that the cost of copying exceeds any savings
-	from reduced TLB misses.
-
-compact_pagemigrate_failed
-	is incremented when the underlying mechanism
-	for moving a page failed.
-
-compact_blocks_moved
-	is incremented each time memory compaction examines
-	a huge page aligned range of pages.
-
 It is possible to establish how long the stalls were using the function
 tracer to record how long was spent in __alloc_pages_nodemask and
 using the mm_page_alloc tracepoint to identify which allocations were

Documentation/admin-guide/sysctl/vm.rst

@@ -873,12 +873,17 @@ file-backed pages is less than the high watermark in a zone.
 unprivileged_userfaultfd
 ========================
 
-This flag controls whether unprivileged users can use the userfaultfd
-system calls.  Set this to 1 to allow unprivileged users to use the
-userfaultfd system calls, or set this to 0 to restrict userfaultfd to only
-privileged users (with SYS_CAP_PTRACE capability).
+This flag controls the mode in which unprivileged users can use the
+userfaultfd system calls. Set this to 0 to restrict unprivileged users
+to handle page faults in user mode only. In this case, users without
+SYS_CAP_PTRACE must pass UFFD_USER_MODE_ONLY in order for userfaultfd to
+succeed. Prohibiting use of userfaultfd for handling faults from kernel
+mode may make certain vulnerabilities more difficult to exploit.
 
-The default value is 1.
+Set this to 1 to allow unprivileged users to use the userfaultfd system
+calls without any restrictions.
+
+The default value is 0.
 
 
 user_reserve_kbytes

Documentation/core-api/memory-allocation.rst

@@ -147,6 +147,10 @@ The address of a chunk allocated with `kmalloc` is aligned to at least
 ARCH_KMALLOC_MINALIGN bytes.  For sizes which are a power of two, the
 alignment is also guaranteed to be at least the respective size.
 
+Chunks allocated with kmalloc() can be resized with krealloc(). Similarly
+to kmalloc_array(): a helper for resizing arrays is provided in the form of
+krealloc_array().
+
 For large allocations you can use vmalloc() and vzalloc(), or directly
 request pages from the page allocator. The memory allocated by `vmalloc`
 and related functions is not physically contiguous.

Documentation/core-api/pin_user_pages.rst

@@ -221,12 +221,12 @@ Unit testing
 ============
 This file::
 
- tools/testing/selftests/vm/gup_benchmark.c
+ tools/testing/selftests/vm/gup_test.c
 
 has the following new calls to exercise the new pin*() wrapper functions:
 
-* PIN_FAST_BENCHMARK (./gup_benchmark -a)
-* PIN_BENCHMARK (./gup_benchmark -b)
+* PIN_FAST_BENCHMARK (./gup_test -a)
+* PIN_BASIC_TEST (./gup_test -b)
 
 You can monitor how many total dma-pinned pages have been acquired and released
 since the system was booted, via two new /proc/vmstat entries: ::

Documentation/dev-tools/kasan.rst

@@ -190,8 +190,9 @@ function calls GCC directly inserts the code to check the shadow memory.
 This option significantly enlarges kernel but it gives x1.1-x2 performance
 boost over outline instrumented kernel.
 
-Generic KASAN prints up to 2 call_rcu() call stacks in reports, the last one
-and the second to last.
+Generic KASAN also reports the last 2 call stacks to creation of work that
+potentially has access to an object. Call stacks for the following are shown:
+call_rcu() and workqueue queuing.
 
 Software tag-based KASAN
 ~~~~~~~~~~~~~~~~~~~~~~~~

Documentation/filesystems/tmpfs.rst

@@ -4,7 +4,7 @@
 Tmpfs
 =====
 
-Tmpfs is a file system which keeps all files in virtual memory.
+Tmpfs is a file system which keeps all of its files in virtual memory.
 
 
 Everything in tmpfs is temporary in the sense that no files will be
@@ -35,7 +35,7 @@ tmpfs has the following uses:
    memory.
 
    This mount does not depend on CONFIG_TMPFS. If CONFIG_TMPFS is not
-   set, the user visible part of tmpfs is not build. But the internal
+   set, the user visible part of tmpfs is not built. But the internal
    mechanisms are always present.
 
 2) glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for
@@ -50,7 +50,7 @@ tmpfs has the following uses:
    This mount is _not_ needed for SYSV shared memory. The internal
    mount is used for that. (In the 2.3 kernel versions it was
    necessary to mount the predecessor of tmpfs (shm fs) to use SYSV
-   shared memory)
+   shared memory.)
 
 3) Some people (including me) find it very convenient to mount it
    e.g. on /tmp and /var/tmp and have a big swap partition. And now
@@ -83,7 +83,7 @@ If nr_blocks=0 (or size=0), blocks will not be limited in that instance;
 if nr_inodes=0, inodes will not be limited.  It is generally unwise to
 mount with such options, since it allows any user with write access to
 use up all the memory on the machine; but enhances the scalability of
-that instance in a system with many cpus making intensive use of it.
+that instance in a system with many CPUs making intensive use of it.
 
 
 tmpfs has a mount option to set the NUMA memory allocation policy for

Documentation/vm/memory-model.rst

@@ -51,8 +51,7 @@ call :c:func:`free_area_init` function. Yet, the mappings array is not
 usable until the call to :c:func:`memblock_free_all` that hands all the
 memory to the page allocator.
 
-If an architecture enables `CONFIG_ARCH_HAS_HOLES_MEMORYMODEL` option,
-it may free parts of the `mem_map` array that do not cover the
+An architecture may free parts of the `mem_map` array that do not cover the
 actual physical pages. In such case, the architecture specific
 :c:func:`pfn_valid` implementation should take the holes in the
 `mem_map` into account.

Documentation/vm/page_owner.rst

@@ -41,17 +41,17 @@ size change due to this facility.
 - Without page owner::
 
    text    data     bss     dec     hex filename
-   40662   1493     644   42799    a72f mm/page_alloc.o
+   48392   2333     644   51369    c8a9 mm/page_alloc.o
 
 - With page owner::
 
    text    data     bss     dec     hex filename
-   40892   1493     644   43029    a815 mm/page_alloc.o
-   1427      24       8    1459     5b3 mm/page_ext.o
-   2722      50       0    2772     ad4 mm/page_owner.o
+   48800   2445     644   51889    cab1 mm/page_alloc.o
+   6574     108      29    6711    1a37 mm/page_owner.o
+   1025       8       8    1041     411 mm/page_ext.o
 
-Although, roughly, 4 KB code is added in total, page_alloc.o increase by
-230 bytes and only half of it is in hotpath. Building the kernel with
+Although, roughly, 8 KB code is added in total, page_alloc.o increase by
+520 bytes and less than half of it is in hotpath. Building the kernel with
 page owner and turning it on if needed would be great option to debug
 kernel memory problem.
 

arch/Kconfig

@@ -261,7 +261,7 @@ config ARCH_HAS_SET_DIRECT_MAP
 
 #
 # Select if the architecture provides the arch_dma_set_uncached symbol to
-# either provide an uncached segement alias for a DMA allocation, or
+# either provide an uncached segment alias for a DMA allocation, or
 # to remap the page tables in place.
 #
 config ARCH_HAS_DMA_SET_UNCACHED
@@ -314,14 +314,14 @@ config ARCH_32BIT_OFF_T
 config HAVE_ASM_MODVERSIONS
 	bool
 	help
-	  This symbol should be selected by an architecure if it provides
+	  This symbol should be selected by an architecture if it provides
 	  <asm/asm-prototypes.h> to support the module versioning for symbols
 	  exported from assembly code.
 
 config HAVE_REGS_AND_STACK_ACCESS_API
 	bool
 	help
-	  This symbol should be selected by an architecure if it supports
+	  This symbol should be selected by an architecture if it supports
 	  the API needed to access registers and stack entries from pt_regs,
 	  declared in asm/ptrace.h
 	  For example the kprobes-based event tracer needs this API.
@@ -336,7 +336,7 @@ config HAVE_RSEQ
 config HAVE_FUNCTION_ARG_ACCESS_API
 	bool
 	help
-	  This symbol should be selected by an architecure if it supports
+	  This symbol should be selected by an architecture if it supports
 	  the API needed to access function arguments from pt_regs,
 	  declared in asm/ptrace.h
 
@@ -665,6 +665,13 @@ config HAVE_IRQ_TIME_ACCOUNTING
 	  Archs need to ensure they use a high enough resolution clock to
 	  support irq time accounting and then call enable_sched_clock_irqtime().
 
+config HAVE_MOVE_PUD
+	bool
+	help
+	  Architectures that select this are able to move page tables at the
+	  PUD level. If there are only 3 page table levels, the move effectively
+	  happens at the PGD level.
+
 config HAVE_MOVE_PMD
 	bool
 	help
@@ -1054,6 +1061,12 @@ config ARCH_WANT_LD_ORPHAN_WARN
 	  by the linker, since the locations of such sections can change between linker
 	  versions.
 
+config HAVE_ARCH_PFN_VALID
+	bool
+
+config ARCH_SUPPORTS_DEBUG_PAGEALLOC
+	bool
+
 source "kernel/gcov/Kconfig"
 
 source "scripts/gcc-plugins/Kconfig"

arch/alpha/Kconfig

@@ -40,6 +40,7 @@ config ALPHA
 	select CPU_NO_EFFICIENT_FFS if !ALPHA_EV67
 	select MMU_GATHER_NO_RANGE
 	select SET_FS
+	select SPARSEMEM_EXTREME if SPARSEMEM
 	help
 	  The Alpha is a 64-bit general-purpose processor designed and
 	  marketed by the Digital Equipment Corporation of blessed memory,
@@ -551,12 +552,19 @@ config NR_CPUS
 
 config ARCH_DISCONTIGMEM_ENABLE
 	bool "Discontiguous Memory Support"
+	depends on BROKEN
 	help
 	  Say Y to support efficient handling of discontiguous physical memory,
 	  for architectures which are either NUMA (Non-Uniform Memory Access)
 	  or have huge holes in the physical address space for other reasons.
 	  See <file:Documentation/vm/numa.rst> for more.
 
+config ARCH_SPARSEMEM_ENABLE
+	bool "Sparse Memory Support"
+	help
+	  Say Y to support efficient handling of discontiguous physical memory,
+	  for systems that have huge holes in the physical address space.
+
 config NUMA
 	bool "NUMA Support (EXPERIMENTAL)"
 	depends on DISCONTIGMEM && BROKEN