mm, compaction: finish scanning the current pageblock if requested

cc->finish_pageblock is set when the current pageblock should be rescanned
but fast_find_migrateblock can select an alternative block.  Disable
fast_find_migrateblock when the current pageblock scan should be
completed.

Link: https://lkml.kernel.org/r/20230125134434.18017-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: check if a page has been captured before draining PCP pages

If a page has been captured then draining is unnecssary so check first for
a captured page.

Link: https://lkml.kernel.org/r/20230125134434.18017-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: rename compact_control->rescan to finish_pageblock

Patch series "Fix excessive CPU usage during compaction".

Commit 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock")
fixed a problem where pageblocks found by fast_find_migrateblock() were
ignored. Unfortunately there were numerous bug reports complaining about high
CPU usage and massive stalls once 6.1 was released. Due to the severity,
the patch was reverted by Vlastimil as a short-term fix[1] to -stable.

The underlying problem for each of the bugs is suspected to be the
repeated scanning of the same pageblocks.  This series should guarantee
forward progress even with commit 7efc3b726103.  More information is in
the changelog for patch 4.

[1] http://lore.kernel.org/r/20230113173345.9692-1-vbabka@suse.cz

This patch (of 4):

The rescan field was not well named albeit accurate at the time.  Rename
the field to finish_pageblock to indicate that the remainder of the
pageblock should be scanned regardless of COMPACT_CLUSTER_MAX.  The intent
is that pageblocks with transient failures get marked for skipping to
avoid revisiting the same pageblock.

Link: https://lkml.kernel.org/r/20230125134434.18017-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/gup.c: fix typo in comments

Link: https://lkml.kernel.org/r/20230125180847.4542-1-jongwooo.han@gmail.com
Signed-off-by: Jongwoo Han <jongwooo.han@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kasan: reset page tags properly with sampling

The implementation of page_alloc poisoning sampling assumed that
tag_clear_highpage resets page tags for __GFP_ZEROTAGS allocations.
However, this is no longer the case since commit 70c248aca9e7 ("mm: kasan:
Skip unpoisoning of user pages").

This leads to kernel crashes when MTE-enabled userspace mappings are used
with Hardware Tag-Based KASAN enabled.

Reset page tags for __GFP_ZEROTAGS allocations in post_alloc_hook().

Also clarify and fix related comments.

[andreyknvl@google.com: update comment]
Link: https://lkml.kernel.org/r/5dbd866714b4839069e2d8469ac45b60953db290.1674592780.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/24ea20c1b19c2b4b56cf9f5b354915f8dbccfc77.1674592496.git.andreyknvl@google.com
Fixes: 44383cef54c0 ("kasan: allow sampling page_alloc allocations for HW_TAGS")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Peter Collingbourne <pcc@google.com>
Tested-by: Peter Collingbourne <pcc@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/sparse: fix "unused function 'pgdat_to_phys'" warning

W=1 build with clangs complains:

mm/sparse.c:347:27: warning: unused function 'pgdat_to_phys' [-Wunused-function]
static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat)
                             ^
1 warning generated.

pgdat_to_phys() is only used by functions defined when
CONFIG_MEMORY_HOTREMOVE=y.

Move pgdat_to_phys() under #ifdef CONFIG_MEMORY_HOTREMOVE
to make clang happy.

Link: https://lkml.kernel.org/r/20230121101151.1703292-1-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202301210155.1E5zABb5-lkp@intel.com
Cc: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_owner: record single timestamp value for high order allocations

When allocating a high-order page, separate allocation timestamp is
recorded for each sub-page resulting in different timestamp values between
them.

This behavior is not consistent with the behavior when recording free
timestamp and caused confusion when analyzing memory dumps.  Record single
timestamp for the entire allocation, aligning with the behavior for free
timestamps.

Link: https://lkml.kernel.org/r/20230121165054.520507-1-42.hyeyoo@gmail.com
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: memory-failure: document memory failure stats

Add documentation for memory_failure's per NUMA node sysfs entries

Link: https://lkml.kernel.org/r/20230120034622.2698268-4-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: memory-failure: bump memory failure stats to pglist_data

Right before memory_failure finishes its handling, accumulate poisoned
page's resolution counters to pglist_data's memory_failure_stats, so as to
update the corresponding sysfs entries.

Tested:
1) Start an application to allocate memory buffer chunks
2) Convert random memory buffer addresses to physical addresses
3) Inject memory errors using EINJ at chosen physical addresses
4) Access poisoned memory buffer and recover from SIGBUS
5) Check counter values under
   /sys/devices/system/node/node*/memory_failure/*

Link: https://lkml.kernel.org/r/20230120034622.2698268-3-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: memory-failure: add memory failure stats to sysfs

Patch series "Introduce per NUMA node memory error statistics", v2.

Background
==========

In the RFC for Kernel Support of Memory Error Detection [1], one advantage
of software-based scanning over hardware patrol scrubber is the ability to
make statistics visible to system administrators.  The statistics include
2 categories:

* Memory error statistics, for example, how many memory error are
  encountered, how many of them are recovered by the kernel.  Note these
  memory errors are non-fatal to kernel: during the machine check
  exception (MCE) handling kernel already classified MCE's severity to be
  unnecessary to panic (but either action required or optional).

* Scanner statistics, for example how many times the scanner have fully
  scanned a NUMA node, how many errors are first detected by the scanner.

The memory error statistics are useful to userspace and actually not
specific to scanner detected memory errors, and are the focus of this
patchset.

Motivation
==========

Memory error stats are important to userspace but insufficient in kernel
today.  Datacenter administrators can better monitor a machine's memory
health with the visible stats.  For example, while memory errors are
inevitable on servers with 10+ TB memory, starting server maintenance when
there are only 1~2 recovered memory errors could be overreacting; in cloud
production environment maintenance usually means live migrate all the
workload running on the server and this usually causes nontrivial
disruption to the customer.  Providing insight into the scope of memory
errors on a system helps to determine the appropriate follow-up action.
In addition, the kernel's existing memory error stats need to be
standardized so that userspace can reliably count on their usefulness.

Today kernel provides following memory error info to userspace, but they
are not sufficient or have disadvantages:
* HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total,
  not per NUMA node stats though
* ras:memory_failure_event: only available after explicitly enabled
* /dev/mcelog provides many useful info about the MCEs, but doesn't
  capture how memory_failure recovered memory MCEs
* kernel logs: userspace needs to process log text

Exposing memory error stats is also a good start for the in-kernel memory
error detector.  Today the data source of memory error stats are either
direct memory error consumption, or hardware patrol scrubber detection
(either signaled as UCNA or SRAO).  Once in-kernel memory scanner is
implemented, it will be the main source as it is usually configured to
scan memory DIMMs constantly and faster than hardware patrol scrubber.

How Implemented
===============

As Naoya pointed out [2], exposing memory error statistics to userspace is
useful independent of software or hardware scanner.  Therefore we
implement the memory error statistics independent of the in-kernel memory
error detector.  It exposes the following per NUMA node memory error
counters:

  /sys/devices/system/node/node${X}/memory_failure/total
  /sys/devices/system/node/node${X}/memory_failure/recovered
  /sys/devices/system/node/node${X}/memory_failure/ignored
  /sys/devices/system/node/node${X}/memory_failure/failed
  /sys/devices/system/node/node${X}/memory_failure/delayed

These counters describe how many raw pages are poisoned and after the
attempted recoveries by the kernel, their resolutions: how many are
recovered, ignored, failed, or delayed respectively.  This approach can be
easier to extend for future use cases than /proc/meminfo, trace event, and
log.  The following math holds for the statistics:

* total = recovered + ignored + failed + delayed

These memory error stats are reset during machine boot.

The 1st commit introduces these sysfs entries.  The 2nd commit populates
memory error stats every time memory_failure attempts memory error
recovery.  The 3rd commit adds documentations for introduced stats.

[1] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#mc22959244f5388891c523882e61163c6e4d703af
[2] https://lore.kernel.org/linux-mm/7E670362-C29E-4626-B546-26530D54F937@gmail.com/T/#m52d8d7a333d8536bd7ce74253298858b1c0c0ac6

This patch (of 3):

Today kernel provides following memory error info to userspace, but each
has its own disadvantage

* HardwareCorrupted in /proc/meminfo: number of bytes poisoned in total,
  not per NUMA node stats though

* ras:memory_failure_event: only available after explicitly enabled

* /dev/mcelog provides many useful info about the MCEs, but
  doesn't capture how memory_failure recovered memory MCEs

* kernel logs: userspace needs to process log text

Exposes per NUMA node memory error stats as sysfs entries:

  /sys/devices/system/node/node${X}/memory_failure/total
  /sys/devices/system/node/node${X}/memory_failure/recovered
  /sys/devices/system/node/node${X}/memory_failure/ignored
  /sys/devices/system/node/node${X}/memory_failure/failed
  /sys/devices/system/node/node${X}/memory_failure/delayed

These counters describe how many raw pages are poisoned and after the
attempted recoveries by the kernel, their resolutions: how many are
recovered, ignored, failed, or delayed respectively.  The following math
holds for the statistics:

* total = recovered + ignored + failed + delayed

Link: https://lkml.kernel.org/r/20230120034622.2698268-1-jiaqiyan@google.com
Link: https://lkml.kernel.org/r/20230120034622.2698268-2-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: simplify lru_gen_look_around()

Update the folio generation in place with or without
current->reclaim_state->mm_walk.  The LRU lock is held for longer, if
mm_walk is NULL and the number of folios to update is more than
PAGEVEC_SIZE.

This causes a measurable regression from the LRU lock contention during a
microbencmark.  But a tiny regression is not worth the complexity.

Link: https://lkml.kernel.org/r/20230118001827.1040870-8-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: improve walk_pmd_range()

Improve readability of walk_pmd_range() and walk_pmd_range_locked().

Link: https://lkml.kernel.org/r/20230118001827.1040870-7-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: improve lru_gen_exit_memcg()

Add warnings and poison ->next.

Link: https://lkml.kernel.org/r/20230118001827.1040870-6-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: section for memcg LRU

Move memcg LRU code into a dedicated section.  Improve the design doc to
outline its architecture.

Link: https://lkml.kernel.org/r/20230118001827.1040870-5-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: section for Bloom filters

Move Bloom filters code into a dedicated section.  Improve the design doc
to explain Bloom filter usage and connection between aging and eviction in
their use.

Link: https://lkml.kernel.org/r/20230118001827.1040870-4-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: section for rmap/PT walk feedback

Add a section for lru_gen_look_around() in the code and the design doc.

Link: https://lkml.kernel.org/r/20230118001827.1040870-3-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: multi-gen LRU: section for working set protection

Patch series "mm: multi-gen LRU: improve".

This patch series improves a few MGLRU functions, collects related
functions, and adds additional documentation.

This patch (of 7):

Add a section for working set protection in the code and the design doc.
The admin doc already contains its usage.

Link: https://lkml.kernel.org/r/20230118001827.1040870-1-talumbau@google.com
Link: https://lkml.kernel.org/r/20230118001827.1040870-2-talumbau@google.com
Signed-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: move KMEMLEAK's Kconfig items from lib to mm

Have the kmemleak's source code and Kconfig items be in the same directory.

Link: https://lkml.kernel.org/r/1674091345-14799-1-git-send-email-zhaoyang.huang@unisoc.com
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: ke.wang <ke.wang@unisoc.com>
Cc: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core-test: add a test for damon_update_monitoring_results()

Add a simple unit test for damon_update_monitoring_results() function.

Link: https://lkml.kernel.org/r/20230119013831.1911-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core: update monitoring results for new monitoring attributes

region->nr_accesses is the number of sampling intervals in the last
aggregation interval that access to the region has found, and region->age
is the number of aggregation intervals that its access pattern has
maintained.  Hence, the real meaning of the two fields' values is
depending on current sampling and aggregation intervals.

This means the values need to be updated for every sampling and/or
aggregation intervals updates.  As DAMON core doesn't, it is a duty of
in-kernel DAMON framework applications like DAMON sysfs interface, or the
userspace users.

Handling it in userspace or in-kernel DAMON application is complicated,
inefficient, and repetitive compared to doing the update in DAMON core.
Do the update in DAMON core.

Link: https://lkml.kernel.org/r/20230119013831.1911-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon: update comments in damon.h for damon_attrs

Patch series "mm/damon: misc fixes".

This patchset contains three miscellaneous simple fixes for DAMON online
tuning.

This patch (of 3):

Commit cbeaa77b0449 ("mm/damon/core: use a dedicated struct for monitoring
attributes") moved monitoring intervals from damon_ctx to a new struct,
damon_attrs, but a comment in the header file has not updated for the
change.  Update it.

Link: https://lkml.kernel.org/r/20230119013831.1911-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230119013831.1911-2-sj@kernel.org
Fixes: cbeaa77b0449 ("mm/damon/core: use a dedicated struct for monitoring attributes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/kmemleak: fix UAF bug in kmemleak_scan()

Commit 6edda04ccc7c ("mm/kmemleak: prevent soft lockup in first object
iteration loop of kmemleak_scan()") fixes soft lockup problem in
kmemleak_scan() by periodically doing a cond_resched().  It does take a
reference of the current object before doing it.  Unfortunately, if the
object has been deleted from the object_list, the next object pointed to
by its next pointer may no longer be valid after coming back from
cond_resched().  This can result in use-after-free and other nasty
problem.

Fix this problem by adding a del_state flag into kmemleak_object structure
to synchronize the object deletion process between kmemleak_cond_resched()
and __remove_object() to make sure that the object remained in the
object_list in the duration of the cond_resched() call.

Link: https://lkml.kernel.org/r/20230119040111.350923-3-longman@redhat.com
Fixes: 6edda04ccc7c ("mm/kmemleak: prevent soft lockup in first object iteration loop of kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/kmemleak: simplify kmemleak_cond_resched() usage

Patch series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF", v2.

It was found that a KASAN use-after-free error was reported in the
kmemleak_scan() function.  After further examination, it is believe that
even though a reference is taken from the current object, it does not
prevent the object pointed to by the next pointer from going away after a
cond_resched().

To fix that, additional flags are added to make sure that the current
object won't be removed from the object_list during the duration of the
cond_resched() to ensure the validity of the next pointer.

While making the change, I also simplify the current usage of
kmemleak_cond_resched() to make it easier to understand.

This patch (of 2):

The presence of a pinned argument and the 64k loop count make
kmemleak_cond_resched() a bit more complex to read.  The pinned argument
is used only by first kmemleak_scan() loop.

Simplify the usage of kmemleak_cond_resched() by removing the pinned
argument and always do a get_object()/put_object() sequence.  In addition,
the 64k loop is removed by using need_resched() to decide if
kmemleak_cond_resched() should be called.

Link: https://lkml.kernel.org/r/20230119040111.350923-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20230119040111.350923-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kselftest: vm: add tests for memory-deny-write-execute

Add some tests to cover the new PR_SET_MDWE prctl.

Link: https://lkml.kernel.org/r/20230119160344.54358-3-joey.gouly@arm.com
Co-developed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: nd <nd@arm.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Topi Miettinen <toiwoton@gmail.com>
Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: implement memory-deny-write-execute as a prctl

Patch series "mm: In-kernel support for memory-deny-write-execute (MDWE)",
v2.

The background to this is that systemd has a configuration option called
MemoryDenyWriteExecute [2], implemented as a SECCOMP BPF filter.  Its aim
is to prevent a user task from inadvertently creating an executable
mapping that is (or was) writeable.  Since such BPF filter is stateless,
it cannot detect mappings that were previously writeable but subsequently
changed to read-only.  Therefore the filter simply rejects any
mprotect(PROT_EXEC).  The side-effect is that on arm64 with BTI support
(Branch Target Identification), the dynamic loader cannot change an ELF
section from PROT_EXEC to PROT_EXEC|PROT_BTI using mprotect().  For
libraries, it can resort to unmapping and re-mapping but for the main
executable it does not have a file descriptor.  The original bug report in
the Red Hat bugzilla - [3] - and subsequent glibc workaround for libraries
- [4].

This series adds in-kernel support for this feature as a prctl
PR_SET_MDWE, that is inherited on fork().  The prctl denies PROT_WRITE |
PROT_EXEC mappings.  Like the systemd BPF filter it also denies adding
PROT_EXEC to mappings.  However unlike the BPF filter it only denies it if
the mapping didn't previous have PROT_EXEC.  This allows to PROT_EXEC ->
PROT_EXEC | PROT_BTI with mprotect(), which is a problem with the BPF
filter.

This patch (of 2):

The aim of such policy is to prevent a user task from creating an
executable mapping that is also writeable.

An example of mmap() returning -EACCESS if the policy is enabled:

mmap(0, size, PROT_READ | PROT_WRITE | PROT_EXEC, flags, 0, 0);

Similarly, mprotect() would return -EACCESS below:

addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0);
mprotect(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC);

The BPF filter that systemd MDWE uses is stateless, and disallows
mprotect() with PROT_EXEC completely. This new prctl allows PROT_EXEC to
be enabled if it was already PROT_EXEC, which allows the following case:

addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0);
mprotect(addr, size, PROT_READ | PROT_EXEC | PROT_BTI);

where PROT_BTI enables branch tracking identification on arm64.

Link: https://lkml.kernel.org/r/20230119160344.54358-1-joey.gouly@arm.com
Link: https://lkml.kernel.org/r/20230119160344.54358-2-joey.gouly@arm.com
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: nd <nd@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Topi Miettinen <toiwoton@gmail.com>
Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/mm: allow users to provide additional cflags/ldflags

Right now there is no way to provide additional cflags/ldflags when
building tools/vm binaries.  And using eg.  make CFLAGS=<options> will
override the CFLAGS being set in the Makefile, making the build fail since
it requires the include of the ../lib dir (for libapi).

This change then allows you to specify:
CFLAGS=<options> LDFLAGS=<options> make V=1 -C tools/vm

And the options will be correctly appended as can be seen from the
make output.

Link: https://lkml.kernel.org/r/20230116224921.4106324-1-herton@redhat.com
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Justin Forbes <jforbes@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Scott Weaver <scweaver@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation: mm: use `s/higmem/highmem/` fix typo for highmem

We should use highmem replace higmem.

Link: https://lkml.kernel.org/r/20230118025403.1531-1-wangdeming@inspur.com
Signed-off-by: Deming Wang <wangdeming@inspur.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/cma: fix potential memory loss on cma_declare_contiguous_nid

Suppose memblock_alloc_range_nid() with highmem_start succeeds when
cma_declare_contiguous_nid is called with !fixed on a 32-bit system with
PHYS_ADDR_T_64BIT enabled with memblock.bottom_up == false.

But the next trial to memblock_alloc_range_nid() to allocate in [SIZE_4G,
limits) nullifies former successfully allocated addr and it retries
memblock_alloc_ragne_nid().

In this situation, the first successfully allocated address area is lost.

Change the order of allocation (SIZE_4G, high_memory and base) and check
whether the allocated succeeded to prevent potential memory loss.

Link: https://lkml.kernel.org/r/20230118080523.44522-1-ppbuk5246@gmail.com
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

swap_state: update shadow_nodes for anonymous page

Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is
updated when page cache add or delete since long time ago workingset only
supported page cache.  But when workingset supports anonymous page
detection, we missied updating shadow nodes for it.  This caused that
shadow nodes of anonymous page will never be reclaimd by
scan_shadow_nodes() even they use much memory and system memory is tense.

So update shadow_nodes of anonymous page when swap cache is add or delete
by calling xas_set_update(..workingset_update_node).

Link: https://lkml.kernel.org/r/202301182013032211005@zte.com.cn
Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb: convert get_hwpoison_huge_page() to folios

Straightforward conversion of get_hwpoison_huge_page() to
get_hwpoison_hugetlb_folio().  Reduces two references to a head page in
memory-failure.c

[arnd@arndb.de: fix get_hwpoison_hugetlb_folio() stub]
Link: https://lkml.kernel.org/r/20230119111920.635260-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20230118174039.14247-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: set default zspage chain size to 8

This changes key characteristics (pages per-zspage and objects per-zspage)
of a number of size classes which in results in different pool
configuration.  With zspage chain size of 8 we have more size clases
clusters (123) and higher huge size class watermark (3632 bytes).

Please read zsmalloc documentation for more details.

Link: https://lkml.kernel.org/r/20230118005210.2814763-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: make zspage chain size configurable

Remove hard coded limit on the maximum number of physical pages
per-zspage.

This will allow tuning of zsmalloc pool as zspage chain size changes
`pages per-zspage` and `objects per-zspage` characteristics of size
classes which also affects size classes clustering (the way size classes
are merged).

Link: https://lkml.kernel.org/r/20230118005210.2814763-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: skip chain size calculation for pow_of_2 classes

If a class size is power of 2 then it wastes no memory and the best
configuration is 1 physical page per-zspage.

Link: https://lkml.kernel.org/r/20230118005210.2814763-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: rework zspage chain size selection

Patch series "zsmalloc: make zspage chain size configurable".

Computers are bad at division.  We currently decide the best zspage chain
size (max number of physical pages per-zspage) by looking at a `used
percentage` value.  This is not enough as we lose precision during usage
percentage calculations For example, let's look at size class 208:

pages per zspage       wasted bytes         used%
       1                   144               96
       2                    80               99
       3                    16               99
       4                   160               99

Current algorithm will select 2 page per zspage configuration, as it's the
first one to reach 99%.  However, 3 pages per zspage waste less memory.

Change algorithm and select zspage configuration that has lowest wasted
value.

Link: https://lkml.kernel.org/r/20230118005210.2814763-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20230118005210.2814763-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: use deferred_pages_enabled() wherever applicable

Instead of directly accessing static deferred_pages, replace such
instances with the helper deferred_pages_enabled().  No functional change
is intended.

Link: https://lkml.kernel.org/r/20230105082506.241529-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_ext: init page_ext early if there are no deferred struct pages

page_ext must be initialized after all struct pages are initialized.
Therefore, page_ext is initialized after page_alloc_init_late(), and can
optionally be initialized earlier via early_page_ext kernel parameter
which as a side effect also disables deferred struct pages.

Allow to automatically init page_ext early when there are no deferred
struct pages in order to be able to use page_ext during kernel boot and
track for example page allocations early.

[pasha.tatashin@soleen.com: fix build with CONFIG_PAGE_EXTENSION=n]
Link: https://lkml.kernel.org/r/20230118155251.2522985-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230117204617.1553748-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/core: skip apply schemes if empty

Sometimes there is no scheme in damon's context, for example just use damo
record to monitor workload's data access pattern.

If current damon context doesn't have any scheme in the list, kdamond has
no need to iterate over list of all targets and regions but do nothing.

So, skip apply schemes when ctx->schemes is empty.

Link: https://lkml.kernel.org/r/20230116062347.1148553-1-huaisheng.ye@intel.com
Signed-off-by: Huaisheng Ye <huaisheng.ye@intel.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/secretmem: remove redundant initiialization of pointer file

The pointer file is being initialized with a value that is never read, it
is being re-assigned later on.  Clean up code by removing the redundant
initialization.

Link: https://lkml.kernel.org/r/20230116164332.79500-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

readahead: convert readahead_expand() to use a folio

Replace the uses of page with a folio.  Also add a missing test for
workingset in the leading edge expansion.

Link: https://lkml.kernel.org/r/20230116193941.2148487-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: convert filemap_range_has_page() to use a folio

The folio isn't returned from this function, so this is an entirely
internal change.

Link: https://lkml.kernel.org/r/20230116193941.2148487-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: convert filemap_map_pmd() to take a folio

Patch series "Some more filemap folio conversions".

Three more places which could easily be converted to folios.  The third
one fixes a minor bug in readahead_expand(), but it's only a performance
bug and there are few users of readahead_expand(), so I don't think it's
worth backporting.

This patch (of 3):

Save a few calls to compound_head().  We specify exactly which page from
the folio to use by passing in start_pgoff, which means this will work for
a folio which is larger than PMD size.  The rest of the VM isn't prepared
for that yet, but now this function is.

Link: https://lkml.kernel.org/r/20230116193941.2148487-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116193941.2148487-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

rmap: add folio parameter to __page_set_anon_rmap()

Avoid the compound_head() call in PageAnon() by passing in the folio that
all callers have.  Also save me from wondering whether page->mapping can
ever be overwritten on a tail page (I don't think it can, but I'm not 100%
sure).

Link: https://lkml.kernel.org/r/20230116192959.2147032-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: clean up mlock_page / munlock_page references in comments

Change documentation and comments that refer to now-renamed functions.

Link: https://lkml.kernel.org/r/20230116192827.2146732-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove munlock_vma_page()

All callers now have a folio and can call munlock_vma_folio().  Update the
documentation to refer to munlock_vma_folio().

Link: https://lkml.kernel.org/r/20230116192827.2146732-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove mlock_vma_page()

All callers now have a folio and can call mlock_vma_folio().  Update the
documentation to refer to mlock_vma_folio().

Link: https://lkml.kernel.org/r/20230116192827.2146732-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove page_evictable()

Patch series "Remove leftover mlock/munlock page wrappers".

We no longer need the various mlock page functions as all callers have
folios.

This patch (of 4):

This function now has no users.  Also update the unevictable-lru
documentation to discuss folios instead of pages (mostly).

[akpm@linux-foundation.org: fix Documentation/mm/unevictable-lru.rst underlining]
Link: https://lkml.kernel.org/r/20230117145106.585b277b@canb.auug.org.au
Link: https://lkml.kernel.org/r/20230116192827.2146732-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116192827.2146732-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: convert mem_cgroup_css_from_page() to mem_cgroup_css_from_folio()

Only one caller doesn't have a folio, so move the page_folio() call to
that one caller from mem_cgroup_css_from_folio().

Link: https://lkml.kernel.org/r/20230116192507.2146150-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/fs: convert inode_attach_wb() to take a folio

Patch series "Writeback folio conversions".

Remove more calls to compound_head() by passing folios around instead of
pages.

This patch (of 2):

The only caller of inode_attach_wb() which doesn't pass NULL already has a
folio, so convert the whole call-chain to take folios.

Link: https://lkml.kernel.org/r/20230116192507.2146150-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116192507.2146150-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: use a folio in copy_present_pte()

We still have to keep the page around because we need to know which page
in the folio we're copying, but we can replace five implict calls to
compound_head() with one.

Link: https://lkml.kernel.org/r/20230116191813.2145215-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: use a folio in copy_pte_range()

Allocate an order-0 folio instead of a page and pass it all the way down
the call chain.  Removes dozens of calls to compound_head().

Link: https://lkml.kernel.org/r/20230116191813.2145215-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: convert wp_page_copy() to use folios

Use new_folio instead of new_page throughout, because we allocated it
and know it's an order-0 folio.  Most old_page uses become old_folio,
but use vmf->page where we need the precise page.

Link: https://lkml.kernel.org/r/20230116191813.2145215-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: convert do_anonymous_page() to use a folio

Removes six calls to compound_head(); some inline and some external.

Link: https://lkml.kernel.org/r/20230116191813.2145215-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: add vma_alloc_zeroed_movable_folio()

Replace alloc_zeroed_user_highpage_movable().  The main difference is
returning a folio containing a single page instead of returning the page,
but take the opportunity to rename the function to match other allocation
functions a little better and rewrite the documentation to place more
emphasis on the zeroing rather than the highmem aspect.

Link: https://lkml.kernel.org/r/20230116191813.2145215-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: remove find_get_pages_range_tag()

All callers to find_get_pages_range_tag(), find_get_pages_tag(),
pagevec_lookup_range_tag(), and pagevec_lookup_tag() have been removed.

Link: https://lkml.kernel.org/r/20230104211448.4804-24-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_clear_dirty_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 2 calls to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-23-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_copy_dirty_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 8 calls to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-22-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_btree_lookup_dirty_buffers() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 1 call to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-21-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_lookup_dirty_node_buffers() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 1 call to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-20-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: convert nilfs_lookup_dirty_data_buffers() to use filemap_get_folios_tag()

Convert function to use folios throughout. This is in preparation for
the removal of find_get_pages_range_tag(). This change removes 4 calls
to compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-19-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

gfs2: convert gfs2_write_cache_jdata() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pgaes_range_tag().  This change removes 8 calls to
compound_head().

Also had to modify and rename gfs2_write_jdata_pagevec() to take in and
utilize folio_batch rather than pagevec and use folios rather than pages.
gfs2_write_jdata_batch() now supports large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-18-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert f2fs_sync_meta_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 5 calls to
compound_head().

Initially the function was checking if the previous page index is truly
the previous page i.e.  1 index behind the current page.  To convert to
folios and maintain this check we need to make the check folio->index !=
prev + folio_nr_pages(previous folio) since we don't know how many pages
are in a folio.

At index i == 0 the check is guaranteed to succeed, so to workaround
indexing bounds we can simply ignore the check for that specific index.
This makes the initial assignment of prev trivial, so I removed that as
well.

Also modify a comment in commit_checkpoint for consistency.

Link: https://lkml.kernel.org/r/20230104211448.4804-17-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert last_fsync_dnode() to use filemap_get_folios_tag()

Convert to use a folio_batch instead of pagevec.  This is in preparation
for the removal of find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-16-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert f2fs_write_cache_pages() to use filemap_get_folios_tag()

Convert the function to use a folio_batch instead of pagevec.  This is in
preparation for the removal of find_get_pages_range_tag().

Also modified f2fs_all_cluster_page_ready to take in a folio_batch instead
of pagevec.  This does NOT support large folios.  The function currently
only utilizes folios of size 1 so this shouldn't cause any issues right
now.

This version of the patch limits the number of pages fetched to
F2FS_ONSTACK_PAGES.  If that ever happens, update the start index here
since filemap_get_folios_tag() updates the index to be after the last
found folio, not necessarily the last used page.

Link: https://lkml.kernel.org/r/20230104211448.4804-15-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert f2fs_sync_node_pages() to use filemap_get_folios_tag()

Convert function to use a folio_batch instead of pagevec.  This is in
preparation for the removal of find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-14-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert f2fs_flush_inline_data() to use filemap_get_folios_tag()

Convert function to use a folio_batch instead of pagevec. This is in
preparation for the removal of find_get_pages_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-13-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

f2fs: convert f2fs_fsync_node_pages() to use filemap_get_folios_tag()

Convert function to use a folio_batch instead of pagevec.  This is in
preparation for the removal of find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-12-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ext4: convert mpage_prepare_extent_to_map() to use filemap_get_folios_tag()

Convert the function to use folios throughout.  This is in preparation for
the removal of find_get_pages_range_tag().  Now supports large folios.
This change removes 11 calls to compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-11-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

cifs: convert wdata_alloc_and_fillpages() to use filemap_get_folios_tag()

This is in preparation for the removal of find_get_pages_range_tag().  Now
also supports the use of large folios.

Since tofind might be larger than the max number of folios in a
folio_batch (15), we loop through filling in wdata->pages pulling more
batches until we either reach tofind pages or run out of folios.

This function may not return all pages in the last found folio before
tofind pages are reached.

Link: https://lkml.kernel.org/r/20230104211448.4804-10-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Cc: Tom Talpey <tom@talpey.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ceph: convert ceph_writepages_start() to use filemap_get_folios_tag()

Convert function to use a folio_batch instead of pagevec.  This is in
preparation for the removal of find_get_pages_range_tag().

Also some minor renaming for consistency.

Link: https://lkml.kernel.org/r/20230104211448.4804-9-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

btrfs: convert extent_write_cache_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  Now also supports large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-8-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

btrfs: convert btree_write_cache_pages() to use filemap_get_folio_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-7-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

afs: convert afs_writepages_region() to use filemap_get_folios_tag()

Convert to use folios throughout.  This function is in preparation to
remove find_get_pages_range_tag().

Also modify this function to write the whole batch one at a time, rather
than calling for a new set every single write.

Link: https://lkml.kernel.org/r/20230104211448.4804-6-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

page-writeback: convert write_cache_pages() to use filemap_get_folios_tag()

Convert function to use folios throughout.  This is in preparation for the
removal of find_get_pages_range_tag().  This change removes 8 calls to
compound_head(), and the function now supports large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-5-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcow (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: convert __filemap_fdatawait_range() to use filemap_get_folios_tag()

Convert function to use folios.  This is in preparation for the removal of
find_get_pages_range_tag().  This change removes 2 calls to
compound_head().

Link: https://lkml.kernel.org/r/20230104211448.4804-4-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcow (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

filemap: add filemap_get_folios_tag()

This is the equivalent of find_get_pages_range_tag(), except for folios
instead of pages.

One noteable difference is filemap_get_folios_tag() does not take in a
maximum pages argument.  It instead tries to fill a folio batch and stops
either once full (15 folios) or reaching the end of the search range.

The new function supports large folios, the initial function did not since
all callers don't use large folios.

Link: https://lkml.kernel.org/r/20230104211448.4804-3-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcow (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

pagemap: add filemap_grab_folio()

Patch series "Convert to filemap_get_folios_tag()", v5.

This patch series replaces find_get_pages_range_tag() with
filemap_get_folios_tag().  This also allows the removal of multiple calls
to compound_head() throughout.

It also makes a good chunk of the straightforward conversions to folios,
and takes the opportunity to introduce a function that grabs a folio from
the pagecache.

This patch (of 23):

Add function filemap_grab_folio() to grab a folio from the page cache.
This function is meant to serve as a folio replacement for
grab_cache_page, and is used to facilitate the removal of
find_get_pages_range_tag().

Link: https://lkml.kernel.org/r/20230104211448.4804-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20230104211448.4804-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: fix khugepaged with shmem_enabled=advise

Pass vm_flags as a parameter to shmem_is_huge, rather than reading the
flags from the vm_area_struct in question.  This allows the updated flags
from hugepage_madvise to be passed to the check, which is necessary
because madvise does not update the vm_area_struct's flags until after
hugepage_madvise returns.

This fixes an issue when shmem_enabled=madvise, where MADV_HUGEPAGE on
shmem was not able to register the mm_struct with khugepaged.  Prior to
cd89fb065099, the mm_struct was registered by MADV_HUGEPAGE regardless of
the value of shmem_enabled (which was only checked when scanning vmas).

Link: https://lkml.kernel.org/r/20230113023011.1784015-1-stevensd@google.com
Fixes: cd89fb065099 ("mm,thp,shmem: make khugepaged obey tmpfs mount flags")
Signed-off-by: David Stevens <stevensd@chromium.org>
Cc: David Stevens <stevensd@chromium.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: discard __GFP_ATOMIC

__GFP_ATOMIC serves little purpose.  Its main effect is to set
ALLOC_HARDER which adds a few little boosts to increase the chance of an
allocation succeeding, one of which is to lower the water-mark at which it
will succeed.

It is *always* paired with __GFP_HIGH which sets ALLOC_HIGH which also
adjusts this watermark.  It is probable that other users of __GFP_HIGH
should benefit from the other little bonuses that __GFP_ATOMIC gets.

__GFP_ATOMIC also gives a warning if used with __GFP_DIRECT_RECLAIM.
There is little point to this.  We already get a might_sleep() warning if
__GFP_DIRECT_RECLAIM is set.

__GFP_ATOMIC allows the "watermark_boost" to be side-stepped.  It is
probable that testing ALLOC_HARDER is a better fit here.

__GFP_ATOMIC is used by tegra-smmu.c to check if the allocation might
sleep.  This should test __GFP_DIRECT_RECLAIM instead.

This patch:
 - removes __GFP_ATOMIC
 - allows __GFP_HIGH allocations to ignore watermark boosting as well
   as GFP_ATOMIC requests.
 - makes other adjustments as suggested by the above.

The net result is not change to GFP_ATOMIC allocations.  Other
allocations that use __GFP_HIGH will benefit from a few different extra
privileges.  This affects:
  xen, dm, md, ntfs3
  the vermillion frame buffer
  hibernation
  ksm
  swap
all of which likely produce more benefit than cost if these selected
allocation are more likely to succeed quickly.

[mgorman: Minor adjustments to rework on top of a series]
Link: https://lkml.kernel.org/r/163712397076.13692.4727608274002939094@noble.neil.brown.name
Link: https://lkml.kernel.org/r/20230113111217.14134-7-mgorman@techsingularity.net
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves

GFP_ATOMIC allocations get flagged ALLOC_HARDER which is a vague
description.  In preparation for the removal of GFP_ATOMIC redefine
__GFP_ATOMIC to simply mean non-blocking and renaming ALLOC_HARDER to
ALLOC_NON_BLOCK accordingly.  __GFP_HIGH is required for access to
reserves but non-blocking is granted more access.  For example, GFP_NOWAIT
is non-blocking but has no special access to reserves.  A __GFP_NOFAIL
blocking allocation is granted access similar to __GFP_HIGH if the only
alternative is an OOM kill.

Link: https://lkml.kernel.org/r/20230113111217.14134-6-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: explicitly define what alloc flags deplete min reserves

As there are more ALLOC_ flags that affect reserves, define what flags
affect reserves and clarify the effect of each flag.

Link: https://lkml.kernel.org/r/20230113111217.14134-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: explicitly record high-order atomic allocations in alloc_flags

A high-order ALLOC_HARDER allocation is assumed to be atomic.  While that
is accurate, it changes later in the series.  In preparation, explicitly
record high-order atomic allocations in gfp_to_alloc_flags().

Link: https://lkml.kernel.org/r/20230113111217.14134-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: treat RT tasks similar to __GFP_HIGH

RT tasks are allowed to dip below the min reserve but ALLOC_HARDER is
typically combined with ALLOC_MIN_RESERVE so RT tasks are a little
unusual.  While there is some justification for allowing RT tasks access
to memory reserves, there is a strong chance that a RT task that is also
under memory pressure is at risk of missing deadlines anyway.  Relax how
much reserves an RT task can access by treating it the same as __GFP_HIGH
allocations.

Note that in a future kernel release that the RT special casing will be
removed.  Hard realtime tasks should be locking down resources in advance
and ensuring enough memory is available.  Even a soft-realtime task like
audio or video live decoding which cannot jitter should be allocating both
memory and any disk space required up-front before the recording starts
instead of relying on reserves.  At best, reserve access will only delay
the problem by a very short interval.

Link: https://lkml.kernel.org/r/20230113111217.14134-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc: rename ALLOC_HIGH to ALLOC_MIN_RESERVE

Patch series "Discard __GFP_ATOMIC", v3.

Neil's patch has been residing in mm-unstable as commit 2fafb4fe8f7a ("mm:
discard __GFP_ATOMIC") for a long time and recently brought up again.
Most recently, I was worried that __GFP_HIGH allocations could use
high-order atomic reserves which is unintentional but there was no
response so lets revisit -- this series reworks how min reserves are used,
protects highorder reserves and then finishes with Neil's patch with very
minor modifications so it fits on top.

There was a review discussion on renaming __GFP_DIRECT_RECLAIM to
__GFP_ALLOW_BLOCKING but I didn't think it was that big an issue and is
orthogonal to the removal of __GFP_ATOMIC.

There were some concerns about how the gfp flags affect the min reserves
but it never reached a solid conclusion so I made my own attempt.

The series tries to iron out some of the details on how reserves are used.
ALLOC_HIGH becomes ALLOC_MIN_RESERVE and ALLOC_HARDER becomes
ALLOC_NON_BLOCK and documents how the reserves are affected.  For example,
ALLOC_NON_BLOCK (no direct reclaim) on its own allows 25% of the min
reserve.  ALLOC_MIN_RESERVE (__GFP_HIGH) allows 50% and both combined
allows deeper access again.  ALLOC_OOM allows access to 75%.

High-order atomic allocations are explicitly handled with the caveat that
no __GFP_ATOMIC flag means that any high-order allocation that specifies
GFP_HIGH and cannot enter direct reclaim will be treated as if it was
GFP_ATOMIC.

This patch (of 6):

__GFP_HIGH aliases to ALLOC_HIGH but the name does not really hint what it
means.  As ALLOC_HIGH is internal to the allocator, rename it to
ALLOC_MIN_RESERVE to document that the min reserves can be depleted.

Link: https://lkml.kernel.org/r/20230113111217.14134-1-mgorman@techsingularity.net
Link: https://lkml.kernel.org/r/20230113111217.14134-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_ext: do not allocate space for page_ext->flags if not needed

There is 8 byte page_ext->flags field allocated per page whenever
CONFIG_PAGE_EXTENSION is enabled.  However, not every user of page_ext
uses flags.  Therefore, check whether flags is needed at least by one user
and if so allocate space for it.

For example when page_table_check is enabled, on a machine with 128G
of memory before the fix:

[    2.244288] allocated 536870912 bytes of page_ext
after the fix:
[    2.160154] allocated 268435456 bytes of page_ext

Also, add a kernel-doc comment before page_ext_operations that describes
the fields, and remove check if need() is set, as that is now a required
field.

[pasha.tatashin@soleen.com: address comments from Mike Rapoport]
Link: https://lkml.kernel.org/r/20230117202103.1412449-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20230113154253.92480-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE

__HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that
support swp PTEs, so let's drop it.

Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

xtensa/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using bit 1.  This bit
should be safe to use for our usecase.

Most importantly, we can still distinguish swap PTEs from PAGE_NONE PTEs
(see pte_present()) and don't use one of the two reserved attribute masks
(1101 and 1111).  Attribute mask 1100 and 1110 now identify swap PTEs.

While at it, remove SWP_TYPE_BITS (not really helpful as it's not used in
the actual swap macros) and mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-26-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also on 32bit

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE just like we already do on
x86-64.  After deciphering the PTE layout it becomes clear that there are
still unused bits for 2-level and 3-level page tables that we should be
able to use.  Reusing a bit avoids stealing one bit from the swap offset.

While at it, mask the type in __swp_entry(); use some helper definitions
to make the macros easier to grasp.

Link: https://lkml.kernel.org/r/20230113171026.582290-25-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

um/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using bit 10, which is yet
unused for swap PTEs.

The pte_mkuptodate() is a bit weird in __pte_to_swp_entry() for a swap PTE
...  but it only messes with bit 1 and 2 and there is a comment in
set_pte(), so leave these bits alone.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-24-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type.  Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit was effectively unused.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-23-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by reusing the SRMMU_DIRTY bit
as that seems to be safe to reuse inside a swap PTE.  This avoids having
to steal one bit from the swap offset.

While at it, relocate the swap PTE layout documentation and use the same
style now used for most other archs.  Note that the old documentation was
wrong: we use 20 bit for the offset and the reserved bits were 8 instead
of 7 bits in the ascii art.

Link: https://lkml.kernel.org/r/20230113171026.582290-22-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

sh/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using bit 6 in the PTE,
reducing the swap type in the !CONFIG_X2TLB case to 5 bits.  Generic MM
currently only uses 5 bits for the type (MAX_SWAPFILES_SHIFT), so the
stolen bit is effectively unused.

Interrestingly, the swap type in the !CONFIG_X2TLB case could currently
overlap with the _PAGE_PRESENT bit, because there is a sneaky shift by 1
in __pte_to_swp_entry() and __swp_entry_to_pte().  Bit 0-7 in the
architecture specific swap PTE would get shifted to bit 1-8 in the PTE.
As generic MM uses 5 bits only, this didn't matter so far.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-21-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

riscv/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
offset.  This reduces the maximum swap space per file: on 32bit to 16 GiB
(was 32 GiB).

Note that this bit does not conflict with swap PMDs and could also be used
in swap PMD context later.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-20-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

powerpc/nohash/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit and 64bit.

On 64bit, let's use MSB 56 (LSB 7), located right next to the page type.
On 32bit, let's use LSB 2 to avoid stealing one bit from the swap offset.

There seems to be no real reason why these bits cannot be used for swap
PTEs.  The important part is that _PAGE_PRESENT and _PAGE_HASHPTE remain
0.

While at it, mask the type in __swp_entry() and remove _PAGE_BIT_SWAP_TYPE
from pte-e500.h: while it was used in 64bit code it was ignored in 32bit
code.

Link: https://lkml.kernel.org/r/20230113171026.582290-19-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

powerpc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit book3s

We already implemented support for 64bit book3s in commit bff9beaa2e80
("powerpc/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE for book3s")

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also in 32bit by reusing yet
unused LSB 2 / MSB 29.  There seems to be no real reason why that bit
cannot be used, and reusing it avoids having to steal one bit from the
swap offset.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-18-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parisc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using the yet-unused
_PAGE_ACCESSED location in the swap PTE.  Looking at pte_present() and
pte_none() checks, there seems to be no actual reason why we cannot use
it: we only have to make sure we're not using _PAGE_PRESENT.

Reusing this bit avoids having to steal one bit from the swap offset.

Link: https://lkml.kernel.org/r/20230113171026.582290-17-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

openrisc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type.  Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.

While at it, mask the type in __swp_entry().

Link: https://lkml.kernel.org/r/20230113171026.582290-16-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nios2/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using the yet-unused bit
31.

Link: https://lkml.kernel.org/r/20230113171026.582290-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nios2/mm: refactor swap PTE layout

nios2 disables swap for a good reason: it doesn't even provide sufficient
type bits as required by core MM.  However, swap entries are nowadays also
used for other purposes (migration entries, PTE markers, HWPoison, ...),
and accidential use could be problematic.

Let's properly use 5 bits for the swap type and document the layout.  Bits
26--31 should get ignored by hardware completely, so they can be used.

Link: https://lkml.kernel.org/r/20230113171026.582290-14-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mips/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE.

On 64bit, steal one bit from the type.  Generic MM currently only uses 5
bits for the type (MAX_SWAPFILES_SHIFT), so the stolen bit is effectively
unused.

On 32bit we're able to locate unused bits.  As the PTE layout for 32 bit
is very confusing, document it a bit better.

While at it, mask the type in __swp_entry()/mk_swap_pte().

Link: https://lkml.kernel.org/r/20230113171026.582290-13-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

microblaze/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type.  Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.

The shift by 2 when converting between PTE and arch-specific swap entry
makes the swap PTE layout a little bit harder to decipher.

While at it, drop the comment from paulus---copy-and-paste leftover from
powerpc where we actually have _PAGE_HASHPTE---and mask the type in
__swp_entry_to_pte() as well.

Link: https://lkml.kernel.org/r/20230113171026.582290-12-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>