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404 Commits

Author SHA1 Message Date
Linus Torvalds
7a3fad30fd Random number generator updates for Linux 6.11-rc1.
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Merge tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "This adds getrandom() support to the vDSO.

  First, it adds a new kind of mapping to mmap(2), MAP_DROPPABLE, which
  lets the kernel zero out pages anytime under memory pressure, which
  enables allocating memory that never gets swapped to disk but also
  doesn't count as being mlocked.

  Then, the vDSO implementation of getrandom() is introduced in a
  generic manner and hooked into random.c.

  Next, this is implemented on x86. (Also, though it's not ready for
  this pull, somebody has begun an arm64 implementation already)

  Finally, two vDSO selftests are added.

  There are also two housekeeping cleanup commits"

* tag 'random-6.11-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  MAINTAINERS: add random.h headers to RNG subsection
  random: note that RNDGETPOOL was removed in 2.6.9-rc2
  selftests/vDSO: add tests for vgetrandom
  x86: vdso: Wire up getrandom() vDSO implementation
  random: introduce generic vDSO getrandom() implementation
  mm: add MAP_DROPPABLE for designating always lazily freeable mappings
2024-07-24 10:29:50 -07:00
Jason A. Donenfeld
9651fcedf7 mm: add MAP_DROPPABLE for designating always lazily freeable mappings
The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:

- It shouldn't be written to core dumps.
  * Easy: VM_DONTDUMP.
- It should be zeroed on fork.
  * Easy: VM_WIPEONFORK.

- It shouldn't be written to swap.
  * Uh-oh: mlock is rlimited.
  * Uh-oh: mlock isn't inherited by forks.

- It shouldn't reserve actual memory, but it also shouldn't crash when
  page faulting in memory if none is available
  * Uh-oh: VM_NORESERVE means segfaults.

It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:

1) Due to being wiped during fork(), the vDSO code is already robust to
   having the contents of the pages it reads zeroed out midway through
   the function's execution.

2) In the absolute worst case of whatever contingency we're coding for,
   we have the option to fallback to the getrandom() syscall, and
   everything is fine.

3) The buffers the function uses are only ever useful for a maximum of
   60 seconds -- a sort of cache, rather than a long term allocation.

These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:

a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
   zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
   and no signal is sent.

This way, allocations used by vDSO getrandom() can use:

    VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE

And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.

In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.

Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.

Finally, the provided self test ensures that this is working as desired.

Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-07-19 20:22:12 +02:00
Christophe Leroy
e6c0c03245 mm: provide mm_struct and address to huge_ptep_get()
On powerpc 8xx huge_ptep_get() will need to know whether the given ptep is
a PTE entry or a PMD entry.  This cannot be known with the PMD entry
itself because there is no easy way to know it from the content of the
entry.

So huge_ptep_get() will need to know either the size of the page or get
the pmd.

In order to be consistent with huge_ptep_get_and_clear(), give mm and
address to huge_ptep_get().

Link: https://lkml.kernel.org/r/cc00c70dd384298796a4e1b25d6c4eb306d3af85.1719928057.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:15 -07:00
Andrii Nakryiko
bfc69fd05e fs/procfs: add build ID fetching to PROCMAP_QUERY API
The need to get ELF build ID reliably is an important aspect when dealing
with profiling and stack trace symbolization, and /proc/<pid>/maps textual
representation doesn't help with this.

To get backing file's ELF build ID, application has to first resolve VMA,
then use it's start/end address range to follow a special
/proc/<pid>/map_files/<start>-<end> symlink to open the ELF file (this is
necessary because backing file might have been removed from the disk or
was already replaced with another binary in the same file path.

Such approach, beyond just adding complexity of having to do a bunch of
extra work, has extra security implications.  Because application opens
underlying ELF file and needs read access to its entire contents (as far
as kernel is concerned), kernel puts additional capable() checks on
following /proc/<pid>/map_files/<start>-<end> symlink.  And that makes
sense in general.

But in the case of build ID, profiler/symbolizer doesn't need the contents
of ELF file, per se.  It's only build ID that is of interest, and ELF
build ID itself doesn't provide any sensitive information.

So this patch adds a way to request backing file's ELF build ID along the
rest of VMA information in the same API.  User has control over whether
this piece of information is requested or not by either setting
build_id_size field to zero or non-zero maximum buffer size they provided
through build_id_addr field (which encodes user pointer as __u64 field). 
This is a completely optional piece of information, and so has no
performance implications for user cases that don't care about build ID,
while improving performance and simplifying the setup for those
application that do need it.

Kernel already implements build ID fetching, which is used from BPF
subsystem.  We are reusing this code here, but plan a follow up changes to
make it work better under more relaxed assumption (compared to what
existing code assumes) of being called from user process context, in which
page faults are allowed.  BPF-specific implementation currently bails out
if necessary part of ELF file is not paged in, all due to extra
BPF-specific restrictions (like the need to fetch build ID in restrictive
contexts such as NMI handler).

[andrii@kernel.org: fix integer to pointer cast warning in do_procmap_query()]
  Link: https://lkml.kernel.org/r/20240701174805.1897344-1-andrii@kernel.org
Link: https://lkml.kernel.org/r/20240627170900.1672542-4-andrii@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:12 -07:00
Andrii Nakryiko
ed5d583a88 fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps
/proc/<pid>/maps file is extremely useful in practice for various tasks
involving figuring out process memory layout, what files are backing any
given memory range, etc.  One important class of applications that
absolutely rely on this are profilers/stack symbolizers (perf tool being
one of them).  Patterns of use differ, but they generally would fall into
two categories.

In on-demand pattern, a profiler/symbolizer would normally capture stack
trace containing absolute memory addresses of some functions, and would
then use /proc/<pid>/maps file to find corresponding backing ELF files
(normally, only executable VMAs are of interest), file offsets within
them, and then continue from there to get yet more information (ELF
symbols, DWARF information) to get human-readable symbolic information. 
This pattern is used by Meta's fleet-wide profiler, as one example.

In preprocessing pattern, application doesn't know the set of addresses of
interest, so it has to fetch all relevant VMAs (again, probably only
executable ones), store or cache them, then proceed with profiling and
stack trace capture.  Once done, it would do symbolization based on stored
VMA information.  This can happen at much later point in time.  This
patterns is used by perf tool, as an example.

In either case, there are both performance and correctness requirement
involved.  This address to VMA information translation has to be done as
efficiently as possible, but also not miss any VMA (especially in the case
of loading/unloading shared libraries).  In practice, correctness can't be
guaranteed (due to process dying before VMA data can be captured, or
shared library being unloaded, etc), but any effort to maximize the chance
of finding the VMA is appreciated.

Unfortunately, for all the /proc/<pid>/maps file universality and
usefulness, it doesn't fit the above use cases 100%.

First, it's main purpose is to emit all VMAs sequentially, but in practice
captured addresses would fall only into a smaller subset of all process'
VMAs, mainly containing executable text.  Yet, library would need to parse
most or all of the contents to find needed VMAs, as there is no way to
skip VMAs that are of no use.  Efficient library can do the linear pass
and it is still relatively efficient, but it's definitely an overhead that
can be avoided, if there was a way to do more targeted querying of the
relevant VMA information.

Second, it's a text based interface, which makes its programmatic use from
applications and libraries more cumbersome and inefficient due to the need
to handle text parsing to get necessary pieces of information.  The
overhead is actually payed both by kernel, formatting originally binary
VMA data into text, and then by user space application, parsing it back
into binary data for further use.

For the on-demand pattern of usage, described above, another problem when
writing generic stack trace symbolization library is an unfortunate
performance-vs-correctness tradeoff that needs to be made.  Library has to
make a decision to either cache parsed contents of /proc/<pid>/maps (after
initial processing) to service future requests (if application requests to
symbolize another set of addresses (for the same process), captured at
some later time, which is typical for periodic/continuous profiling cases)
to avoid higher costs of re-parsing this file.  Or it has to choose to
cache the contents in memory to speed up future requests.  In the former
case, more memory is used for the cache and there is a risk of getting
stale data if application loads or unloads shared libraries, or otherwise
changed its set of VMAs somehow, e.g., through additional mmap() calls. 
In the latter case, it's the performance hit that comes from re-opening
the file and re-parsing its contents all over again.

This patch aims to solve this problem by providing a new API built on top
of /proc/<pid>/maps.  It's meant to address both non-selectiveness and
text nature of /proc/<pid>/maps, by giving user more control of what sort
of VMA(s) needs to be queried, and being binary-based interface eliminates
the overhead of text formatting (on kernel side) and parsing (on user
space side).

It's also designed to be extensible and forward/backward compatible by
including required struct size field, which user has to provide.  We use
established copy_struct_from_user() approach to handle extensibility.

User has a choice to pick either getting VMA that covers provided address
or -ENOENT if none is found (exact, least surprising, case).  Or, with an
extra query flag (PROCMAP_QUERY_COVERING_OR_NEXT_VMA), they can get either
VMA that covers the address (if there is one), or the closest next VMA
(i.e., VMA with the smallest vm_start > addr).  The latter allows more
efficient use, but, given it could be a surprising behavior, requires an
explicit opt-in.

There is another query flag that is useful for some use cases. 
PROCMAP_QUERY_FILE_BACKED_VMA instructs this API to only return
file-backed VMAs.  Combining this with PROCMAP_QUERY_COVERING_OR_NEXT_VMA
makes it possible to efficiently iterate only file-backed VMAs of the
process, which is what profilers/symbolizers are normally interested in.

All the above querying flags can be combined with (also optional) set of
desired VMA permissions flags.  This allows to, for example, iterate only
an executable subset of VMAs, which is what preprocessing pattern, used by
perf tool, would benefit from, as the assumption is that captured stack
traces would have addresses of executable code.  This saves time by
skipping non-executable VMAs altogether efficienty.

All these querying flags (modifiers) are orthogonal and can be combined in
a semantically meaningful and natural way.

Basing this ioctl()-based API on top of /proc/<pid>/maps's FD makes sense
given it's querying the same set of VMA data.  It's also benefitial
because permission checks for /proc/<pid>/maps is performed at open time
once, and the actual data read of text contents of /proc/<pid>/maps is
done without further permission checks.  We piggyback on this pattern with
ioctl()-based API as well, as that's a desired property.  Both for
performance reasons, but also for security and flexibility reasons.

Allowing application to open an FD for /proc/self/maps without any extra
capabilities, and then passing it to some sort of profiling agent through
Unix-domain socket, would allow such profiling agent to not require some
of the capabilities that are otherwise expected when opening
/proc/<pid>/maps file for *another* process.  This is a desirable property
for some more restricted setups.

This new ioctl-based implementation doesn't interfere with seq_file-based
implementation of /proc/<pid>/maps textual interface, and so could be used
together or independently without paying any price for that.

Note also, that fetching VMA name (e.g., backing file path, or special
hard-coded or user-provided names) is optional just like build ID.  If
user sets vma_name_size to zero, kernel code won't attempt to retrieve it,
saving resources.

Earlier versions of this patch set were adding per-VMA locking, which is
why we have a code structure that is ready for abstracting mmap_lock vs
vm_lock differences (query_vma_setup(), query_vma_teardown(), and
query_vma_find_by_addr()), but given anon_vma_name() is not yet compatible
with per-VMA locking, initial implementation sticks to using only
mmap_lock for now.  It will be easy to add back per-VMA locking once all
the pieces are ready later on.  Which is why we keep existing code
structure with setup/teardown/query helper functions.

[andrii@kernel.org: improve PROCMAP_QUERY's compat mode handling]
  Link: https://lkml.kernel.org/r/20240701174805.1897344-2-andrii@kernel.org
Link: https://lkml.kernel.org/r/20240627170900.1672542-3-andrii@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:11 -07:00
Andrii Nakryiko
acd4b2ecf3 fs/procfs: extract logic for getting VMA name constituents
Patch series "ioctl()-based API to query VMAs from /proc/<pid>/maps", v6.

Implement binary ioctl()-based interface to /proc/<pid>/maps file to allow
applications to query VMA information more efficiently than reading *all*
VMAs nonselectively through text-based interface of /proc/<pid>/maps file.

Patch #2 goes into a lot of details and background on some common patterns
of using /proc/<pid>/maps in the area of performance profiling and
subsequent symbolization of captured stack traces.  As mentioned in that
patch, patterns of VMA querying can differ depending on specific use case,
but can generally be grouped into two main categories: the need to query a
small subset of VMAs covering a given batch of addresses, or
reading/storing/caching all (typically, executable) VMAs upfront for later
processing.

The new PROCMAP_QUERY ioctl() API added in this patch set was motivated by
the former pattern of usage.  Earlier revisions had a patch adding a tool
that faithfully reproduces an efficient VMA matching pass of a symbolizer,
collecting a subset of covering VMAs for a given set of addresses as
efficiently as possible.  This tool served both as a testing ground, as
well as a benchmarking tool.  It implements everything both for currently
existing text-based /proc/<pid>/maps interface, as well as for newly-added
PROCMAP_QUERY ioctl().  This revision dropped the tool from the patch set
and, once the API lands upstream, this tool might be added separately on
Github as an example.

Based on discussion on earlier revisions of this patch set, it turned out
that this ioctl() API is competitive with highly-optimized text-based
pre-processing pattern that perf tool is using.  Based on perf discussion,
this revision adds more flexibility in specifying a subset of VMAs that
are of interest.  Now it's possible to specify desired permissions of VMAs
(e.g., request only executable ones) and/or restrict to only a subset of
VMAs that have file backing.  This further improves the efficiency when
using this new API thanks to more selective (executable VMAs only)
querying.

In addition to a custom benchmarking tool, and experimental perf
integration (available at [0]), Daniel Mueller has since also implemented
an experimental integration into blazesym (see [1]), a library used for
stack trace symbolization by our server fleet-wide profiler and another
on-device profiler agent that runs on weaker ARM devices.  The latter
ARM-based device profiler is especially sensitive to performance, and so
we benchmarked and compared text-based /proc/<pid>/maps solution to the
equivalent one using PROCMAP_QUERY ioctl().

Results are very encouraging, giving us 5x improvement for end-to-end
so-called "address normalization" pass, which is the part of the
symbolization process that happens locally on ARM device, before being
sent out for further heavier-weight processing on more powerful remote
server.  Note that this is not an artificial microbenchmark.  It's a full
end-to-end API call being measured with real-world data on real-world
device.

  TEXT-BASED
  ==========
  Benchmarking main/normalize_process_no_build_ids_uncached_maps
  main/normalize_process_no_build_ids_uncached_maps
	  time:   [49.777 µs 49.982 µs 50.250 µs]

  IOCTL-BASED
  ===========
  Benchmarking main/normalize_process_no_build_ids_uncached_maps
  main/normalize_process_no_build_ids_uncached_maps
	  time:   [10.328 µs 10.391 µs 10.457 µs]
	  change: [−79.453% −79.304% −79.166%] (p = 0.00 < 0.02)
	  Performance has improved.

You can see above that we see the drop from 50µs down to 10µs for
exactly the same amount of work, with the same data and target process.

With the aforementioned custom tool, we see about ~40x improvement (it
might vary a bit, depending on a specific captured set of addresses).  And
even for perf-based benchmark it's on par or slightly ahead when using
permission-based filtering (fetching only executable VMAs).

Earlier revisions attempted to use per-VMA locking, if kernel was compiled
with CONFIG_PER_VMA_LOCK=y, but it turned out that anon_vma_name() is not
yet compatible with per-VMA locking and assumes mmap_lock to be taken,
which makes the use of per-VMA locking for this API premature.  It was
agreed ([2]) to continue for now with just mmap_lock, but the code
structure is such that it should be easy to add per-VMA locking support
once all the pieces are ready.

One thing that did not change was basing this new API as an ioctl()
command on /proc/<pid>/maps file.  An ioctl-based API on top of pidfd was
considered, but has its own downsides.  Implementing ioctl() directly on
pidfd will cause access permission checks on every single ioctl(), which
leads to performance concerns and potential spam of capable() audit
messages.  It also prevents a nice pattern, possible with
/proc/<pid>/maps, in which application opens /proc/self/maps FD (requiring
no additional capabilities) and passed this FD to profiling agent for
querying.  To achieve similar pattern, a new file would have to be created
from pidf just for VMA querying, which is considered to be inferior to
just querying /proc/<pid>/maps FD as proposed in current approach.  These
aspects were discussed in the hallway track at recent LSF/MM/BPF 2024 and
sticking to procfs ioctl() was the final agreement we arrived at.

  [0] https://github.com/anakryiko/linux/commits/procfs-proc-maps-ioctl-v2/
  [1] https://github.com/libbpf/blazesym/pull/675
  [2] https://lore.kernel.org/bpf/7rm3izyq2vjp5evdjc7c6z4crdd3oerpiknumdnmmemwyiwx7t@hleldw7iozi3/


This patch (of 6):

Extract generic logic to fetch relevant pieces of data to describe VMA
name.  This could be just some string (either special constant or
user-provided), or a string with some formatted wrapping text (e.g.,
"[anon_shmem:<something>]"), or, commonly, file path.  seq_file-based
logic has different methods to handle all three cases, but they are
currently mixed in with extracting underlying sources of data.

This patch splits this into data fetching and data formatting, so that
data fetching can be reused later on.

There should be no functional changes.

Link: https://lkml.kernel.org/r/20240627170900.1672542-1-andrii@kernel.org
Link: https://lkml.kernel.org/r/20240627170900.1672542-2-andrii@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-12 15:52:11 -07:00
Kefeng Wang
aca08acce7 fs/proc/task_mmu: use folio API in pte_is_pinned()
Patch series "mm: remove page_maybe_dma_pinned() and page_mkclean()".

Most page_maybe_dma_pinned() and page_mkclean() callers have been
converted to the folio equivalents, after two more convertsions,
remove them and update the comment and documention.


This patch (of 4):

Convert to use vm_normal_folio() and folio_maybe_dma_pinned() API, which
helps to remove page_maybe_dma_pinned() in the subsequent change.

Link: https://lkml.kernel.org/r/20240604114822.2089819-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240604114822.2089819-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:17 -07:00
David Hildenbrand
cdd9a571b7 fs/proc: move page_mapcount() to fs/proc/internal.h
...  and rename it to folio_precise_page_mapcount().  fs/proc is the last
remaining user, and that should stay that way.

While at it, cleanup kpagecount_read() a bit: there are still some legacy
leftovers -- when the interface was introduced it returned the page
refcount, but was changed briefly afterwards to return the page mapcount. 
Further, some simple folio conversion.

Once we stop using the per-page mapcounts of large folios, all
folio_precise_page_mapcount() users will have to implement an alternative
way to achieve what they are trying to achieve, possibly in a less precise
way.

[dan.carpenter@linaro.org: fix uninitialized variable in pagemap_pmd_range()]
  Link: https://lkml.kernel.org/r/9d6eaba7-92f8-4a70-8765-38a519680a87@moroto.mountain
Link: https://lkml.kernel.org/r/20240607122357.115423-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:06 -07:00
David Hildenbrand
3689c3ebdd fs/proc/task_mmu: account non-present entries as "maybe shared, but no idea how often"
We currently rely on mapcount information for pages referenced by
non-present entries to calculate the USS (shared vs.  private) and the
PSS.

However, relying on mapcounts for non-present entries doesn't make any
sense.  We have to treat such entries as "maybe shared, but no idea how
often", implying that they will *not* get accounted towards the USS, and
will get fully accounted to the PSS (no idea how often shared).

There is one exception: device exclusive entries essentially behave like
present entries (e.g., mapcount incremented).

In smaps_pmd_entry(), use is_pfn_swap_entry() instead of
is_migration_entry(), which should not make a real difference but makes
the code look more similar to the PTE variant.

While at it, adjust the comments in smaps_account().

Link: https://lkml.kernel.org/r/20240607122357.115423-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:06 -07:00
David Hildenbrand
2c1f057e5b fs/proc/task_mmu: properly detect PM_MMAP_EXCLUSIVE per page of PMD-mapped THPs
We added PM_MMAP_EXCLUSIVE in 2015 via commit 77bb499bb6 ("pagemap: add
mmap-exclusive bit for marking pages mapped only here"), when THPs could
not be partially mapped and page_mapcount() returned something that was
true for all pages of the THP.

In 2016, we added support for partially mapping THPs via commit
53f9263bab ("mm: rework mapcount accounting to enable 4k mapping of
THPs") but missed to determine PM_MMAP_EXCLUSIVE as well per page.

Checking page_mapcount() on the head page does not tell the whole story.

We should check each individual page.  In a future without per-page
mapcounts it will be different, but we'll change that to be consistent
with PTE-mapped THPs once we deal with that.

Link: https://lkml.kernel.org/r/20240607122357.115423-4-david@redhat.com
Fixes: 53f9263bab ("mm: rework mapcount accounting to enable 4k mapping of THPs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:05 -07:00
David Hildenbrand
da7f31ed0f fs/proc/task_mmu: don't indicate PM_MMAP_EXCLUSIVE without PM_PRESENT
Relying on the mapcount for non-present PTEs that reference pages doesn't
make any sense: they are not accounted in the mapcount, so page_mapcount()
== 1 won't return the result we actually want to know.

While we don't check the mapcount for migration entries already, we could
end up checking it for swap, hwpoison, device exclusive, ...  entries,
which we really shouldn't.

There is one exception: device private entries, which we consider
fake-present (e.g., incremented the mapcount).  But we won't care about
that for now for PM_MMAP_EXCLUSIVE, because indicating PM_SWAP for them
although they are fake-present already sounds suspiciously wrong.

Let's never indicate PM_MMAP_EXCLUSIVE without PM_PRESENT.

Link: https://lkml.kernel.org/r/20240607122357.115423-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:05 -07:00
David Hildenbrand
3f9f022e97 fs/proc/task_mmu: indicate PM_FILE for PMD-mapped file THP
Patch series "fs/proc: move page_mapcount() to fs/proc/internal.h".

With all other page_mapcount() users in the tree gone, move
page_mapcount() to fs/proc/internal.h, rename it and extend the
documentation to prevent future (ab)use.

... of course, I find some issues while working on that code that I sort
first ;)

We'll now only end up calling page_mapcount() [now
folio_precise_page_mapcount()] on pages mapped via present page table
entries.  Except for /proc/kpagecount, that still does questionable
things, but we'll leave that legacy interface as is for now.

Did a quick sanity check.  Likely we would want some better selfestest for
/proc/$/pagemap + smaps.  I'll see if I can find some time to write some
more.


This patch (of 6):

Looks like we never taught pagemap_pmd_range() about the existence of
PMD-mapped file THPs.  Seems to date back to the times when we first added
support for non-anon THPs in the form of shmem THP.

Link: https://lkml.kernel.org/r/20240607122357.115423-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240607122357.115423-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Fixes: 800d8c63b2 ("shmem: add huge pages support")
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:05 -07:00
Jeff Xu
399ab86ea5 /proc/pid/smaps: add mseal info for vma
Add sl in /proc/pid/smaps to indicate vma is sealed

Link: https://lkml.kernel.org/r/20240614232014.806352-2-jeffxu@google.com
Fixes: 8be7258aad ("mseal: add mseal syscall")
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Röttger <sroettger@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:09 -07:00
Yuanyuan Zhong
6d065f507d mm: /proc/pid/smaps_rollup: avoid skipping vma after getting mmap_lock again
After switching smaps_rollup to use VMA iterator, searching for next entry
is part of the condition expression of the do-while loop.  So the current
VMA needs to be addressed before the continue statement.

Otherwise, with some VMAs skipped, userspace observed memory
consumption from /proc/pid/smaps_rollup will be smaller than the sum of
the corresponding fields from /proc/pid/smaps.

Link: https://lkml.kernel.org/r/20240523183531.2535436-1-yzhong@purestorage.com
Fixes: c4c84f0628 ("fs/proc/task_mmu: stop using linked list and highest_vm_end")
Signed-off-by: Yuanyuan Zhong <yzhong@purestorage.com>
Reviewed-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-24 11:55:07 -07:00
Linus Torvalds
61307b7be4 The usual shower of singleton fixes and minor series all over MM,
documented (hopefully adequately) in the respective changelogs.  Notable
 series include:
 
 - Lucas Stach has provided some page-mapping
   cleanup/consolidation/maintainability work in the series "mm/treewide:
   Remove pXd_huge() API".
 
 - In the series "Allow migrate on protnone reference with
   MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
   MPOL_PREFERRED_MANY mode, yielding almost doubled performance in one
   test.
 
 - In their series "Memory allocation profiling" Kent Overstreet and
   Suren Baghdasaryan have contributed a means of determining (via
   /proc/allocinfo) whereabouts in the kernel memory is being allocated:
   number of calls and amount of memory.
 
 - Matthew Wilcox has provided the series "Various significant MM
   patches" which does a number of rather unrelated things, but in largely
   similar code sites.
 
 - In his series "mm: page_alloc: freelist migratetype hygiene" Johannes
   Weiner has fixed the page allocator's handling of migratetype requests,
   with resulting improvements in compaction efficiency.
 
 - In the series "make the hugetlb migration strategy consistent" Baolin
   Wang has fixed a hugetlb migration issue, which should improve hugetlb
   allocation reliability.
 
 - Liu Shixin has hit an I/O meltdown caused by readahead in a
   memory-tight memcg.  Addressed in the series "Fix I/O high when memory
   almost met memcg limit".
 
 - In the series "mm/filemap: optimize folio adding and splitting" Kairui
   Song has optimized pagecache insertion, yielding ~10% performance
   improvement in one test.
 
 - Baoquan He has cleaned up and consolidated the early zone
   initialization code in the series "mm/mm_init.c: refactor
   free_area_init_core()".
 
 - Baoquan has also redone some MM initializatio code in the series
   "mm/init: minor clean up and improvement".
 
 - MM helper cleanups from Christoph Hellwig in his series "remove
   follow_pfn".
 
 - More cleanups from Matthew Wilcox in the series "Various page->flags
   cleanups".
 
 - Vlastimil Babka has contributed maintainability improvements in the
   series "memcg_kmem hooks refactoring".
 
 - More folio conversions and cleanups in Matthew Wilcox's series
 
 	"Convert huge_zero_page to huge_zero_folio"
 	"khugepaged folio conversions"
 	"Remove page_idle and page_young wrappers"
 	"Use folio APIs in procfs"
 	"Clean up __folio_put()"
 	"Some cleanups for memory-failure"
 	"Remove page_mapping()"
 	"More folio compat code removal"
 
 - David Hildenbrand chipped in with "fs/proc/task_mmu: convert hugetlb
   functions to work on folis".
 
 - Code consolidation and cleanup work related to GUP's handling of
   hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
 
 - Rick Edgecombe has developed some fixes to stack guard gaps in the
   series "Cover a guard gap corner case".
 
 - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the series
   "mm/ksm: fix ksm exec support for prctl".
 
 - Baolin Wang has implemented NUMA balancing for multi-size THPs.  This
   is a simple first-cut implementation for now.  The series is "support
   multi-size THP numa balancing".
 
 - Cleanups to vma handling helper functions from Matthew Wilcox in the
   series "Unify vma_address and vma_pgoff_address".
 
 - Some selftests maintenance work from Dev Jain in the series
   "selftests/mm: mremap_test: Optimizations and style fixes".
 
 - Improvements to the swapping of multi-size THPs from Ryan Roberts in
   the series "Swap-out mTHP without splitting".
 
 - Kefeng Wang has significantly optimized the handling of arm64's
   permission page faults in the series
 
 	"arch/mm/fault: accelerate pagefault when badaccess"
 	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
 
 - GUP cleanups from David Hildenbrand in "mm/gup: consistently call it
   GUP-fast".
 
 - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault path to
   use struct vm_fault".
 
 - selftests build fixes from John Hubbard in the series "Fix
   selftests/mm build without requiring "make headers"".
 
 - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
   series "Improved Memory Tier Creation for CPUless NUMA Nodes".  Fixes
   the initialization code so that migration between different memory types
   works as intended.
 
 - David Hildenbrand has improved follow_pte() and fixed an errant driver
   in the series "mm: follow_pte() improvements and acrn follow_pte()
   fixes".
 
 - David also did some cleanup work on large folio mapcounts in his
   series "mm: mapcount for large folios + page_mapcount() cleanups".
 
 - Folio conversions in KSM in Alex Shi's series "transfer page to folio
   in KSM".
 
 - Barry Song has added some sysfs stats for monitoring multi-size THP's
   in the series "mm: add per-order mTHP alloc and swpout counters".
 
 - Some zswap cleanups from Yosry Ahmed in the series "zswap same-filled
   and limit checking cleanups".
 
 - Matthew Wilcox has been looking at buffer_head code and found the
   documentation to be lacking.  The series is "Improve buffer head
   documentation".
 
 - Multi-size THPs get more work, this time from Lance Yang.  His series
   "mm/madvise: enhance lazyfreeing with mTHP in madvise_free" optimizes
   the freeing of these things.
 
 - Kemeng Shi has added more userspace-visible writeback instrumentation
   in the series "Improve visibility of writeback".
 
 - Kemeng Shi then sent some maintenance work on top in the series "Fix
   and cleanups to page-writeback".
 
 - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in the
   series "Improve anon_vma scalability for anon VMAs".  Intel's test bot
   reported an improbable 3x improvement in one test.
 
 - SeongJae Park adds some DAMON feature work in the series
 
 	"mm/damon: add a DAMOS filter type for page granularity access recheck"
 	"selftests/damon: add DAMOS quota goal test"
 
 - Also some maintenance work in the series
 
 	"mm/damon/paddr: simplify page level access re-check for pageout"
 	"mm/damon: misc fixes and improvements"
 
 - David Hildenbrand has disabled some known-to-fail selftests ni the
   series "selftests: mm: cow: flag vmsplice() hugetlb tests as XFAIL".
 
 - memcg metadata storage optimizations from Shakeel Butt in "memcg:
   reduce memory consumption by memcg stats".
 
 - DAX fixes and maintenance work from Vishal Verma in the series
   "dax/bus.c: Fixups for dax-bus locking".
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Merge tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull mm updates from Andrew Morton:
 "The usual shower of singleton fixes and minor series all over MM,
  documented (hopefully adequately) in the respective changelogs.
  Notable series include:

   - Lucas Stach has provided some page-mapping cleanup/consolidation/
     maintainability work in the series "mm/treewide: Remove pXd_huge()
     API".

   - In the series "Allow migrate on protnone reference with
     MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
     MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
     one test.

   - In their series "Memory allocation profiling" Kent Overstreet and
     Suren Baghdasaryan have contributed a means of determining (via
     /proc/allocinfo) whereabouts in the kernel memory is being
     allocated: number of calls and amount of memory.

   - Matthew Wilcox has provided the series "Various significant MM
     patches" which does a number of rather unrelated things, but in
     largely similar code sites.

   - In his series "mm: page_alloc: freelist migratetype hygiene"
     Johannes Weiner has fixed the page allocator's handling of
     migratetype requests, with resulting improvements in compaction
     efficiency.

   - In the series "make the hugetlb migration strategy consistent"
     Baolin Wang has fixed a hugetlb migration issue, which should
     improve hugetlb allocation reliability.

   - Liu Shixin has hit an I/O meltdown caused by readahead in a
     memory-tight memcg. Addressed in the series "Fix I/O high when
     memory almost met memcg limit".

   - In the series "mm/filemap: optimize folio adding and splitting"
     Kairui Song has optimized pagecache insertion, yielding ~10%
     performance improvement in one test.

   - Baoquan He has cleaned up and consolidated the early zone
     initialization code in the series "mm/mm_init.c: refactor
     free_area_init_core()".

   - Baoquan has also redone some MM initializatio code in the series
     "mm/init: minor clean up and improvement".

   - MM helper cleanups from Christoph Hellwig in his series "remove
     follow_pfn".

   - More cleanups from Matthew Wilcox in the series "Various
     page->flags cleanups".

   - Vlastimil Babka has contributed maintainability improvements in the
     series "memcg_kmem hooks refactoring".

   - More folio conversions and cleanups in Matthew Wilcox's series:
	"Convert huge_zero_page to huge_zero_folio"
	"khugepaged folio conversions"
	"Remove page_idle and page_young wrappers"
	"Use folio APIs in procfs"
	"Clean up __folio_put()"
	"Some cleanups for memory-failure"
	"Remove page_mapping()"
	"More folio compat code removal"

   - David Hildenbrand chipped in with "fs/proc/task_mmu: convert
     hugetlb functions to work on folis".

   - Code consolidation and cleanup work related to GUP's handling of
     hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".

   - Rick Edgecombe has developed some fixes to stack guard gaps in the
     series "Cover a guard gap corner case".

   - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
     series "mm/ksm: fix ksm exec support for prctl".

   - Baolin Wang has implemented NUMA balancing for multi-size THPs.
     This is a simple first-cut implementation for now. The series is
     "support multi-size THP numa balancing".

   - Cleanups to vma handling helper functions from Matthew Wilcox in
     the series "Unify vma_address and vma_pgoff_address".

   - Some selftests maintenance work from Dev Jain in the series
     "selftests/mm: mremap_test: Optimizations and style fixes".

   - Improvements to the swapping of multi-size THPs from Ryan Roberts
     in the series "Swap-out mTHP without splitting".

   - Kefeng Wang has significantly optimized the handling of arm64's
     permission page faults in the series
	"arch/mm/fault: accelerate pagefault when badaccess"
	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"

   - GUP cleanups from David Hildenbrand in "mm/gup: consistently call
     it GUP-fast".

   - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
     path to use struct vm_fault".

   - selftests build fixes from John Hubbard in the series "Fix
     selftests/mm build without requiring "make headers"".

   - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
     series "Improved Memory Tier Creation for CPUless NUMA Nodes".
     Fixes the initialization code so that migration between different
     memory types works as intended.

   - David Hildenbrand has improved follow_pte() and fixed an errant
     driver in the series "mm: follow_pte() improvements and acrn
     follow_pte() fixes".

   - David also did some cleanup work on large folio mapcounts in his
     series "mm: mapcount for large folios + page_mapcount() cleanups".

   - Folio conversions in KSM in Alex Shi's series "transfer page to
     folio in KSM".

   - Barry Song has added some sysfs stats for monitoring multi-size
     THP's in the series "mm: add per-order mTHP alloc and swpout
     counters".

   - Some zswap cleanups from Yosry Ahmed in the series "zswap
     same-filled and limit checking cleanups".

   - Matthew Wilcox has been looking at buffer_head code and found the
     documentation to be lacking. The series is "Improve buffer head
     documentation".

   - Multi-size THPs get more work, this time from Lance Yang. His
     series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
     optimizes the freeing of these things.

   - Kemeng Shi has added more userspace-visible writeback
     instrumentation in the series "Improve visibility of writeback".

   - Kemeng Shi then sent some maintenance work on top in the series
     "Fix and cleanups to page-writeback".

   - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
     the series "Improve anon_vma scalability for anon VMAs". Intel's
     test bot reported an improbable 3x improvement in one test.

   - SeongJae Park adds some DAMON feature work in the series
	"mm/damon: add a DAMOS filter type for page granularity access recheck"
	"selftests/damon: add DAMOS quota goal test"

   - Also some maintenance work in the series
	"mm/damon/paddr: simplify page level access re-check for pageout"
	"mm/damon: misc fixes and improvements"

   - David Hildenbrand has disabled some known-to-fail selftests ni the
     series "selftests: mm: cow: flag vmsplice() hugetlb tests as
     XFAIL".

   - memcg metadata storage optimizations from Shakeel Butt in "memcg:
     reduce memory consumption by memcg stats".

   - DAX fixes and maintenance work from Vishal Verma in the series
     "dax/bus.c: Fixups for dax-bus locking""

* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
  memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
  selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
  selftests: cgroup: add tests to verify the zswap writeback path
  mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
  mm/damon/core: fix return value from damos_wmark_metric_value
  mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
  selftests: cgroup: remove redundant enabling of memory controller
  Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
  Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
  Docs/mm/damon/design: use a list for supported filters
  Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
  Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
  selftests/damon: classify tests for functionalities and regressions
  selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
  selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
  selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
  mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
  selftests/damon: add a test for DAMOS quota goal
  ...
2024-05-19 09:21:03 -07:00
Matthew Wilcox
e0ffb29bc5 mm: simplify thp_vma_allowable_order
Combine the three boolean arguments into one flags argument for
readability.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:53 -07:00
David Hildenbrand
6401a2e690 fs/proc/task_mmu: convert smaps_hugetlb_range() to work on folios
Let's get rid of another page_mapcount() check and simply use
folio_likely_mapped_shared(), which is precise for hugetlb folios.

While at it, use huge_ptep_get() + pte_page() instead of ptep_get() +
vm_normal_page(), just like we do in pagemap_hugetlb_range().

No functional change intended.

Link: https://lkml.kernel.org/r/20240417092313.753919-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:41 -07:00
David Hildenbrand
88e4e47c12 fs/proc/task_mmu: convert pagemap_hugetlb_range() to work on folios
Patch series "fs/proc/task_mmu: convert hugetlb functions to work on folis".

Let's convert two more functions, getting rid of two more page_mapcount()
calls.


This patch (of 2):

Let's get rid of another page_mapcount() check and simply use
folio_likely_mapped_shared(), which is precise for hugetlb folios.

While at it, also check for PMD table sharing, like we do in
smaps_hugetlb_range().

No functional change intended, except that we would now detect hugetlb
folios shared via PMD table sharing correctly.

Link: https://lkml.kernel.org/r/20240417092313.753919-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240417092313.753919-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:41 -07:00
Ryan Roberts
2c7ad9a590 fs/proc/task_mmu: fix uffd-wp confusion in pagemap_scan_pmd_entry()
pagemap_scan_pmd_entry() checks if uffd-wp is set on each pte to avoid
unnecessary if set.  However it was previously checking with
`pte_uffd_wp(ptep_get(pte))` without first confirming that the pte was
present.  It is only valid to call pte_uffd_wp() for present ptes.  For
swap ptes, pte_swp_uffd_wp() must be called because the uffd-wp bit may be
kept in a different position, depending on the arch.

This was leading to test failures in the pagemap_ioctl mm selftest, when
bringing up uffd-wp support on arm64 due to incorrectly interpretting the
uffd-wp status of migration entries.

Let's fix this by using the correct check based on pte_present().  While
we are at it, let's pass the pte to make_uffd_wp_pte() to avoid the
pointless extra ptep_get() which can't be optimized out due to READ_ONCE()
on many arches.

Link: https://lkml.kernel.org/r/20240429114104.182890-1-ryan.roberts@arm.com
Fixes: 12f6b01a0b ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag")
Closes: https://lore.kernel.org/linux-arm-kernel/ZiuyGXt0XWwRgFh9@x1n/
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com> 
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:28:07 -07:00
Ryan Roberts
c70dce4982 fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan
make_uffd_wp_pte() was previously doing:

  pte = ptep_get(ptep);
  ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

But if another thread accessed or dirtied the pte between the first 2
calls, this could lead to loss of that information.  Since
ptep_modify_prot_start() gets and clears atomically, the following is the
correct pattern and prevents any possible race.  Any access after the
first call would see an invalid pte and cause a fault:

  pte = ptep_modify_prot_start(ptep);
  pte = pte_mkuffd_wp(pte);
  ptep_modify_prot_commit(ptep, pte);

Link: https://lkml.kernel.org/r/20240429114017.182570-1-ryan.roberts@arm.com
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:28:06 -07:00
Matthew Wilcox (Oracle)
039d26d10d proc: convert smaps_pmd_entry to use a folio
Replace two calls to compound_head() with one.

Link: https://lkml.kernel.org/r/20240403171456.1445117-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:36 -07:00
Matthew Wilcox (Oracle)
27bb0a70e5 proc: pass a folio to smaps_page_accumulate()
Both callers already have a folio; pass it in instead of doing the
conversion each time.

Link: https://lkml.kernel.org/r/20240403171456.1445117-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:36 -07:00
Matthew Wilcox (Oracle)
cfc96da432 proc: convert smaps_page_accumulate to use a folio
Replaces three calls to compound_head() with one.  Shrinks the function
from 2614 bytes to 1112 bytes in an allmodconfig build.

Link: https://lkml.kernel.org/r/20240403171456.1445117-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:35 -07:00
Matthew Wilcox (Oracle)
f1dc623fa0 proc: convert gather_stats to use a folio
Patch series "Use folio APIs in procfs".

We're down to very few users of the PageFoo macros, with proc being a
major user.

After this patchset and another patchset I have for khugepaged, we can get
rid of PageActive, PageReadahead and PageSwapBacked.  This patchset has
the usual advantages in its own right of removing hidden calls to
compound_head().  We have the page table lock, so the mapcount & refcount
are stable and there can't be any races with folios suddenly becoming tail
pages.


This patch (of 4):

Replaces six calls to compound_head() with one.  Shrinks the function from
5054 bytes to 1756 bytes in an allmodconfig build.

Link: https://lkml.kernel.org/r/20240403171456.1445117-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240403171456.1445117-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:35 -07:00
Matthew Wilcox (Oracle)
6c977f36dc proc: convert smaps_account() to use a folio
Replace seven calls to compound_head() with one.

Link: https://lkml.kernel.org/r/20240402201252.917342-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:34 -07:00
Matthew Wilcox (Oracle)
03aa577f3b proc: convert clear_refs_pte_range to use a folio
Patch series "Remove page_idle and page_young wrappers".

There are only a couple of places left using the page wrappers for idle &
young tracking.  Convert the two users in proc and then we can remove the
wrappers.  That enables the further simplification of autogenerating the
definitions when CONFIG_PAGE_IDLE_FLAG is disabled.  


This patch (of 4):

Replaces four calls to compound_head() with two.

Link: https://lkml.kernel.org/r/20240402201252.917342-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240402201252.917342-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 20:56:34 -07:00
Hui Zhu
cabbb6d51e fs/proc/task_mmu.c: add_to_pagemap: remove useless parameter addr
Function parameter addr of add_to_pagemap() is useless.  Remove it.

Link: https://lkml.kernel.org/r/20240111084533.40038-1-teawaterz@linux.alibaba.com
Signed-off-by: Hui Zhu <teawater@antgroup.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-21 16:00:04 -08:00
Matthew Wilcox (Oracle)
7101422464 proc: use pfn_swap_entry_folio where obvious
These callers only pass the result to PageAnon(), so we can save the extra
call to compound_head() by using pfn_swap_entry_folio().

Link: https://lkml.kernel.org/r/20240111152429.3374566-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-21 16:00:03 -08:00
Muhammad Usama Anjum
4cccb6221c fs/proc/task_mmu: move mmu notification mechanism inside mm lock
Move mmu notification mechanism inside mm lock to prevent race condition
in other components which depend on it.  The notifier will invalidate
memory range.  Depending upon the number of iterations, different memory
ranges would be invalidated.

The following warning would be removed by this patch:
WARNING: CPU: 0 PID: 5067 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734

There is no behavioural and performance change with this patch when
there is no component registered with the mmu notifier.

[akpm@linux-foundation.org: narrow the scope of `range', per Sean]
Link: https://lkml.kernel.org/r/20240109112445.590736-1-usama.anjum@collabora.com
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reported-by: syzbot+81227d2bd69e9dedb802@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000f6d051060c6785bc@google.com/
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-01-12 15:20:46 -08:00
Linus Torvalds
fb46e22a9e Many singleton patches against the MM code. The patch series which
are included in this merge do the following:
 
 - Peng Zhang has done some mapletree maintainance work in the
   series
 
 	"maple_tree: add mt_free_one() and mt_attr() helpers"
 	"Some cleanups of maple tree"
 
 - In the series "mm: use memmap_on_memory semantics for dax/kmem"
   Vishal Verma has altered the interworking between memory-hotplug
   and dax/kmem so that newly added 'device memory' can more easily
   have its memmap placed within that newly added memory.
 
 - Matthew Wilcox continues folio-related work (including a few
   fixes) in the patch series
 
 	"Add folio_zero_tail() and folio_fill_tail()"
 	"Make folio_start_writeback return void"
 	"Fix fault handler's handling of poisoned tail pages"
 	"Convert aops->error_remove_page to ->error_remove_folio"
 	"Finish two folio conversions"
 	"More swap folio conversions"
 
 - Kefeng Wang has also contributed folio-related work in the series
 
 	"mm: cleanup and use more folio in page fault"
 
 - Jim Cromie has improved the kmemleak reporting output in the
   series "tweak kmemleak report format".
 
 - In the series "stackdepot: allow evicting stack traces" Andrey
   Konovalov to permits clients (in this case KASAN) to cause
   eviction of no longer needed stack traces.
 
 - Charan Teja Kalla has fixed some accounting issues in the page
   allocator's atomic reserve calculations in the series "mm:
   page_alloc: fixes for high atomic reserve caluculations".
 
 - Dmitry Rokosov has added to the samples/ dorectory some sample
   code for a userspace memcg event listener application.  See the
   series "samples: introduce cgroup events listeners".
 
 - Some mapletree maintanance work from Liam Howlett in the series
   "maple_tree: iterator state changes".
 
 - Nhat Pham has improved zswap's approach to writeback in the
   series "workload-specific and memory pressure-driven zswap
   writeback".
 
 - DAMON/DAMOS feature and maintenance work from SeongJae Park in
   the series
 
 	"mm/damon: let users feed and tame/auto-tune DAMOS"
 	"selftests/damon: add Python-written DAMON functionality tests"
 	"mm/damon: misc updates for 6.8"
 
 - Yosry Ahmed has improved memcg's stats flushing in the series
   "mm: memcg: subtree stats flushing and thresholds".
 
 - In the series "Multi-size THP for anonymous memory" Ryan Roberts
   has added a runtime opt-in feature to transparent hugepages which
   improves performance by allocating larger chunks of memory during
   anonymous page faults.
 
 - Matthew Wilcox has also contributed some cleanup and maintenance
   work against eh buffer_head code int he series "More buffer_head
   cleanups".
 
 - Suren Baghdasaryan has done work on Andrea Arcangeli's series
   "userfaultfd move option".  UFFDIO_MOVE permits userspace heap
   compaction algorithms to move userspace's pages around rather than
   UFFDIO_COPY'a alloc/copy/free.
 
 - Stefan Roesch has developed a "KSM Advisor", in the series
   "mm/ksm: Add ksm advisor".  This is a governor which tunes KSM's
   scanning aggressiveness in response to userspace's current needs.
 
 - Chengming Zhou has optimized zswap's temporary working memory
   use in the series "mm/zswap: dstmem reuse optimizations and
   cleanups".
 
 - Matthew Wilcox has performed some maintenance work on the
   writeback code, both code and within filesystems.  The series is
   "Clean up the writeback paths".
 
 - Andrey Konovalov has optimized KASAN's handling of alloc and
   free stack traces for secondary-level allocators, in the series
   "kasan: save mempool stack traces".
 
 - Andrey also performed some KASAN maintenance work in the series
   "kasan: assorted clean-ups".
 
 - David Hildenbrand has gone to town on the rmap code.  Cleanups,
   more pte batching, folio conversions and more.  See the series
   "mm/rmap: interface overhaul".
 
 - Kinsey Ho has contributed some maintenance work on the MGLRU
   code in the series "mm/mglru: Kconfig cleanup".
 
 - Matthew Wilcox has contributed lruvec page accounting code
   cleanups in the series "Remove some lruvec page accounting
   functions".
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Merge tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Peng Zhang has done some mapletree maintainance work in the series

	'maple_tree: add mt_free_one() and mt_attr() helpers'
	'Some cleanups of maple tree'

   - In the series 'mm: use memmap_on_memory semantics for dax/kmem'
     Vishal Verma has altered the interworking between memory-hotplug
     and dax/kmem so that newly added 'device memory' can more easily
     have its memmap placed within that newly added memory.

   - Matthew Wilcox continues folio-related work (including a few fixes)
     in the patch series

	'Add folio_zero_tail() and folio_fill_tail()'
	'Make folio_start_writeback return void'
	'Fix fault handler's handling of poisoned tail pages'
	'Convert aops->error_remove_page to ->error_remove_folio'
	'Finish two folio conversions'
	'More swap folio conversions'

   - Kefeng Wang has also contributed folio-related work in the series

	'mm: cleanup and use more folio in page fault'

   - Jim Cromie has improved the kmemleak reporting output in the series
     'tweak kmemleak report format'.

   - In the series 'stackdepot: allow evicting stack traces' Andrey
     Konovalov to permits clients (in this case KASAN) to cause eviction
     of no longer needed stack traces.

   - Charan Teja Kalla has fixed some accounting issues in the page
     allocator's atomic reserve calculations in the series 'mm:
     page_alloc: fixes for high atomic reserve caluculations'.

   - Dmitry Rokosov has added to the samples/ dorectory some sample code
     for a userspace memcg event listener application. See the series
     'samples: introduce cgroup events listeners'.

   - Some mapletree maintanance work from Liam Howlett in the series
     'maple_tree: iterator state changes'.

   - Nhat Pham has improved zswap's approach to writeback in the series
     'workload-specific and memory pressure-driven zswap writeback'.

   - DAMON/DAMOS feature and maintenance work from SeongJae Park in the
     series

	'mm/damon: let users feed and tame/auto-tune DAMOS'
	'selftests/damon: add Python-written DAMON functionality tests'
	'mm/damon: misc updates for 6.8'

   - Yosry Ahmed has improved memcg's stats flushing in the series 'mm:
     memcg: subtree stats flushing and thresholds'.

   - In the series 'Multi-size THP for anonymous memory' Ryan Roberts
     has added a runtime opt-in feature to transparent hugepages which
     improves performance by allocating larger chunks of memory during
     anonymous page faults.

   - Matthew Wilcox has also contributed some cleanup and maintenance
     work against eh buffer_head code int he series 'More buffer_head
     cleanups'.

   - Suren Baghdasaryan has done work on Andrea Arcangeli's series
     'userfaultfd move option'. UFFDIO_MOVE permits userspace heap
     compaction algorithms to move userspace's pages around rather than
     UFFDIO_COPY'a alloc/copy/free.

   - Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm:
     Add ksm advisor'. This is a governor which tunes KSM's scanning
     aggressiveness in response to userspace's current needs.

   - Chengming Zhou has optimized zswap's temporary working memory use
     in the series 'mm/zswap: dstmem reuse optimizations and cleanups'.

   - Matthew Wilcox has performed some maintenance work on the writeback
     code, both code and within filesystems. The series is 'Clean up the
     writeback paths'.

   - Andrey Konovalov has optimized KASAN's handling of alloc and free
     stack traces for secondary-level allocators, in the series 'kasan:
     save mempool stack traces'.

   - Andrey also performed some KASAN maintenance work in the series
     'kasan: assorted clean-ups'.

   - David Hildenbrand has gone to town on the rmap code. Cleanups, more
     pte batching, folio conversions and more. See the series 'mm/rmap:
     interface overhaul'.

   - Kinsey Ho has contributed some maintenance work on the MGLRU code
     in the series 'mm/mglru: Kconfig cleanup'.

   - Matthew Wilcox has contributed lruvec page accounting code cleanups
     in the series 'Remove some lruvec page accounting functions'"

* tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits)
  mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
  mm, treewide: introduce NR_PAGE_ORDERS
  selftests/mm: add separate UFFDIO_MOVE test for PMD splitting
  selftests/mm: skip test if application doesn't has root privileges
  selftests/mm: conform test to TAP format output
  selftests: mm: hugepage-mmap: conform to TAP format output
  selftests/mm: gup_test: conform test to TAP format output
  mm/selftests: hugepage-mremap: conform test to TAP format output
  mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
  mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
  mm/memcontrol: remove __mod_lruvec_page_state()
  mm/khugepaged: use a folio more in collapse_file()
  slub: use a folio in __kmalloc_large_node
  slub: use folio APIs in free_large_kmalloc()
  slub: use alloc_pages_node() in alloc_slab_page()
  mm: remove inc/dec lruvec page state functions
  mm: ratelimit stat flush from workingset shrinker
  kasan: stop leaking stack trace handles
  mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
  mm/mglru: add dummy pmd_dirty()
  ...
2024-01-09 11:18:47 -08:00
Linus Torvalds
c604110e66 vfs-6.8.misc
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Merge tag 'vfs-6.8.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Add Jan Kara as VFS reviewer

   - Show correct device and inode numbers in proc/<pid>/maps for vma
     files on stacked filesystems. This is now easily doable thanks to
     the backing file work from the last cycles. This comes with
     selftests

  Cleanups:

   - Remove a redundant might_sleep() from wait_on_inode()

   - Initialize pointer with NULL, not 0

   - Clarify comment on access_override_creds()

   - Rework and simplify eventfd_signal() and eventfd_signal_mask()
     helpers

   - Process aio completions in batches to avoid needless wakeups

   - Completely decouple struct mnt_idmap from namespaces. We now only
     keep the actual idmapping around and don't stash references to
     namespaces

   - Reformat maintainer entries to indicate that a given subsystem
     belongs to fs/

   - Simplify fput() for files that were never opened

   - Get rid of various pointless file helpers

   - Rename various file helpers

   - Rename struct file members after SLAB_TYPESAFE_BY_RCU switch from
     last cycle

   - Make relatime_need_update() return bool

   - Use GFP_KERNEL instead of GFP_USER when allocating superblocks

   - Replace deprecated ida_simple_*() calls with their current ida_*()
     counterparts

  Fixes:

   - Fix comments on user namespace id mapping helpers. They aren't
     kernel doc comments so they shouldn't be using /**

   - s/Retuns/Returns/g in various places

   - Add missing parameter documentation on can_move_mount_beneath()

   - Rename i_mapping->private_data to i_mapping->i_private_data

   - Fix a false-positive lockdep warning in pipe_write() for watch
     queues

   - Improve __fget_files_rcu() code generation to improve performance

   - Only notify writer that pipe resizing has finished after setting
     pipe->max_usage otherwise writers are never notified that the pipe
     has been resized and hang

   - Fix some kernel docs in hfsplus

   - s/passs/pass/g in various places

   - Fix kernel docs in ntfs

   - Fix kcalloc() arguments order reported by gcc 14

   - Fix uninitialized value in reiserfs"

* tag 'vfs-6.8.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits)
  reiserfs: fix uninit-value in comp_keys
  watch_queue: fix kcalloc() arguments order
  ntfs: dir.c: fix kernel-doc function parameter warnings
  fs: fix doc comment typo fs tree wide
  selftests/overlayfs: verify device and inode numbers in /proc/pid/maps
  fs/proc: show correct device and inode numbers in /proc/pid/maps
  eventfd: Remove usage of the deprecated ida_simple_xx() API
  fs: super: use GFP_KERNEL instead of GFP_USER for super block allocation
  fs/hfsplus: wrapper.c: fix kernel-doc warnings
  fs: add Jan Kara as reviewer
  fs/inode: Make relatime_need_update return bool
  pipe: wakeup wr_wait after setting max_usage
  file: remove __receive_fd()
  file: stop exposing receive_fd_user()
  fs: replace f_rcuhead with f_task_work
  file: remove pointless wrapper
  file: s/close_fd_get_file()/file_close_fd()/g
  Improve __fget_files_rcu() code generation (and thus __fget_light())
  file: massage cleanup of files that failed to open
  fs/pipe: Fix lockdep false-positive in watchqueue pipe_write()
  ...
2024-01-08 10:26:08 -08:00
Andrei Vagin
3efdc78fdc
fs/proc: show correct device and inode numbers in /proc/pid/maps
/proc/pid/maps shows device and inode numbers of vma->vm_file-s. Here is
an issue. If a mapped file is on a stackable file system (e.g.,
overlayfs), vma->vm_file is a backing file whose f_inode is on the
underlying filesystem. To show correct numbers, we need to get a user
file and shows its numbers. The same trick is used to show file paths in
/proc/pid/maps.

Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Andrei Vagin <avagin@google.com>
Link: https://lore.kernel.org/r/20231214064439.1023011-1-avagin@google.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-21 13:17:54 +01:00
Ryan Roberts
3485b88390 mm: thp: introduce multi-size THP sysfs interface
In preparation for adding support for anonymous multi-size THP, introduce
new sysfs structure that will be used to control the new behaviours.  A
new directory is added under transparent_hugepage for each supported THP
size, and contains an `enabled` file, which can be set to "inherit" (to
inherit the global setting), "always", "madvise" or "never".  For now, the
kernel still only supports PMD-sized anonymous THP, so only 1 directory is
populated.

The first half of the change converts transhuge_vma_suitable() and
hugepage_vma_check() so that they take a bitfield of orders for which the
user wants to determine support, and the functions filter out all the
orders that can't be supported, given the current sysfs configuration and
the VMA dimensions.  The resulting functions are renamed to
thp_vma_suitable_orders() and thp_vma_allowable_orders() respectively. 
Convenience functions that take a single, unencoded order and return a
boolean are also defined as thp_vma_suitable_order() and
thp_vma_allowable_order().

The second half of the change implements the new sysfs interface.  It has
been done so that each supported THP size has a `struct thpsize`, which
describes the relevant metadata and is itself a kobject.  This is pretty
minimal for now, but should make it easy to add new per-thpsize files to
the interface if needed in future (e.g.  per-size defrag).  Rather than
keep the `enabled` state directly in the struct thpsize, I've elected to
directly encode it into huge_anon_orders_[always|madvise|inherit]
bitfields since this reduces the amount of work required in
thp_vma_allowable_orders() which is called for every page fault.

See Documentation/admin-guide/mm/transhuge.rst, as modified by this
commit, for details of how the new sysfs interface works.

[ryan.roberts@arm.com: fix build warning when CONFIG_SYSFS is disabled]
  Link: https://lkml.kernel.org/r/20231211125320.3997543-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20231207161211.2374093-4-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-20 14:48:12 -08:00
Andrei Vagin
e6a9a2cbc1 fs/proc/task_mmu: report SOFT_DIRTY bits through the PAGEMAP_SCAN ioctl
The PAGEMAP_SCAN ioctl returns information regarding page table entries. 
It is more efficient compared to reading pagemap files.  CRIU can start to
utilize this ioctl, but it needs info about soft-dirty bits to track
memory changes.

We are aware of a new method for tracking memory changes implemented in
the PAGEMAP_SCAN ioctl.  For CRIU, the primary advantage of this method is
its usability by unprivileged users.  However, it is not feasible to
transparently replace the soft-dirty tracker with the new one.  The main
problem here is userfault descriptors that have to be preserved between
pre-dump iterations.  It means criu continues supporting the soft-dirty
method to avoid breakage for current users.  The new method will be
implemented as a separate feature.

[avagin@google.com: update tools/include/uapi/linux/fs.h]
  Link: https://lkml.kernel.org/r/20231107164139.576046-1-avagin@google.com
Link: https://lkml.kernel.org/r/20231106220959.296568-1-avagin@google.com
Signed-off-by: Andrei Vagin <avagin@google.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-10 16:51:35 -08:00
Peter Xu
4980e837ca mm/pagemap: fix wr-protect even if PM_SCAN_WP_MATCHING not set
The new pagemap ioctl contains a fast path for wr-protections without
looking into category masks.  It forgets to check PM_SCAN_WP_MATCHING
before applying the wr-protections.  It can cause, e.g., pte markers
installed on archs that do not even support uffd wr-protect.

WARNING: CPU: 0 PID: 5059 at mm/memory.c:1520 zap_pte_range mm/memory.c:1520 [inline]

Link: https://lkml.kernel.org/r/20231116201547.536857-3-peterx@redhat.com
Fixes: 12f6b01a0b ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: syzbot+7ca4b2719dc742b8d0a4@syzkaller.appspotmail.com
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-06 16:12:45 -08:00
Peter Xu
0dff1b407d mm/pagemap: fix ioctl(PAGEMAP_SCAN) on vma check
Patch series "mm/pagemap: A few fixes to the recent PAGEMAP_SCAN".

This series should fix two known reports from syzbot on the new
PAGEMAP_SCAN ioctl():

https://lore.kernel.org/all/000000000000b0e576060a30ee3b@google.com/
https://lore.kernel.org/all/000000000000773fa7060a31e2cc@google.com/

The 3rd patch is something I found when testing these patches.


This patch (of 3):

The new ioctl(PAGEMAP_SCAN) relies on vma wr-protect capability provided
by userfault, however in the vma test it didn't explicitly require the vma
to have wr-protect function enabled, even if PM_SCAN_WP_MATCHING flag is
set.

It means the pagemap code can now apply uffd-wp bit to a page in the vma
even if not registered to userfaultfd at all.

Then in whatever way as long as the pte got written and page fault
resolved, we'll apply the write bit even if uffd-wp bit is set.  We'll see
a pte that has both UFFD_WP and WRITE bit set.  Anything later that looks
up the pte for uffd-wp bit will trigger the warning:

WARNING: CPU: 1 PID: 5071 at arch/x86/include/asm/pgtable.h:403 pte_uffd_wp arch/x86/include/asm/pgtable.h:403 [inline]

Fix it by doing proper check over the vma attributes when
PM_SCAN_WP_MATCHING is specified.

Link: https://lkml.kernel.org/r/20231116201547.536857-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20231116201547.536857-2-peterx@redhat.com
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: syzbot+e94c5aaf7890901ebf9b@syzkaller.appspotmail.com
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-06 16:12:44 -08:00
Linus Torvalds
8f6f76a6a2 As usual, lots of singleton and doubleton patches all over the tree and
there's little I can say which isn't in the individual changelogs.
 
 The lengthier patch series are
 
 - "kdump: use generic functions to simplify crashkernel reservation in
   arch", from Baoquan He.  This is mainly cleanups and consolidation of
   the "crashkernel=" kernel parameter handling.
 
 - After much discussion, David Laight's "minmax: Relax type checks in
   min() and max()" is here.  Hopefully reduces some typecasting and the
   use of min_t() and max_t().
 
 - A group of patches from Oleg Nesterov which clean up and slightly fix
   our handling of reads from /proc/PID/task/...  and which remove
   task_struct.therad_group.
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Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:
 "As usual, lots of singleton and doubleton patches all over the tree
  and there's little I can say which isn't in the individual changelogs.

  The lengthier patch series are

   - 'kdump: use generic functions to simplify crashkernel reservation
     in arch', from Baoquan He. This is mainly cleanups and
     consolidation of the 'crashkernel=' kernel parameter handling

   - After much discussion, David Laight's 'minmax: Relax type checks in
     min() and max()' is here. Hopefully reduces some typecasting and
     the use of min_t() and max_t()

   - A group of patches from Oleg Nesterov which clean up and slightly
     fix our handling of reads from /proc/PID/task/... and which remove
     task_struct.thread_group"

* tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits)
  scripts/gdb/vmalloc: disable on no-MMU
  scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n
  .mailmap: add address mapping for Tomeu Vizoso
  mailmap: update email address for Claudiu Beznea
  tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions
  .mailmap: map Benjamin Poirier's address
  scripts/gdb: add lx_current support for riscv
  ocfs2: fix a spelling typo in comment
  proc: test ProtectionKey in proc-empty-vm test
  proc: fix proc-empty-vm test with vsyscall
  fs/proc/base.c: remove unneeded semicolon
  do_io_accounting: use sig->stats_lock
  do_io_accounting: use __for_each_thread()
  ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error()
  ocfs2: fix a typo in a comment
  scripts/show_delta: add __main__ judgement before main code
  treewide: mark stuff as __ro_after_init
  fs: ocfs2: check status values
  proc: test /proc/${pid}/statm
  compiler.h: move __is_constexpr() to compiler.h
  ...
2023-11-02 20:53:31 -10:00
Linus Torvalds
ecae0bd517 Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
 
 - Kemeng Shi has contributed some compation maintenance work in the
   series "Fixes and cleanups to compaction".
 
 - Joel Fernandes has a patchset ("Optimize mremap during mutual
   alignment within PMD") which fixes an obscure issue with mremap()'s
   pagetable handling during a subsequent exec(), based upon an
   implementation which Linus suggested.
 
 - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the
   following patch series:
 
 	mm/damon: misc fixups for documents, comments and its tracepoint
 	mm/damon: add a tracepoint for damos apply target regions
 	mm/damon: provide pseudo-moving sum based access rate
 	mm/damon: implement DAMOS apply intervals
 	mm/damon/core-test: Fix memory leaks in core-test
 	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
 
 - In the series "Do not try to access unaccepted memory" Adrian Hunter
   provides some fixups for the recently-added "unaccepted memory' feature.
   To increase the feature's checking coverage.  "Plug a few gaps where
   RAM is exposed without checking if it is unaccepted memory".
 
 - In the series "cleanups for lockless slab shrink" Qi Zheng has done
   some maintenance work which is preparation for the lockless slab
   shrinking code.
 
 - Qi Zheng has redone the earlier (and reverted) attempt to make slab
   shrinking lockless in the series "use refcount+RCU method to implement
   lockless slab shrink".
 
 - David Hildenbrand contributes some maintenance work for the rmap code
   in the series "Anon rmap cleanups".
 
 - Kefeng Wang does more folio conversions and some maintenance work in
   the migration code.  Series "mm: migrate: more folio conversion and
   unification".
 
 - Matthew Wilcox has fixed an issue in the buffer_head code which was
   causing long stalls under some heavy memory/IO loads.  Some cleanups
   were added on the way.  Series "Add and use bdev_getblk()".
 
 - In the series "Use nth_page() in place of direct struct page
   manipulation" Zi Yan has fixed a potential issue with the direct
   manipulation of hugetlb page frames.
 
 - In the series "mm: hugetlb: Skip initialization of gigantic tail
   struct pages if freed by HVO" has improved our handling of gigantic
   pages in the hugetlb vmmemmep optimizaton code.  This provides
   significant boot time improvements when significant amounts of gigantic
   pages are in use.
 
 - Matthew Wilcox has sent the series "Small hugetlb cleanups" - code
   rationalization and folio conversions in the hugetlb code.
 
 - Yin Fengwei has improved mlock()'s handling of large folios in the
   series "support large folio for mlock"
 
 - In the series "Expose swapcache stat for memcg v1" Liu Shixin has
   added statistics for memcg v1 users which are available (and useful)
   under memcg v2.
 
 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
   prctl so that userspace may direct the kernel to not automatically
   propagate the denial to child processes.  The series is named "MDWE
   without inheritance".
 
 - Kefeng Wang has provided the series "mm: convert numa balancing
   functions to use a folio" which does what it says.
 
 - In the series "mm/ksm: add fork-exec support for prctl" Stefan Roesch
   makes is possible for a process to propagate KSM treatment across
   exec().
 
 - Huang Ying has enhanced memory tiering's calculation of memory
   distances.  This is used to permit the dax/kmem driver to use "high
   bandwidth memory" in addition to Optane Data Center Persistent Memory
   Modules (DCPMM).  The series is named "memory tiering: calculate
   abstract distance based on ACPI HMAT"
 
 - In the series "Smart scanning mode for KSM" Stefan Roesch has
   optimized KSM by teaching it to retain and use some historical
   information from previous scans.
 
 - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the
   series "mm: memcg: fix tracking of pending stats updates values".
 
 - In the series "Implement IOCTL to get and optionally clear info about
   PTEs" Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits
   us to atomically read-then-clear page softdirty state.  This is mainly
   used by CRIU.
 
 - Hugh Dickins contributed the series "shmem,tmpfs: general maintenance"
   - a bunch of relatively minor maintenance tweaks to this code.
 
 - Matthew Wilcox has increased the use of the VMA lock over file-backed
   page faults in the series "Handle more faults under the VMA lock".  Some
   rationalizations of the fault path became possible as a result.
 
 - In the series "mm/rmap: convert page_move_anon_rmap() to
   folio_move_anon_rmap()" David Hildenbrand has implemented some cleanups
   and folio conversions.
 
 - In the series "various improvements to the GUP interface" Lorenzo
   Stoakes has simplified and improved the GUP interface with an eye to
   providing groundwork for future improvements.
 
 - Andrey Konovalov has sent along the series "kasan: assorted fixes and
   improvements" which does those things.
 
 - Some page allocator maintenance work from Kemeng Shi in the series
   "Two minor cleanups to break_down_buddy_pages".
 
 - In thes series "New selftest for mm" Breno Leitao has developed
   another MM self test which tickles a race we had between madvise() and
   page faults.
 
 - In the series "Add folio_end_read" Matthew Wilcox provides cleanups
   and an optimization to the core pagecache code.
 
 - Nhat Pham has added memcg accounting for hugetlb memory in the series
   "hugetlb memcg accounting".
 
 - Cleanups and rationalizations to the pagemap code from Lorenzo
   Stoakes, in the series "Abstract vma_merge() and split_vma()".
 
 - Audra Mitchell has fixed issues in the procfs page_owner code's new
   timestamping feature which was causing some misbehaviours.  In the
   series "Fix page_owner's use of free timestamps".
 
 - Lorenzo Stoakes has fixed the handling of new mappings of sealed files
   in the series "permit write-sealed memfd read-only shared mappings".
 
 - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
   series "Batch hugetlb vmemmap modification operations".
 
 - Some buffer_head folio conversions and cleanups from Matthew Wilcox in
   the series "Finish the create_empty_buffers() transition".
 
 - As a page allocator performance optimization Huang Ying has added
   automatic tuning to the allocator's per-cpu-pages feature, in the series
   "mm: PCP high auto-tuning".
 
 - Roman Gushchin has contributed the patchset "mm: improve performance
   of accounted kernel memory allocations" which improves their performance
   by ~30% as measured by a micro-benchmark.
 
 - folio conversions from Kefeng Wang in the series "mm: convert page
   cpupid functions to folios".
 
 - Some kmemleak fixups in Liu Shixin's series "Some bugfix about
   kmemleak".
 
 - Qi Zheng has improved our handling of memoryless nodes by keeping them
   off the allocation fallback list.  This is done in the series "handle
   memoryless nodes more appropriately".
 
 - khugepaged conversions from Vishal Moola in the series "Some
   khugepaged folio conversions".
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Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
2023-11-02 19:38:47 -10:00
Hugh Dickins
ddc1a5cbc0 mempolicy: alloc_pages_mpol() for NUMA policy without vma
Shrink shmem's stack usage by eliminating the pseudo-vma from its folio
allocation.  alloc_pages_mpol(gfp, order, pol, ilx, nid) becomes the
principal actor for passing mempolicy choice down to __alloc_pages(),
rather than vma_alloc_folio(gfp, order, vma, addr, hugepage).

vma_alloc_folio() and alloc_pages() remain, but as wrappers around
alloc_pages_mpol().  alloc_pages_bulk_*() untouched, except to provide the
additional args to policy_nodemask(), which subsumes policy_node(). 
Cleanup throughout, cutting out some unhelpful "helpers".

It would all be much simpler without MPOL_INTERLEAVE, but that adds a
dynamic to the constant mpol: complicated by v3.6 commit 09c231cb8b
("tmpfs: distribute interleave better across nodes"), which added ino bias
to the interleave, hidden from mm/mempolicy.c until this commit.

Hence "ilx" throughout, the "interleave index".  Originally I thought it
could be done just with nid, but that's wrong: the nodemask may come from
the shared policy layer below a shmem vma, or it may come from the task
layer above a shmem vma; and without the final nodemask then nodeid cannot
be decided.  And how ilx is applied depends also on page order.

The interleave index is almost always irrelevant unless MPOL_INTERLEAVE:
with one exception in alloc_pages_mpol(), where the NO_INTERLEAVE_INDEX
passed down from vma-less alloc_pages() is also used as hint not to use
THP-style hugepage allocation - to avoid the overhead of a hugepage arg
(though I don't understand why we never just added a GFP bit for THP - if
it actually needs a different allocation strategy from other pages of the
same order).  vma_alloc_folio() still carries its hugepage arg here, but
it is not used, and should be removed when agreed.

get_vma_policy() no longer allows a NULL vma: over time I believe we've
eradicated all the places which used to need it e.g.  swapoff and madvise
used to pass NULL vma to read_swap_cache_async(), but now know the vma.

[hughd@google.com: handle NULL mpol being passed to __read_swap_cache_async()]
  Link: https://lkml.kernel.org/r/ea419956-4751-0102-21f7-9c93cb957892@google.com
Link: https://lkml.kernel.org/r/74e34633-6060-f5e3-aee-7040d43f2e93@google.com
Link: https://lkml.kernel.org/r/1738368e-bac0-fd11-ed7f-b87142a939fe@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun heo <tj@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Domenico Cerasuolo <mimmocerasuolo@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-25 16:47:16 -07:00
Amir Goldstein
08582d678f
fs: create helper file_user_path() for user displayed mapped file path
Overlayfs uses backing files with "fake" overlayfs f_path and "real"
underlying f_inode, in order to use underlying inode aops for mapped
files and to display the overlayfs path in /proc/<pid>/maps.

In preparation for storing the overlayfs "fake" path instead of the
underlying "real" path in struct backing_file, define a noop helper
file_user_path() that returns f_path for now.

Use the new helper in procfs and kernel logs whenever a path of a
mapped file is displayed to users.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231009153712.1566422-3-amir73il@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:03:15 +02:00
Alexey Dobriyan
860a2e7fa4 proc: use initializer for clearing some buffers
Save LOC by using dark magic of initialisation instead of memset().

Those buffer aren't passed to userspace directly so padding is not
an issue.

Link: https://lkml.kernel.org/r/3821d3a2-6e10-4629-b0d5-9519d828ab72@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18 14:43:22 -07:00
Muhammad Usama Anjum
12f6b01a0b fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag
Adding fast code paths to handle specifically only get and/or clear
operation of PAGE_IS_WRITTEN, increases its performance by 0-35%.  The
results of some test cases are given below:

Test-case-1
t1 = (Get + WP) time
t2 = WP time
                       t1            t2
Without this patch:    140-170mcs    90-115mcs
With this patch:       110mcs        80mcs
Worst case diff:       35% faster    30% faster

Test-case-2
t3 = atomic Get and WP
                      t3
Without this patch:   120-140mcs
With this patch:      100-110mcs
Worst case diff:      21% faster

Link: https://lkml.kernel.org/r/20230821141518.870589-4-usama.anjum@collabora.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Miroslaw <emmir@google.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yun Zhou <yun.zhou@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18 14:34:13 -07:00
Muhammad Usama Anjum
52526ca7fd fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs
The PAGEMAP_SCAN IOCTL on the pagemap file can be used to get or optionally
clear the info about page table entries. The following operations are
supported in this IOCTL:
- Scan the address range and get the memory ranges matching the provided
  criteria. This is performed when the output buffer is specified.
- Write-protect the pages. The PM_SCAN_WP_MATCHING is used to write-protect
  the pages of interest. The PM_SCAN_CHECK_WPASYNC aborts the operation if
  non-Async Write Protected pages are found. The ``PM_SCAN_WP_MATCHING``
  can be used with or without PM_SCAN_CHECK_WPASYNC.
- Both of those operations can be combined into one atomic operation where
  we can get and write protect the pages as well.

Following flags about pages are currently supported:
- PAGE_IS_WPALLOWED - Page has async-write-protection enabled
- PAGE_IS_WRITTEN - Page has been written to from the time it was write protected
- PAGE_IS_FILE - Page is file backed
- PAGE_IS_PRESENT - Page is present in the memory
- PAGE_IS_SWAPPED - Page is in swapped
- PAGE_IS_PFNZERO - Page has zero PFN
- PAGE_IS_HUGE - Page is THP or Hugetlb backed

This IOCTL can be extended to get information about more PTE bits. The
entire address range passed by user [start, end) is scanned until either
the user provided buffer is full or max_pages have been found.

[akpm@linux-foundation.org: update it for "mm: hugetlb: add huge page size param to set_huge_pte_at()"]
[akpm@linux-foundation.org: fix CONFIG_HUGETLB_PAGE=n warning]
[arnd@arndb.de: hide unused pagemap_scan_backout_range() function]
  Link: https://lkml.kernel.org/r/20230927060257.2975412-1-arnd@kernel.org
[sfr@canb.auug.org.au: fix "fs/proc/task_mmu: hide unused pagemap_scan_backout_range() function"]
  Link: https://lkml.kernel.org/r/20230928092223.0625c6bf@canb.auug.org.au
Link: https://lkml.kernel.org/r/20230821141518.870589-3-usama.anjum@collabora.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Miroslaw <emmir@google.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yun Zhou <yun.zhou@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18 14:34:12 -07:00
Linus Torvalds
5eea5820c7 - Stefan Roesch has added ksm statistics to /proc/pid/smaps
- Also a number of singleton patches, mainly cleanups and leftovers.
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Merge tag 'mm-stable-2023-09-04-14-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - Stefan Roesch has added ksm statistics to /proc/pid/smaps

 - Also a number of singleton patches, mainly cleanups and leftovers

* tag 'mm-stable-2023-09-04-14-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/kmemleak: move up cond_resched() call in page scanning loop
  mm: page_alloc: remove stale CMA guard code
  MAINTAINERS: add rmap.h to mm entry
  rmap: remove anon_vma_link() nommu stub
  proc/ksm: add ksm stats to /proc/pid/smaps
  mm/hwpoison: rename hwp_walk* to hwpoison_walk*
  mm: memory-failure: add PageOffline() check
2023-09-05 10:56:27 -07:00
Stefan Roesch
8b47933544 proc/ksm: add ksm stats to /proc/pid/smaps
With madvise and prctl KSM can be enabled for different VMA's.  Once it is
enabled we can query how effective KSM is overall.  However we cannot
easily query if an individual VMA benefits from KSM.

This commit adds a KSM section to the /prod/<pid>/smaps file.  It reports
how many of the pages are KSM pages.  Note that KSM-placed zeropages are
not included, only actual KSM pages.

Here is a typical output:

7f420a000000-7f421a000000 rw-p 00000000 00:00 0
Size:             262144 kB
KernelPageSize:        4 kB
MMUPageSize:           4 kB
Rss:               51212 kB
Pss:                8276 kB
Shared_Clean:        172 kB
Shared_Dirty:      42996 kB
Private_Clean:       196 kB
Private_Dirty:      7848 kB
Referenced:        15388 kB
Anonymous:         51212 kB
KSM:               41376 kB
LazyFree:              0 kB
AnonHugePages:         0 kB
ShmemPmdMapped:        0 kB
FilePmdMapped:         0 kB
Shared_Hugetlb:        0 kB
Private_Hugetlb:       0 kB
Swap:             202016 kB
SwapPss:            3882 kB
Locked:                0 kB
THPeligible:    0
ProtectionKey:         0
ksm_state:          0
ksm_skip_base:      0
ksm_skip_count:     0
VmFlags: rd wr mr mw me nr mg anon

This information also helps with the following workflow:
- First enable KSM for all the VMA's of a process with prctl.
- Then analyze with the above smaps report which VMA's benefit the most
- Change the application (if possible) to add the corresponding madvise
calls for the VMA's that benefit the most

[shr@devkernel.io: v5]
  Link: https://lkml.kernel.org/r/20230823170107.1457915-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20230822180539.1424843-1-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-09-02 15:17:33 -07:00
Linus Torvalds
df57721f9a Add x86 shadow stack support
Convert IBT selftest to asm to fix objtool warning
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Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 shadow stack support from Dave Hansen:
 "This is the long awaited x86 shadow stack support, part of Intel's
  Control-flow Enforcement Technology (CET).

  CET consists of two related security features: shadow stacks and
  indirect branch tracking. This series implements just the shadow stack
  part of this feature, and just for userspace.

  The main use case for shadow stack is providing protection against
  return oriented programming attacks. It works by maintaining a
  secondary (shadow) stack using a special memory type that has
  protections against modification. When executing a CALL instruction,
  the processor pushes the return address to both the normal stack and
  to the special permission shadow stack. Upon RET, the processor pops
  the shadow stack copy and compares it to the normal stack copy.

  For more information, refer to the links below for the earlier
  versions of this patch set"

Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/

* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  x86/shstk: Change order of __user in type
  x86/ibt: Convert IBT selftest to asm
  x86/shstk: Don't retry vm_munmap() on -EINTR
  x86/kbuild: Fix Documentation/ reference
  x86/shstk: Move arch detail comment out of core mm
  x86/shstk: Add ARCH_SHSTK_STATUS
  x86/shstk: Add ARCH_SHSTK_UNLOCK
  x86: Add PTRACE interface for shadow stack
  selftests/x86: Add shadow stack test
  x86/cpufeatures: Enable CET CR4 bit for shadow stack
  x86/shstk: Wire in shadow stack interface
  x86: Expose thread features in /proc/$PID/status
  x86/shstk: Support WRSS for userspace
  x86/shstk: Introduce map_shadow_stack syscall
  x86/shstk: Check that signal frame is shadow stack mem
  x86/shstk: Check that SSP is aligned on sigreturn
  x86/shstk: Handle signals for shadow stack
  x86/shstk: Introduce routines modifying shstk
  x86/shstk: Handle thread shadow stack
  x86/shstk: Add user-mode shadow stack support
  ...
2023-08-31 12:20:12 -07:00
Andrew Morton
5994eabf3b merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes 2023-08-21 14:26:20 -07:00
Hugh Dickins
daa60ae64c mm,thp: fix smaps THPeligible output alignment
Extract from current /proc/self/smaps output:

Swap:                  0 kB
SwapPss:               0 kB
Locked:                0 kB
THPeligible:    0
ProtectionKey:         0

That's not the alignment shown in Documentation/filesystems/proc.rst: it's
an ugly artifact from missing out the %8 other fields are using; but
there's even one selftest which expects it to look that way.  Hoping no
other smaps parsers depend on THPeligible to look so ugly, fix these.

Link: https://lkml.kernel.org/r/cfb81f7a-f448-5bc2-b0e1-8136fcd1dd8c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21 13:38:01 -07:00
Kefeng Wang
11250fd12e mm: factor out VMA stack and heap checks
Patch series "mm: convert to vma_is_initial_heap/stack()", v3.

Add vma_is_initial_stack() and vma_is_initial_heap() helpers and use them
to simplify code.


This patch (of 4):

Factor out VMA stack and heap checks and name them vma_is_initial_stack()
and vma_is_initial_heap() for general use.

Link: https://lkml.kernel.org/r/20230728050043.59880-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20230728050043.59880-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21 13:37:31 -07:00
Suren Baghdasaryan
49b0638502 mm: enable page walking API to lock vmas during the walk
walk_page_range() and friends often operate under write-locked mmap_lock. 
With introduction of vma locks, the vmas have to be locked as well during
such walks to prevent concurrent page faults in these areas.  Add an
additional member to mm_walk_ops to indicate locking requirements for the
walk.

The change ensures that page walks which prevent concurrent page faults
by write-locking mmap_lock, operate correctly after introduction of
per-vma locks.  With per-vma locks page faults can be handled under vma
lock without taking mmap_lock at all, so write locking mmap_lock would
not stop them.  The change ensures vmas are properly locked during such
walks.

A sample issue this solves is do_mbind() performing queue_pages_range()
to queue pages for migration.  Without this change a concurrent page
can be faulted into the area and be left out of migration.

Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Suggested-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21 13:07:20 -07:00