If mas_store_gfp() in the gather loop failed, the 'error' variable that
ultimately gets returned was not being set. In many cases, its original
value of -ENOMEM was still in place, and that was fine. But if VMAs had
been split at the start or end of the range, then 'error' could be zero.
Change to the 'error = foo(); if (error) goto …' idiom to fix the bug.
Also clean up a later case which avoided the same bug by *explicitly*
setting error = -ENOMEM right before calling the function that might
return -ENOMEM.
In a final cosmetic change, move the 'Point of no return' comment to
*after* the goto. That's been in the wrong place since the preallocation
was removed, and this new error path was added.
Fixes: 606c812eb1 ("mm/mmap: Fix error path in do_vmi_align_munmap()")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
brings some order to the documentation directory, declutters the top-level
directory, and makes the documentation organization more closely match that
of the source.
-----BEGIN PGP SIGNATURE-----
iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAmSbDsIPHGNvcmJldEBs
d24ubmV0AAoJEBdDWhNsDH5Y+ksH/2Xqun1ipPvu66+bBdPIf8N9AVFatl2q3mt4
tgX3A4RH3Ejklb4GbRLOIP23PmCxt7LRv4P05ttw8VpTP3A+Cw1d1s2RxiXGvfDE
j7IW6hrpUmVoDdiDCRGtjdIa7MVI5aAsj8CCTjEFywGi5CQe0Uzq4aTUKoxJDEnu
GYVy2CwDNEt4GTQ6ClPpFx2rc4UZf/H2XqXsnod9ef8A5Nkt3EtgoS1hh3o1QZGA
Mqx2HAOVS1tb6GUVUbVLCdj40+YjBLjXFlsH4dA+wsFFdUlZLKuTesdiAMg2X6eT
E8C/6oRT+OiWbrnXUTJEn8z98Ds8VHn7D4n97O9bIQ+R9AFtmPI=
=H/+D
-----END PGP SIGNATURE-----
Merge tag 'docs-arm64-move' of git://git.lwn.net/linux
Pull arm64 documentation move from Jonathan Corbet:
"Move the arm64 architecture documentation under Documentation/arch/.
This brings some order to the documentation directory, declutters the
top-level directory, and makes the documentation organization more
closely match that of the source"
* tag 'docs-arm64-move' of git://git.lwn.net/linux:
perf arm-spe: Fix a dangling Documentation/arm64 reference
mm: Fix a dangling Documentation/arm64 reference
arm64: Fix dangling references to Documentation/arm64
dt-bindings: fix dangling Documentation/arm64 reference
docs: arm64: Move arm64 documentation under Documentation/arch/
- Introduce cmpxchg128() -- aka. the demise of cmpxchg_double().
The cmpxchg128() family of functions is basically & functionally
the same as cmpxchg_double(), but with a saner interface: instead
of a 6-parameter horror that forced u128 - u64/u64-halves layout
details on the interface and exposed users to complexity,
fragility & bugs, use a natural 3-parameter interface with u128 types.
- Restructure the generated atomic headers, and add
kerneldoc comments for all of the generic atomic{,64,_long}_t
operations. Generated definitions are much cleaner now,
and come with documentation.
- Implement lock_set_cmp_fn() on lockdep, for defining an ordering
when taking multiple locks of the same type. This gets rid of
one use of lockdep_set_novalidate_class() in the bcache code.
- Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended
variable shadowing generating garbage code on Clang on certain
ARM builds.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----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=DsYj
-----END PGP SIGNATURE-----
Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Introduce cmpxchg128() -- aka. the demise of cmpxchg_double()
The cmpxchg128() family of functions is basically & functionally the
same as cmpxchg_double(), but with a saner interface.
Instead of a 6-parameter horror that forced u128 - u64/u64-halves
layout details on the interface and exposed users to complexity,
fragility & bugs, use a natural 3-parameter interface with u128
types.
- Restructure the generated atomic headers, and add kerneldoc comments
for all of the generic atomic{,64,_long}_t operations.
The generated definitions are much cleaner now, and come with
documentation.
- Implement lock_set_cmp_fn() on lockdep, for defining an ordering when
taking multiple locks of the same type.
This gets rid of one use of lockdep_set_novalidate_class() in the
bcache code.
- Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable
shadowing generating garbage code on Clang on certain ARM builds.
* tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc
percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg()
locking/atomic: treewide: delete arch_atomic_*() kerneldoc
locking/atomic: docs: Add atomic operations to the driver basic API documentation
locking/atomic: scripts: generate kerneldoc comments
docs: scripts: kernel-doc: accept bitwise negation like ~@var
locking/atomic: scripts: simplify raw_atomic*() definitions
locking/atomic: scripts: simplify raw_atomic_long*() definitions
locking/atomic: scripts: split pfx/name/sfx/order
locking/atomic: scripts: restructure fallback ifdeffery
locking/atomic: scripts: build raw_atomic_long*() directly
locking/atomic: treewide: use raw_atomic*_<op>()
locking/atomic: scripts: add trivial raw_atomic*_<op>()
locking/atomic: scripts: factor out order template generation
locking/atomic: scripts: remove leftover "${mult}"
locking/atomic: scripts: remove bogus order parameter
locking/atomic: xtensa: add preprocessor symbols
locking/atomic: x86: add preprocessor symbols
locking/atomic: sparc: add preprocessor symbols
locking/atomic: sh: add preprocessor symbols
...
It feels very unlikely that anybody would want to do a GUP in an
unmapped area under the stack pointer, but real users sometimes do some
really strange things. So add a (temporary) warning for the case where
a GUP fails and expanding the stack might have made it work.
It's trivial to do the expansion in the caller as part of getting the mm
lock in the first place - see __access_remote_vm() for ptrace, for
example - it's just that it's unnecessarily painful to do it deep in the
guts of the GUP lookup when we might have to drop and re-take the lock.
I doubt anybody actually does anything quite this strange, but let's be
proactive: adding these warnings is simple, and will make debugging it
much easier if they trigger.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This finishes the job of always holding the mmap write lock when
extending the user stack vma, and removes the 'write_locked' argument
from the vm helper functions again.
For some cases, we just avoid expanding the stack at all: drivers and
page pinning really shouldn't be extending any stacks. Let's see if any
strange users really wanted that.
It's worth noting that architectures that weren't converted to the new
lock_mm_and_find_vma() helper function are left using the legacy
"expand_stack()" function, but it has been changed to drop the mmap_lock
and take it for writing while expanding the vma. This makes it fairly
straightforward to convert the remaining architectures.
As a result of dropping and re-taking the lock, the calling conventions
for this function have also changed, since the old vma may no longer be
valid. So it will now return the new vma if successful, and NULL - and
the lock dropped - if the area could not be extended.
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # ia64
Tested-by: Frank Scheiner <frank.scheiner@web.de> # ia64
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Remove repeated 'the' in comments
- Remove unused current_untag_mask()
- Document urgent tip branch timing
- Clean up MSR kernel-doc notation
- Clean up paravirt_ops doc
- Update Srivatsa S. Bhat's maintained areas
- Remove unused extern declaration acpi_copy_wakeup_routine()
-----BEGIN PGP SIGNATURE-----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=N82i
-----END PGP SIGNATURE-----
Merge tag 'x86_cleanups_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Dave Hansen:
"As usual, these are all over the map. The biggest cluster is work from
Arnd to eliminate -Wmissing-prototype warnings:
- Address -Wmissing-prototype warnings
- Remove repeated 'the' in comments
- Remove unused current_untag_mask()
- Document urgent tip branch timing
- Clean up MSR kernel-doc notation
- Clean up paravirt_ops doc
- Update Srivatsa S. Bhat's maintained areas
- Remove unused extern declaration acpi_copy_wakeup_routine()"
* tag 'x86_cleanups_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
x86/acpi: Remove unused extern declaration acpi_copy_wakeup_routine()
Documentation: virt: Clean up paravirt_ops doc
x86/mm: Remove unused current_untag_mask()
x86/mm: Remove repeated word in comments
x86/lib/msr: Clean up kernel-doc notation
x86/platform: Avoid missing-prototype warnings for OLPC
x86/mm: Add early_memremap_pgprot_adjust() prototype
x86/usercopy: Include arch_wb_cache_pmem() declaration
x86/vdso: Include vdso/processor.h
x86/mce: Add copy_mc_fragile_handle_tail() prototype
x86/fbdev: Include asm/fb.h as needed
x86/hibernate: Declare global functions in suspend.h
x86/entry: Add do_SYSENTER_32() prototype
x86/quirks: Include linux/pnp.h for arch_pnpbios_disabled()
x86/mm: Include asm/numa.h for set_highmem_pages_init()
x86: Avoid missing-prototype warnings for doublefault code
x86/fpu: Include asm/fpu/regset.h
x86: Add dummy prototype for mk_early_pgtbl_32()
x86/pci: Mark local functions as 'static'
x86/ftrace: Move prepare_ftrace_return prototype to header
...
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using it
and thus preventing a whole set of attacks against such guests like
memory replay and the like.
There are a couple of strategies of how memory should be accepted
- the current implementation does an on-demand way of accepting.
-----BEGIN PGP SIGNATURE-----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=FS95
-----END PGP SIGNATURE-----
Merge tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing update from Borislav Petkov:
- Add support for unaccepted memory as specified in the UEFI spec v2.9.
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using
it and thus preventing a whole set of attacks against such guests
like memory replay and the like.
There are a couple of strategies of how memory should be accepted -
the current implementation does an on-demand way of accepting.
* tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: sevguest: Add CONFIG_CRYPTO dependency
x86/efi: Safely enable unaccepted memory in UEFI
x86/sev: Add SNP-specific unaccepted memory support
x86/sev: Use large PSC requests if applicable
x86/sev: Allow for use of the early boot GHCB for PSC requests
x86/sev: Put PSC struct on the stack in prep for unaccepted memory support
x86/sev: Fix calculation of end address based on number of pages
x86/tdx: Add unaccepted memory support
x86/tdx: Refactor try_accept_one()
x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub
efi/unaccepted: Avoid load_unaligned_zeropad() stepping into unaccepted memory
efi: Add unaccepted memory support
x86/boot/compressed: Handle unaccepted memory
efi/libstub: Implement support for unaccepted memory
efi/x86: Get full memory map in allocate_e820()
mm: Add support for unaccepted memory
-----BEGIN PGP SIGNATURE-----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=zP4Y
-----END PGP SIGNATURE-----
Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull request via Keith:
- Various cleanups all around (Irvin, Chaitanya, Christophe)
- Better struct packing (Christophe JAILLET)
- Reduce controller error logs for optional commands (Keith)
- Support for >=64KiB block sizes (Daniel Gomez)
- Fabrics fixes and code organization (Max, Chaitanya, Daniel
Wagner)
- bcache updates via Coly:
- Fix a race at init time (Mingzhe Zou)
- Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye)
- use page pinning in the block layer for dio (David)
- convert old block dio code to page pinning (David, Christoph)
- cleanups for pktcdvd (Andy)
- cleanups for rnbd (Guoqing)
- use the unchecked __bio_add_page() for the initial single page
additions (Johannes)
- fix overflows in the Amiga partition handling code (Michael)
- improve mq-deadline zoned device support (Bart)
- keep passthrough requests out of the IO schedulers (Christoph, Ming)
- improve support for flush requests, making them less special to deal
with (Christoph)
- add bdev holder ops and shutdown methods (Christoph)
- fix the name_to_dev_t() situation and use cases (Christoph)
- decouple the block open flags from fmode_t (Christoph)
- ublk updates and cleanups, including adding user copy support (Ming)
- BFQ sanity checking (Bart)
- convert brd from radix to xarray (Pankaj)
- constify various structures (Thomas, Ivan)
- more fine grained persistent reservation ioctl capability checks
(Jingbo)
- misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan,
Jordy, Li, Min, Yu, Zhong, Waiman)
* tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits)
scsi/sg: don't grab scsi host module reference
ext4: Fix warning in blkdev_put()
block: don't return -EINVAL for not found names in devt_from_devname
cdrom: Fix spectre-v1 gadget
block: Improve kernel-doc headers
blk-mq: don't insert passthrough request into sw queue
bsg: make bsg_class a static const structure
ublk: make ublk_chr_class a static const structure
aoe: make aoe_class a static const structure
block/rnbd: make all 'class' structures const
block: fix the exclusive open mask in disk_scan_partitions
block: add overflow checks for Amiga partition support
block: change all __u32 annotations to __be32 in affs_hardblocks.h
block: fix signed int overflow in Amiga partition support
block: add capacity validation in bdev_add_partition()
block: fine-granular CAP_SYS_ADMIN for Persistent Reservation
block: disallow Persistent Reservation on partitions
reiserfs: fix blkdev_put() warning from release_journal_dev()
block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()
block: document the holder argument to blkdev_get_by_path
...
-----BEGIN PGP SIGNATURE-----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=KhW4
-----END PGP SIGNATURE-----
Merge tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux
Pull splice updates from Jens Axboe:
"This kills off ITER_PIPE to avoid a race between truncate,
iov_iter_revert() on the pipe and an as-yet incomplete DMA to a bio
with unpinned/unref'ed pages from an O_DIRECT splice read. This causes
memory corruption.
Instead, we either use (a) filemap_splice_read(), which invokes the
buffered file reading code and splices from the pagecache into the
pipe; (b) copy_splice_read(), which bulk-allocates a buffer, reads
into it and then pushes the filled pages into the pipe; or (c) handle
it in filesystem-specific code.
Summary:
- Rename direct_splice_read() to copy_splice_read()
- Simplify the calculations for the number of pages to be reclaimed
in copy_splice_read()
- Turn do_splice_to() into a helper, vfs_splice_read(), so that it
can be used by overlayfs and coda to perform the checks on the
lower fs
- Make vfs_splice_read() jump to copy_splice_read() to handle
direct-I/O and DAX
- Provide shmem with its own splice_read to handle non-existent pages
in the pagecache. We don't want a ->read_folio() as we don't want
to populate holes, but filemap_get_pages() requires it
- Provide overlayfs with its own splice_read to call down to a lower
layer as overlayfs doesn't provide ->read_folio()
- Provide coda with its own splice_read to call down to a lower layer
as coda doesn't provide ->read_folio()
- Direct ->splice_read to copy_splice_read() in tty, procfs, kernfs
and random files as they just copy to the output buffer and don't
splice pages
- Provide wrappers for afs, ceph, ecryptfs, ext4, f2fs, nfs, ntfs3,
ocfs2, orangefs, xfs and zonefs to do locking and/or revalidation
- Make cifs use filemap_splice_read()
- Replace pointers to generic_file_splice_read() with pointers to
filemap_splice_read() as DIO and DAX are handled in the caller;
filesystems can still provide their own alternate ->splice_read()
op
- Remove generic_file_splice_read()
- Remove ITER_PIPE and its paraphernalia as generic_file_splice_read
was the only user"
* tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux: (31 commits)
splice: kdoc for filemap_splice_read() and copy_splice_read()
iov_iter: Kill ITER_PIPE
splice: Remove generic_file_splice_read()
splice: Use filemap_splice_read() instead of generic_file_splice_read()
cifs: Use filemap_splice_read()
trace: Convert trace/seq to use copy_splice_read()
zonefs: Provide a splice-read wrapper
xfs: Provide a splice-read wrapper
orangefs: Provide a splice-read wrapper
ocfs2: Provide a splice-read wrapper
ntfs3: Provide a splice-read wrapper
nfs: Provide a splice-read wrapper
f2fs: Provide a splice-read wrapper
ext4: Provide a splice-read wrapper
ecryptfs: Provide a splice-read wrapper
ceph: Provide a splice-read wrapper
afs: Provide a splice-read wrapper
9p: Add splice_read wrapper
net: Make sock_splice_read() use copy_splice_read() by default
tty, proc, kernfs, random: Use copy_splice_read()
...
Make calls to extend_vma() and find_extend_vma() fail if the write lock
is required.
To avoid making this a flag-day event, this still allows the old
read-locking case for the trivial situations, and passes in a flag to
say "is it write-locked". That way write-lockers can say "yes, I'm
being careful", and legacy users will continue to work in all the common
cases until they have been fully converted to the new world order.
Co-Developed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arm has an additional check for address < FIRST_USER_ADDRESS before
expanding the stack. Since FIRST_USER_ADDRESS is defined everywhere
(generally as 0), move that check to the generic expand_downwards().
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is done as a separate patch from introducing the new
lock_mm_and_find_vma() helper, because while it's an obvious change,
it's not what x86 used to do in this area.
We already abort the page fault on fatal signals anyway, so why should
we wait for the mmap lock only to then abort later? With the new helper
function that returns without the lock held on failure anyway, this is
particularly easy and straightforward.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
.. and make x86 use it.
This basically extracts the existing x86 "find and expand faulting vma"
code, but extends it to also take the mmap lock for writing in case we
actually do need to expand the vma.
We've historically short-circuited that case, and have some rather ugly
special logic to serialize the stack segment expansion (since we only
hold the mmap lock for reading) that doesn't match the normal VM
locking.
That slight violation of locking worked well, right up until it didn't:
the maple tree code really does want proper locking even for simple
extension of an existing vma.
So extract the code for "look up the vma of the fault" from x86, fix it
up to do the necessary write locking, and make it available as a helper
function for other architectures that can use the common helper.
Note: I say "common helper", but it really only handles the normal
stack-grows-down case. Which is all architectures except for PA-RISC
and IA64. So some rare architectures can't use the helper, but if they
care they'll just need to open-code this logic.
It's also worth pointing out that this code really would like to have an
optimistic "mmap_upgrade_trylock()" to make it quicker to go from a
read-lock (for the common case) to taking the write lock (for having to
extend the vma) in the normal single-threaded situation where there is
no other locking activity.
But that _is_ all the very uncommon special case, so while it would be
nice to have such an operation, it probably doesn't matter in reality.
I did put in the skeleton code for such a possible future expansion,
even if it only acts as pseudo-documentation for what we're doing.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ackerley Tng reported an issue with hugetlbfs fallocate as noted in the
Closes tag. The issue showed up after the conversion of hugetlb page
cache lookup code to use page_cache_next_miss. User visible effects are:
- hugetlbfs fallocate incorrectly returns -EEXIST if pages are presnet
in the file.
- hugetlb pages will not be included in core dumps if they need to be
brought in via GUP.
- userfaultfd UFFDIO_COPY will not notice pages already present in the
cache. It may try to allocate a new page and potentially return
ENOMEM as opposed to EEXIST.
Revert the use page_cache_next_miss() in hugetlb code.
IMPORTANT NOTE FOR STABLE BACKPORTS:
This patch will apply cleanly to v6.3. However, due to the change of
filemap_get_folio() return values, it will not function correctly. This
patch must be modified for stable backports.
[dan.carpenter@linaro.org: fix hugetlbfs_pagecache_present()]
Link: https://lkml.kernel.org/r/efa86091-6a2c-4064-8f55-9b44e1313015@moroto.mountain
Link: https://lkml.kernel.org/r/20230621212403.174710-2-mike.kravetz@oracle.com
Fixes: d0ce0e47b3 ("mm/hugetlb: convert hugetlb fault paths to use alloc_hugetlb_folio()")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-by: Ackerley Tng <ackerleytng@google.com>
Closes: https://lore.kernel.org/linux-mm/cover.1683069252.git.ackerleytng@google.com
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 9425c591e0
The reverted commit fixed up routines primarily used by readahead code
such that they could also be used by hugetlb. Unfortunately, this
caused a performance regression as pointed out by the Closes: tag.
The hugetlb code which uses page_cache_next_miss will be addressed in
a subsequent patch.
Link: https://lkml.kernel.org/r/20230621212403.174710-1-mike.kravetz@oracle.com
Fixes: 9425c591e0 ("page cache: fix page_cache_next/prev_miss off by one")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202306211346.1e9ff03e-oliver.sang@intel.com
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When memory.reclaim was introduced, it became the first case where
cgroup_reclaim() is true for the root cgroup. Johannes concluded [1] that
for most cases this is okay, except for one case. Historically, kswapd
would throttle reclaim on a node if a lot of pages marked for reclaim are
under writeback (aka the node is congested). This occurred by setting
LRUVEC_CONGESTED bit in lruvec->flags. The bit would be cleared when the
node is balanced.
Similarly, cgroup reclaim would set the same bit when an lruvec is
congested, and clear it on the way out of reclaim (to throttle local
reclaimers).
Before the introduction of memory.reclaim, the root memcg was the only
target of kswapd reclaim, and non-root memcgs were the only targets of
cgroup reclaim, so they would never interfere. Using the same bit for
both was fine. After memory.reclaim, it is possible for cgroup reclaim on
the root cgroup to clear the bit set by kswapd. This would result in
reclaim on the node to be unthrottled before the node is balanced.
Fix this by introducing separate bits for cgroup-level and node-level
congestion. kswapd can unthrottle an lruvec that is marked as congested
by cgroup reclaim (as the entire node should no longer be congested), but
not vice versa (to prevent premature unthrottling before the entire node
is balanced).
[1]https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/
Link: https://lkml.kernel.org/r/20230621023101.432780-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Evidently, global_reclaim() can be a confusing name. Especially that it
used to exist before with a subtly different definition (removed by commit
b5ead35e7e ("mm: vmscan: naming fixes: global_reclaim() and
sane_reclaim()"). It can be interpreted as non-cgroup reclaim, even
though it returns true for cgroup reclaim on the root memcg (through
memory.reclaim).
Rename it to root_reclaim() in an attempt to make it less ambiguous, and
add documentation to it as well as cgroup_reclaim.
Link: https://lkml.kernel.org/r/20230621023053.432374-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Directly use a folio instead of page_folio() when page successfully
isolated (hugepage and movable page) and after folio_get_nontail_page(),
which removes several calls to compound_head().
Link: https://lkml.kernel.org/r/20230619110718.65679-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If exclusive loads are enabled for zswap, we invalidate the entry before
returning from zswap_frontswap_load(), after dropping the local reference.
However, the tree lock is dropped during decompression after the local
reference is acquired, so the entry could be invalidated before we drop
the local ref. If this happens, the entry is freed once we drop the local
ref, and zswap_invalidate_entry() tries to invalidate an already freed
entry.
Fix this by:
(a) Making sure zswap_invalidate_entry() is always called with a local
ref held, to avoid being called on a freed entry.
(b) Making sure zswap_invalidate_entry() only drops the ref if the entry
was actually on the rbtree. Otherwise, another invalidation could
have already happened, and the initial ref is already dropped.
With these changes, there is no need to check that there is no need to
make sure the entry still exists in the tree in zswap_reclaim_entry()
before invalidating it, as zswap_reclaim_entry() will make this check
internally.
Link: https://lkml.kernel.org/r/20230621093009.637544-1-yosryahmed@google.com
Fixes: b9c91c4341 ("mm: zswap: support exclusive loads")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These files no longer need pagevec.h, mostly due to function declarations
being moved out of it.
Link: https://lkml.kernel.org/r/20230621164557.3510324-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Most of these should just refer to the LRU cache rather than the data
structure used to implement the LRU cache.
Link: https://lkml.kernel.org/r/20230621164557.3510324-13-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We don't use pagevecs for the LRU cache any more, and we don't know that
the failed invalidations were due to the folio being in an LRU cache. So
rename it to be more accurate.
Link: https://lkml.kernel.org/r/20230621164557.3510324-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All users are now converted to use the folio_batch so we can get rid of
this data structure.
Link: https://lkml.kernel.org/r/20230621164557.3510324-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit bf75f20056 ("mm/page_alloc: add page->buddy_list and
page->pcp_list") introduces page->buddy_list and page->pcp_list as a union
with page->lru, but missed to change get_page_from_free_area() to use
page->buddy_list to clarify the correct type of list for a free page.
Link: https://lkml.kernel.org/r/7e7ab533247d40c0ea0373c18a6a48e5667f9e10.1687333557.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now that the driver core allows for struct class to be in read-only
memory, move the bdi_class structure to be declared at build time placing
it into read-only memory, instead of having to be dynamically allocated at
load time.
Link: https://lkml.kernel.org/r/20230620183314.682822-2-gregkh@linuxfoundation.org
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Delete a triply out-of-date comment from add_swap_count_continuation():
1. vmalloc_to_page() changed from pte_offset_map() to pte_offset_kernel()
2. pte_offset_map() changed from using kmap_atomic() to kmap_local_page()
3. kmap_atomic() changed from using fixed FIX_KMAP addresses in 2.6.37.
Link: https://lkml.kernel.org/r/9022632b-ba9d-8cb0-c25-4be9786481b5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
early_pfn_to_nid() is called frequently in init_reserved_page(), it
returns the node id of the PFN. These PFN are probably from the same
memory region, they have the same node id. It's not necessary to call
early_pfn_to_nid() for each PFN.
Pass nid to reserve_bootmem_region() and drop the call to
early_pfn_to_nid() in init_reserved_page(). Also, set nid on all reserved
pages before doing this, as some reserved memory regions may not be set
nid.
The most beneficial function is memmap_init_reserved_pages() if
CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.
The following data was tested on an x86 machine with 190GB of RAM.
before:
memmap_init_reserved_pages() 67ms
after:
memmap_init_reserved_pages() 20ms
Link: https://lkml.kernel.org/r/20230619023406.424298-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These routines are not intended to return zero, the callers cannot do
anything sane with a 0 return. They should return an error which means
future calls to GUP will not succeed, or they should return some non-zero
number of pinned pages which means GUP should be called again.
If start + nr_pages overflows it should return -EOVERFLOW to signal the
arguments are invalid.
Syzkaller keeps tripping on this when fuzzing GUP arguments.
Link: https://lkml.kernel.org/r/0-v1-3d5ed1f20d50+104-gup_overflow_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reported-by: syzbot+353c7be4964c6253f24a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000094fdd05faa4d3a4@google.com
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
syzbot is reporting lockdep warning in __stack_depot_save(), for
the caller of __stack_depot_save() (i.e. __kasan_record_aux_stack() in
this report) is responsible for masking __GFP_KSWAPD_RECLAIM flag in
order not to wake kswapd which in turn wakes kcompactd.
Since kasan/kmsan functions might be called with arbitrary locks held,
mask __GFP_KSWAPD_RECLAIM flag from all GFP_NOWAIT/GFP_ATOMIC allocations
in kasan/kmsan.
Note that kmsan_save_stack_with_flags() is changed to mask both
__GFP_DIRECT_RECLAIM flag and __GFP_KSWAPD_RECLAIM flag, for
wakeup_kswapd() from wake_all_kswapds() from __alloc_pages_slowpath()
calls wakeup_kcompactd() if __GFP_KSWAPD_RECLAIM flag is set and
__GFP_DIRECT_RECLAIM flag is not set.
Link: https://lkml.kernel.org/r/656cb4f5-998b-c8d7-3c61-c2d37aa90f9a@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ece2915262061d6e0ac1@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=ece2915262061d6e0ac1
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On some machines, the normal zone can have a large memory hole like below
memory layout, and we can see the range from 0x100000000 to 0x1800000000
is a hole. So when isolating some migratable pages, the scanner can meet
the hole and it will take more time to skip the large hole. From my
measurement, I can see the isolation scanner will take 80us ~ 100us to
skip the large hole [0x100000000 - 0x1800000000].
So adding a new helper to fast search next online memory section to skip
the large hole can help to find next suitable pageblock efficiently. With
this patch, I can see the large hole scanning only takes < 1us.
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000040000000-0x00000000ffffffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal [mem 0x0000000100000000-0x0000001fa7ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x0000000fffffffff]
[ 0.000000] node 0: [mem 0x0000001800000000-0x0000001fa3c7ffff]
[ 0.000000] node 0: [mem 0x0000001fa3c80000-0x0000001fa3ffffff]
[ 0.000000] node 0: [mem 0x0000001fa4000000-0x0000001fa402ffff]
[ 0.000000] node 0: [mem 0x0000001fa4030000-0x0000001fa40effff]
[ 0.000000] node 0: [mem 0x0000001fa40f0000-0x0000001fa73cffff]
[ 0.000000] node 0: [mem 0x0000001fa73d0000-0x0000001fa745ffff]
[ 0.000000] node 0: [mem 0x0000001fa7460000-0x0000001fa746ffff]
[ 0.000000] node 0: [mem 0x0000001fa7470000-0x0000001fa758ffff]
[ 0.000000] node 0: [mem 0x0000001fa7590000-0x0000001fa7ffffff]
[baolin.wang@linux.alibaba.com: limit next_ptn to not exceed cc->free_pfn]
Link: https://lkml.kernel.org/r/a1d859c28af0c7e85e91795e7473f553eb180a9d.1686813379.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/75b4c8ca36bf44ad8c42bf0685ac19d272e426ec.1686705221.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The arm64 documentation has moved under Documentation/arch/. Fix up a
reference in mm/mremap.c to match.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This includes a wholesale reversion of the post-6.4 series "make slab shrink
lockless". After input from Dave Chinner it has been decided that we
should go a different way. Thread starts at
https://lkml.kernel.org/r/ZH6K0McWBeCjaf16@dread.disaster.area.
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZJH/qAAKCRDdBJ7gKXxA
jq7uAP9AtDGHfvOuW5jlHdYfpUBnbfuQDKjiik71UuIxyhtwQQEAqpOBv7UDuhHj
NbNIGTIi/xM5vkpjV6CBo9ymR7qTKwo=
=uGuc
-----END PGP SIGNATURE-----
Merge tag 'mm-hotfixes-stable-2023-06-20-12-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull hotfixes from Andrew Morton:
"19 hotfixes. 8 of these are cc:stable.
This includes a wholesale reversion of the post-6.4 series 'make slab
shrink lockless'. After input from Dave Chinner it has been decided
that we should go a different way [1]"
Link: https://lkml.kernel.org/r/ZH6K0McWBeCjaf16@dread.disaster.area [1]
* tag 'mm-hotfixes-stable-2023-06-20-12-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
selftests/mm: fix cross compilation with LLVM
mailmap: add entries for Ben Dooks
nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
Revert "mm: vmscan: make global slab shrink lockless"
Revert "mm: vmscan: make memcg slab shrink lockless"
Revert "mm: vmscan: add shrinker_srcu_generation"
Revert "mm: shrinkers: make count and scan in shrinker debugfs lockless"
Revert "mm: vmscan: hold write lock to reparent shrinker nr_deferred"
Revert "mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers()"
Revert "mm: shrinkers: convert shrinker_rwsem to mutex"
nilfs2: fix buffer corruption due to concurrent device reads
scripts/gdb: fix SB_* constants parsing
scripts: fix the gfp flags header path in gfp-translate
udmabuf: revert 'Add support for mapping hugepages (v4)'
mm/khugepaged: fix iteration in collapse_file
memfd: check for non-NULL file_seals in memfd_create() syscall
mm/vmalloc: do not output a spurious warning when huge vmalloc() fails
mm/mprotect: fix do_mprotect_pkey() limit check
writeback: fix dereferencing NULL mapping->host on writeback_page_template
No user checks the return value of mem_cgroup_scan_tasks(). Make the
return value void.
Link: https://lkml.kernel.org/r/20230616063030.977586-1-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 5ff6e2fff8 ("mm/damon/core: fix divide error in
damon_nr_accesses_to_accesses_bp()") fixed a bug by adding arguments
validation in damon_set_attrs(). Add a unit test for the added validation
to ensure the bug cannot occur again.
Link: https://lkml.kernel.org/r/20230615183323.87561-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
try_get_folio() takes in a page, then chooses to do some folio operations
based on the flags (either FOLL_GET or FOLL_PIN). We can rewrite this
function to be more purpose oriented.
After calling try_get_folio(), if neither FOLL_GET nor FOLL_PIN are set,
warn and fail. If FOLL_GET is set we can return the result. If FOLL_GET
is not set then FOLL_PIN is set, so we pin the folio.
This change assists with folio conversions, and makes the function more
readable.
Link: https://lkml.kernel.org/r/20230614021312.34085-5-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
verify_dma_pinned() checks that pages are dma-pinned. We can convert this
to use folios.
Link: https://lkml.kernel.org/r/20230614021312.34085-4-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KASAN's boot time kernel parameter 'kasan.fault=' currently supports
'report' and 'panic', which results in either only reporting bugs or also
panicking on reports.
However, some users may wish to have more control over when KASAN reports
result in a kernel panic: in particular, KASAN reported invalid _writes_
are of special interest, because they have greater potential to corrupt
random kernel memory or be more easily exploited.
To panic on invalid writes only, introduce 'kasan.fault=panic_on_write',
which allows users to choose to continue running on invalid reads, but
panic only on invalid writes.
Link: https://lkml.kernel.org/r/20230614095158.1133673-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Taras Madan <tarasmadan@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When an entry started writeback, it used to be invalidated with ref count
logic alone, meaning that it would stay on the tree until all references
were put. The problem with this behavior is that as soon as the writeback
started, the ownership of the data held by the entry is passed to the
swapcache and should not be left in zswap too. Currently there are no
known issues because of this, but this change explicitly invalidates an
entry that started writeback to reduce opportunities for future bugs.
This patch is a follow up on the series titled "mm: zswap: move writeback
LRU from zpool to zswap" + commit f090b7949768("mm: zswap: support
exclusive loads").
Link: https://lkml.kernel.org/r/20230614143122.74471-1-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since commit c7c3dec1c9 ("mm: rmap: remove lock_page_memcg()"),
no more user, kill lock_page_memcg() and unlock_page_memcg().
Link: https://lkml.kernel.org/r/20230614143612.62575-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cma: display pfn as well as pfn_to_page(pfn)
page_owner: display pfn in hex rather than decimal
Link: https://lkml.kernel.org/r/20230613092533.15449-1-quic_yingangl@quicinc.com
Signed-off-by: Kassey Li <quic_yingangl@quicinc.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These are equivalent, but DEFINE_READ_MOSTLY_HASHTABLE exists to define
a hashtable in the .data..read_mostly section.
Link: https://lkml.kernel.org/r/20230609-khugepage-v1-1-dad4e8382298@google.com
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When running UnixBench/Execl throughput case, false sharing is observed
due to frequent read on base_addr and write on free_bytes, chunk_md.
UnixBench/Execl represents a class of workload where bash scripts are
spawned frequently to do some short jobs. It will do system call on execl
frequently, and execl will call mm_init to initialize mm_struct of the
process. mm_init will call __percpu_counter_init for percpu_counters
initialization. Then pcpu_alloc is called to read the base_addr of
pcpu_chunk for memory allocation. Inside pcpu_alloc, it will call
pcpu_alloc_area to allocate memory from a specified chunk. This function
will update "free_bytes" and "chunk_md" to record the rest free bytes and
other meta data for this chunk. Correspondingly, pcpu_free_area will also
update these 2 members when free memory.
Call trace from perf is as below:
+ 57.15% 0.01% execl [kernel.kallsyms] [k] __percpu_counter_init
+ 57.13% 0.91% execl [kernel.kallsyms] [k] pcpu_alloc
- 55.27% 54.51% execl [kernel.kallsyms] [k] osq_lock
- 53.54% 0x654278696e552f34
main
__execve
entry_SYSCALL_64_after_hwframe
do_syscall_64
__x64_sys_execve
do_execveat_common.isra.47
alloc_bprm
mm_init
__percpu_counter_init
pcpu_alloc
- __mutex_lock.isra.17
In current pcpu_chunk layout, `base_addr' is in the same cache line with
`free_bytes' and `chunk_md', and `base_addr' is at the last 8 bytes. This
patch moves `bound_map' up to `base_addr', to let `base_addr' locate in a
new cacheline.
With this change, on Intel Sapphire Rapids 112C/224T platform, based on
v6.4-rc4, the 160 parallel score improves by 24%.
The pcpu_chunk struct is a backing data structure per chunk, so the
additional memory should not be dramatic. A chunk covers ballpark
between 64kb and 512kb memory depending on some config and boot time
stuff, so I believe the additional memory used here is nominal at best.
Working the #s on my desktop:
Percpu: 58624 kB
28 cores -> ~2.1MB of percpu memory.
At say ~128KB per chunk -> 33 chunks, generously 40 chunks.
Adding alignment might bump the chunk size ~64 bytes, so in total ~2KB
of overhead?
I believe we can do a little better to avoid eating that full padding,
so likely less than that.
[dennis@kernel.org: changelog details]
Link: https://lkml.kernel.org/r/20230610030730.110074-1-yu.ma@intel.com
Signed-off-by: Yu Ma <yu.ma@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
establish_demotion_targets() is defined while CONFIG_MIGRATION is
enabled. There's no need to check it again.
Link: https://lkml.kernel.org/r/20230610034114.981861-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add __meminit to kcompactd_run() and kcompactd_stop() to ensure they're
default to __init when memory hotplug is not enabled.
Link: https://lkml.kernel.org/r/20230610034615.997813-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Android reported a performance regression in the userfaultfd unmap path.
A closer inspection on the userfaultfd_unmap_prep() change showed that a
second tree walk would be necessary in the reworked code.
Fix the regression by passing each VMA that will be unmapped through to
the userfaultfd_unmap_prep() function as they are added to the unmap list,
instead of re-walking the tree for the VMA.
Link: https://lkml.kernel.org/r/20230601015402.2819343-1-Liam.Howlett@oracle.com
Fixes: 69dbe6daf1 ("userfaultfd: use maple tree iterator to iterate VMAs")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The patch ("mm/folio: Avoid special handling for order value 0 in
folio_set_order") [1] removed the need for special handling of order = 0
in folio_set_order. Now, folio_set_order and set_compound_order becomes
similar function. This patch removes the set_compound_order and uses
folio_set_order instead.
[1] https://lore.kernel.org/all/20230609183032.13E08C433D2@smtp.kernel.org/
Link: https://lkml.kernel.org/r/20230612093514.689846-1-tsahu@linux.ibm.com
Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Previously, zswap_header served the purpose of storing the swpentry within
zpool pages. This allowed zpool implementations to pass relevant
information to the writeback function. However, with the current
implementation, writeback is directly handled within zswap. Consequently,
there is no longer a necessity for zswap_header, as the swp_entry_t can be
stored directly in zswap_entry.
Link: https://lkml.kernel.org/r/20230612093815.133504-8-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Tested-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
zswap_writeback_entry() used to be a callback for the backends, which
don't know about struct zswap_entry.
Now that the only user is the generic zswap LRU reclaimer, it can be
simplified: pass the pinned zswap_entry directly, and consolidate the
refcount management in the shrink function.
Link: https://lkml.kernel.org/r/20230612093815.133504-7-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Tested-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now that all three zswap backends have removed their shrink code, it is
no longer necessary for the zpool interface to include shrink/writeback
endpoints.
Link: https://lkml.kernel.org/r/20230612093815.133504-6-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: zswap: move writeback LRU from zpool to zswap", v3.
This series aims to improve the zswap reclaim mechanism by reorganizing
the LRU management. In the current implementation, the LRU is maintained
within each zpool driver, resulting in duplicated code across the three
drivers. The proposed change consists in moving the LRU management from
the individual implementations up to the zswap layer.
The primary objective of this refactoring effort is to simplify the
codebase. By unifying the reclaim loop and consolidating LRU handling
within zswap, we can eliminate redundant code and improve
maintainability. Additionally, this change enables the reclamation of
stored pages in their actual LRU order. Presently, the zpool drivers
link backing pages in an LRU, causing compressed pages with different
LRU positions to be written back simultaneously.
The series consists of several patches. The first patch implements the
LRU and the reclaim loop in zswap, but it is not used yet because all
three driver implementations are marked as zpool_evictable.
The following three commits modify each zpool driver to be not
zpool_evictable, allowing the use of the reclaim loop in zswap.
As the drivers removed their shrink functions, the zpool interface is
then trimmed by removing zpool_evictable, zpool_ops, and zpool_shrink.
Finally, the code in zswap is further cleaned up by simplifying the
writeback function and removing the now unnecessary zswap_header.
This patch (of 7):
Each zpool driver (zbud, z3fold and zsmalloc) implements its own shrink
function, which is called from zpool_shrink. However, with this commit, a
unified shrink function is added to zswap. The ultimate goal is to
eliminate the need for zpool_shrink once all zpool implementations have
dropped their shrink code.
To ensure the functionality of each commit, this change focuses solely on
adding the mechanism itself. No modifications are made to the backends,
meaning that functionally, there are no immediate changes. The zswap
mechanism will only come into effect once the backends have removed their
shrink code. The subsequent commits will address the modifications needed
in the backends.
Link: https://lkml.kernel.org/r/20230612093815.133504-1-cerasuolodomenico@gmail.com
Link: https://lkml.kernel.org/r/20230612093815.133504-2-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Convert all instances of direct pte_t* dereferencing to instead use
ptep_get() helper. This means that by default, the accesses change from a
C dereference to a READ_ONCE(). This is technically the correct thing to
do since where pgtables are modified by HW (for access/dirty) they are
volatile and therefore we should always ensure READ_ONCE() semantics.
But more importantly, by always using the helper, it can be overridden by
the architecture to fully encapsulate the contents of the pte. Arch code
is deliberately not converted, as the arch code knows best. It is
intended that arch code (arm64) will override the default with its own
implementation that can (e.g.) hide certain bits from the core code, or
determine young/dirty status by mixing in state from another source.
Conversion was done using Coccinelle:
----
// $ make coccicheck \
// COCCI=ptepget.cocci \
// SPFLAGS="--include-headers" \
// MODE=patch
virtual patch
@ depends on patch @
pte_t *v;
@@
- *v
+ ptep_get(v)
----
Then reviewed and hand-edited to avoid multiple unnecessary calls to
ptep_get(), instead opting to store the result of a single call in a
variable, where it is correct to do so. This aims to negate any cost of
READ_ONCE() and will benefit arch-overrides that may be more complex.
Included is a fix for an issue in an earlier version of this patch that
was pointed out by kernel test robot. The issue arose because config
MMU=n elides definition of the ptep helper functions, including
ptep_get(). HUGETLB_PAGE=n configs still define a simple
huge_ptep_clear_flush() for linking purposes, which dereferences the ptep.
So when both configs are disabled, this caused a build error because
ptep_get() is not defined. Fix by continuing to do a direct dereference
when MMU=n. This is safe because for this config the arch code cannot be
trying to virtualize the ptes because none of the ptep helpers are
defined.
Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Encapsulate PTE contents from non-arch code", v3.
A series to improve the encapsulation of pte entries by disallowing
non-arch code from directly dereferencing pte_t pointers.
This means that by default, the accesses change from a C dereference to a
READ_ONCE(). This is technically the correct thing to do since where
pgtables are modified by HW (for access/dirty) they are volatile and
therefore we should always ensure READ_ONCE() semantics.
But more importantly, by always using the helper, it can be overridden by
the architecture to fully encapsulate the contents of the pte. Arch code
is deliberately not converted, as the arch code knows best. It is
intended that arch code (arm64) will override the default with its own
implementation that can (e.g.) hide certain bits from the core code, or
determine young/dirty status by mixing in state from another source.
This patch (of 3):
The page table dumper uses walk_page_range_novma() to walk the page
tables, which does not lock the PTL before calling the pte_entry()
callback. Therefore, the page table dumper's callback must use
ptep_get_lockless() rather than ptep_get() to ensure that the pte it reads
is not torn or otherwise corrupt when racing with writers.
Link: https://lkml.kernel.org/r/20230612151545.3317766-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20230612151545.3317766-2-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Do not create kmalloc() caches which are not aligned to
dma_get_cache_alignment(). There is no functional change since for
current architectures defining ARCH_DMA_MINALIGN, ARCH_KMALLOC_MINALIGN
equals ARCH_DMA_MINALIGN (and dma_get_cache_alignment()). On
architectures without a specific ARCH_DMA_MINALIGN,
dma_get_cache_alignment() is 1, so no change to the kmalloc() caches.
Link: https://lkml.kernel.org/r/20230612153201.554742-5-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the slab variant of kmem_cache_init(), call new_kmalloc_cache() instead
of initialising the kmalloc_caches array directly. With this,
create_kmalloc_cache() is now only called from new_kmalloc_cache() in the
same file, so make it static. In addition, the useroffset argument is
always 0 while usersize is the same as size. Remove them.
Link: https://lkml.kernel.org/r/20230612153201.554742-4-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Huge pmd sharing operates on PUD not PMD, huge_pte_lock() is not suitable
in this case because it should only work for last level pte changes, while
pmd sharing is always one level higher.
Meanwhile, here we're locking over the spte pgtable lock which is even not
a lock for current mm but someone else's.
It seems even racy on operating on the lock, as after put_page() of the
spte pgtable page logically the page can be released, so at least the
spin_unlock() needs to be done after the put_page().
No report I am aware, I'm not even sure whether it'll just work on taking
the spte pmd lock, because while we're holding i_mmap read lock it probably
means the vma interval tree is frozen, all pte allocators over this pud
entry could always find the specific svma and spte page, so maybe they'll
serialize on this spte page lock? Even so, doesn't seem to be expected.
It just seems to be an accident of cb900f4121.
Fix it with the proper pud lock (which is the mm's page_table_lock).
Link: https://lkml.kernel.org/r/20230612160420.809818-1-peterx@redhat.com
Fixes: cb900f4121 ("mm, hugetlb: convert hugetlbfs to use split pmd lock")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All users can use the folio equivalent so this function can be safely
removed.
Link: https://lkml.kernel.org/r/20230612163405.99345-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tarun Sahu <tsahu@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offet_map_lock() may not find a page table: handle appropriately.
[hughd@google.com: __wp_page_copy_user(): don't call update_mmu_tlb() with NULL]
Link: https://lkml.kernel.org/r/1a4db221-7872-3594-57ce-42369945ec8d@google.com
Link: https://lkml.kernel.org/r/a194441b-63f3-adb6-5964-7ca3171ae7c2@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
swap_vma_readahead() has been proceeding in an unconventional way, its
preliminary swap_ra_info() doing the pte_offset_map() and pte_unmap(),
then relying on that pte pointer even after the pte_unmap() - in its
CONFIG_64BIT case (I think !CONFIG_HIGHPTE was intended; whereas 32-bit
copied ptes to stack while they were mapped, but had to limit how many).
Though it would be difficult to construct a failing testcase, accessing
page table after pte_unmap() will become bad practice, even on 64-bit: an
rcu_read_unlock() in pte_unmap() will allow page table to be freed.
Move relevant definitions from include/linux/swap.h to mm/swap_state.c,
nothing else used them. Delete the CONFIG_64BIT distinction and buffer,
delete all reference to ptes from swap_ra_info(), use pte_offset_map()
repeatedly in swap_vma_readahead(), breaking from the loop if it fails.
(Will the repeated "map" and "unmap" show up as a slowdown anywhere? If
so, maybe modify __read_swap_cache_async() to do the pte_unmap() only when
it does not find the page already in the swapcache.)
Use ptep_get_lockless(), mainly for its READ_ONCE(). Correctly advance
the address passed down to each call of __read__swap_cache_async().
Link: https://lkml.kernel.org/r/b7c64ab3-9e44-aac0-d2b-c57de578af1c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Delete pmd_trans_unstable, pmd_none_or_trans_huge_or_clear_bad() and
pmd_devmap_trans_unstable(), all now unused.
With mixed feelings, delete all the comments on pmd_trans_unstable().
That was very good documentation of a subtle state, and this series does
not even eliminate that state: but rather, normalizes and extends it,
asking pte_offset_map[_lock]() callers to anticipate failure, without
regard for whether mmap_read_lock() or mmap_write_lock() is held.
Retain pud_trans_unstable(), which has one use in __handle_mm_fault(), but
delete its equivalent pud_none_or_trans_huge_or_dev_or_clear_bad(). While
there, move the default arch_needs_pgtable_deposit() definition up near
where pgtable_trans_huge_deposit() and withdraw() are declared.
Link: https://lkml.kernel.org/r/5abdab3-3136-b42e-274d-9c6281bfb79@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
handle_pte_fault() use pte_offset_map_nolock() to get the vmf.ptl which
corresponds to vmf.pte, instead of pte_lockptr() being used later, when
there's a chance that the pmd entry might have changed, perhaps to none,
or to a huge pmd, with no split ptlock in its struct page.
Remove its pmd_devmap_trans_unstable() call: pte_offset_map_nolock() will
handle that case by failing. Update the "morph" comment above, looking
forward to when shmem or file collapse to THP may not take mmap_lock for
write (or not at all).
do_numa_page() use the vmf->ptl from handle_pte_fault() at first, but
refresh it when refreshing vmf->pte.
do_swap_page()'s pte_unmap_same() (the thing that takes ptl to verify a
two-part PAE orig_pte) use the vmf->ptl from handle_pte_fault() too; but
do_swap_page() is also used by anon THP's __collapse_huge_page_swapin(),
so adjust that to set vmf->ptl by pte_offset_map_nolock().
Link: https://lkml.kernel.org/r/c1107654-3929-60ac-223e-6877cbb86065@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
copy_pte_range(): use pte_offset_map_nolock(), and allow for it to fail;
but with a comment on some further assumptions that are being made there.
zap_pte_range() and zap_pmd_range(): adjust their interaction so that a
pte_offset_map_lock() failure in zap_pte_range() leads to a retry in
zap_pmd_range(); remove call to pmd_none_or_trans_huge_or_clear_bad().
Allow pte_offset_map_lock() to fail in many functions. Update comment on
calling pte_alloc() in do_anonymous_page(). Remove redundant calls to
pmd_trans_unstable(), pmd_devmap_trans_unstable(), pmd_none() and
pmd_bad(); but leave pmd_none_or_clear_bad() calls in free_pmd_range() and
copy_pmd_range(), those do simplify the next level down.
Link: https://lkml.kernel.org/r/bb548d50-e99a-f29e-eab1-a43bef2a1287@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
__collapse_huge_page_swapin(): don't drop the map after every pte, it only
has to be dropped by do_swap_page(); give up if pte_offset_map() fails;
trace_mm_collapse_huge_page_swapin() at the end, with result; fix comment
on returned result; fix vmf.pgoff, though it's not used.
collapse_huge_page(): use pte_offset_map_lock() on the _pmd returned from
clearing; allow failure, but it should be impossible there.
hpage_collapse_scan_pmd() and collapse_pte_mapped_thp() allow for
pte_offset_map_lock() failure.
Link: https://lkml.kernel.org/r/6513e85-d798-34ec-3762-7c24ffb9329@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
__split_huge_zero_page_pmd() use a single pte_offset_map() to sweep the
extent: it's already under pmd_lock(), so this is no worse for latency;
and since it's supposed to have full control of the just-withdrawn page
table, here choose to VM_BUG_ON if it were to fail. And please don't
increment haddr by PAGE_SIZE, that should remain huge aligned: declare a
separate addr (not a bugfix, but it was deceptive).
__split_huge_pmd_locked() likewise (but it had declared a separate addr);
and change its BUG_ON(!pte_none) to VM_BUG_ON, for consistency with zero
(those deposited page tables are sometimes victims of random corruption).
Link: https://lkml.kernel.org/r/90cbed7f-90d9-b779-4a46-d2485baf9595@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is now no reason for follow_pmd_mask()'s FOLL_SPLIT_PMD block to
distinguish huge_zero_page from a normal THP: follow_page_pte() handles
any instability, and here it's a good idea to replace any pmd_none(*pmd)
by a page table a.s.a.p, in the huge_zero_page case as for a normal THP;
and this removes an unnecessary possibility of -EBUSY failure.
(Hmm, couldn't the normal THP case have hit an unstably refaulted THP
before? But there are only two, exceptional, users of FOLL_SPLIT_PMD.)
Link: https://lkml.kernel.org/r/59fd15dd-4d39-5ec-2043-1d5117f7f85@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
migrate_vma_collect_pmd(): remove the pmd_trans_unstable() handling after
splitting huge zero pmd, and the pmd_none() handling after successfully
splitting huge page: those are now managed inside pte_offset_map_lock(),
and by "goto again" when it fails.
But the skip after unsuccessful split_huge_page() must stay: it avoids an
endless loop. The skip when pmd_bad()? Remove that: it will be treated
as a hole rather than a skip once cleared by pte_offset_map_lock(), but
with different timing that would be so anyway; and it's arguably best to
leave the pmd_bad() handling centralized there.
migrate_vma_insert_page(): remove comment on the old pte_offset_map() and
old locking limitations; remove the pmd_trans_unstable() check and just
proceed to pte_offset_map_lock(), aborting when it fails (page has been
charged to memcg, but as in other cases, it's uncharged when freed).
Link: https://lkml.kernel.org/r/1131be62-2e84-da2f-8f45-807b2cbeeec5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
MGLRU's walk_pte_range() use the safer pte_offset_map_nolock(), rather
than pte_lockptr(), to get the ptl for its trylock. Just return false and
move on to next extent if it fails, like when the trylock fails. Remove
the VM_WARN_ON_ONCE(pmd_leaf) since that will happen, rarely.
Link: https://lkml.kernel.org/r/51ece73e-7398-2e4a-2384-56708c87844f@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Adjust unuse_pte() and unuse_pte_range() to allow pte_offset_map_lock()
and pte_offset_map() failure; remove pmd_none_or_trans_huge_or_clear_bad()
from unuse_pmd_range() now that pte_offset_map() does all that itself.
Link: https://lkml.kernel.org/r/c4d831-13c3-9dfd-70c2-64514ad951fd@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Some nearby MADV_WILLNEED cleanup unrelated to pte_offset_map_lock().
shmem_swapin_range() is a better name than force_shm_swapin_readahead().
Fix unimportant off-by-one on end_index. Call the swp_entry_t "entry"
rather than "swap": either is okay, but entry is the name used elsewhere
in mm/madvise.c. Do not assume GFP_HIGHUSER_MOVABLE: that's right for
anon swap, but shmem should take gfp from mapping. Pass the actual vma
and address to read_swap_cache_async(), in case a NUMA mempolicy applies.
lru_add_drain() at outer level, like madvise_willneed()'s other branch.
Link: https://lkml.kernel.org/r/67e18875-ffb3-ec27-346-f350e07bed87@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Came here to make madvise's several pte_offset_map_lock() scans advance to
next extent on failure, and remove superfluous pmd_trans_unstable() and
pmd_none_or_trans_huge_or_clear_bad() calls. But also did some nearby
cleanup.
swapin_walk_pmd_entry(): don't name an address "index"; don't drop the
lock after every pte, only when calling out to read_swap_cache_async().
madvise_cold_or_pageout_pte_range() and madvise_free_pte_range(): prefer
"start_pte" for pointer, orig_pte usually denotes a saved pte value; leave
lazy MMU mode before unlocking; merge the success and failure paths after
split_folio().
Link: https://lkml.kernel.org/r/cc4d9a88-9da6-362-50d9-6735c2b125c6@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
move_ptes() return -EAGAIN if pte_offset_map_lock() of old fails, or if
pte_offset_map_nolock() of new fails: move_page_tables() retry if so.
But that does need a pmd_none() check inside, to stop endless loop when
huge shmem is truncated (thank you to syzbot); and move_huge_pmd() must
tolerate that a page table might have been allocated there just before (of
course it would be more satisfying to remove the empty page table, but
this is not a path worth optimizing).
Link: https://lkml.kernel.org/r/65e5e84a-f04-947-23f2-b97d3462e1e@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
change_pmd_range() had special pmd_none_or_clear_bad_unless_trans_huge(),
required to avoid "bad" choices when setting automatic NUMA hinting under
mmap_read_lock(); but most of that is already covered in pte_offset_map()
now. change_pmd_range() just wants a pmd_none() check before wasting time
on MMU notifiers, then checks on the read-once _pmd value to work out
what's needed for huge cases. If change_pte_range() returns -EAGAIN to
retry if pte_offset_map_lock() fails, nothing more special is needed.
Link: https://lkml.kernel.org/r/725a42a9-91e9-c868-925-e3a5fd40bb4f@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Following the examples of nearby code, various functions can just give up
if pte_offset_map() or pte_offset_map_lock() fails. And there's no need
for a preliminary pmd_trans_unstable() or other such check, since such
cases are now safely handled inside.
Link: https://lkml.kernel.org/r/7b9bd85d-1652-cbf2-159d-f503b45e5b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Failures here would be surprising: pte_advanced_tests() and
pte_clear_tests() and __page_table_check_pte_clear_range() each issue a
warning if pte_offset_map() or pte_offset_map_lock() fails.
Link: https://lkml.kernel.org/r/3ea9e4f-e5cf-d7d9-4c2-291b3c5a3636@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mfill_atomic_install_pte() and mfill_atomic_pte_zeropage() treat failed
pte_offset_map_lock() as -EAGAIN, which mfill_atomic() already returns to
user for a similar race.
Link: https://lkml.kernel.org/r/50cf3930-1bfa-4de9-a079-3da47b7ce17b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
hmm_vma_walk_pmd() is called through mm_walk, but already has a goto again
loop of its own, so take part in that if pte_offset_map() fails.
Link: https://lkml.kernel.org/r/d6c6dd68-25d4-653b-f94b-a45c53ee04b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
vmalloc_to_page() was using pte_offset_map() (followed by pte_unmap()),
but it's intended for userspace page tables: prefer pte_offset_kernel().
Link: https://lkml.kernel.org/r/696386a-84f8-b33c-82e5-f865ed6eb39@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
wp_clean_pmd_entry() need not check pmd_trans_unstable() or pmd_none(),
wp_clean_pud_entry() need not check pud_trans_unstable() or pud_none():
it's just the ACTION_CONTINUE when trans_huge or devmap that's needed to
prevent splitting, and we're hoping to remove pmd_trans_unstable(). Is
that PUD #ifdef necessary? Maybe some configs are missing a stub.
Link: https://lkml.kernel.org/r/d3379c7-65db-26d3-1764-8e866490925f@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
walk_pte_range() has a no_vma option to serve walk_page_range_novma(). I
don't know of any problem, but it looks safer to check for init_mm, and
use pte_offset_kernel() rather than pte_offset_map() in that case:
pte_offset_map()'s pmdval validation is intended for userspace.
Allow for its pte_offset_map() or pte_offset_map_lock() to fail, and retry
with ACTION_AGAIN if so. Add a second check for ACTION_AGAIN in
walk_pmd_range(), to catch it after return from walk_pte_range().
Remove the pmd_trans_unstable() check after split_huge_pmd() in
walk_pmd_range(): walk_pte_range() now handles those cases safely (and
they must fail powerpc's is_hugepd() check).
Link: https://lkml.kernel.org/r/3eba6f0-2b-fb66-6bb6-2ee8533e221@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Simple walk_page_range() users should set ACTION_AGAIN to retry when
pte_offset_map_lock() fails.
No need to check pmd_trans_unstable(): that was precisely to avoid the
possiblity of calling pte_offset_map() on a racily removed or inserted THP
entry, but such cases are now safely handled inside it. Likewise there is
no need to check pmd_none() or pmd_bad() before calling it.
Link: https://lkml.kernel.org/r/c77d9d10-3aad-e3ce-4896-99e91c7947f3@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: SeongJae Park <sj@kernel.org> for mm/damon part
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
map_pte() use pte_offset_map_nolock(), to make sure of the ptl belonging
to pte, even if pmd entry is then changed racily: page_vma_mapped_walk()
use that instead of getting pte_lockptr() later, or restart if map_pte()
found no page table.
Link: https://lkml.kernel.org/r/cba186e0-5ed7-e81b-6cd-dade4c33c248@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
No functional change here, but adjust the format of map_pte() so that the
following commit will be easier to read: separate out the PVMW_SYNC case
first, and remove two levels of indentation from the ZONE_DEVICE case.
Link: https://lkml.kernel.org/r/bf723f59-e3fc-6839-1cc3-c0631ee248bc@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Revert commit a7a69d8ba8 ("mm/thp: another PVMW_SYNC fix in
page_vma_mapped_walk()"): I was proud of that "Aha!" commit at the time,
but in revisiting page_vma_mapped_walk() for pte_offset_map() failure,
that block raised a doubt: and it now seems utterly bogus. The prior
map_pte() has taken ptl unconditionally when PVMW_SYNC: I must have
forgotten that when making the change. It did no harm, but could not have
fixed a BUG or WARN, and is hard to reconcile with coming changes.
Link: https://lkml.kernel.org/r/87475a22-e59e-2d8b-d78a-df376d314bd@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
filemap_map_pages() allow pte_offset_map_lock() to fail; and remove the
pmd_devmap_trans_unstable() check from filemap_map_pmd(), which can safely
return to filemap_map_pages() and let pte_offset_map_lock() discover that.
Link: https://lkml.kernel.org/r/54607cf4-ddb6-7ef3-043-1d2de1a9a71@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make pte_offset_map() a wrapper for __pte_offset_map() (optionally outputs
pmdval), pte_offset_map_lock() a sparse __cond_lock wrapper for
__pte_offset_map_lock(): those __funcs added in mm/pgtable-generic.c.
__pte_offset_map() do pmdval validation (including pmd_clear_bad() when
pmd_bad()), returning NULL if pmdval is not for a page table.
__pte_offset_map_lock() verify pmdval unchanged after getting the lock,
trying again if it changed.
No #ifdef CONFIG_TRANSPARENT_HUGEPAGE around them: that could be done to
cover the imminent case, but we expect to generalize it later, and it
makes a mess of where to do the pmd_bad() clearing.
Add pte_offset_map_nolock(): outputs ptl like pte_offset_map_lock(),
without actually taking the lock. This will be preferred to open uses of
pte_lockptr(), because (when split ptlock is in page table's struct page)
it points to the right lock for the returned pte pointer, even if *pmd
gets changed racily afterwards.
Update corresponding Documentation.
Do not add the anticipated rcu_read_lock() and rcu_read_unlock()s yet:
they have to wait until all architectures are balancing pte_offset_map()s
with pte_unmap()s (as in the arch series posted earlier). But comment
where they will go, so that it's easy to add them for experiments. And
only when those are in place can transient racy failure cases be enabled.
Add more safety for the PAE mismatched pmd_low pmd_high case at that time.
Link: https://lkml.kernel.org/r/2929bfd-9893-a374-e463-4c3127ff9b9d@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
migration_entry_wait_on_locked() does not need to take a mapped pte
pointer, its callers can do the unmap first. Annotate it with
__releases(ptl) to reduce sparse warnings.
Fold __migration_entry_wait_huge() into migration_entry_wait_huge(). Fold
__migration_entry_wait() into migration_entry_wait(), preferring the
tighter pte_offset_map_lock() to pte_offset_map() and pte_lockptr().
Link: https://lkml.kernel.org/r/b0e2a532-cdf2-561b-e999-f3b13b8d6d3@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: allow pte_offset_map[_lock]() to fail", v2.
What is it all about? Some mmap_lock avoidance i.e. latency reduction.
Initially just for the case of collapsing shmem or file pages to THPs; but
likely to be relied upon later in other contexts e.g. freeing of empty
page tables (but that's not work I'm doing). mmap_write_lock avoidance
when collapsing to anon THPs? Perhaps, but again that's not work I've
done: a quick attempt was not as easy as the shmem/file case.
I would much prefer not to have to make these small but wide-ranging
changes for such a niche case; but failed to find another way, and have
heard that shmem MADV_COLLAPSE's usefulness is being limited by that
mmap_write_lock it currently requires.
These changes (though of course not these exact patches) have been in
Google's data centre kernel for three years now: we do rely upon them.
What is this preparatory series about?
The current mmap locking will not be enough to guard against that tricky
transition between pmd entry pointing to page table, and empty pmd entry,
and pmd entry pointing to huge page: pte_offset_map() will have to
validate the pmd entry for itself, returning NULL if no page table is
there. What to do about that varies: sometimes nearby error handling
indicates just to skip it; but in many cases an ACTION_AGAIN or "goto
again" is appropriate (and if that risks an infinite loop, then there must
have been an oops, or pfn 0 mistaken for page table, before).
Given the likely extension to freeing empty page tables, I have not
limited this set of changes to a THP config; and it has been easier, and
sets a better example, if each site is given appropriate handling: even
where deeper study might prove that failure could only happen if the pmd
table were corrupted.
Several of the patches are, or include, cleanup on the way; and by the
end, pmd_trans_unstable() and suchlike are deleted: pte_offset_map() and
pte_offset_map_lock() then handle those original races and more. Most
uses of pte_lockptr() are deprecated, with pte_offset_map_nolock() taking
its place.
This patch (of 32):
Use pmdp_get_lockless() in preference to READ_ONCE(*pmdp), to get a more
reliable result with PAE (or READ_ONCE as before without PAE); and remove
the unnecessary extra barrier()s which got left behind in its callers.
HOWEVER: Note the small print in linux/pgtable.h, where it was designed
specifically for fast GUP, and depends on interrupts being disabled for
its full guarantee: most callers which have been added (here and before)
do NOT have interrupts disabled, so there is still some need for caution.
Link: https://lkml.kernel.org/r/f35279a9-9ac0-de22-d245-591afbfb4dc@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It would be better to replace the traditional ternary conditional
operator with min() in zero_iter
Link: https://lkml.kernel.org/r/20230609093057.27777-1-luhongfei@vivo.com
Signed-off-by: Lu Hongfei <luhongfei@vivo.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
folio_set_order(folio, 0) is used in kernel at two places
__destroy_compound_gigantic_folio and __prep_compound_gigantic_folio.
Currently, It is called to clear out the folio->_folio_nr_pages and
folio->_folio_order.
For __destroy_compound_gigantic_folio:
In past, folio_set_order(folio, 0) was needed because page->mapping used
to overlap with _folio_nr_pages and _folio_order. So if these fields were
left uncleared during freeing gigantic hugepages, they were causing
"BUG: bad page state" due to non-zero page->mapping. Now, After
Commit a01f43901c ("hugetlb: be sure to free demoted CMA pages to
CMA") page->mapping has explicitly been cleared out for tail pages. Also,
_folio_order and _folio_nr_pages no longer overlaps with page->mapping.
So, folio_set_order(folio, 0) can be removed from freeing gigantic
folio path (__destroy_compound_gigantic_folio).
Another place, folio_set_order(folio, 0) is called inside
__prep_compound_gigantic_folio during error path. Here,
folio_set_order(folio, 0) can also be removed if we move
folio_set_order(folio, order) after for loop.
The patch also moves _folio_set_head call in __prep_compound_gigantic_folio()
such that we avoid clearing them in the error path.
Also, as Mike pointed out:
"It would actually be better to move the calls _folio_set_head and
folio_set_order in __prep_compound_gigantic_folio() as suggested here. Why?
In the current code, the ref count on the 'head page' is still 1 (or more)
while those calls are made. So, someone could take a speculative ref on the
page BEFORE the tail pages are set up."
This way, folio_set_order(folio, 0) is no more needed. And it will also
helps removing the confusion of folio order being set to 0 (as _folio_order
field is part of first tail page).
Testing: I have run LTP tests, which all passes. and also I have written
the test in LTP which tests the bug caused by compound_nr and page->mapping
overlapping.
https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/hugetlb/hugemmap/hugemmap32.c
Running on older kernel ( < 5.10-rc7) with the above bug this fails while
on newer kernel and, also with this patch it passes.
Link: https://lkml.kernel.org/r/20230609162907.111756-1-tsahu@linux.ibm.com
Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Problem: The interruption caused by vmstat_update is undesirable
for certain applications.
With workloads that are running on isolated cpus with nohz full mode to
shield off any kernel interruption. For example, a VM running a
time sensitive application with a 50us maximum acceptable interruption
(use case: soft PLC).
oslat 1094.456862: sys_mlock(start: 7f7ed0000b60, len: 1000)
oslat 1094.456971: workqueue_queue_work: ... function=vmstat_update ...
oslat 1094.456974: sched_switch: prev_comm=oslat ... ==> next_comm=kworker/5:1 ...
kworker 1094.456978: sched_switch: prev_comm=kworker/5:1 ==> next_comm=oslat ...
The example above shows an additional 7us for the
oslat -> kworker -> oslat
switches. In the case of a virtualized CPU, and the vmstat_update
interruption in the host (of a qemu-kvm vcpu), the latency penalty
observed in the guest is higher than 50us, violating the acceptable
latency threshold.
The isolated vCPU can perform operations that modify per-CPU page counters,
for example to complete I/O operations:
CPU 11/KVM-9540 [001] dNh1. 2314.248584: mod_zone_page_state <-__folio_end_writeback
CPU 11/KVM-9540 [001] dNh1. 2314.248585: <stack trace>
=> 0xffffffffc042b083
=> mod_zone_page_state
=> __folio_end_writeback
=> folio_end_writeback
=> iomap_finish_ioend
=> blk_mq_end_request_batch
=> nvme_irq
=> __handle_irq_event_percpu
=> handle_irq_event
=> handle_edge_irq
=> __common_interrupt
=> common_interrupt
=> asm_common_interrupt
=> vmx_do_interrupt_nmi_irqoff
=> vmx_handle_exit_irqoff
=> vcpu_enter_guest
=> vcpu_run
=> kvm_arch_vcpu_ioctl_run
=> kvm_vcpu_ioctl
=> __x64_sys_ioctl
=> do_syscall_64
=> entry_SYSCALL_64_after_hwframe
In kernel users of vmstat counters either require the precise value and
they are using zone_page_state_snapshot interface or they can live with an
imprecision as the regular flushing can happen at arbitrary time and
cumulative error can grow (see calculate_normal_threshold).
From that POV the regular flushing can be postponed for CPUs that have
been isolated from the kernel interference without critical infrastructure
ever noticing. Skip regular flushing from vmstat_shepherd for all
isolated CPUs to avoid interference with the isolated workload.
Suggested by Michal Hocko.
Link: https://lkml.kernel.org/r/ZIDoV/zxFKVmQl7W@tpad
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Woodhouse