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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- The series "Enable strict percpu address space checks" from Uros
Bizjak uses x86 named address space qualifiers to provide
compile-time checking of percpu area accesses.
This has caused a small amount of fallout - two or three issues were
reported. In all cases the calling code was found to be incorrect.
- The series "Some cleanup for memcg" from Chen Ridong implements some
relatively monir cleanups for the memcontrol code.
- The series "mm: fixes for device-exclusive entries (hmm)" from David
Hildenbrand fixes a boatload of issues which David found then using
device-exclusive PTE entries when THP is enabled. More work is
needed, but this makes thins better - our own HMM selftests now
succeed.
- The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
remove the z3fold and zbud implementations. They have been deprecated
for half a year and nobody has complained.
- The series "mm: further simplify VMA merge operation" from Lorenzo
Stoakes implements numerous simplifications in this area. No runtime
effects are anticipated.
- The series "mm/madvise: remove redundant mmap_lock operations from
process_madvise()" from SeongJae Park rationalizes the locking in the
madvise() implementation. Performance gains of 20-25% were observed
in one MADV_DONTNEED microbenchmark.
- The series "Tiny cleanup and improvements about SWAP code" from
Baoquan He contains a number of touchups to issues which Baoquan
noticed when working on the swap code.
- The series "mm: kmemleak: Usability improvements" from Catalin
Marinas implements a couple of improvements to the kmemleak
user-visible output.
- The series "mm/damon/paddr: fix large folios access and schemes
handling" from Usama Arif provides a couple of fixes for DAMON's
handling of large folios.
- The series "mm/damon/core: fix wrong and/or useless damos_walk()
behaviors" from SeongJae Park fixes a few issues with the accuracy of
kdamond's walking of DAMON regions.
- The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
Stoakes changes the interaction between framebuffer deferred-io and
core MM. No functional changes are anticipated - this is preparatory
work for the future removal of page structure fields.
- The series "mm/damon: add support for hugepage_size DAMOS filter"
from Usama Arif adds a DAMOS filter which permits the filtering by
huge page sizes.
- The series "mm: permit guard regions for file-backed/shmem mappings"
from Lorenzo Stoakes extends the guard region feature from its
present "anon mappings only" state. The feature now covers shmem and
file-backed mappings.
- The series "mm: batched unmap lazyfree large folios during
reclamation" from Barry Song cleans up and speeds up the unmapping
for pte-mapped large folios.
- The series "reimplement per-vma lock as a refcount" from Suren
Baghdasaryan puts the vm_lock back into the vma. Our reasons for
pulling it out were largely bogus and that change made the code more
messy. This patchset provides small (0-10%) improvements on one
microbenchmark.
- The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
improves" from SeongJae Park does some maintenance work on the DAMON
docs.
- The series "hugetlb/CMA improvements for large systems" from Frank
van der Linden addresses a pile of issues which have been observed
when using CMA on large machines.
- The series "mm/damon: introduce DAMOS filter type for unmapped pages"
from SeongJae Park enables users of DMAON/DAMOS to filter my the
page's mapped/unmapped status.
- The series "zsmalloc/zram: there be preemption" from Sergey
Senozhatsky teaches zram to run its compression and decompression
operations preemptibly.
- The series "selftests/mm: Some cleanups from trying to run them" from
Brendan Jackman fixes a pile of unrelated issues which Brendan
encountered while runnimg our selftests.
- The series "fs/proc/task_mmu: add guard region bit to pagemap" from
Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
determine whether a particular page is a guard page.
- The series "mm, swap: remove swap slot cache" from Kairui Song
removes the swap slot cache from the allocation path - it simply
wasn't being effective.
- The series "mm: cleanups for device-exclusive entries (hmm)" from
David Hildenbrand implements a number of unrelated cleanups in this
code.
- The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
implements a number of preparatoty cleanups to the GENERIC_PTDUMP
Kconfig logic.
- The series "mm/damon: auto-tune aggregation interval" from SeongJae
Park implements a feedback-driven automatic tuning feature for
DAMON's aggregation interval tuning.
- The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
preparation for implementing lazy mmu mode for arm64 to optimize
vmalloc.
- The series "mm/page_alloc: Some clarifications for migratetype
fallback" from Brendan Jackman reworks some commentary to make the
code easier to follow.
- The series "page_counter cleanup and size reduction" from Shakeel
Butt cleans up the page_counter code and fixes a size increase which
we accidentally added late last year.
- The series "Add a command line option that enables control of how
many threads should be used to allocate huge pages" from Thomas
Prescher does that. It allows the careful operator to significantly
reduce boot time by tuning the parallalization of huge page
initialization.
- The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
from Tang Yizhou fixes the tracing output from the dirty page
balancing code.
- The series "mm/damon: make allow filters after reject filters useful
and intuitive" from SeongJae Park improves the handling of allow and
reject filters. Behaviour is made more consistent and the documention
is updated accordingly.
- The series "Switch zswap to object read/write APIs" from Yosry Ahmed
updates zswap to the new object read/write APIs and thus permits the
removal of some legacy code from zpool and zsmalloc.
- The series "Some trivial cleanups for shmem" from Baolin Wang does as
it claims.
- The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
Alistair Popple regularizes the weird ZONE_DEVICE page refcount
handling in DAX, permittig the removal of a number of special-case
checks.
- The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
preparatoty refactoring and cleanup of the mremap() code.
- The series "mm: MM owner tracking for large folios (!hugetlb) +
CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
which we determine whether a large folio is known to be mapped
exclusively into a single MM.
- The series "mm/damon: add sysfs dirs for managing DAMOS filters based
on handling layers" from SeongJae Park adds a couple of new sysfs
directories to ease the management of DAMON/DAMOS filters.
- The series "arch, mm: reduce code duplication in mem_init()" from
Mike Rapoport consolidates many per-arch implementations of
mem_init() into code generic code, where that is practical.
- The series "mm/damon/sysfs: commit parameters online via
damon_call()" from SeongJae Park continues the cleaning up of sysfs
access to DAMON internal data.
- The series "mm: page_ext: Introduce new iteration API" from Luiz
Capitulino reworks the page_ext initialization to fix a boot-time
crash which was observed with an unusual combination of compile and
cmdline options.
- The series "Buddy allocator like (or non-uniform) folio split" from
Zi Yan reworks the code to split a folio into smaller folios. The
main benefit is lessened memory consumption: fewer post-split folios
are generated.
- The series "Minimize xa_node allocation during xarry split" from Zi
Yan reduces the number of xarray xa_nodes which are generated during
an xarray split.
- The series "drivers/base/memory: Two cleanups" from Gavin Shan
performs some maintenance work on the drivers/base/memory code.
- The series "Add tracepoints for lowmem reserves, watermarks and
totalreserve_pages" from Martin Liu adds some more tracepoints to the
page allocator code.
- The series "mm/madvise: cleanup requests validations and
classifications" from SeongJae Park cleans up some warts which
SeongJae observed during his earlier madvise work.
- The series "mm/hwpoison: Fix regressions in memory failure handling"
from Shuai Xue addresses two quite serious regressions which Shuai
has observed in the memory-failure implementation.
- The series "mm: reliable huge page allocator" from Johannes Weiner
makes huge page allocations cheaper and more reliable by reducing
fragmentation.
- The series "Minor memcg cleanups & prep for memdescs" from Matthew
Wilcox is preparatory work for the future implementation of memdescs.
- The series "track memory used by balloon drivers" from Nico Pache
introduces a way to track memory used by our various balloon drivers.
- The series "mm/damon: introduce DAMOS filter type for active pages"
from Nhat Pham permits users to filter for active/inactive pages,
separately for file and anon pages.
- The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
separates the proactive reclaim statistics from the direct reclaim
statistics.
- The series "mm/vmscan: don't try to reclaim hwpoison folio" from
Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
code.
* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
x86/mm: restore early initialization of high_memory for 32-bits
mm/vmscan: don't try to reclaim hwpoison folio
mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
selftests/mm: speed up split_huge_page_test
selftests/mm: uffd-unit-tests support for hugepages > 2M
docs/mm/damon/design: document active DAMOS filter type
mm/damon: implement a new DAMOS filter type for active pages
fs/dax: don't disassociate zero page entries
MM documentation: add "Unaccepted" meminfo entry
selftests/mm: add commentary about 9pfs bugs
fork: use __vmalloc_node() for stack allocation
docs/mm: Physical Memory: Populate the "Zones" section
xen: balloon: update the NR_BALLOON_PAGES state
hv_balloon: update the NR_BALLOON_PAGES state
balloon_compaction: update the NR_BALLOON_PAGES state
meminfo: add a per node counter for balloon drivers
mm: remove references to folio in __memcg_kmem_uncharge_page()
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, there are three major updates: (1) folio conversion,
(2) refactoring for mount API conversion, (3) some performance
improvement such as direct IO, checkpoint speed, and IO priority
hints.
For stability, there are patches which add more sanity checks and
fixes some major issues like i_size in atomic write operations and
write pointer recovery in zoned devices.
Enhancements:
- huge folio converion work by Matthew Wilcox
- clean up for mount API conversion by Eric Sandeen
- improve direct IO speed in the overwrite case
- add some sanity check on node consistency
- set highest IO priority for checkpoint thread
- keep POSIX_FADV_NOREUSE ranges and add sysfs entry to reclaim pages
- add ioctl to get IO priority hint
- add carve_out sysfs node for fsstat
Bug fixes:
- disable nat_bits during umount to avoid potential nat entry corruption
- fix missing i_size update on atomic writes
- fix missing discard for active segments
- fix running out of free segments
- fix out-of-bounds access in f2fs_truncate_inode_blocks()
- call f2fs_recover_quota_end() correctly
- fix potential deadloop in prepare_compress_overwrite()
- fix the missing write pointer correction for zoned device
- fix to avoid panic once fallocation fails for pinfile
- don't retry IO for corrupted data scenario
There are many other clean up patches and minor bug fixes as usual"
* tag 'f2fs-for-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (68 commits)
f2fs: fix missing discard for active segments
f2fs: optimize f2fs DIO overwrites
f2fs: fix to avoid atomicity corruption of atomic file
f2fs: pass sbi rather than sb to parse_options()
f2fs: pass sbi rather than sb to quota qf_name helpers
f2fs: defer readonly check vs norecovery
f2fs: Pass sbi rather than sb to f2fs_set_test_dummy_encryption
f2fs: make LAZYTIME a mount option flag
f2fs: make INLINECRYPT a mount option flag
f2fs: factor out an f2fs_default_check function
f2fs: consolidate unsupported option handling errors
f2fs: use f2fs_sb_has_device_alias during option parsing
f2fs: add carve_out sysfs node
f2fs: fix to avoid running out of free segments
f2fs: Remove f2fs_write_node_page()
f2fs: Remove f2fs_write_meta_page()
f2fs: Remove f2fs_write_data_page()
f2fs: Remove check for ->writepage
Revert "f2fs: rebuild nat_bits during umount"
f2fs: fix to avoid accessing uninitialized curseg
...
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git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Move vm_table members out of kernel/sysctl.c
All vm_table array members have moved to their respective subsystems
leading to the removal of vm_table from kernel/sysctl.c. This
increases modularity by placing the ctl_tables closer to where they
are actually used and at the same time reducing the chances of merge
conflicts in kernel/sysctl.c.
- ctl_table range fixes
Replace the proc_handler function that checks variable ranges in
coredump_sysctls and vdso_table with the one that actually uses the
extra{1,2} pointers as min/max values. This tightens the range of the
values that users can pass into the kernel effectively preventing
{under,over}flows.
- Misc fixes
Correct grammar errors and typos in test messages. Update sysctl
files in MAINTAINERS. Constified and removed array size in
declaration for alignment_tbl
* tag 'sysctl-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (22 commits)
selftests/sysctl: fix wording of help messages
selftests: fix spelling/grammar errors in sysctl/sysctl.sh
MAINTAINERS: Update sysctl file list in MAINTAINERS
sysctl: Fix underflow value setting risk in vm_table
coredump: Fixes core_pipe_limit sysctl proc_handler
sysctl: remove unneeded include
sysctl: remove the vm_table
sh: vdso: move the sysctl to arch/sh/kernel/vsyscall/vsyscall.c
x86: vdso: move the sysctl to arch/x86/entry/vdso/vdso32-setup.c
fs: dcache: move the sysctl to fs/dcache.c
sunrpc: simplify rpcauth_cache_shrink_count()
fs: drop_caches: move sysctl to fs/drop_caches.c
fs: fs-writeback: move sysctl to fs/fs-writeback.c
mm: nommu: move sysctl to mm/nommu.c
security: min_addr: move sysctl to security/min_addr.c
mm: mmap: move sysctl to mm/mmap.c
mm: util: move sysctls to mm/util.c
mm: vmscan: move vmscan sysctls to mm/vmscan.c
mm: swap: move sysctl to mm/swap.c
mm: filemap: move sysctl to mm/filemap.c
...
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"15 hotfixes. 7 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
13 are for MM and the other two are for squashfs and procfs.
All are singletons. Please see the individual changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-17-20-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/page_alloc: fix memory accept before watermarks gets initialized
mm: decline to manipulate the refcount on a slab page
memcg: drain obj stock on cpu hotplug teardown
mm/huge_memory: drop beyond-EOF folios with the right number of refs
selftests/mm: run_vmtests.sh: fix half_ufd_size_MB calculation
mm: fix error handling in __filemap_get_folio() with FGP_NOWAIT
mm: memcontrol: fix swap counter leak from offline cgroup
mm/vma: do not register private-anon mappings with khugepaged during mmap
squashfs: fix invalid pointer dereference in squashfs_cache_delete
mm/migrate: fix shmem xarray update during migration
mm/hugetlb: fix surplus pages in dissolve_free_huge_page()
mm/damon/core: initialize damos->walk_completed in damon_new_scheme()
mm/damon: respect core layer filters' allowance decision on ops layer
filemap: move prefaulting out of hot write path
proc: fix UAF in proc_get_inode()
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Patch series "Minimize xa_node allocation during xarry split", v3.
When splitting a multi-index entry in XArray from order-n to order-m,
existing xas_split_alloc()+xas_split() approach requires 2^(n %
XA_CHUNK_SHIFT) xa_node allocations. But its callers,
__filemap_add_folio() and shmem_split_large_entry(), use at most 1
xa_node. To minimize xa_node allocation and remove the limitation of no
split from order-12 (or above) to order-0 (or anything between 0 and
5)[1], xas_try_split() was added[2], which allocates (n / XA_CHUNK_SHIFT -
m / XA_CHUNK_SHIFT) xa_node. It is used for non-uniform folio split, but
can be used by __filemap_add_folio() and shmem_split_large_entry().
xas_split_alloc() and xas_split() split an order-9 to order-0:
---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
| | | |
------- --- --- -------
| | ... | |
V V V V
----------- ----------- ----------- -----------
| xa_node | | xa_node | ... | xa_node | | xa_node |
----------- ----------- ----------- -----------
xas_try_split() splits an order-9 to order-0:
---------------------------------
| | | | | | | | |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| | | | | | | | |
---------------------------------
|
|
V
-----------
| xa_node |
-----------
xas_try_split() is designed to be called iteratively with n = m + 1.
xas_try_split_mini_order() is added to minmize the number of calls to
xas_try_split() by telling the caller the next minimal order to split to
instead of n - 1. Splitting order-n to order-m when m= l * XA_CHUNK_SHIFT
does not require xa_node allocation and requires 1 xa_node when n=l *
XA_CHUNK_SHIFT and m = n - 1, so it is OK to use xas_try_split() with n >
m + 1 when no new xa_node is needed.
xfstests quick group test passed on xfs and tmpfs.
[1] https://lore.kernel.org/linux-mm/Z6YX3RznGLUD07Ao@casper.infradead.org/
[2] https://lore.kernel.org/linux-mm/20250226210032.2044041-1-ziy@nvidia.com/
This patch (of 2):
During __filemap_add_folio(), a shadow entry is covering n slots and a
folio covers m slots with m < n is to be added. Instead of splitting all
n slots, only the m slots covered by the folio need to be split and the
remaining n-m shadow entries can be retained with orders ranging from m to
n-1. This method only requires
(n/XA_CHUNK_SHIFT) - (m/XA_CHUNK_SHIFT)
new xa_nodes instead of
(n % XA_CHUNK_SHIFT) * ((n/XA_CHUNK_SHIFT) - (m/XA_CHUNK_SHIFT))
new xa_nodes, compared to the original xas_split_alloc() + xas_split()
one. For example, to insert an order-0 folio when an order-9 shadow entry
is present (assuming XA_CHUNK_SHIFT is 6), 1 xa_node is needed instead of
8.
xas_try_split_min_order() is introduced to reduce the number of calls to
xas_try_split() during split.
Link: https://lkml.kernel.org/r/20250314222113.711703-1-ziy@nvidia.com
Link: https://lkml.kernel.org/r/20250314222113.711703-2-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mattew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The folio_test_large() check in filemap_free_folio() is unnecessary
because folio_nr_pages(), which is called internally already performs this
check. Removing the redundant condition simplifies the code and avoids
double validation.
This change improves code readability and reduces unnecessary operations
in the folio freeing path.
Link: https://lkml.kernel.org/r/20250213055612.490993-1-guanjun@linux.alibaba.com
Signed-off-by: Guanjun <guanjun@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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original report:
https://lore.kernel.org/all/CAKhLTr1UL3ePTpYjXOx2AJfNk8Ku2EdcEfu+CH1sf3Asr=B-Dw@mail.gmail.com/T/
When doing buffered writes with FGP_NOWAIT, under memory pressure, the
system returned ENOMEM despite there being plenty of available memory, to
be reclaimed from page cache. The user space used io_uring interface,
which in turn submits I/O with FGP_NOWAIT (the fast path).
retsnoop pointed to iomap_get_folio:
00:34:16.180612 -> 00:34:16.180651 TID/PID 253786/253721
(reactor-1/combined_tests):
entry_SYSCALL_64_after_hwframe+0x76
do_syscall_64+0x82
__do_sys_io_uring_enter+0x265
io_submit_sqes+0x209
io_issue_sqe+0x5b
io_write+0xdd
xfs_file_buffered_write+0x84
iomap_file_buffered_write+0x1a6
32us [-ENOMEM] iomap_write_begin+0x408
iter=&{.inode=0xffff8c67aa031138,.len=4096,.flags=33,.iomap={.addr=0xffffffffffffffff,.length=4096,.type=1,.flags=3,.bdev=0x…
pos=0 len=4096 foliop=0xffffb32c296b7b80
! 4us [-ENOMEM] iomap_get_folio
iter=&{.inode=0xffff8c67aa031138,.len=4096,.flags=33,.iomap={.addr=0xffffffffffffffff,.length=4096,.type=1,.flags=3,.bdev=0x…
pos=0 len=4096
This is likely a regression caused by 66dabbb65d67 ("mm: return an ERR_PTR
from __filemap_get_folio"), which moved error handling from
io_map_get_folio() to __filemap_get_folio(), but broke FGP_NOWAIT
handling, so ENOMEM is being escaped to user space. Had it correctly
returned -EAGAIN with NOWAIT, either io_uring or user space itself would
be able to retry the request.
It's not enough to patch io_uring since the iomap interface is the one
responsible for it, and pwritev2(RWF_NOWAIT) and AIO interfaces must
return the proper error too.
The patch was tested with scylladb test suite (its original reproducer),
and the tests all pass now when memory is pressured.
Link: https://lkml.kernel.org/r/20250224143700.23035-1-raphaelsc@scylladb.com
Fixes: 66dabbb65d67 ("mm: return an ERR_PTR from __filemap_get_folio")
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is a generic anti-pattern that shows up in the VFS and several
filesystems where the hot write paths touch userspace twice when they
could get away with doing it once.
Dave Chinner suggested that they should all be fixed up[1]. I agree[2].
But, the series to do that fixup spans a bunch of filesystems and a lot of
people. This patch fixes common code that absolutely everyone uses. It
has measurable performance benefits[3].
I think this patch can go in and not be held up by the others.
I will post them separately to their separate maintainers for
consideration. But, honestly, I'm not going to lose any sleep if
the maintainers don't pick those up.
1. https://lore.kernel.org/all/Z5f-x278Z3wTIugL@dread.disaster.area/
2. https://lore.kernel.org/all/20250129181749.C229F6F3@davehans-spike.ostc.intel.com/
3. https://lore.kernel.org/all/202502121529.d62a409e-lkp@intel.com/
This patch:
There is a bit of a sordid history here. I originally wrote
998ef75ddb57 ("fs: do not prefault sys_write() user buffer pages")
to fix a performance issue that showed up on early SMAP hardware.
But that was reverted with 00a3d660cbac because it exposed an
underlying filesystem bug.
This is a reimplementation of the original commit along with some
simplification and comment improvements.
The basic problem is that the generic write path has two userspace
accesses: one to prefault the write source buffer and then another to
perform the actual write. On x86, this means an extra STAC/CLAC pair.
These are relatively expensive instructions because they function as
barriers.
Keep the prefaulting behavior but move it into the slow path that gets
run when the write did not make any progress. This avoids livelocks
that can happen when the write's source and destination target the
same folio. Contrary to the existing comments, the fault-in does not
prevent deadlocks. That's accomplished by using an "atomic" usercopy
that disables page faults.
The end result is that the generic write fast path now touches
userspace once instead of twice.
0day has shown some improvements on a couple of microbenchmarks:
https://lore.kernel.org/all/202502121529.d62a409e-lkp@intel.com/
Link: https://lkml.kernel.org/r/20250228203722.CAEB63AC@davehans-spike.ostc.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/yxyuijjfd6yknryji2q64j3keq2ygw6ca6fs5jwyolklzvo45s@4u63qqqyosy2/
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This reverts commit fac84846a28c0950d4433118b3dffd44306df62d.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250312073852.2123409-7-amir73il@gmail.com
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This reverts commit 8392bc2ff8c8bf7c4c5e6dfa71ccd893a3c046f6.
In the use case of buffered write whose input buffer is mmapped file on a
filesystem with a pre-content mark, the prefaulting of the buffer can
happen under the filesystem freeze protection (obtained in vfs_write())
which breaks assumptions of pre-content hook and introduces potential
deadlock of HSM handler in userspace with filesystem freezing.
Now that we have pre-content hooks at file mmap() time, disable the
pre-content event hooks on page fault to avoid the potential deadlock.
Reported-by: syzbot+7229071b47908b19d5b7@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-fsdevel/7ehxrhbvehlrjwvrduoxsao5k3x4aw275patsb3krkwuq573yv@o2hskrfawbnc/
Fixes: 8392bc2ff8c8 ("fsnotify: generate pre-content permission event on page fault")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250312073852.2123409-5-amir73il@gmail.com
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The fix to atomically read the pipe head and tail state when not holding
the pipe mutex has caused a number of headaches due to the size change
of the involved types.
It turns out that we don't have _that_ many places that access these
fields directly and were affected, but we have more than we strictly
should have, because our low-level helper functions have been designed
to have intimate knowledge of how the pipes work.
And as a result, that random noise of direct 'pipe->head' and
'pipe->tail' accesses makes it harder to pinpoint any actual potential
problem spots remaining.
For example, we didn't have a "is the pipe full" helper function, but
instead had a "given these pipe buffer indexes and this pipe size, is
the pipe full". That's because some low-level pipe code does actually
want that much more complicated interface.
But most other places literally just want a "is the pipe full" helper,
and not having it meant that those places ended up being unnecessarily
much too aware of this all.
It would have been much better if only the very core pipe code that
cared had been the one aware of this all.
So let's fix it - better late than never. This just introduces the
trivial wrappers for "is this pipe full or empty" and to get how many
pipe buffers are used, so that instead of writing
if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
the places that literally just want to know if a pipe is full can just
say
if (pipe_is_full(pipe))
instead. The existing trivial cases were converted with a 'sed' script.
This cuts down on the places that access pipe->head and pipe->tail
directly outside of the pipe code (and core splice code) quite a lot.
The splice code in particular still revels in doing the direct low-level
accesses, and the fuse fuse_dev_splice_write() code also seems a bit
unnecessarily eager to go very low-level, but it's at least a bit better
than it used to be.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This compatibility wrapper has no callers left, so remove it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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iocb->ki_pos has been updated with the number of written bytes since
generic_perform_write().
Besides __filemap_fdatawrite_range() accepts the inclusive end of the
data range.
Fixes: 1d4457576570 ("mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250218120209.88093-2-jefflexu@linux.alibaba.com
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This moves the filemap related sysctl to mm/filemap.c, and
removes the redundant external variable declaration.
Signed-off-by: Kaixiong Yu <yukaixiong@huawei.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs.
- "Allocate and free frozen pages" from Matthew Wilcox reorganizes
the page allocator so we end up with the ability to allocate and
free zero-refcount pages. So that callers (ie, slab) can avoid a
refcount inc & dec
- "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
use large folios other than PMD-sized ones
- "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
and fixes for this small built-in kernel selftest
- "mas_anode_descend() related cleanup" from Wei Yang tidies up part
of the mapletree code
- "mm: fix format issues and param types" from Keren Sun implements a
few minor code cleanups
- "simplify split calculation" from Wei Yang provides a few fixes and
a test for the mapletree code
- "mm/vma: make more mmap logic userland testable" from Lorenzo
Stoakes continues the work of moving vma-related code into the
(relatively) new mm/vma.c
- "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
Hildenbrand cleans up and rationalizes handling of gfp flags in the
page allocator
- "readahead: Reintroduce fix for improper RA window sizing" from Jan
Kara is a second attempt at fixing a readahead window sizing issue.
It should reduce the amount of unnecessary reading
- "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
addresses an issue where "huge" amounts of pte pagetables are
accumulated:
https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/
Qi's series addresses this windup by synchronously freeing PTE
memory within the context of madvise(MADV_DONTNEED)
- "selftest/mm: Remove warnings found by adding compiler flags" from
Muhammad Usama Anjum fixes some build warnings in the selftests
code when optional compiler warnings are enabled
- "mm: don't use __GFP_HARDWALL when migrating remote pages" from
David Hildenbrand tightens the allocator's observance of
__GFP_HARDWALL
- "pkeys kselftests improvements" from Kevin Brodsky implements
various fixes and cleanups in the MM selftests code, mainly
pertaining to the pkeys tests
- "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
estimate application working set size
- "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
provides some cleanups to memcg's hugetlb charging logic
- "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
removes the global swap cgroup lock. A speedup of 10% for a
tmpfs-based kernel build was demonstrated
- "zram: split page type read/write handling" from Sergey Senozhatsky
has several fixes and cleaups for zram in the area of
zram_write_page(). A watchdog softlockup warning was eliminated
- "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
Brodsky cleans up the pagetable destructor implementations. A rare
use-after-free race is fixed
- "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
simplifies and cleans up the debugging code in the VMA merging
logic
- "Account page tables at all levels" from Kevin Brodsky cleans up
and regularizes the pagetable ctor/dtor handling. This results in
improvements in accounting accuracy
- "mm/damon: replace most damon_callback usages in sysfs with new
core functions" from SeongJae Park cleans up and generalizes
DAMON's sysfs file interface logic
- "mm/damon: enable page level properties based monitoring" from
SeongJae Park increases the amount of information which is
presented in response to DAMOS actions
- "mm/damon: remove DAMON debugfs interface" from SeongJae Park
removes DAMON's long-deprecated debugfs interfaces. Thus the
migration to sysfs is completed
- "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
Peter Xu cleans up and generalizes the hugetlb reservation
accounting
- "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
removes a never-used feature of the alloc_pages_bulk() interface
- "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
extends DAMOS filters to support not only exclusion (rejecting),
but also inclusion (allowing) behavior
- "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
introduces a new memory descriptor for zswap.zpool that currently
overlaps with struct page for now. This is part of the effort to
reduce the size of struct page and to enable dynamic allocation of
memory descriptors
- "mm, swap: rework of swap allocator locks" from Kairui Song redoes
and simplifies the swap allocator locking. A speedup of 400% was
demonstrated for one workload. As was a 35% reduction for kernel
build time with swap-on-zram
- "mm: update mips to use do_mmap(), make mmap_region() internal"
from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
mmap_region() can be made MM-internal
- "mm/mglru: performance optimizations" from Yu Zhao fixes a few
MGLRU regressions and otherwise improves MGLRU performance
- "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
Park updates DAMON documentation
- "Cleanup for memfd_create()" from Isaac Manjarres does that thing
- "mm: hugetlb+THP folio and migration cleanups" from David
Hildenbrand provides various cleanups in the areas of hugetlb
folios, THP folios and migration
- "Uncached buffered IO" from Jens Axboe implements the new
RWF_DONTCACHE flag which provides synchronous dropbehind for
pagecache reading and writing. To permite userspace to address
issues with massive buildup of useless pagecache when
reading/writing fast devices
- "selftests/mm: virtual_address_range: Reduce memory" from Thomas
Weißschuh fixes and optimizes some of the MM selftests"
* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm/compaction: fix UBSAN shift-out-of-bounds warning
s390/mm: add missing ctor/dtor on page table upgrade
kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
tools: add VM_WARN_ON_VMG definition
mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
seqlock: add missing parameter documentation for raw_seqcount_try_begin()
mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
mm/page_alloc: remove the incorrect and misleading comment
zram: remove zcomp_stream_put() from write_incompressible_page()
mm: separate move/undo parts from migrate_pages_batch()
mm/kfence: use str_write_read() helper in get_access_type()
selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
selftests/mm: vm_util: split up /proc/self/smaps parsing
selftests/mm: virtual_address_range: unmap chunks after validation
selftests/mm: virtual_address_range: mmap() without PROT_WRITE
selftests/memfd/memfd_test: fix possible NULL pointer dereference
mm: add FGP_DONTCACHE folio creation flag
mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
...
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Callers can pass this in for uncached folio creation, in which case if a
folio is newly created it gets marked as uncached. If a folio exists for
this index and lookup succeeds, then it will not get marked as uncached.
If an !uncached lookup finds a cached folio, clear the flag. For that
case, there are competeting uncached and cached users of the folio, and it
should not get pruned.
Link: https://lkml.kernel.org/r/20241220154831.1086649-13-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Works like filemap_fdatawrite_range(), except it's a non-integrity data
writeback and hence only starts writeback on the specified range. Will
help facilitate generically starting uncached writeback from
generic_write_sync(), as header dependencies preclude doing this inline
from fs.h.
Link: https://lkml.kernel.org/r/20241220154831.1086649-11-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If the folio is marked as streaming, drop pages when writeback completes.
Intended to be used with RWF_DONTCACHE, to avoid needing sync writes for
uncached IO.
Link: https://lkml.kernel.org/r/20241220154831.1086649-10-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add RWF_DONTCACHE as a read operation flag, which means that any data read
wil be removed from the page cache upon completion. Uses the page cache
to synchronize, and simply prunes folios that were instantiated when the
operation completes. While it would be possible to use private pages for
this, using the page cache as synchronization is handy for a variety of
reasons:
1) No special truncate magic is needed
2) Async buffered reads need some place to serialize, using the page
cache is a lot easier than writing extra code for this
3) The pruning cost is pretty reasonable
and the code to support this is much simpler as a result.
You can think of uncached buffered IO as being the much more attractive
cousin of O_DIRECT - it has none of the restrictions of O_DIRECT. Yes, it
will copy the data, but unlike regular buffered IO, it doesn't run into
the unpredictability of the page cache in terms of reclaim. As an
example, on a test box with 32 drives, reading them with buffered IO looks
as follows:
Reading bs 65536, uncached 0
1s: 145945MB/sec
2s: 158067MB/sec
3s: 157007MB/sec
4s: 148622MB/sec
5s: 118824MB/sec
6s: 70494MB/sec
7s: 41754MB/sec
8s: 90811MB/sec
9s: 92204MB/sec
10s: 95178MB/sec
11s: 95488MB/sec
12s: 95552MB/sec
13s: 96275MB/sec
where it's quite easy to see where the page cache filled up, and
performance went from good to erratic, and finally settles at a much
lower rate. Looking at top while this is ongoing, we see:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7535 root 20 0 267004 0 0 S 3199 0.0 8:40.65 uncached
3326 root 20 0 0 0 0 R 100.0 0.0 0:16.40 kswapd4
3327 root 20 0 0 0 0 R 100.0 0.0 0:17.22 kswapd5
3328 root 20 0 0 0 0 R 100.0 0.0 0:13.29 kswapd6
3332 root 20 0 0 0 0 R 100.0 0.0 0:11.11 kswapd10
3339 root 20 0 0 0 0 R 100.0 0.0 0:16.25 kswapd17
3348 root 20 0 0 0 0 R 100.0 0.0 0:16.40 kswapd26
3343 root 20 0 0 0 0 R 100.0 0.0 0:16.30 kswapd21
3344 root 20 0 0 0 0 R 100.0 0.0 0:11.92 kswapd22
3349 root 20 0 0 0 0 R 100.0 0.0 0:16.28 kswapd27
3352 root 20 0 0 0 0 R 99.7 0.0 0:11.89 kswapd30
3353 root 20 0 0 0 0 R 96.7 0.0 0:16.04 kswapd31
3329 root 20 0 0 0 0 R 96.4 0.0 0:11.41 kswapd7
3345 root 20 0 0 0 0 R 96.4 0.0 0:13.40 kswapd23
3330 root 20 0 0 0 0 S 91.1 0.0 0:08.28 kswapd8
3350 root 20 0 0 0 0 S 86.8 0.0 0:11.13 kswapd28
3325 root 20 0 0 0 0 S 76.3 0.0 0:07.43 kswapd3
3341 root 20 0 0 0 0 S 74.7 0.0 0:08.85 kswapd19
3334 root 20 0 0 0 0 S 71.7 0.0 0:10.04 kswapd12
3351 root 20 0 0 0 0 R 60.5 0.0 0:09.59 kswapd29
3323 root 20 0 0 0 0 R 57.6 0.0 0:11.50 kswapd1
[...]
which is just showing a partial list of the 32 kswapd threads that are
running mostly full tilt, burning ~28 full CPU cores.
If the same test case is run with RWF_DONTCACHE set for the buffered read,
the output looks as follows:
Reading bs 65536, uncached 0
1s: 153144MB/sec
2s: 156760MB/sec
3s: 158110MB/sec
4s: 158009MB/sec
5s: 158043MB/sec
6s: 157638MB/sec
7s: 157999MB/sec
8s: 158024MB/sec
9s: 157764MB/sec
10s: 157477MB/sec
11s: 157417MB/sec
12s: 157455MB/sec
13s: 157233MB/sec
14s: 156692MB/sec
which is just chugging along at ~155GB/sec of read performance. Looking
at top, we see:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7961 root 20 0 267004 0 0 S 3180 0.0 5:37.95 uncached
8024 axboe 20 0 14292 4096 0 R 1.0 0.0 0:00.13 top
where just the test app is using CPU, no reclaim is taking place outside
of the main thread. Not only is performance 65% better, it's also using
half the CPU to do it.
Link: https://lkml.kernel.org/r/20241220154831.1086649-9-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Rather than use the page_cache_sync_readahead() helper, define our own
ractl and use page_cache_sync_ra() directly. In preparation for needing
to modify ractl inside filemap_get_pages().
No functional changes in this patch.
Link: https://lkml.kernel.org/r/20241220154831.1086649-3-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Uncached buffered IO", v8.
5 years ago I posted patches adding support for RWF_UNCACHED, as a way to
do buffered IO that isn't page cache persistent. The approach back then
was to have private pages for IO, and then get rid of them once IO was
done. But that then runs into all the issues that O_DIRECT has, in terms
of synchronizing with the page cache.
So here's a new approach to the same concent, but using the page cache as
synchronization. Due to excessive bike shedding on the naming, this is
now named RWF_DONTCACHE, and is less special in that it's just page cache
IO, except it prunes the ranges once IO is completed.
Why do this, you may ask? The tldr is that device speeds are only getting
faster, while reclaim is not. Doing normal buffered IO can be very
unpredictable, and suck up a lot of resources on the reclaim side. This
leads people to use O_DIRECT as a work-around, which has its own set of
restrictions in terms of size, offset, and length of IO. It's also
inherently synchronous, and now you need async IO as well. While the
latter isn't necessarily a big problem as we have good options available
there, it also should not be a requirement when all you want to do is read
or write some data without caching.
Even on desktop type systems, a normal NVMe device can fill the entire
page cache in seconds. On the big system I used for testing, there's a
lot more RAM, but also a lot more devices. As can be seen in some of the
results in the following patches, you can still fill RAM in seconds even
when there's 1TB of it. Hence this problem isn't solely a "big
hyperscaler system" issue, it's common across the board.
Common for both reads and writes with RWF_DONTCACHE is that they use the
page cache for IO. Reads work just like a normal buffered read would,
with the only exception being that the touched ranges will get pruned
after data has been copied. For writes, the ranges will get writeback
kicked off before the syscall returns, and then writeback completion will
prune the range. Hence writes aren't synchronous, and it's easy to
pipeline writes using RWF_DONTCACHE. Folios that aren't instantiated by
RWF_DONTCACHE IO are left untouched. This means you that uncached IO will
take advantage of the page cache for uptodate data, but not leave anything
it instantiated/created in cache.
File systems need to support this. This patchset adds support for the
generic read path, which covers file systems like ext4. Patches exist to
add support for iomap/XFS and btrfs as well, which sit on top of this
series. If RWF_DONTCACHE IO is attempted on a file system that doesn't
support it, -EOPNOTSUPP is returned. Hence the user can rely on it either
working as designed, or flagging and error if that's not the case. The
intent here is to give the application a sensible fallback path - eg, it
may fall back to O_DIRECT if appropriate, or just live with the fact that
uncached IO isn't available and do normal buffered IO.
Adding "support" to other file systems should be trivial, most of the time
just a one-liner adding FOP_DONTCACHE to the fop_flags in the
file_operations struct, if the file system is using either iomap or the
generic filemap helpers for reading and writing.
Performance results are in patch 8 for reads, and you can find the write
side results in the XFS patch adding support for DONTCACHE writes for XFS:
https://git.kernel.dk/cgit/linux/commit/?h=buffered-uncached-fs.10&id=257e92de795fdff7d7e256501e024fac6da6a7f4
with the tldr being that I see about a 65% improvement in performance for
both, with fully predictable IO times. CPU reduction is substantial as
well, with no kswapd activity at all for reclaim when using uncached IO.
Using it from applications is trivial - just set RWF_DONTCACHE for the
read or write, using pwritev2(2) or preadv2(2). For io_uring, same thing,
just set RWF_DONTCACHE in sqe->rw_flags for a buffered read/write
operation. And that's it.
Patches 1..7 are just prep patches, and should have no functional changes
at all. Patch 8 adds support for the filemap path for RWF_DONTCACHE
reads, and patches 9..12 are just prep patches for supporting the write
side of uncached writes. In the below mentioned branch, there are then
patches to adopt uncached reads and writes for xfs, btrfs, and ext4. The
latter currently relies on bit of a hack for passing whether this is an
uncached write or not through ->write_begin(), which can hopefully go away
once ext4 adopts iomap for buffered writes. I say this is a hack as it's
not the prettiest way to do it, however it is fully solid and will work
just fine.
Passes full xfstests and fsx overnight runs, no issues observed. That
includes the vm running the testing also using RWF_DONTCACHE on the host.
I'll post fsstress and fsx patches for RWF_DONTCACHE separately. As far
as I'm concerned, no further work needs doing here.
And git tree for the patches is here:
https://git.kernel.dk/cgit/linux/log/?h=buffered-uncached.10
with the file system patches on top adding support for xfs/btrfs/ext4
here:
https://git.kernel.dk/cgit/linux/log/?h=buffered-uncached-fs.10
This patch (of 12):
Rather than pass in both the file and position directly from the kiocb,
just take a struct kiocb instead. With the kiocb being passed in, skip
passing in the address_space separately as well. While doing so, move the
ki_flags checking into filemap_create_folio() as well. In preparation for
actually needing the kiocb in the function.
No functional changes in this patch.
Link: https://lkml.kernel.org/r/20241220154831.1086649-1-axboe@kernel.dk
Link: https://lkml.kernel.org/r/20241220154831.1086649-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify pre-content notification support from Jan Kara:
"This introduces a new fsnotify event (FS_PRE_ACCESS) that gets
generated before a file contents is accessed.
The event is synchronous so if there is listener for this event, the
kernel waits for reply. On success the execution continues as usual,
on failure we propagate the error to userspace. This allows userspace
to fill in file content on demand from slow storage. The context in
which the events are generated has been picked so that we don't hold
any locks and thus there's no risk of a deadlock for the userspace
handler.
The new pre-content event is available only for users with global
CAP_SYS_ADMIN capability (similarly to other parts of fanotify
functionality) and it is an administrator responsibility to make sure
the userspace event handler doesn't do stupid stuff that can DoS the
system.
Based on your feedback from the last submission, fsnotify code has
been improved and now file->f_mode encodes whether pre-content event
needs to be generated for the file so the fast path when nobody wants
pre-content event for the file just grows the additional file->f_mode
check. As a bonus this also removes the checks whether the old
FS_ACCESS event needs to be generated from the fast path. Also the
place where the event is generated during page fault has been moved so
now filemap_fault() generates the event if and only if there is no
uptodate folio in the page cache.
Also we have dropped FS_PRE_MODIFY event as current real-world users
of the pre-content functionality don't really use it so let's start
with the minimal useful feature set"
* tag 'fsnotify_hsm_for_v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (21 commits)
fanotify: Fix crash in fanotify_init(2)
fs: don't block write during exec on pre-content watched files
fs: enable pre-content events on supported file systems
ext4: add pre-content fsnotify hook for DAX faults
btrfs: disable defrag on pre-content watched files
xfs: add pre-content fsnotify hook for DAX faults
fsnotify: generate pre-content permission event on page fault
mm: don't allow huge faults for files with pre content watches
fanotify: disable readahead if we have pre-content watches
fanotify: allow to set errno in FAN_DENY permission response
fanotify: report file range info with pre-content events
fanotify: introduce FAN_PRE_ACCESS permission event
fsnotify: generate pre-content permission event on truncate
fsnotify: pass optional file access range in pre-content event
fsnotify: introduce pre-content permission events
fanotify: reserve event bit of deprecated FAN_DIR_MODIFY
fanotify: rename a misnamed constant
fanotify: don't skip extra event info if no info_mode is set
fsnotify: check if file is actually being watched for pre-content events on open
fsnotify: opt-in for permission events at file open time
...
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When the 'cachestat()' system call was added in commit cf264e1329fb
("cachestat: implement cachestat syscall"), it was meant to be a much
more convenient (and performant) version of mincore() that didn't need
mapping things into the user virtual address space in order to work.
But it ended up missing the "check for writability or ownership" fix for
mincore(), done in commit 134fca9063ad ("mm/mincore.c: make mincore()
more conservative").
This just adds equivalent logic to 'cachestat()', modified for the file
context (rather than vma).
Reported-by: Sudheendra Raghav Neela <sneela@tugraz.at>
Fixes: cf264e1329fb ("cachestat: implement cachestat syscall")
Tested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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folio_add_wait_queue() has been unused since 2021's commit 850cba069c26
("cachefiles: Delete the cachefiles driver pending rewrite")
Remove it.
Link: https://lkml.kernel.org/r/20241116151446.95555-1-linux@treblig.org
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We only need to assert that the uptodate flag is clear if we're going to
set it. This hasn't been a problem before now because we have only used
folio_end_read() when completing with an error, but it's convenient to use
it in squashfs if we discover the folio is already uptodate.
Link: https://lkml.kernel.org/r/20250110163300.3346321-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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On 32-bit kernels, folio_seek_hole_data() was inadvertently truncating a
64-bit value to 32 bits, leading to a possible infinite loop when writing
to an xfs filesystem.
Link: https://lkml.kernel.org/r/20250102190540.1356838-1-marco.nelissen@gmail.com
Fixes: 54fa39ac2e00 ("iomap: use mapping_seek_hole_data")
Signed-off-by: Marco Nelissen <marco.nelissen@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since commit 5abc1e37afa0 ("mm: list_lru: allocate list_lru_one only when
needed"), all list_lru users need to allocate the items using the new
infrastructure that provides list_lru info for slab allocation, ensuring
that the corresponding memcg list_lru is allocated before use.
For workingset shadow nodes (which are xa_node), users are converted to
use the new infrastructure by commit 9bbdc0f32409 ("xarray: use
kmem_cache_alloc_lru to allocate xa_node"). The xas->xa_lru will be set
correctly for filemap users. However, there is a missing case: xa_node
allocations caused by madvise(..., MADV_COLLAPSE).
madvise(..., MADV_COLLAPSE) will also read in the absent parts of file
map, and there will be xa_nodes allocated for the caller's memcg (assuming
it's not rootcg). However, these allocations won't trigger memcg list_lru
allocation because the proper xas info was not set.
If nothing else has allocated other xa_nodes for that memcg to trigger
list_lru creation, and memory pressure starts to evict file pages,
workingset_update_node will try to add these xa_nodes to their
corresponding memcg list_lru, and it does not exist (NULL). So they will
be added to rootcg's list_lru instead.
This shouldn't be a significant issue in practice, but it is indeed
unexpected behavior, and these xa_nodes will not be reclaimed effectively.
And may lead to incorrect counting of the list_lru->nr_items counter.
This problem wasn't exposed until recent commit 28e98022b31ef
("mm/list_lru: simplify reparenting and initial allocation") added a
sanity check: only dying memcg could have a NULL list_lru when
list_lru_{add,del} is called. This problem triggered this WARNING.
So make madvise(..., MADV_COLLAPSE) also call xas_set_lru() to pass the
list_lru which we may want to insert xa_node into later. And move
mapping_set_update to mm/internal.h, and turn into a macro to avoid
including extra headers in mm/internal.h.
Link: https://lkml.kernel.org/r/20241222122936.67501-1-ryncsn@gmail.com
Fixes: 9bbdc0f32409 ("xarray: use kmem_cache_alloc_lru to allocate xa_node")
Reported-by: syzbot+38a0cbd267eff2d286ff@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/675d01e9.050a0220.37aaf.00be.GAE@google.com/
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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FS_PRE_ACCESS will be generated on page fault depending on the faulting
method. This pre-content event is meant to be used by hierarchical storage
managers that want to fill in the file content on first read access.
Export a simple helper that file systems that have their own ->fault()
will use, and have a more complicated helper to be do fancy things in
filemap_fault.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/aa56c50ce81b1fd18d7f5d71dd2dfced5eba9687.1731684329.git.josef@toxicpanda.com
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With page faults we can trigger readahead on the file, and then
subsequent faults can find these pages and insert them into the file
without emitting an fanotify event. To avoid this case, disable
readahead if we have pre-content watches on the file. This way we are
guaranteed to get an event for every range we attempt to access on a
pre-content watched file.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/70a54e859f555e54bc7a47b32fe5aca92b085615.1731684329.git.josef@toxicpanda.com
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next_uptodate_folio()
The folio can get freed + buddy-merged + reallocated in the meantime,
resulting in us calling folio_test_locked() possibly on a tail page.
This makes const_folio_flags VM_BUG_ON_PGFLAGS() when stumbling over the
tail page.
Could this result in other issues? Doesn't look like it. False positives
and false negatives don't really matter, because this folio would get
skipped either way when detecting that they have been reallocated in the
meantime.
Fix it by performing the folio_test_locked() checked after grabbing a
reference. If this ever becomes a real problem, we could add a special
helper that racily checks if the bit is set even on tail pages ... but
let's hope that's not required so we can just handle it cleaner: work on
the folio after we hold a reference.
Do we really need the folio_test_locked() check if we are going to trylock
briefly after? Well, we can at least avoid a xas_reload().
It's a bit unclear which exact change introduced that issue. Likely, ever
since we made PG_locked obey to the PF_NO_TAIL policy it could have been
triggered in some way.
Link: https://lkml.kernel.org/r/20241129125303.4033164-1-david@redhat.com
Fixes: 48c935ad88f5 ("page-flags: define PG_locked behavior on compound pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: syzbot+9f9a7f73fb079b2387a6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/674184c9.050a0220.1cc393.0001.GAE@google.com/
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- The series "zram: optimal post-processing target selection" from
Sergey Senozhatsky improves zram's post-processing selection
algorithm. This leads to improved memory savings.
- Wei Yang has gone to town on the mapletree code, contributing several
series which clean up the implementation:
- "refine mas_mab_cp()"
- "Reduce the space to be cleared for maple_big_node"
- "maple_tree: simplify mas_push_node()"
- "Following cleanup after introduce mas_wr_store_type()"
- "refine storing null"
- The series "selftests/mm: hugetlb_fault_after_madv improvements" from
David Hildenbrand fixes this selftest for s390.
- The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
implements some rationaizations and cleanups in the page mapping
code.
- The series "mm: optimize shadow entries removal" from Shakeel Butt
optimizes the file truncation code by speeding up the handling of
shadow entries.
- The series "Remove PageKsm()" from Matthew Wilcox completes the
migration of this flag over to being a folio-based flag.
- The series "Unify hugetlb into arch_get_unmapped_area functions" from
Oscar Salvador implements a bunch of consolidations and cleanups in
the hugetlb code.
- The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
takes away the wp-fault time practice of turning a huge zero page
into small pages. Instead we replace the whole thing with a THP. More
consistent cleaner and potentiall saves a large number of pagefaults.
- The series "percpu: Add a test case and fix for clang" from Andy
Shevchenko enhances and fixes the kernel's built in percpu test code.
- The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
optimizes mremap() by avoiding doing things which we didn't need to
do.
- The series "Improve the tmpfs large folio read performance" from
Baolin Wang teaches tmpfs to copy data into userspace at the folio
size rather than as individual pages. A 20% speedup was observed.
- The series "mm/damon/vaddr: Fix issue in
damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
splitting.
- The series "memcg-v1: fully deprecate charge moving" from Shakeel
Butt removes the long-deprecated memcgv2 charge moving feature.
- The series "fix error handling in mmap_region() and refactor" from
Lorenzo Stoakes cleanup up some of the mmap() error handling and
addresses some potential performance issues.
- The series "x86/module: use large ROX pages for text allocations"
from Mike Rapoport teaches x86 to use large pages for
read-only-execute module text.
- The series "page allocation tag compression" from Suren Baghdasaryan
is followon maintenance work for the new page allocation profiling
feature.
- The series "page->index removals in mm" from Matthew Wilcox remove
most references to page->index in mm/. A slow march towards shrinking
struct page.
- The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
interface tests" from Andrew Paniakin performs maintenance work for
DAMON's self testing code.
- The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
improves zswap's batching of compression and decompression. It is a
step along the way towards using Intel IAA hardware acceleration for
this zswap operation.
- The series "kasan: migrate the last module test to kunit" from
Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
tests over to the KUnit framework.
- The series "implement lightweight guard pages" from Lorenzo Stoakes
permits userapace to place fault-generating guard pages within a
single VMA, rather than requiring that multiple VMAs be created for
this. Improved efficiencies for userspace memory allocators are
expected.
- The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
tracepoints to provide increased visibility into memcg stats flushing
activity.
- The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
fixes a zram buglet which potentially affected performance.
- The series "mm: add more kernel parameters to control mTHP" from
Maíra Canal enhances our ability to control/configuremultisize THP
from the kernel boot command line.
- The series "kasan: few improvements on kunit tests" from Sabyrzhan
Tasbolatov has a couple of fixups for the KASAN KUnit tests.
- The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
from Kairui Song optimizes list_lru memory utilization when lockdep
is enabled.
* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
mm/kfence: add a new kunit test test_use_after_free_read_nofault()
zram: fix NULL pointer in comp_algorithm_show()
memcg/hugetlb: add hugeTLB counters to memcg
vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
zram: ZRAM_DEF_COMP should depend on ZRAM
MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
Docs/mm/damon: recommend academic papers to read and/or cite
mm: define general function pXd_init()
kmemleak: iommu/iova: fix transient kmemleak false positive
mm/list_lru: simplify the list_lru walk callback function
mm/list_lru: split the lock to per-cgroup scope
mm/list_lru: simplify reparenting and initial allocation
mm/list_lru: code clean up for reparenting
mm/list_lru: don't export list_lru_add
mm/list_lru: don't pass unnecessary key parameters
kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
...
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Pull 'struct fd' class updates from Al Viro:
"The bulk of struct fd memory safety stuff
Making sure that struct fd instances are destroyed in the same scope
where they'd been created, getting rid of reassignments and passing
them by reference, converting to CLASS(fd{,_pos,_raw}).
We are getting very close to having the memory safety of that stuff
trivial to verify"
* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
deal with the last remaing boolean uses of fd_file()
css_set_fork(): switch to CLASS(fd_raw, ...)
memcg_write_event_control(): switch to CLASS(fd)
assorted variants of irqfd setup: convert to CLASS(fd)
do_pollfd(): convert to CLASS(fd)
convert do_select()
convert vfs_dedupe_file_range().
convert cifs_ioctl_copychunk()
convert media_request_get_by_fd()
convert spu_run(2)
switch spufs_calls_{get,put}() to CLASS() use
convert cachestat(2)
convert do_preadv()/do_pwritev()
fdget(), more trivial conversions
fdget(), trivial conversions
privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
o2hb_region_dev_store(): avoid goto around fdget()/fdput()
introduce "fd_pos" class, convert fdget_pos() users to it.
fdget_raw() users: switch to CLASS(fd_raw)
convert vmsplice() to CLASS(fd)
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"Features:
- Fixup and improve NLM and kNFSD file lock callbacks
Last year both GFS2 and OCFS2 had some work done to make their
locking more robust when exported over NFS. Unfortunately, part of
that work caused both NLM (for NFS v3 exports) and kNFSD (for
NFSv4.1+ exports) to no longer send lock notifications to clients
This in itself is not a huge problem because most NFS clients will
still poll the server in order to acquire a conflicted lock
It's important for NLM and kNFSD that they do not block their
kernel threads inside filesystem's file_lock implementations
because that can produce deadlocks. We used to make sure of this by
only trusting that posix_lock_file() can correctly handle blocking
lock calls asynchronously, so the lock managers would only setup
their file_lock requests for async callbacks if the filesystem did
not define its own lock() file operation
However, when GFS2 and OCFS2 grew the capability to correctly
handle blocking lock requests asynchronously, they started
signalling this behavior with EXPORT_OP_ASYNC_LOCK, and the check
for also trusting posix_lock_file() was inadvertently dropped, so
now most filesystems no longer produce lock notifications when
exported over NFS
Fix this by using an fop_flag which greatly simplifies the problem
and grooms the way for future uses by both filesystems and lock
managers alike
- Add a sysctl to delete the dentry when a file is removed instead of
making it a negative dentry
Commit 681ce8623567 ("vfs: Delete the associated dentry when
deleting a file") introduced an unconditional deletion of the
associated dentry when a file is removed. However, this led to
performance regressions in specific benchmarks, such as
ilebench.sum_operations/s, prompting a revert in commit
4a4be1ad3a6e ("Revert "vfs: Delete the associated dentry when
deleting a file""). This reintroduces the concept conditionally
through a sysctl
- Expand the statmount() system call:
* Report the filesystem subtype in a new fs_subtype field to
e.g., report fuse filesystem subtypes
* Report the superblock source in a new sb_source field
* Add a new way to return filesystem specific mount options in an
option array that returns filesystem specific mount options
separated by zero bytes and unescaped. This allows caller's to
retrieve filesystem specific mount options and immediately pass
them to e.g., fsconfig() without having to unescape or split
them
* Report security (LSM) specific mount options in a separate
security option array. We don't lump them together with
filesystem specific mount options as security mount options are
generic and most users aren't interested in them
The format is the same as for the filesystem specific mount
option array
- Support relative paths in fsconfig()'s FSCONFIG_SET_STRING command
- Optimize acl_permission_check() to avoid costly {g,u}id ownership
checks if possible
- Use smp_mb__after_spinlock() to avoid full smp_mb() in evict()
- Add synchronous wakeup support for ep_poll_callback.
Currently, epoll only uses wake_up() to wake up task. But sometimes
there are epoll users which want to use the synchronous wakeup flag
to give a hint to the scheduler, e.g., the Android binder driver.
So add a wake_up_sync() define, and use wake_up_sync() when sync is
true in ep_poll_callback()
Fixes:
- Fix kernel documentation for inode_insert5() and iget5_locked()
- Annotate racy epoll check on file->f_ep
- Make F_DUPFD_QUERY associative
- Avoid filename buffer overrun in initramfs
- Don't let statmount() return empty strings
- Add a cond_resched() to dump_user_range() to avoid hogging the CPU
- Don't query the device logical blocksize multiple times for hfsplus
- Make filemap_read() check that the offset is positive or zero
Cleanups:
- Various typo fixes
- Cleanup wbc_attach_fdatawrite_inode()
- Add __releases annotation to wbc_attach_and_unlock_inode()
- Add hugetlbfs tracepoints
- Fix various vfs kernel doc parameters
- Remove obsolete TODO comment from io_cancel()
- Convert wbc_account_cgroup_owner() to take a folio
- Fix comments for BANDWITH_INTERVAL and wb_domain_writeout_add()
- Reorder struct posix_acl to save 8 bytes
- Annotate struct posix_acl with __counted_by()
- Replace one-element array with flexible array member in freevxfs
- Use idiomatic atomic64_inc_return() in alloc_mnt_ns()"
* tag 'vfs-6.13.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
statmount: retrieve security mount options
vfs: make evict() use smp_mb__after_spinlock instead of smp_mb
statmount: add flag to retrieve unescaped options
fs: add the ability for statmount() to report the sb_source
writeback: wbc_attach_fdatawrite_inode out of line
writeback: add a __releases annoation to wbc_attach_and_unlock_inode
fs: add the ability for statmount() to report the fs_subtype
fs: don't let statmount return empty strings
fs:aio: Remove TODO comment suggesting hash or array usage in io_cancel()
hfsplus: don't query the device logical block size multiple times
freevxfs: Replace one-element array with flexible array member
fs: optimize acl_permission_check()
initramfs: avoid filename buffer overrun
fs/writeback: convert wbc_account_cgroup_owner to take a folio
acl: Annotate struct posix_acl with __counted_by()
acl: Realign struct posix_acl to save 8 bytes
epoll: Add synchronous wakeup support for ep_poll_callback
coredump: add cond_resched() to dump_user_range
mm/page-writeback.c: Fix comment of wb_domain_writeout_add()
mm/page-writeback.c: Update comment for BANDWIDTH_INTERVAL
...
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If the caller supplies an iocb->ki_pos value that is close to the
filesystem upper limit, and an iterator with a count that causes us to
overflow that limit, then filemap_read() enters an infinite loop.
This behaviour was discovered when testing xfstests generic/525 with the
"localio" optimisation for loopback NFS mounts.
Reported-by: Mike Snitzer <snitzer@kernel.org>
Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Tested-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The memcg v1's charge move feature has been deprecated. All the places
using the memcg move lock, have stopped using it as they don't need the
protection any more. Let's proceed to remove all the locking code related
to charge moving.
Link: https://lkml.kernel.org/r/20241025012304.2473312-7-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In filemap_fault_recheck_pte_none(), we just do pte_none() check, so
convert it to using pte_offset_map_ro_nolock().
Link: https://lkml.kernel.org/r/9f7cbbaa772385ced1b8931b67a8b9d246c9b82d.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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fdput() can be transposed with copy_to_user()
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
We do check that the read offset is less than the filesystem limit,
however for good measure we should also check that it is positive or
zero, and return EINVAL if that is not the case.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Link: https://lore.kernel.org/r/482ee0b8a30b62324adb9f7c551a99926f037393.1726257832.git.trond.myklebust@hammerspace.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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|
Patch series "memfd-pin huge page fixes".
Fix multiple bugs that occur when using memfd_pin_folios with hugetlb
pages and THP. The hugetlb bugs only bite when the page is not yet
faulted in when memfd_pin_folios is called. The THP bug bites when the
starting offset passed to memfd_pin_folios is not huge page aligned. See
the commit messages for details.
This patch (of 5):
memfd_pin_folios on memory backed by THP panics if the requested start
offset is not huge page aligned:
BUG: kernel NULL pointer dereference, address: 0000000000000036
RIP: 0010:filemap_get_folios_contig+0xdf/0x290
RSP: 0018:ffffc9002092fbe8 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 0000000000000002 RCX: 0000000000000002
The fault occurs here, because xas_load returns a folio with value 2:
filemap_get_folios_contig()
for (folio = xas_load(&xas); folio && xas.xa_index <= end;
folio = xas_next(&xas)) {
...
if (!folio_try_get(folio)) <-- BOOM
"2" is an xarray sibling entry. We get it because memfd_pin_folios does
not round the indices passed to filemap_get_folios_contig to huge page
boundaries for THP, so we load from the middle of a huge page range see a
sibling. (It does round for hugetlbfs, at the is_file_hugepages test).
To fix, if the folio is a sibling, then return the next index as the
starting point for the next call to filemap_get_folios_contig.
Link: https://lkml.kernel.org/r/1725373521-451395-1-git-send-email-steven.sistare@oracle.com
Link: https://lkml.kernel.org/r/1725373521-451395-2-git-send-email-steven.sistare@oracle.com
Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios")
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull 'struct fd' updates from Al Viro:
"Just the 'struct fd' layout change, with conversion to accessor
helpers"
* tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
add struct fd constructors, get rid of __to_fd()
struct fd: representation change
introduce fd_file(), convert all accessors to it.
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:
- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.
- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.
- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.
- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".
- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.
- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.
- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.
- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.
- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.
- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.
- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.
- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().
- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.
- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,
- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.
- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.
- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.
- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.
- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.
- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.
- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.
- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.
- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!
- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.
- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.
- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.
- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.
- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.
- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.
- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.
- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.
- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.
- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.
- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.
- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.
- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.
- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.
- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.
- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.
- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.
- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"
* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...
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|
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs
Pull vfs blocksize updates from Christian Brauner:
"This contains the vfs infrastructure as well as the xfs bits to enable
support for block sizes (bs) larger than page sizes (ps) plus a few
fixes to related infrastructure.
There has been efforts over the last 16 years to enable enable Large
Block Sizes (LBS), that is block sizes in filesystems where bs > page
size. Through these efforts we have learned that one of the main
blockers to supporting bs > ps in filesystems has been a way to
allocate pages that are at least the filesystem block size on the page
cache where bs > ps.
Thanks to various previous efforts it is possible to support bs > ps
in XFS with only a few changes in XFS itself. Most changes are to the
page cache to support minimum order folio support for the target block
size on the filesystem.
A motivation for Large Block Sizes today is to support high-capacity
(large amount of Terabytes) QLC SSDs where the internal Indirection
Unit (IU) are typically greater than 4k to help reduce DRAM and so in
turn cost and space. In practice this then allows different
architectures to use a base page size of 4k while still enabling
support for block sizes aligned to the larger IUs by relying on high
order folios on the page cache when needed.
It also allows to take advantage of the drive's support for atomics
larger than 4k with buffered IO support in Linux. As described this
year at LSFMM, supporting large atomics greater than 4k enables
databases to remove the need to rely on their own journaling, so they
can disable double buffered writes, which is a feature different cloud
providers are already enabling through custom storage solutions"
* tag 'vfs-6.12.blocksize' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
Documentation: iomap: fix a typo
iomap: remove the iomap_file_buffered_write_punch_delalloc return value
iomap: pass the iomap to the punch callback
iomap: pass flags to iomap_file_buffered_write_punch_delalloc
iomap: improve shared block detection in iomap_unshare_iter
iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release
docs:filesystems: fix spelling and grammar mistakes in iomap design page
filemap: fix htmldoc warning for mapping_align_index()
iomap: make zero range flush conditional on unwritten mappings
iomap: fix handling of dirty folios over unwritten extents
iomap: add a private argument for iomap_file_buffered_write
iomap: remove set_memor_ro() on zero page
xfs: enable block size larger than page size support
xfs: make the calculation generic in xfs_sb_validate_fsb_count()
xfs: expose block size in stat
xfs: use kvmalloc for xattr buffers
iomap: fix iomap_dio_zero() for fs bs > system page size
filemap: cap PTE range to be created to allowed zero fill in folio_map_range()
mm: split a folio in minimum folio order chunks
readahead: allocate folios with mapping_min_order in readahead
...
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|
Pull io_uring async discard support from Jens Axboe:
"Sitting on top of both the 6.12 block and io_uring core branches,
here's support for async discard through io_uring.
This allows applications to issue async discards, rather than rely on
the blocking sync ioctl discards we already have. The sync support is
difficult to use outside of idle/cleanup periods.
On a real (but slow) device, testing shows the following results when
compared to sync discard:
qd64 sync discard: 21K IOPS, lat avg 3 msec (max 21 msec)
qd64 async discard: 76K IOPS, lat avg 845 usec (max 2.2 msec)
qd64 sync discard: 14K IOPS, lat avg 5 msec (max 25 msec)
qd64 async discard: 56K IOPS, lat avg 1153 usec (max 3.6 msec)
and synthetic null_blk testing with the same queue depth and block
size settings as above shows:
Type Trim size IOPS Lat avg (usec) Lat Max (usec)
==============================================================
sync 4k 144K 444 20314
async 4k 1353K 47 595
sync 1M 56K 1136 21031
async 1M 94K 680 760"
* tag 'for-6.12/io_uring-discard-20240913' of git://git.kernel.dk/linux:
block: implement async io_uring discard cmd
block: introduce blk_validate_byte_range()
filemap: introduce filemap_invalidate_pages
io_uring/cmd: give inline space in request to cmds
io_uring/cmd: expose iowq to cmds
|
|
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs
Pull vfs folio updates from Christian Brauner:
"This contains work to port write_begin and write_end to rely on folios
for various filesystems.
This converts ocfs2, vboxfs, orangefs, jffs2, hostfs, fuse, f2fs,
ecryptfs, ntfs3, nilfs2, reiserfs, minixfs, qnx6, sysv, ufs, and
squashfs.
After this series lands a bunch of the filesystems in this list do not
mention struct page anymore"
* tag 'vfs-6.12.folio' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (61 commits)
Squashfs: Ensure all readahead pages have been used
Squashfs: Rewrite and update squashfs_readahead_fragment() to not use page->index
Squashfs: Update squashfs_readpage_block() to not use page->index
Squashfs: Update squashfs_readahead() to not use page->index
Squashfs: Update page_actor to not use page->index
jffs2: Use a folio in jffs2_garbage_collect_dnode()
jffs2: Convert jffs2_do_readpage_nolock to take a folio
buffer: Convert __block_write_begin() to take a folio
ocfs2: Convert ocfs2_write_zero_page to use a folio
fs: Convert aops->write_begin to take a folio
fs: Convert aops->write_end to take a folio
vboxsf: Use a folio in vboxsf_write_end()
orangefs: Convert orangefs_write_begin() to use a folio
orangefs: Convert orangefs_write_end() to use a folio
jffs2: Convert jffs2_write_begin() to use a folio
jffs2: Convert jffs2_write_end() to use a folio
hostfs: Convert hostfs_write_end() to use a folio
fuse: Convert fuse_write_begin() to use a folio
fuse: Convert fuse_write_end() to use a folio
f2fs: Convert f2fs_write_begin() to use a folio
...
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kiocb_invalidate_pages() is useful for the write path, however not
everything is backed by kiocb and we want to reuse the function for bio
based discard implementation. Extract and and reuse a new helper called
filemap_invalidate_pages(), which takes a argument indicating whether it
should be non-blocking and might return -EAGAIN.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f81374b52c92d0dce0f01a279d1eed42b54056aa.1726072086.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
The tracing of invalidation and truncation operations on large files
showed that xa_get_order() is among the top functions where kernel spends
a lot of CPUs. xa_get_order() needs to traverse the tree to reach the
right node for a given index and then extract the order of the entry.
However it seems like at many places it is being called within an already
happening tree traversal where there is no need to do another traversal.
Just use xas_get_order() at those places.
Link: https://lkml.kernel.org/r/20240906230512.124643-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In commit b6273b55d885 ("filemap: add trace events for get_pages,
map_pages, and fault"), mm_filemap_get_pages was added to trace page cache
access. However, it tracks an extra page beyond the end of the accessed
range. This patch fixes it by replacing last_index with last_index - 1.
Link: https://lkml.kernel.org/r/20240903102100.70405-1-takayas@chromium.org
Fixes: b6273b55d885 ("filemap: add trace events for get_pages, map_pages, and fault")
Signed-off-by: Takaya Saeki <takayas@chromium.org>
Cc: Junichi Uekawa <uekawa@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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There are no more callers of isolate_lru_page(), remove it.
[wangkefeng.wang@huawei.com: convert page to folio in comment and document, per Matthew]
Link: https://lkml.kernel.org/r/20240826144114.1928071-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240826065814.1336616-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Readahead support for IOCB_NOWAIT was introduced in commit 2e85abf053b9
("mm: allow read-ahead with IOCB_NOWAIT set"). However, this
implementation broke the semantics of IOCB_NOWAIT by potentially causing
it to wait on I/O during memory reclamation. This behavior was later
modified in commit efa8480a8316 ("fs: RWF_NOWAIT should imply IOCB_NOIO").
To resolve the blocking issue during memory reclamation, we can use
memalloc_noio_{save,restore} to ensure non-blocking behavior. This change
restores the original functionality, allowing preadv2(IOCB_NOWAIT) to
trigger readahead if the file content is not present in the page cache.
While this process may trigger direct memory reclamation, the
__GFP_NORETRY flag is set in the readahead GFP flags, ensuring it won't
block.
A use case for this change is when we want to trigger readahead in the
preadv2(2) syscall if the file cache is absent, but without waiting for
certain filesystem locks, like xfs_ilock. A simple example is as follows:
retry:
if (preadv2(fd, iovec, cnt, offset, RWF_NOWAIT) < 0) {
do_other_work();
goto retry;
}
Link: https://lore.gnuweeb.org/io-uring/20200624164127.GP21350@casper.infradead.org/
Link: https://lkml.kernel.org/r/20240820022639.89562-1-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
In the following patches, shmem will support the swap out of large folios,
which means the shmem mappings may contain large order swap entries, so
using xa_get_order() to get the folio order of the shmem swap entry to
update the '*start' correctly.
[hughd@google.com: use xa_get_order() to get the swap entry order]
Link: https://lkml.kernel.org/r/c336e6e4-da7f-b714-c0f1-12df715f2611@google.com
Link: https://lkml.kernel.org/r/6876d55145c1cc80e79df7884aa3a62e397b101d.1723434324.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
