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This was arbitrarily left in mmap.c it makes no sense being there, move it
to vma.c to render it testable.
Link: https://lkml.kernel.org/r/5e5e81807c54dfbe363edb2d431eb3d7a37fcdba.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We build on previous work making expand_downwards() an entirely internal
function.
This logic is subtle and so it is highly useful to get it into vma.c so we
can then userland unit test.
We must additionally move acct_stack_growth() to vma.c as it is a helper
function used by both expand_downwards() and expand_upwards().
We are also then able to mark anon_vma_interval_tree_pre_update_vma() and
anon_vma_interval_tree_post_update_vma() static as these are no longer
used by anything else.
Link: https://lkml.kernel.org/r/0feb104eff85922019d4fb29280f3afb130c5204.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Right now fs/exec.c invokes expand_downwards(), an otherwise internal
implementation detail of the VMA logic in order to ensure that an arg page
can be obtained by get_user_pages_remote().
In order to be able to move the stack expansion logic into mm/vma.c to
make it available to userland testing we need to find an alternative
approach here.
We do so by providing the mmap_read_lock_maybe_expand() function which
also helpfully documents what get_arg_page() is doing here and adds an
additional check against VM_GROWSDOWN to make explicit that the stack
expansion logic is only invoked when the VMA is indeed a downward-growing
stack.
This allows expand_downwards() to become a static function.
Importantly, the VMA referenced by mmap_read_maybe_expand() must NOT be
currently user-visible in any way, that is place within an rmap or VMA
tree. It must be a newly allocated VMA.
This is the case when exec invokes this function.
Link: https://lkml.kernel.org/r/5295d1c70c58e6aa63d14be68d4e1de9fa1c8e6d.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We want to be able to unit test the unmapped area logic, so move it to
mm/vma.c. The wrappers which invoke this remain in place in mm/mmap.c.
In addition, naturally, update the existing test code to enable this to be
compiled in userland.
Link: https://lkml.kernel.org/r/53a57a52a64ea54e9d129d2e2abca3a538022379.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/vma: make more mmap logic userland testable".
This series carries on the work started in previous series and
continued in commit 52956b0d7fb9 ("mm: isolate mmap internal logic to
mm/vma.c"), moving the remainder of memory mapping implementation
details logic into mm/vma.c allowing the bulk of the mapping logic to
be unit tested.
It is highly useful to do so, as this means we can both fundamentally test
this core logic, and introduce regression tests to ensure any issues
previously resolved do not recur.
Vitally, this includes the do_brk_flags() function, meaning we have both
core means of userland mapping memory now testable.
Performance testing was performed after this change given the brk() system
call's sensitivity to change, and no performance regression was observed.
The stack expansion logic is also moved into mm/vma.c, which necessitates
a change in the API exposed to the exec code, removing the invocation of
the expand_downwards() function used in get_arg_page() and instead adding
mmap_read_lock_maybe_expand() to wrap this.
This patch (of 5):
Now we have moved mmap_region() internals to mm/vma.c, making it available
to userland testing, it makes sense to do the same with brk().
This continues the pattern of VMA heavy lifting being done in mm/vma.c in
an environment where it can be subject to straightforward unit and
regression testing, with other VMA-adjacent files becoming wrappers around
this functionality.
[lorenzo.stoakes@oracle.com: add missing personality header import]
Link: https://lkml.kernel.org/r/2a717265-985f-45eb-9257-8b2857088ed4@lucifer.local
Link: https://lkml.kernel.org/r/cover.1733248985.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/3d24b9e67bb0261539ca921d1188a10a1b4d4357.1733248985.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[akpm@linux-foundation.org: tweak grammar, fit to 80 cols]
Link: https://lkml.kernel.org/r/20240920122030.159751-1-gxxa03070307@gmail.com
Signed-off-by: gaoxiang17 <gaoxiang17@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Yes, when making the global variables kasan_ptr_result and
kasan_int_result as static volatile, the warnings are removed and the
variable and assignments are retained, but when just static is used I
understand that it might be optimized.
Add a fix making the global varaibles - static volatile, removing the
warnings:
mm/kasan/kasan_test.c:36:6: warning: symbol 'kasan_ptr_result' was not declared. Should it be static?
mm/kasan/kasan_test.c:37:5: warning: symbol 'kasan_int_result' was not declared. Should it be static?
Link: https://lkml.kernel.org/r/20241011114537.35664-1-niharchaithanya@gmail.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312261010.o0lRiI9b-lkp@intel.com/
Signed-off-by: Nihar Chaithanya <niharchaithanya@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Because swap_cgroup map is now virtually contiguous, swap_cgroup_record()
can be simplified, which eliminates a need to use __lookup_swap_cgroup().
Now as __lookup_swap_cgroup() is really trivial and is used only once, it
can be inlined.
Link: https://lkml.kernel.org/r/20241115190229.676440-2-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently swap_cgroup's map is constructed as a vmalloc()'s-based array of
pointers to individual struct pages. This brings an unnecessary
complexity into the code.
This patch turns the swap_cgroup's map into a single space
allocated by vcalloc().
[akpm@linux-foundation.org: s/vfree/kvfree/, per Shakeel]
Link: https://lkml.kernel.org/r/20241115190229.676440-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove the else block since there is already a break in the statement of
if (iter->oom_lock), just set iter->oom_lock true after the if block ends.
Link: https://lkml.kernel.org/r/20241115235744.1419580-4-kerensun@google.com
Signed-off-by: Keren Sun <kerensun@google.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove whitespaces before newlines for strings in pr_warn_once()
Link: https://lkml.kernel.org/r/20241115235744.1419580-3-kerensun@google.com
Signed-off-by: Keren Sun <kerensun@google.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: fix format issues and param types"
Change the param 'mode' from type 'unsigned' to 'unsigned int' in
memcg_event_wake() and memcg_oom_wake_function(), and for the param 'nid'
in VM_BUG_ON().
Link: https://lkml.kernel.org/r/20241115235744.1419580-2-kerensun@google.com
Signed-off-by: Keren Sun <kerensun@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@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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Verify that the test variable holds the initialization value, rather than
any non-zero value.
Link: https://lkml.kernel.org/r/386ffda192eb4a26f68c526c496afd48a5cd87ce.1732016064.git.ptesarik@suse.com
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Cc: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Fix mm/rodata_test", v2.
Make sure that the test actually reads the read-only memory location.
Verify that the variable contains the expected value rather than any
non-zero value.
This patch (of 2):
The C compiler may optimize away the memory read of a const variable if
its value is known at compile time.
In particular, GCC14 with -O2 generates no code at all for test 1, and it
generates the following x86_64 instructions for test 3:
cmpl $195, 4(%rsp)
je .L14
That is, it replaces the read of rodata_test_data with an immediate value
and compares it to the value of the local variable "zero".
Use READ_ONCE() to undo any such compiler optimizations and enforce a
memory read.
Link: https://lkml.kernel.org/r/cover.1732016064.git.ptesarik@suse.com
Link: https://lkml.kernel.org/r/2a66dee010151b25cb143efb39091ef7530aa00a.1732016064.git.ptesarik@suse.com
Fixes: 2959a5f726f6 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Cc: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now the tmpfs can allow to allocate any sized large folios, and the default
huge policy is still preferred to be 'never'. Due to tmpfs not behaving like
other file systems in some cases as previously explained by David[1]:
: I think I raised this in the past, but tmpfs/shmem is just like any
: other file system .. except it sometimes really isn't and behaves much
: more like (swappable) anonymous memory. (or mlocked files)
:
: There are many systems out there that run without swap enabled, or with
: extremely minimal swap (IIRC until recently kubernetes was completely
: incompatible with swapping). Swap can even be disabled today for shmem
: using a mount option.
:
: That's a big difference to all other file systems where you are
: guaranteed to have backend storage where you can simply evict under
: memory pressure (might temporarily fail, of course).
:
: I *think* that's the reason why we have the "huge=" parameter that also
: controls the THP allocations during page faults (IOW possible memory
: over-allocation). Maybe also because it was a new feature, and we only
: had a single THP size.
Thus adding a new command line to change the default huge policy will be
helpful to use the large folios for tmpfs, which is similar to the
'transparent_hugepage_shmem' cmdline for shmem.
[1] https://lore.kernel.org/all/cbadd5fe-69d5-4c21-8eb8-3344ed36c721@redhat.com/
Link: https://lkml.kernel.org/r/ff390b2656f0d39649547f8f2cbb30fcb7e7be2d.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add large folio support for tmpfs write and fallocate paths matching the
same high order preference mechanism used in the iomap buffered IO path as
used in __filemap_get_folio().
Add shmem_mapping_size_orders() to get a hint for the orders of the folio
based on the file size which takes care of the mapping requirements.
Traditionally, tmpfs only supported PMD-sized large folios. However
nowadays with other file systems supporting any sized large folios, and
extending anonymous to support mTHP, we should not restrict tmpfs to
allocating only PMD-sized large folios, making it more special. Instead,
we should allow tmpfs can allocate any sized large folios.
Considering that tmpfs already has the 'huge=' option to control the
PMD-sized large folios allocation, we can extend the 'huge=' option to
allow any sized large folios. The semantics of the 'huge=' mount option
are:
huge=never: no any sized large folios
huge=always: any sized large folios
huge=within_size: like 'always' but respect the i_size
huge=advise: like 'always' if requested with madvise()
Note: for tmpfs mmap() faults, due to the lack of a write size hint, still
allocate the PMD-sized huge folios if huge=always/within_size/advise is
set.
Moreover, the 'deny' and 'force' testing options controlled by
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', still retain the same
semantics. The 'deny' can disable any sized large folios for tmpfs, while
the 'force' can enable PMD sized large folios for tmpfs.
Link: https://lkml.kernel.org/r/035bf55fbdebeff65f5cb2cdb9907b7d632c3228.1732779148.git.baolin.wang@linux.alibaba.com
Co-developed-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Change the shmem_huge_global_enabled() to return the suitable huge order
bitmap, and return 0 if huge pages are not allowed. This is a preparation
for supporting various huge orders allocation of tmpfs in the following
patches.
No functional changes.
Link: https://lkml.kernel.org/r/9dce1cfad3e9c1587cf1a0ea782ddbebd0e92984.1732779148.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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kasan_record_aux_stack_noalloc() was introduced to record a stack trace
without allocating memory in the process. It has been added to callers
which were invoked while a raw_spinlock_t was held. More and more callers
were identified and changed over time. Is it a good thing to have this
while functions try their best to do a locklessly setup? The only
downside of having kasan_record_aux_stack() not allocate any memory is
that we end up without a stacktrace if stackdepot runs out of memory and
at the same stacktrace was not recorded before To quote Marco Elver from
https://lore.kernel.org/all/CANpmjNPmQYJ7pv1N3cuU8cP18u7PP_uoZD8YxwZd4jtbof9nVQ@mail.gmail.com/
| I'd be in favor, it simplifies things. And stack depot should be
| able to replenish its pool sufficiently in the "non-aux" cases
| i.e. regular allocations. Worst case we fail to record some
| aux stacks, but I think that's only really bad if there's a bug
| around one of these allocations. In general the probabilities
| of this being a regression are extremely small [...]
Make the kasan_record_aux_stack_noalloc() behaviour default as
kasan_record_aux_stack().
[bigeasy@linutronix.de: dressed the diff as patch]
Link: https://lkml.kernel.org/r/20241122155451.Mb2pmeyJ@linutronix.de
Fixes: 7cb3007ce2da ("kasan: generic: introduce kasan_record_aux_stack_noalloc()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: syzbot+39f85d612b7c20d8db48@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67275485.050a0220.3c8d68.0a37.GAE@google.com
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: syzkaller-bugs@googlegroups.com
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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s/equivalend/equivalent/
Link: https://lkml.kernel.org/r/20241120105041.2394283-1-yikming2222@gmail.com
Signed-off-by: Chin Yik Ming <yikming2222@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Prefer 'unsigned int' over plain 'unsigned'. Also make it
consistent with mm/cma.c
Link: https://lkml.kernel.org/r/tencent_1E5E3AA25C261196D8C1F7097F130E382008@qq.com
Signed-off-by: Jiale Yang <295107659@qq.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The return statement at the end of void function is unnecessary. Just
remove it as part of cleanup.
Link: https://lkml.kernel.org/r/20241122173558.20670-1-quic_pintu@quicinc.com
Signed-off-by: Pintu Kumar <quic_pintu@quicinc.com>
Cc: Pintu Agarwal <pintu.ping@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We are starting to deploy mmap_lock tracepoint monitoring across our
fleet and the early results showed that these tracepoints are consuming
significant amount of CPUs in kernfs_path_from_node when enabled.
It seems like the kernel is trying to resolve the cgroup path in the
fast path of the locking code path when the tracepoints are enabled. In
addition for some application their metrics are regressing when
monitoring is enabled.
The cgroup path resolution can be slow and should not be done in the
fast path. Most userspace tools, like bpftrace, provides functionality
to get the cgroup path from cgroup id, so let's just trace the cgroup
id and the users can use better tools to get the path in the slow path.
Link: https://lkml.kernel.org/r/20241125171617.113892-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
damos_set_effective_quota() checks quota contidions but there are some
duplicate checks for quota->goals inside.
This patch reduces one of if statement to simplify the esz calculation
logic by setting esz as ULONG_MAX by default.
Link: https://lkml.kernel.org/r/20241125184307.41746-1-sj@kernel.org
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Since slab does not use the page refcount, it can allocate and free frozen
pages, saving one atomic operation per free.
Link: https://lkml.kernel.org/r/20241125210149.2976098-16-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Provide an interface to allocate pages from the page allocator without
incrementing their refcount. This saves an atomic operation on free,
which may be beneficial to some users (eg slab).
Link: https://lkml.kernel.org/r/20241125210149.2976098-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Defer the initialisation of the page refcount to the new __alloc_pages()
wrapper and turn the old __alloc_pages() into __alloc_frozen_pages().
Link: https://lkml.kernel.org/r/20241125210149.2976098-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove some code duplication by calling set_page_refcounted() at the end
of __alloc_pages() instead of after each call that can allocate a page.
That means that we free a frozen page if we've exceeded the allowed memcg
memory.
Link: https://lkml.kernel.org/r/20241125210149.2976098-13-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for allocating frozen pages, stop initialising the page
refcount in __alloc_pages_slowpath().
Link: https://lkml.kernel.org/r/20241125210149.2976098-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
__alloc_pages_direct_reclaim()
In preparation for allocating frozen pages, stop initialising the page
refcount in __alloc_pages_direct_reclaim().
Link: https://lkml.kernel.org/r/20241125210149.2976098-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
__alloc_pages_direct_compact()
In preparation for allocating frozen pages, stop initialising the page
refcount in __alloc_pages_direct_compact().
Link: https://lkml.kernel.org/r/20241125210149.2976098-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for allocating frozen pages, stop initialising the page
refcount in __alloc_pages_may_oom().
Link: https://lkml.kernel.org/r/20241125210149.2976098-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
__alloc_pages_cpuset_fallback()
In preparation for allocating frozen pages, stop initialising the page
refcount in __alloc_pages_cpuset_fallback().
Link: https://lkml.kernel.org/r/20241125210149.2976098-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for allocating frozen pages, stop initialising the page
refcount in get_page_from_freelist().
Link: https://lkml.kernel.org/r/20241125210149.2976098-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for allocating frozen pages, stop initialising the page
refcount in prep_new_page().
Link: https://lkml.kernel.org/r/20241125210149.2976098-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In preparation for allocating frozen pages, stop initialising the page
refcount in post_alloc_hook().
Link: https://lkml.kernel.org/r/20241125210149.2976098-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We already have the concept of "frozen pages" (eg page_ref_freeze()), so
let's not complicate things by also having the concept of "unref pages".
Link: https://lkml.kernel.org/r/20241125210149.2976098-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers outside mempolicy.c now use folio_alloc_mpol() thanks to
Kefeng's cleanups, so we can remove this as a visible symbol.
And also remove the alloc_hooks for alloc_pages_mpol(), since all users
in mempolicy.c are using the nonprof version.
Link: https://lkml.kernel.org/r/20241125210149.2976098-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Allocate and free frozen pages", v3.
Slab does not need to use the page refcount at all, and it can avoid an
atomic operation on page free. Hugetlb wants to delay setting the
refcount until it has assembled a complete gigantic page. We already have
the ability to freeze a page (safely reduce its reference count to 0), so
this patchset adds APIs to allocate and free pages which are in a frozen
state.
This patchset is also a step towards the Glorious Future in which struct
page doesn't have a refcount; the users which need a refcount will have
one in their per-allocation memdesc.
This patch (of 15):
Save 17 bytes of text by calculating page_zone() once instead of twice.
Link: https://lkml.kernel.org/r/20241125210149.2976098-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20241125210149.2976098-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit ee86814b0562 ("mm/migrate: move NUMA hinting fault folio isolation
+ checks under PTL") removed the code that had used the vma argument in
migrate_misplaced_folio.
Since the vma argument was no longer used in migrate_misplaced_folio, this
patch removes it.
Link: https://lkml.kernel.org/r/20241126155655.466186-1-donettom@linux.ibm.com
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This function has been able to return LRU_STOP since commit b49547ade38a
("mm/zswap: stop lru list shrinking when encounter warm region"). To
reduce confusion, update the comment to also list LRU_STOP as an option.
Link: https://lkml.kernel.org/r/20241127-lru-stop-comment-v1-1-f54a7cba9429@google.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use corrected function parameter names to eliminate kernel-doc
warnings:
slab.h:142: warning: Function parameter or struct member 's' not described in 'slab_folio'
slab.h:142: warning: Excess function parameter 'slab' description in 'slab_folio'
slab.h:168: warning: Function parameter or struct member 's' not described in 'slab_page'
slab.h:168: warning: Excess function parameter 'slab' description in 'slab_page'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
|
|
Commit b35108a51cf7 ("jiffies: Define secs_to_jiffies()") introduced
secs_to_jiffies(). As the value here is a multiple of 1000, use
secs_to_jiffies() instead of msecs_to_jiffies to avoid the multiplication.
This is converted using scripts/coccinelle/misc/secs_to_jiffies.cocci with
the following Coccinelle rules:
@@ constant C; @@
- msecs_to_jiffies(C * 1000)
+ secs_to_jiffies(C)
@@ constant C; @@
- msecs_to_jiffies(C * MSEC_PER_SEC)
+ secs_to_jiffies(C)
Link: https://lkml.kernel.org/r/20241210-converge-secs-to-jiffies-v3-6-ddfefd7e9f2a@linux.microsoft.com
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Daniel Mack <daniel@zonque.org>
Cc: David Airlie <airlied@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dick Kennedy <dick.kennedy@broadcom.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: James Smart <james.smart@broadcom.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Jeff Johnson <jjohnson@kernel.org>
Cc: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jeroen de Borst <jeroendb@google.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Louis Peens <louis.peens@corigine.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Nicolas Palix <nicolas.palix@imag.fr>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Ofir Bitton <obitton@habana.ai>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Praveen Kaligineedi <pkaligineedi@google.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Shailend Chand <shailend@google.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Simon Horman <horms@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
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>
|
|
When MGLRU is enabled, the pgdemote_kswapd, pgdemote_direct, and
pgdemote_khugepaged stats in vmstat are not being updated.
Commit f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA
balancing operations") moved the pgdemote vmstat update from
demote_folio_list() to shrink_inactive_list(), which is in the normal LRU
path. As a result, the pgdemote stats are updated correctly for the
normal LRU but not for MGLRU.
To address this, we have added the pgdemote stat update in the
evict_folios() function, which is in the MGLRU path. With this patch, the
pgdemote stats will now be updated correctly when MGLRU is enabled.
Without this patch vmstat output when MGLRU is enabled
======================================================
pgdemote_kswapd 0
pgdemote_direct 0
pgdemote_khugepaged 0
With this patch vmstat output when MGLRU is enabled
===================================================
pgdemote_kswapd 43234
pgdemote_direct 4691
pgdemote_khugepaged 0
Link: https://lkml.kernel.org/r/20250109060540.451261-1-donettom@linux.ibm.com
Fixes: f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations")
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kaiyang Zhao <kaiyang2@cs.cmu.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The upstream commit adcfb264c3ed ("vmstat: disable vmstat_work on
vmstat_cpu_down_prep()") introduced another warning during the boot phase
so was soon reverted on upstream by commit cd6313beaeae ("Revert "vmstat:
disable vmstat_work on vmstat_cpu_down_prep()""). This commit resolves it
and reattempts the original fix.
Even after mm/vmstat:online teardown, shepherd may still queue work for
the dying cpu until the cpu is removed from online mask. While it's quite
rare, this means that after unbind_workers() unbinds a per-cpu kworker, it
potentially runs vmstat_update for the dying CPU on an irrelevant cpu
before entering atomic AP states. When CONFIG_DEBUG_PREEMPT=y, it results
in the following error with the backtrace.
BUG: using smp_processor_id() in preemptible [00000000] code: \
kworker/7:3/1702
caller is refresh_cpu_vm_stats+0x235/0x5f0
CPU: 0 UID: 0 PID: 1702 Comm: kworker/7:3 Tainted: G
Tainted: [N]=TEST
Workqueue: mm_percpu_wq vmstat_update
Call Trace:
<TASK>
dump_stack_lvl+0x8d/0xb0
check_preemption_disabled+0xce/0xe0
refresh_cpu_vm_stats+0x235/0x5f0
vmstat_update+0x17/0xa0
process_one_work+0x869/0x1aa0
worker_thread+0x5e5/0x1100
kthread+0x29e/0x380
ret_from_fork+0x2d/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
So, for mm/vmstat:online, disable vmstat_work reliably on teardown and
symmetrically enable it on startup.
For secondary CPUs during CPU hotplug scenarios, ensure the delayed work
is disabled immediately after the initialization. These CPUs are not yet
online when start_shepherd_timer() runs on boot CPU. vmstat_cpu_online()
will enable the work for them.
Link: https://lkml.kernel.org/r/20250108042807.3429745-1-koichiro.den@canonical.com
Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Tested-by: Charalampos Mitrodimas <charmitro@posteo.net>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When mremap()ing a memory region previously registered with userfaultfd as
write-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in
flag clearing leads to a mismatch between the vma flags (which have
uffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp
cleared). This mismatch causes a subsequent mprotect(PROT_WRITE) to
trigger a warning in page_table_check_pte_flags() due to setting the pte
to writable while uffd-wp is still set.
Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any
such mremap() so that the values are consistent with the existing clearing
of VM_UFFD_WP. Be careful to clear the logical flag regardless of its
physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover PTE,
huge PMD and hugetlb paths.
Link: https://lkml.kernel.org/r/20250107144755.1871363-2-ryan.roberts@arm.com
Co-developed-by: Mikołaj Lenczewski <miko.lenczewski@arm.com>
Signed-off-by: Mikołaj Lenczewski <miko.lenczewski@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Closes: https://lore.kernel.org/linux-mm/810b44a8-d2ae-4107-b665-5a42eae2d948@arm.com/
Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl")
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") when the switch to the
crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was
retrieved using get_cpu_ptr() which disables preemption and makes sure the
CPU cannot go away from under us. Preemption cannot be disabled with the
crypto_acomp API as a sleepable context is needed.
Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating
and freeing resources with compression/decompression paths. Make sure
that acomp_ctx.req is NULL when the resources are freed. In the
compression/decompression paths, check if acomp_ctx.req is NULL after
acquiring the mutex (meaning the CPU was offlined) and retry on the new
CPU.
The initialization of acomp_ctx.mutex is moved from the CPU hotplug
callback to the pool initialization where it belongs (where the mutex is
allocated). In addition to adding clarity, this makes sure that CPU
hotplug cannot reinitialize a mutex that is already locked by
compression/decompression.
Previously a fix was attempted by holding cpus_read_lock() [1]. This
would have caused a potential deadlock as it is possible for code already
holding the lock to fall into reclaim and enter zswap (causing a
deadlock). A fix was also attempted using SRCU for synchronization, but
Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug
notifiers [2].
Alternative fixes that were considered/attempted and could have worked:
- Refcounting the per-CPU acomp_ctx. This involves complexity in
handling the race between the refcount dropping to zero in
zswap_[de]compress() and the refcount being re-initialized when the
CPU is onlined.
- Disabling migration before getting the per-CPU acomp_ctx [3], but
that's discouraged and is a much bigger hammer than needed, and could
result in subtle performance issues.
[1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/
[2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/
[3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/
[yosryahmed@google.com: remove comment]
Link: https://lkml.kernel.org/r/CAJD7tkaxS1wjn+swugt8QCvQ-rVF5RZnjxwPGX17k8x9zSManA@mail.gmail.com
Link: https://lkml.kernel.org/r/20250108222441.3622031-1-yosryahmed@google.com
Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tPg6OaQ@mail.gmail.com/
Cc: Barry Song <baohua@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This reverts commit eaebeb93922ca6ab0dd92027b73d0112701706ef.
Commit eaebeb93922c ("mm: zswap: fix race between [de]compression and CPU
hotunplug") used the CPU hotplug lock in zswap compress/decompress
operations to protect against a race with CPU hotunplug making some
per-CPU resources go away.
However, zswap compress/decompress can be reached through reclaim while
the lock is held, resulting in a potential deadlock as reported by syzbot:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00006-g5428dc1906dd #0 Not tainted
------------------------------------------------------
kswapd0/89 is trying to acquire lock:
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: acomp_ctx_get_cpu mm/zswap.c:886 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_compress mm/zswap.c:908 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store_page mm/zswap.c:1439 [inline]
ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
but task is already holding lock:
ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline]
ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb58/0x2f30 mm/vmscan.c:7253
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__fs_reclaim_acquire mm/page_alloc.c:3853 [inline]
fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3867
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4070 [inline]
slab_alloc_node mm/slub.c:4148 [inline]
__kmalloc_cache_node_noprof+0x40/0x3a0 mm/slub.c:4337
kmalloc_node_noprof include/linux/slab.h:924 [inline]
alloc_worker kernel/workqueue.c:2638 [inline]
create_worker+0x11b/0x720 kernel/workqueue.c:2781
workqueue_prepare_cpu+0xe3/0x170 kernel/workqueue.c:6628
cpuhp_invoke_callback+0x48d/0x830 kernel/cpu.c:194
__cpuhp_invoke_callback_range kernel/cpu.c:965 [inline]
cpuhp_invoke_callback_range kernel/cpu.c:989 [inline]
cpuhp_up_callbacks kernel/cpu.c:1020 [inline]
_cpu_up+0x2b3/0x580 kernel/cpu.c:1690
cpu_up+0x184/0x230 kernel/cpu.c:1722
cpuhp_bringup_mask+0xdf/0x260 kernel/cpu.c:1788
cpuhp_bringup_cpus_parallel+0xf9/0x160 kernel/cpu.c:1878
bringup_nonboot_cpus+0x2b/0x50 kernel/cpu.c:1892
smp_init+0x34/0x150 kernel/smp.c:1009
kernel_init_freeable+0x417/0x5d0 init/main.c:1569
kernel_init+0x1d/0x2b0 init/main.c:1466
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
-> #0 (cpu_hotplug_lock){++++}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x42/0x150 kernel/cpu.c:490
acomp_ctx_get_cpu mm/zswap.c:886 [inline]
zswap_compress mm/zswap.c:908 [inline]
zswap_store_page mm/zswap.c:1439 [inline]
zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
swap_writepage+0x647/0xce0 mm/page_io.c:279
shmem_writepage+0x1248/0x1610 mm/shmem.c:1579
pageout mm/vmscan.c:696 [inline]
shrink_folio_list+0x35ee/0x57e0 mm/vmscan.c:1374
shrink_inactive_list mm/vmscan.c:1967 [inline]
shrink_list mm/vmscan.c:2205 [inline]
shrink_lruvec+0x16db/0x2f30 mm/vmscan.c:5734
mem_cgroup_shrink_node+0x385/0x8e0 mm/vmscan.c:6575
mem_cgroup_soft_reclaim mm/memcontrol-v1.c:312 [inline]
memcg1_soft_limit_reclaim+0x346/0x810 mm/memcontrol-v1.c:362
balance_pgdat mm/vmscan.c:6975 [inline]
kswapd+0x17b3/0x2f30 mm/vmscan.c:7253
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(cpu_hotplug_lock);
lock(fs_reclaim);
rlock(cpu_hotplug_lock);
*** DEADLOCK ***
1 lock held by kswapd0/89:
#0: ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline]
#0: ffffffff8ea355a0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb58/0x2f30 mm/vmscan.c:7253
stack backtrace:
CPU: 0 UID: 0 PID: 89 Comm: kswapd0 Not tainted 6.13.0-rc6-syzkaller-00006-g5428dc1906dd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
cpus_read_lock+0x42/0x150 kernel/cpu.c:490
acomp_ctx_get_cpu mm/zswap.c:886 [inline]
zswap_compress mm/zswap.c:908 [inline]
zswap_store_page mm/zswap.c:1439 [inline]
zswap_store+0xa74/0x1ba0 mm/zswap.c:1546
swap_writepage+0x647/0xce0 mm/page_io.c:279
shmem_writepage+0x1248/0x1610 mm/shmem.c:1579
pageout mm/vmscan.c:696 [inline]
shrink_folio_list+0x35ee/0x57e0 mm/vmscan.c:1374
shrink_inactive_list mm/vmscan.c:1967 [inline]
shrink_list mm/vmscan.c:2205 [inline]
shrink_lruvec+0x16db/0x2f30 mm/vmscan.c:5734
mem_cgroup_shrink_node+0x385/0x8e0 mm/vmscan.c:6575
mem_cgroup_soft_reclaim mm/memcontrol-v1.c:312 [inline]
memcg1_soft_limit_reclaim+0x346/0x810 mm/memcontrol-v1.c:362
balance_pgdat mm/vmscan.c:6975 [inline]
kswapd+0x17b3/0x2f30 mm/vmscan.c:7253
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Revert the change. A different fix for the race with CPU hotunplug will
follow.
Link: https://lkml.kernel.org/r/20250107222236.2715883-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sam Sun <samsun1006219@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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During testing it has been detected, that it is possible to get div by
zero error in bdi_set_min_bytes. The error is caused by the function
bdi_ratio_from_pages(). bdi_ratio_from_pages() calls global_dirty_limits.
If the dirty threshold is 0, the div by zero is raised. This can happen
if the root user is setting:
echo 0 > /proc/sys/vm/dirty_ratio
The following is a test case:
echo 0 > /proc/sys/vm/dirty_ratio
cd /sys/class/bdi/<device>
echo 1 > strict_limit
echo 8192 > min_bytes
==> error is raised.
The problem is addressed by returning -EINVAL if dirty_ratio or
dirty_bytes is set to 0.
[shr@devkernel.io: check for -EINVAL in bdi_set_min_bytes() and bdi_set_max_bytes()]
Link: https://lkml.kernel.org/r/20250108014723.166637-1-shr@devkernel.io
[shr@devkernel.io: v3]
Link: https://lkml.kernel.org/r/20250109063411.6591-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20250104012037.159386-1-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reported-by: cheung wall <zzqq0103.hey@gmail.com>
Closes: https://lore.kernel.org/linux-mm/87pll35yd0.fsf@devkernel.io/T/#t
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Qiang Zhang <zzqq0103.hey@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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