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Shrikanth reported a hard lockup which he observed once. The stack trace
shows the following CID related participants:
watchdog: CPU 23 self-detected hard LOCKUP @ mm_get_cid+0xe8/0x188
NIP: mm_get_cid+0xe8/0x188
LR: mm_get_cid+0x108/0x188
mm_cid_switch_to+0x3c4/0x52c
__schedule+0x47c/0x700
schedule_idle+0x3c/0x64
do_idle+0x160/0x1b0
cpu_startup_entry+0x48/0x50
start_secondary+0x284/0x288
start_secondary_prolog+0x10/0x14
watchdog: CPU 11 self-detected hard LOCKUP @ plpar_hcall_norets_notrace+0x18/0x2c
NIP: plpar_hcall_norets_notrace+0x18/0x2c
LR: queued_spin_lock_slowpath+0xd88/0x15d0
_raw_spin_lock+0x80/0xa0
raw_spin_rq_lock_nested+0x3c/0xf8
mm_cid_fixup_cpus_to_tasks+0xc8/0x28c
sched_mm_cid_exit+0x108/0x22c
do_exit+0xf4/0x5d0
make_task_dead+0x0/0x178
system_call_exception+0x128/0x390
system_call_vectored_common+0x15c/0x2ec
The task on CPU11 is running the CID ownership mode change fixup function
and is stuck on a runqueue lock. The task on CPU23 is trying to get a CID
from the pool with the same runqueue lock held, but the pool is empty.
After decoding a similar issue in the opposite direction switching from per
task to per CPU mode the tool which models the possible scenarios failed to
come up with a similar loop hole.
This showed up only once, was not reproducible and according to tooling not
related to a overlooked scheduling scenario permutation. But the fact that
it was observed on a PowerPC system gave the right hint: PowerPC is a
weakly ordered architecture.
The transition mechanism does:
WRITE_ONCE(mm->mm_cid.transit, MM_CID_TRANSIT);
WRITE_ONCE(mm->mm_cid.percpu, new_mode);
fixup()
WRITE_ONCE(mm->mm_cid.transit, 0);
mm_cid_schedin() does:
if (!READ_ONCE(mm->mm_cid.percpu))
...
cid |= READ_ONCE(mm->mm_cid.transit);
so weakly ordered systems can observe percpu == false and transit == 0 even
if the fixup function has not yet completed. As a consequence the task will
not drop the CID when scheduling out before the fixup is completed, which
means the CID space can be exhausted and the next task scheduling in will
loop in mm_get_cid() and the fixup thread can livelock on the held runqueue
lock as above.
This could obviously be solved by using:
smp_store_release(&mm->mm_cid.percpu, true);
and
smp_load_acquire(&mm->mm_cid.percpu);
but that brings a memory barrier back into the scheduler hotpath, which was
just designed out by the CID rewrite.
That can be completely avoided by combining the per CPU mode and the
transit storage into a single mm_cid::mode member and ordering the stores
against the fixup functions to prevent the CPU from reordering them.
That makes the update of both states atomic and a concurrent read observes
always consistent state.
The price is an additional AND operation in mm_cid_schedin() to evaluate
the per CPU or the per task path, but that's in the noise even on strongly
ordered architectures as the actual load can be significantly more
expensive and the conditional branch evaluation is there anyway.
Fixes: fbd0e71dc370 ("sched/mmcid: Provide CID ownership mode fixup functions")
Closes: https://lore.kernel.org/bdfea828-4585-40e8-8835-247c6a8a76b0@linux.ibm.com
Reported-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260201192834.965217106@kernel.org
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Add support for Samsung's S2MPG11 PMIC, which is a Power Management IC
for mobile applications with buck converters, various LDOs, power
meters, NTC thermistor inputs, and additional GPIO interfaces. It
typically complements an S2MPG10 PMIC in a main/sub configuration as
the sub-PMIC.
Like S2MPG10, communication is not via I2C, but via the Samsung ACPM
firmware.
While at it, we can also switch to asynchronous probe, which helps with
probe performance, as the drivers for s2mpg10 and s2mpg11 can probe in
parallel.
Note: The firmware uses the ACPM channel ID and the Speedy channel ID
to select the PMIC address. Since these are firmware properties, they
can not be retrieved from DT, but instead are deducted from the
compatible for now.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-9-3b1f9831fffd@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>
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Bucks can reasonably be supplies for LDOs, but not the other way
around. Since rail registration is going to be ordered by 'enum
s2mpg10_regulators', it makes sense to specify bucks first, so that
during LDO registration it is more likely that the corresponding supply
is known already.
This can improve probe speed, as no unnecessary deferrals and retries
are required anymore.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-8-3b1f9831fffd@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>
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It is possible to put the KTD2801 chip in an unknown/undefined state by
changing the brightness very rapidly (for example, with a brightness
slider). When this happens, the brightness is stuck on max and cannot be
changed until the chip is power cycled.
Fix this by disabling interrupts while talking to the chip. While at it,
make expresswire_power_off() use fsleep() and also unexport some
functions meant to be internal.
Fixes: 1368d06dd2c9 ("leds: Introduce ExpressWire library")
Tested-by: Karel Balej <balejk@matfyz.cz>
Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz>
Link: https://patch.msgid.link/20251217-expresswire-fix-v2-1-4a02b10acd96@dujemihanovic.xyz
Signed-off-by: Lee Jones <lee@kernel.org>
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When a cache has high s->align value and s->object_size is not aligned
to it, each object ends up with some unused space because of alignment.
If this wasted space is big enough, we can use it to store the
slabobj_ext metadata instead of wasting it.
On my system, this happens with caches like kmem_cache, mm_struct, pid,
task_struct, sighand_cache, xfs_inode, and others.
To place the slabobj_ext metadata within each object, the existing
slab_obj_ext() logic can still be used by setting:
- slab->obj_exts = slab_address(slab) + (slabobj_ext offset)
- stride = s->size
slab_obj_ext() doesn't need know where the metadata is stored,
so this method works without adding extra overhead to slab_obj_ext().
A good example benefiting from this optimization is xfs_inode
(object_size: 992, align: 64). To measure memory savings, 2 millions of
files were created on XFS.
[ MEMCG=y, MEM_ALLOC_PROFILING=n ]
Before patch (creating ~2.64M directories on xfs):
Slab: 5175976 kB
SReclaimable: 3837524 kB
SUnreclaim: 1338452 kB
After patch (creating ~2.64M directories on xfs):
Slab: 5152912 kB
SReclaimable: 3838568 kB
SUnreclaim: 1314344 kB (-23.54 MiB)
Enjoy the memory savings!
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-10-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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To access SLUB's internal implementation details beyond cache flags in
ksize(), move __ksize(), ksize(), and slab_ksize() to mm/slub.c.
[vbabka@suse.cz: also make __ksize() static and move its kerneldoc to
ksize() ]
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-9-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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When a slab cache has a constructor, the free pointer is placed after the
object because certain fields must not be overwritten even after the
object is freed.
However, some fields that the constructor does not initialize can safely
be overwritten after free. Allow specifying the free pointer offset within
the object, reducing the overall object size when some fields can be reused
for the free pointer.
Adjust the document accordingly.
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260113061845.159790-3-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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hv_stats_page belongs in hvhdk.h, move it there.
It does not require a union to access the data for different counters,
just use a single u64 array for simplicity and to match the Windows
definitions.
While at it, correct the ARM64 value for VpRootDispatchThreadBlocked.
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Acked-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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ASPEED clock controller provides a couple of resets. Add the define of
video to allow referring to it.
Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
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Variable arrays should be defined as [], not [0], otherwise
the kernel complains:
memcpy : detected field-spanning write (size 9) of single field "param->set_program_ex.data" at drivers/platform/chrome/cros_ec_lightbar.c:603 (size 0)
Fixes: 9600b8bdbfe4 ("platform/chrome: lightbar: Add support for large sequence")
Signed-off-by: Gwendal Grignou <gwendal@google.com>
Link: https://lore.kernel.org/r/20260204034848.697033-1-gwendal@google.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
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Many USB network drivers use identical code to pass ioctl
requests on to the MII layer. Reduce code duplication by
refactoring this code into a helper function.
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev> (v1)
Reviewed-by: Andrew Lunn <andrew@lunn.ch> (v3)
Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260203013517.26170-1-enelsonmoore@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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mldsa_verify() implements ML-DSA.Verify with ctx='', so document this
more explicitly. Remove the one-liner comment above mldsa_verify()
which was somewhat misleading.
Reviewed-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20260202221552.174341-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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The added print statement from a recent fix causes the driver to fail
building when CONFIG_PM is disabled:
drivers/ufs/host/ufs-mediatek.c: In function 'ufs_mtk_resume':
drivers/ufs/host/ufs-mediatek.c:1890:40: error: 'struct dev_pm_info' has no member named 'request'
1890 | hba->dev->power.request,
It seems unlikely that the driver can work at all without CONFIG_PM, so
just add a dependency and remove the existing ifdef checks, rather than
adding another ifdef.
Fixes: 15ef3f5aa822 ("scsi: ufs: host: mediatek: Enhance recovery on resume failure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20260202095052.1232703-1-arnd@kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Just like looping through children and available children, add a scoped
helper for for_each_compatible_node() so error paths can drop
of_node_put() leading to simpler code.
Suggested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260109-of-for-each-compatible-scoped-v3-1-c22fa2c0749a@oss.qualcomm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
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Remove includes which are not referenced by either DTS files or drivers.
There's a few more which are new, so they are excluded for now.
Reviewed-by: Linus Walleij <linusw@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20251212231203.727227-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux into i2c/for-mergewindow
i2c-host for v6.20
- amd-mp2, designware, mlxbf, rtl9300, spacemit, tegra: cleanups
- designware: use a dedicated algorithm for AMD Navi
- designware: replace magic numbers with named constants
- designware: replace min_t() with min() to avoid u8 truncation
- designware: refactor core to enable mode switching
- imx-lpi2c: add runtime PM support for IRQ and clock handling
- lan9691-i2c: add new driver
- rtl9300: use OF helpers directly and avoid fwnode handling
- spacemit: add bus reset support
- units: add HZ_PER_GHZ and use it in several i2c drivers
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The verifier assigns ids to scalar registers/stack slots when they are
linked through a mov or stack spill/fill instruction. These ids are
later used to propagate newly found bounds from one register to all
registers that share the same id. The verifier also compares the ids of
these registers in current state and cached state when making pruning
decisions.
When an ID becomes singular (i.e., only a single register or stack slot
has that ID), it can no longer participate in bounds propagation. During
comparisons between current and cached states for pruning decisions,
however, such stale IDs can prevent pruning of otherwise equivalent
states.
Find and clear all singular ids before caching a state in
is_state_visited(). struct bpf_idset which is currently unused has been
repurposed for this use case.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Some platforms require panic handling to execute on a specific CPU for
crash dump to work reliably. This can be due to firmware limitations,
interrupt routing constraints, or platform-specific requirements where
only a single CPU is able to safely enter the crash kernel.
Add the panic_force_cpu= kernel command-line parameter to redirect panic
execution to a designated CPU. When the parameter is provided, the CPU
that initially triggers panic forwards the panic context to the target CPU
via IPI, which then proceeds with the normal panic and kexec flow.
The IPI delivery is implemented as a weak function
(panic_smp_redirect_cpu) so architectures with NMI support can override it
for more reliable delivery.
If the specified CPU is invalid, offline, or a panic is already in
progress on another CPU, the redirection is skipped and panic continues on
the current CPU.
[pnina.feder@mobileye.com: fix unused variable warning]
Link: https://lkml.kernel.org/r/20260126122618.2967950-1-pnina.feder@mobileye.com
Link: https://lkml.kernel.org/r/20260122102457.1154599-1-pnina.feder@mobileye.com
Signed-off-by: Pnina Feder <pnina.feder@mobileye.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a new field async_depth to request_queue and related APIs, this is
currently not used, following patches will convert elevators to use
this instead of internal async_depth.
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This value represents the number of requests for elevator tags, or drivers
tags if elevator is none. The max value for elevator tags is 2048, and
in drivers at most 16 bits is used for tag.
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When cpuset isolated partitions get updated, unbound kthreads get
indifferently affine to all non isolated CPUs, regardless of their
individual affinity preferences.
For example kswapd is a per-node kthread that prefers to be affine to
the node it refers to. Whenever an isolated partition is created,
updated or deleted, kswapd's node affinity is going to be broken if any
CPU in the related node is not isolated because kswapd will be affine
globally.
Fix this with letting the consolidated kthread managed affinity code do
the affinity update on behalf of cpuset.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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Tasks that have all their allowed CPUs offline don't want their affinity
to fallback on either nohz_full CPUs or on domain isolated CPUs. And
since nohz_full implies domain isolation, checking the latter is enough
to verify both.
Therefore exclude domain isolation from fallback task affinity.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
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It doesn't make sense to use nohz_full without also isolating the
related CPUs from the domain topology, either through the use of
isolcpus= or cpuset isolated partitions.
And now HK_TYPE_DOMAIN includes all kinds of domain isolated CPUs.
This means that HK_TYPE_DOMAIN should always be a subset of
HK_TYPE_KERNEL_NOISE (of which HK_TYPE_TICK is only an alias).
Therefore if a CPU is not HK_TYPE_DOMAIN, it shouldn't be
HK_TYPE_KERNEL_NOISE either. Testing the former is then enough.
Simplify cpu_is_isolated() accordingly.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
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The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
housekeeping cpumask. There is no usecase left interested in just
checking what is isolated by cpuset and not by the isolcpus= kernel
boot parameter.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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Until now, cpuset would propagate isolated partition changes to
workqueues so that unbound workers get properly reaffined.
Since housekeeping now centralizes, synchronize and propagates isolation
cpumask changes, perform the work from that subsystem for consolidation
and consistency purposes.
For simplification purpose, the target function is adapted to take the
new housekeeping mask instead of the isolated mask.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime. In
order to synchronize against PCI probe works and make sure that no
asynchronous probing is still pending or executing on a newly isolated
CPU, the housekeeping subsystem must flush the PCI probe works.
However the PCI probe works can't be flushed easily since they are
queued to the main per-CPU workqueue pool.
Solve this with creating a PCI probe-specific pool and provide and use
the appropriate flushing API.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: linux-pci@vger.kernel.org
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The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime.
In order to synchronize against vmstat workqueue to make sure
that no asynchronous vmstat work is still pending or executing on a
newly made isolated CPU, the housekeeping susbsystem must flush the
vmstat workqueues.
This involves flushing the whole mm_percpu_wq workqueue, shared with
LRU drain, introducing here a welcome side effect.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: linux-mm@kvack.org
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The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime. In
order to synchronize against memcg workqueue to make sure that no
asynchronous draining is still pending or executing on a newly made
isolated CPU, the housekeeping susbsystem must flush the memcg
workqueues.
However the memcg workqueues can't be flushed easily since they are
queued to the main per-CPU workqueue pool.
Solve this with creating a memcg specific pool and provide and use the
appropriate flushing API.
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
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Until now, HK_TYPE_DOMAIN used to only include boot defined isolated
CPUs passed through isolcpus= boot option. Users interested in also
knowing the runtime defined isolated CPUs through cpuset must use
different APIs: cpuset_cpu_is_isolated(), cpu_is_isolated(), etc...
There are many drawbacks to that approach:
1) Most interested subsystems want to know about all isolated CPUs, not
just those defined on boot time.
2) cpuset_cpu_is_isolated() / cpu_is_isolated() are not synchronized with
concurrent cpuset changes.
3) Further cpuset modifications are not propagated to subsystems
Solve 1) and 2) and centralize all isolated CPUs within the
HK_TYPE_DOMAIN housekeeping cpumask.
Subsystems can rely on RCU to synchronize against concurrent changes.
The propagation mentioned in 3) will be handled in further patches.
[Chen Ridong: Fix cpu_hotplug_lock deadlock and use correct static
branch API]
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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cpuset modifies partitions, including isolated, while holding the cpuset
mutex.
This means that holding the cpuset mutex is safe to synchronize against
housekeeping cpumask changes.
Provide a lockdep check to validate that.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
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cpuset modifies partitions, including isolated, while holding the cpu
hotplug lock read-held.
This means that write-holding the CPU hotplug lock is safe to
synchronize against housekeeping cpumask changes.
Provide a lockdep check to validate that.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: linux-kernel@vger.kernel.org
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HK_TYPE_DOMAIN will soon integrate not only boot defined isolcpus= CPUs
but also cpuset isolated partitions.
Housekeeping still needs a way to record what was initially passed
to isolcpus= in order to keep these CPUs isolated after a cpuset
isolated partition is modified or destroyed while containing some of
them.
Create a new HK_TYPE_DOMAIN_BOOT to keep track of those.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
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Add 2-bit tcpi_ecn_mode feild within tcp_info to indicate which ECN
mode is negotiated: ECN_MODE_DISABLED, ECN_MODE_RFC3168, ECN_MODE_ACCECN,
or ECN_MODE_PENDING. This is done by utilizing available bits from
tcpi_accecn_opt_seen (reduced from 16 bits to 2 bits) and
tcpi_accecn_fail_mode (reduced from 16 bits to 4 bits).
Also, an extra 24-bit tcpi_options2 field is identified to represent
newer options and connection features, as all 8 bits of tcpi_options
field have been used.
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Co-developed-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-14-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Detect spurious retransmission of a previously sent ACK carrying the
AccECN option after the second retransmission. Since this might be caused
by the middlebox dropping ACK with options it does not recognize, disable
the sending of the AccECN option in all subsequent ACKs. This patch
follows Section 3.2.3.2.2 of AccECN spec (RFC9768), and a new field
(accecn_opt_sent_w_dsack) is added to indicate that an AccECN option was
sent with duplicate SACK info.
Also, a new AccECN option sending mode is added to tcp_ecn_option sysctl:
(TCP_ECN_OPTION_PERSIST), which ignores the AccECN fallback policy and
persistently sends AccECN option once it fits into TCP option space.
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-13-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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According to Section 3.2.2.1 of AccECN spec (RFC9768), if the Server
is in AccECN mode and in SYN-RCVD state, and if it receives a value of
zero on a pure ACK with SYN=0 and no SACK blocks, for the rest of the
connection the Server MUST NOT set ECT on outgoing packets and MUST
NOT respond to AccECN feedback. Nonetheless, as a Data Receiver it
MUST NOT disable AccECN feedback.
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-12-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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For Accurate ECN, the first SYN/ACK sent by the TCP server shall set
the ACE flag (Table 1 of RFC9768) and the AccECN option to complete the
capability negotiation. However, if the TCP server needs to retransmit
such a SYN/ACK (for example, because it did not receive an ACK
acknowledging its SYN/ACK, or received a second SYN requesting AccECN
support), the TCP server retransmits the SYN/ACK without the AccECN
option. This is because the SYN/ACK may be lost due to congestion, or a
middlebox may block the AccECN option. Furthermore, if this retransmission
also times out, to expedite connection establishment, the TCP server
should retransmit the SYN/ACK with (AE,CWR,ECE) = (0,0,0) and without the
AccECN option, while maintaining AccECN feedback mode.
This complies with Section 3.2.3.2.2 of the AccECN spec RFC9768.
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-10-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Before this patch, retransmitted SYN/ACK did not have a specific
synack_type; however, the upcoming patch needs to distinguish between
retransmitted and non-retransmitted SYN/ACK for AccECN negotiation to
transmit the fallback SYN/ACK during AccECN negotiation. Therefore, this
patch introduces a new synack_type (TCP_SYNACK_RETRANS).
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-9-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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According to Sections 3.1.2 and 3.1.3 of AccECN spec (RFC9768).
In Section 3.1.2, it says an AccECN implementation has no need to
recognize or support the Server response labelled 'Nonce' or ECN-nonce
feedback more generally, as RFC 3540 has been reclassified as Historic.
AccECN is compatible with alternative ECN feedback integrity approaches
to the nonce. The SYN/ACK labelled 'Nonce' with (AE,CWR,ECE) = (1,0,1)
is reserved for future use. A TCP Client (A) that receives such a SYN/ACK
follows the procedure for forward compatibility given in Section 3.1.3.
Then in Section 3.1.3, it says if a TCP Client has sent a SYN requesting
AccECN feedback with (AE,CWR,ECE) = (1,1,1) then receives a SYN/ACK with
the currently reserved combination (AE,CWR,ECE) = (1,0,1) but it does not
have logic specific to such a combination, the Client MUST enable AccECN
mode as if the SYN/ACK onfirmed that the Server supported AccECN and as
if it fed back that the IP-ECN field on the SYN had arrived unchanged.
Fixes: 3cae34274c79 ("tcp: accecn: AccECN negotiation").
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-7-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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When AccECN is not successfully negociated for a TCP flow, it defaults
fallback to classic ECN (RFC3168). However, L4S service will fallback
to non-ECN.
This patch enables congestion control module to control whether it
should not fallback to classic ECN after unsuccessful AccECN negotiation.
A new CA module flag (TCP_CONG_NO_FALLBACK_RFC3168) identifies this
behavior expected by the CA.
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-6-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Two flags for congestion control (CC) module are added in this patch
related to AccECN negotiation. First, a new flag (TCP_CONG_NEEDS_ACCECN)
defines that the CC expects to negotiate AccECN functionality using the
ECE, CWR and AE flags in the TCP header.
Second, during ECN negotiation, ECT(0) in the IP header is used. This
patch enables CC to control whether ECT(0) or ECT(1) should be used on
a per-segment basis. A new flag (TCP_CONG_ECT_1_NEGOTIATION) defines the
expected ECT value in the IP header by the CA when not-yet initialized
for the connection.
The detailed AccECN negotiaotn can be found in IETF RFC9768.
Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com>
Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com>
Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-5-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Add newly acked pkts EWMA. When ACK thinning occurs, select
between safer and unsafe cep delta in AccECN processing based
on it. If the packets ACKed per ACK tends to be large, don't
conservatively assume ACE field overflow.
This patch uses the existing 2-byte holes in the rx group for new
u16 variables withtout creating more holes. Below are the pahole
outcomes before and after this patch:
[BEFORE THIS PATCH]
struct tcp_sock {
[...]
u32 delivered_ecn_bytes[3]; /* 2744 12 */
/* XXX 4 bytes hole, try to pack */
[...]
__cacheline_group_end__tcp_sock_write_rx[0]; /* 2816 0 */
[...]
/* size: 3264, cachelines: 51, members: 177 */
}
[AFTER THIS PATCH]
struct tcp_sock {
[...]
u32 delivered_ecn_bytes[3]; /* 2744 12 */
u16 pkts_acked_ewma; /* 2756 2 */
/* XXX 2 bytes hole, try to pack */
[...]
__cacheline_group_end__tcp_sock_write_rx[0]; /* 2816 0 */
[...]
/* size: 3264, cachelines: 51, members: 178 */
}
Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260131222515.8485-2-chia-yu.chang@nokia-bell-labs.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Last user dsa_loop has been migrated away from modalias-based matching,
so we can remove this feature now. It was the only user of MDIO_NAME_SIZE,
so remove also this constant.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://patch.msgid.link/ce1c6df0-4785-4b28-8322-32dc6bceea18@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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The struct revocable handle stores the SRCU read-side index (idx) for
the duration of a resource access. If multiple threads share the same
struct revocable instance, they race on writing to the idx field,
corrupting the SRCU state and potentially causing unsafe unlocks.
Refactor the API to replace revocable_alloc()/revocable_free() with
revocable_init()/revocable_deinit(). This change requires the caller
to provide the storage for struct revocable.
By moving storage ownership to the caller, the API ensures that
concurrent users maintain their own private idx storage, eliminating
the race condition.
Reported-by: Johan Hovold <johan@kernel.org>
Closes: https://lore.kernel.org/all/20260124170535.11756-4-johan@kernel.org/
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://patch.msgid.link/20260129143733.45618-4-tzungbi@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are two race conditions when allocating a revocable instance:
1. After a struct revocable_provider is revoked, the caller might still
hold a dangling pointer to it. A subsequent call to
revocable_alloc() can trigger a use-after-free.
2. If revocable_provider_release() runs concurrently with
revocable_alloc(), the memory of struct revocable_provider can be
accessed during or after kfree().
To fix these:
- Manage the lifetime of struct revocable_provider using RCU. Annotate
pointers to it with __rcu and use kfree_rcu() for deallocation.
- Update revocable_alloc() to safely acquire a reference using RCU
primitives.
- Update revocable_provider_revoke() to take a double pointer (`**rp`).
It atomically NULLs out the caller's pointer before starting
revocation. This prevents the caller from holding a dangling pointer.
- Drop devm_revocable_provider_alloc(). The devm-managed model cannot
support the required double-pointer semantic for safe pointer nulling.
Reported-by: Johan Hovold <johan@kernel.org>
Closes: https://lore.kernel.org/all/aXdy-b3GOJkzGqYo@hovoldconsulting.com/
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://patch.msgid.link/20260129143733.45618-2-tzungbi@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Update to avoid conflicts with /urgent patches.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
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If we encounter a filesystem with the remap-tree incompat flag set,
validate its compatibility with the other flags, and load the remap tree
using the values that have been added to the superblock.
The remap-tree feature depends on the free-space-tree, but no-holes and
block-group-tree have been made dependencies to reduce the testing
matrix. Similarly I'm not aware of any reason why mixed-bg and zoned would be
incompatible with remap-tree, but this is blocked for the time being
until it can be fully tested.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add a struct btrfs_block_group_item_v2, which is used in the block group
tree if the remap-tree incompat flag is set.
This adds two new fields to the block group item: `remap_bytes` and
`identity_remap_count`.
`remap_bytes` records the amount of data that's physically within this
block group, but nominally in another, remapped block group. This is
necessary because this data will need to be moved first if this block
group is itself relocated. If `remap_bytes` > 0, this is an indicator to
the relocation thread that it will need to search the remap-tree for
backrefs. A block group must also have `remap_bytes` == 0 before it can
be dropped.
`identity_remap_count` records how many identity remap items are located
in the remap tree for this block group. When relocation is begun for
this block group, this is set to the number of holes in the free-space
tree for this range. As identity remaps are converted into actual remaps
by the relocation process, this number is decreased. Once it reaches 0,
either because of relocation or because extents have been deleted, the
block group has been fully remapped and its chunk's device extents are
removed.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add a new METADATA_REMAP chunk type, which is a metadata chunk that holds the
remap tree.
This is needed for bootstrapping purposes: the remap tree can't itself
be remapped, and must be relocated the existing way, by COWing every
leaf. The remap tree can't go in the SYSTEM chunk as space there is
limited, because a copy of the chunk item gets placed in the superblock.
The changes in fs/btrfs/volumes.h are because we're adding a new block
group type bit after the profile bits, and so can no longer rely on the
const_ilog2 trick.
The sizing to 32MB per chunk, matching the SYSTEM chunk, is an estimate
here, we can adjust it later if it proves to be too big or too small.
This works out to be ~500,000 remap items, which for a 4KB block size
covers ~2GB of remapped data in the worst case and ~500TB in the best case.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add an incompat flag for the new remap-tree feature, and the constants
and definitions needed to support it.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Make sure sub-command of lightbar command starts with a 8bit
parameter to ensure alignment.
Fixes: 9600b8bdbfe4 ("platform/chrome: lightbar: Add support for large sequence")
Signed-off-by: Gwendal Grignou <gwendal@google.com>
Link: https://lore.kernel.org/r/20260202100621.3608437-1-gwendal@google.com
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
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