The decision to keep a timer which is associated to the local CPU on that
CPU does not take NOHZ information into account. As a result there are a
lot of hrtimer base switch invocations which end up not switching the base
and stay on the local CPU. That's just work for nothing and can be further
improved.
If the local CPU is part of the NOISE housekeeping mask, then check:
1) Whether the local CPU has the tick running, which means it is
either not idle or already expecting a timer soon.
2) Whether the tick is stopped and need_resched() is set, which
means the CPU is about to exit idle.
This reduces the amount of hrtimer base switch attempts, which end up on
the local CPU anyway, significantly and prepares for further optimizations.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.673473029@kernel.org
The decision whether to keep timers on the local CPU or on the CPU they are
associated to is suboptimal and causes the expensive switch_hrtimer_base()
mechanism to be invoked more than necessary. This is especially true for
pinned timers.
Rewrite the decision logic so that the current base is kept if:
1) The callback is running on the base
2) The timer is associated to the local CPU and the first expiring timer as
that allows to optimize for reprogramming avoidance
3) The timer is associated to the local CPU and pinned
4) The timer is associated to the local CPU and timer migration is
disabled.
Only #2 was covered by the original code, but especially #3 makes a
difference for high frequency rearming timers like the scheduler hrtick
timer. If timer migration is disabled, then #4 avoids most of the base
switches.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.607935269@kernel.org
All 'u8' flags are true booleans, so make it entirely clear that these can
only contain true or false.
This is especially true for hrtimer::state, which has a historical leftover
of using the state with bitwise operations. That was used in the early
hrtimer implementation with several bits, but then converted to a boolean
state. But that conversion missed to replace the bit OR and bit check
operations all over the place, which creates suboptimal code. As of today
'state' is a misnomer because it's only purpose is to reflect whether the
timer is enqueued into the RB-tree or not. Rename it to 'is_queued' and
make all operations on it boolean.
This reduces text size from 8926 to 8732 bytes.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.542427240@kernel.org
Use bool for the various flags as that creates better code in the hot path.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.475262618@kernel.org
As this code has some major surgery ahead, clean up coding style and bring
comments up to date.
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.342740952@kernel.org
hrtimer_start() when invoked with an already armed timer traces like:
<comm>-.. [032] d.h2. 5.002263: hrtimer_cancel: hrtimer= ....
<comm>-.. [032] d.h1. 5.002263: hrtimer_start: hrtimer= ....
Which is incorrect as the timer doesn't get canceled. Just the expiry time
changes. The internal dequeue operation which is required for that is not
really interesting for trace analysis. But it makes it tedious to keep real
cancellations and the above case apart.
Remove the cancel tracing in hrtimer_start() and add a 'was_armed'
indicator to the hrtimer start tracepoint, which clearly indicates what the
state of the hrtimer is when hrtimer_start() is invoked:
<comm>-.. [032] d.h1. 6.200103: hrtimer_start: hrtimer= .... was_armed=0
<comm>-.. [032] d.h1. 6.200558: hrtimer_start: hrtimer= .... was_armed=1
Fixes: c6a2a17702 ("hrtimer: Add tracepoint for hrtimers")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.208491877@kernel.org
The debug object coverage in hrtimer_start_range_ns() happens too late to
do anything useful. Implement the init assert assertion part and invoke
that early in hrtimer_start_range_ns().
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.143098153@kernel.org
Some clockevent devices are coupled to the system clocksource by
implementing a less than or equal comparator which compares the programmed
absolute expiry time against the underlying time counter.
The timekeeping core provides a function to convert and absolute
CLOCK_MONOTONIC based expiry time to a absolute clock cycles time which can
be directly fed into the comparator. That spares two time reads in the next
event progamming path, one to convert the absolute nanoseconds time to a
delta value and the other to convert the delta value back to a absolute
time value suitable for the comparator.
Provide a new clocksource callback which takes the absolute cycle value and
wire it up in clockevents_program_event(). Similar to clocksources allow
architectures to inline the rearm operation.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.010425428@kernel.org
Some architectures have clockevent devices which are coupled to the system
clocksource by implementing a less than or equal comparator which compares
the programmed absolute expiry time against the underlying time
counter. Well known examples are TSC/TSC deadline timer and the S390 TOD
clocksource/comparator.
While the concept is nice it has some downsides:
1) The clockevents core code is strictly based on relative expiry times
as that's the most common case for clockevent device hardware. That
requires to convert the absolute expiry time provided by the caller
(hrtimers, NOHZ code) to a relative expiry time by reading and
substracting the current time.
The clockevent::set_next_event() callback must then read the counter
again to convert the relative expiry back into a absolute one.
2) The conversion factors from nanoseconds to counter clock cycles are
set up when the clockevent is registered. When NTP applies corrections
then the clockevent conversion factors can deviate from the
clocksource conversion substantially which either results in timers
firing late or in the worst case early. The early expiry then needs to
do a reprogam with a short delta.
In most cases this is papered over by the fact that the read in the
set_next_event() callback happens after the read which is used to
calculate the delta. So the tendency is that timers expire mostly
late.
All of this can be avoided by providing support for these devices in the
core code:
1) The timekeeping core keeps track of the last update to the clocksource
by storing the base nanoseconds and the corresponding clocksource
counter value. That's used to keep the conversion math for reading the
time within 64-bit in the common case.
This information can be used to avoid both reads of the underlying
clocksource in the clockevents reprogramming path:
delta = expiry - base_ns;
cycles = base_cycles + ((delta * clockevent::mult) >> clockevent::shift);
The resulting cycles value can be directly used to program the
comparator.
2) As #1 does not longer provide the "compensation" through the second
read the deviation of the clocksource and clockevent conversions
caused by NTP become more prominent.
This can be cured by letting the timekeeping core compute and store
the reverse conversion factors when the clocksource cycles to
nanoseconds factors are modified by NTP:
CS::MULT (1 << NS_TO_CYC_SHIFT)
--------------- = ----------------------
(1 << CS:SHIFT) NS_TO_CYC_MULT
Ergo: NS_TO_CYC_MULT = (1 << (CS::SHIFT + NS_TO_CYC_SHIFT)) / CS::MULT
The NS_TO_CYC_SHIFT value is calculated when the clocksource is
installed so that it aims for a one hour maximum sleep time.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.944763521@kernel.org
On some architectures clocksource::read() boils down to a single
instruction, so the indirect function call is just a massive overhead
especially with speculative execution mitigations in effect.
Allow architectures to enable conditional inlining of that read to avoid
that by:
- providing a static branch to switch to the inlined variant
- disabling the branch before clocksource changes
- enabling the branch after a clocksource change, when the clocksource
indicates in a feature flag that it is the one which provides the
inlined variant
This is intentionally not a static call as that would only remove the
indirect call, but not the rest of the overhead.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.675151545@kernel.org
The only real usecase for this is the hrtimer based broadcast device.
No point in using two different feature flags for this.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.609049777@kernel.org
The sequence of cancel and start is inefficient. It has to do the timer
lock/unlock twice and in the worst case has to reprogram the underlying
clock event device twice.
The reason why it is done this way is the usage of hrtimer_forward_now(),
which requires the timer to be inactive.
But that can be completely avoided as the forward can be done on a variable
and does not need any of the overrun accounting provided by
hrtimer_forward_now().
Implement a trivial forwarding mechanism and replace the cancel/reprogram
sequence with hrtimer_start(..., new_expiry).
For the non high resolution case the timer is not actually armed, but used
for storage so that code checking for expiry times can unconditially look
it up in the timer. So it is safe for that case to set the new expiry time
directly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.542178086@kernel.org
The hrtick timer is frequently rearmed before expiry and most of the time
the new expiry is past the armed one. As this happens on every context
switch it becomes expensive with scheduling heavy work loads especially in
virtual machines as the "hardware" reprogamming implies a VM exit.
Add a lazy rearm mode flag which skips the reprogamming if:
1) The timer was the first expiring timer before the rearm
2) The new expiry time is farther out than the armed time
This avoids a massive amount of reprogramming operations of the hrtick
timer for the price of eventually taking the alredy armed interrupt for
nothing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.408524456@kernel.org
The scheduler evaluates this via hrtimer_is_hres_active() every time it has
to update HRTICK. This needs to follow three pointers, which is expensive.
Provide a static branch based mechanism to avoid that.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163429.136503358@kernel.org
Much like hrtimer_reprogram(), skip programming if the cpu_base is running
the hrtimer interrupt.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260224163429.069535561@kernel.org
Add .kunitconfig file to the time directory to enable easy execution of
KUnit tests.
With the .kunitconfig, developers can run the tests:
$ ./tools/testing/kunit/kunit.py run --kunitconfig kernel/time
Also, add the new .kunitconfig file to the TIMEKEEPING section in the
MAINTAINERS file.
Signed-off-by: Ryota Sakamoto <sakamo.ryota@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260223-add-time-kunitconfig-v1-1-1801eeb33ece@gmail.com
The current cpuset partition code is able to dynamically update
the sched domains of a running system and the corresponding
HK_TYPE_DOMAIN housekeeping cpumask to perform what is essentially the
"isolcpus=domain,..." boot command line feature at run time.
The housekeeping cpumask update requires flushing a number of different
workqueues which may not be safe with cpus_read_lock() held as the
workqueue flushing code may acquire cpus_read_lock() or acquiring locks
which have locking dependency with cpus_read_lock() down the chain. Below
is an example of such circular locking problem.
======================================================
WARNING: possible circular locking dependency detected
6.18.0-test+ #2 Tainted: G S
------------------------------------------------------
test_cpuset_prs/10971 is trying to acquire lock:
ffff888112ba4958 ((wq_completion)sync_wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x7a/0x180
but task is already holding lock:
ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (cpuset_mutex){+.+.}-{4:4}:
-> #3 (cpu_hotplug_lock){++++}-{0:0}:
-> #2 (rtnl_mutex){+.+.}-{4:4}:
-> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
-> #0 ((wq_completion)sync_wq){+.+.}-{0:0}:
Chain exists of:
(wq_completion)sync_wq --> cpu_hotplug_lock --> cpuset_mutex
5 locks held by test_cpuset_prs/10971:
#0: ffff88816810e440 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0xf9/0x1d0
#1: ffff8891ab620890 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x260/0x5f0
#2: ffff8890a78b83e8 (kn->active#187){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b6/0x5f0
#3: ffffffffadf32900 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_partition_write+0x77/0x130
#4: ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
Call Trace:
<TASK>
:
touch_wq_lockdep_map+0x93/0x180
__flush_workqueue+0x111/0x10b0
housekeeping_update+0x12d/0x2d0
update_parent_effective_cpumask+0x595/0x2440
update_prstate+0x89d/0xce0
cpuset_partition_write+0xc5/0x130
cgroup_file_write+0x1a5/0x680
kernfs_fop_write_iter+0x3df/0x5f0
vfs_write+0x525/0xfd0
ksys_write+0xf9/0x1d0
do_syscall_64+0x95/0x520
entry_SYSCALL_64_after_hwframe+0x76/0x7e
To avoid such a circular locking dependency problem, we have to
call housekeeping_update() without holding the cpus_read_lock() and
cpuset_mutex. The current set of wq's flushed by housekeeping_update()
may not have work functions that call cpus_read_lock() directly,
but we are likely to extend the list of wq's that are flushed in the
future. Moreover, the current set of work functions may hold locks that
may have cpu_hotplug_lock down the dependency chain.
So housekeeping_update() is now called after releasing cpus_read_lock
and cpuset_mutex at the end of a cpuset operation. These two locks are
then re-acquired later before calling rebuild_sched_domains_locked().
To enable mutual exclusion between the housekeeping_update() call and
other cpuset control file write actions, a new top level cpuset_top_mutex
is introduced. This new mutex will be acquired first to allow sharing
variables used by both code paths. However, cpuset update from CPU
hotplug can still happen in parallel with the housekeeping_update()
call, though that should be rare in production environment.
As cpus_read_lock() is now no longer held when
tmigr_isolated_exclude_cpumask() is called, it needs to acquire it
directly.
The lockdep_is_cpuset_held() is also updated to return true if either
cpuset_top_mutex or cpuset_mutex is held.
Fixes: 03ff735101 ("cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
* Removed macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it is more
verbose than the macro version, it helps when debugging and better aligns with
coding-style.rst.
* General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays. Add
missing kernel doc to proc_dointvec_conv.
* Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks of
testing
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Merge tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Remove macros from proc handler converters
Replace the proc converter macros with "regular" functions. Though it
is more verbose than the macro version, it helps when debugging and
better aligns with coding-style.rst.
- General cleanup
Remove superfluous ctl_table forward declarations. Const qualify the
memory_allocation_profiling_sysctl and loadpin_sysctl_table arrays.
Add missing kernel doc to proc_dointvec_conv.
- Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. And went into linux-next after rc4, giving it a good 3 weeks
of testing
* tag 'sysctl-7.00-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions
sysctl: Replace unidirectional INT converter macros with functions
sysctl: Add kernel doc to proc_douintvec_conv
sysctl: Replace UINT converter macros with functions
sysctl: Add CONFIG_PROC_SYSCTL guards for converter macros
sysctl: clarify proc_douintvec_minmax doc
sysctl: Return -ENOSYS from proc_douintvec_conv when CONFIG_PROC_SYSCTL=n
sysctl: Remove unused ctl_table forward declarations
loadpin: Implement custom proc_handler for enforce
alloc_tag: move memory_allocation_profiling_sysctls into .rodata
sysctl: Add missing kernel-doc for proc_dointvec_conv
For common cases (HZ=100, 250 or 1000), these helpers are at most one
multiply, so there is no point calling a tiny function.
Keep them out of line for HZ=300 and others.
This saves cycles in TCP fast path, among other things.
$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/8 grow/shrink: 25/89 up/down: 530/-3474 (-2944)
...
nla_put_msecs 193 - -193
message_stats_print 2131 920 -1211
Total: Before=25365208, After=25362264, chg -0.01%
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260210170226.57209-1-edumazet@google.com
- Inline timecounter_cyc2time() as that is now used in the networking
hotpath. Inlining it significantly improves performance.
- Optimize the tick dependency check in case that the tracepoint is disabled,
which improves the hotpath performance in the tick management code, which
is a hotpath on transitions in and out of idle.
- The usual cleanups and improvements
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Merge tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner:
- Inline timecounter_cyc2time() as that is now used in the networking
hotpath. Inlining it significantly improves performance.
- Optimize the tick dependency check in case that the tracepoint is
disabled, which improves the hotpath performance in the tick
management code, which is a hotpath on transitions in and out of
idle.
- The usual cleanups and improvements
* tag 'timers-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/kunit: Document handling of negative years of is_leap()
tick/nohz: Optimize check_tick_dependency() with early return
time/sched_clock: Use ACCESS_PRIVATE() to evaluate hrtimer::function
hrtimer: Drop _tv64() helpers
hrtimer: Remove public definition of HIGH_RES_NSEC
hrtimer: Remove unused resolution constants
time/timecounter: Inline timecounter_cyc2time()
Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes: reduce
the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number
of preemption models from four to just two: 'full' and 'lazy'
on up-to-date architectures (arm64, loongarch, powerpc,
riscv, s390, x86).
None and voluntary are only available as legacy features
on platforms that don't implement lazy preemption yet,
or which don't even support preemption.
The goal is to eventually remove cond_resched() and
voluntary preemption altogether.
(Peter Zijlstra)
RSEQ based 'scheduler time slice extension' support:
This allows a thread to request a time slice extension when it
enters a critical section to avoid contention on a resource when
the thread is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
(Thomas Gleixner)
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
(Peter Zijlstra)
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU,
which improves the scalability of various workloads.
(Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching
(Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups:
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
(Shrikanth Hegde)
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
(Yury Norov)
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and
Joel Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements, which is part of the
scheduler tree in this cycle due to interdependencies with the RSEQ
based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
(Jinjie Ruan)
Scheduler core updates:
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
(Peter Zijlstra)
Fair scheduler updates/refactoring:
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
(Peter Zijlstra)
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers
for wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
(Ingo Molnar)
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of
throttled cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing (zenghongling)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes (Peter Zijlstra)
Reduce the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number of
preemption models from four to just two: 'full' and 'lazy' on
up-to-date architectures (arm64, loongarch, powerpc, riscv, s390,
x86).
None and voluntary are only available as legacy features on
platforms that don't implement lazy preemption yet, or which don't
even support preemption.
The goal is to eventually remove cond_resched() and voluntary
preemption altogether.
RSEQ based 'scheduler time slice extension' support (Thomas Gleixner
and Peter Zijlstra):
This allows a thread to request a time slice extension when it enters
a critical section to avoid contention on a resource when the thread
is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU, which
improves the scalability of various workloads (Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching (Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups (Shrikanth Hegde):
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Cleanups (Yury Norov):
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and Joel
Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements (Jinjie Ruan)
This is part of the scheduler tree in this cycle due to inter-
dependencies with the RSEQ based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
Scheduler core updates (Peter Zijlstra):
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
Fair scheduler updates/refactoring (Peter Zijlstra and Ingo Molnar):
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers for
wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of throttled
cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing
(zenghongling)"
* tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
sched: Re-evaluate scheduling when migrating queued tasks out of throttled cgroups
sched/cpufreq: Use %pe format for PTR_ERR() printing
sched/rt: Skip currently executing CPU in rto_next_cpu()
sched/clock: Avoid false sharing for sched_clock_irqtime
selftests/sched_ext: Add test for DL server total_bw consistency
selftests/sched_ext: Add test for sched_ext dl_server
sched/debug: Fix dl_server (re)start conditions
sched/debug: Add support to change sched_ext server params
sched_ext: Add a DL server for sched_ext tasks
sched/debug: Stop and start server based on if it was active
sched/debug: Fix updating of ppos on server write ops
sched/deadline: Clear the defer params
entry: Inline syscall_exit_work() and syscall_trace_enter()
entry: Add arch_ptrace_report_syscall_entry/exit()
entry: Rework syscall_exit_to_user_mode_work() for architecture reuse
entry: Remove unused syscall argument from syscall_trace_enter()
sched: remove task_struct->faults_disabled_mapping
sched: Update rq->avg_idle when a task is moved to an idle CPU
selftests/rseq: Add rseq slice histogram script
hrtimer: Fix trace oddity
...
Lock debugging:
- Implement compiler-driven static analysis locking context
checking, using the upcoming Clang 22 compiler's context
analysis features. (Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context
tracking Sparse warnings, the overwhelming majority of which
are false positives. On an allmodconfig kernel the number of
false positive context tracking Sparse warnings grows to
over 5,200... On the plus side of the balance actual locking
bugs found by Sparse context analysis is also rather ... sparse:
I found only 3 such commits in the last 3 years. So the
rate of false positives and the maintenance overhead is
rather high and there appears to be no active policy in
place to achieve a zero-warnings baseline to move the
annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive
in trying to find bugs, at least in principle. Plus it has
a different model to enabling it: it's enabled subsystem by
subsystem, which results in zero warnings on all relevant
kernel builds (as far as our testing managed to cover it).
Which allowed us to enable it by default, similar to other
compiler warnings, with the expectation that there are no
warnings going forward. This enforces a zero-warnings baseline
on clang-22+ builds. (Which are still limited in distribution,
admittedly.)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more
subsystems and drivers enabling the feature. Context tracking
can be enabled for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y
(default disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional
function calls.
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline
(Arnd Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings
(Tamir Duberstein)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Lock debugging:
- Implement compiler-driven static analysis locking context checking,
using the upcoming Clang 22 compiler's context analysis features
(Marco Elver)
We removed Sparse context analysis support, because prior to
removal even a defconfig kernel produced 1,700+ context tracking
Sparse warnings, the overwhelming majority of which are false
positives. On an allmodconfig kernel the number of false positive
context tracking Sparse warnings grows to over 5,200... On the plus
side of the balance actual locking bugs found by Sparse context
analysis is also rather ... sparse: I found only 3 such commits in
the last 3 years. So the rate of false positives and the
maintenance overhead is rather high and there appears to be no
active policy in place to achieve a zero-warnings baseline to move
the annotations & fixers to developers who introduce new code.
Clang context analysis is more complete and more aggressive in
trying to find bugs, at least in principle. Plus it has a different
model to enabling it: it's enabled subsystem by subsystem, which
results in zero warnings on all relevant kernel builds (as far as
our testing managed to cover it). Which allowed us to enable it by
default, similar to other compiler warnings, with the expectation
that there are no warnings going forward. This enforces a
zero-warnings baseline on clang-22+ builds (Which are still limited
in distribution, admittedly)
Hopefully the Clang approach can lead to a more maintainable
zero-warnings status quo and policy, with more and more subsystems
and drivers enabling the feature. Context tracking can be enabled
for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
disabled), but this will generate a lot of false positives.
( Having said that, Sparse support could still be added back,
if anyone is interested - the removal patch is still
relatively straightforward to revert at this stage. )
Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)
- Add support for Atomic<i8/i16/bool> and replace most Rust native
AtomicBool usages with Atomic<bool>
- Clean up LockClassKey and improve its documentation
- Add missing Send and Sync trait implementation for SetOnce
- Make ARef Unpin as it is supposed to be
- Add __rust_helper to a few Rust helpers as a preparation for
helper LTO
- Inline various lock related functions to avoid additional function
calls
WW mutexes:
- Extend ww_mutex tests and other test-ww_mutex updates (John
Stultz)
Misc fixes and cleanups:
- rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
Bergmann)
- locking/local_lock: Include more missing headers (Peter Zijlstra)
- seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)
- rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
Duberstein)"
* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
rcu: Mark lockdep_assert_rcu_helper() __always_inline
compiler-context-analysis: Remove __assume_ctx_lock from initializers
tomoyo: Use scoped init guard
crypto: Use scoped init guard
kcov: Use scoped init guard
compiler-context-analysis: Introduce scoped init guards
cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
seqlock: fix scoped_seqlock_read kernel-doc
tools: Update context analysis macros in compiler_types.h
rust: sync: Replace `kernel::c_str!` with C-Strings
rust: sync: Inline various lock related methods
rust: helpers: Move #define __rust_helper out of atomic.c
rust: wait: Add __rust_helper to helpers
rust: time: Add __rust_helper to helpers
rust: task: Add __rust_helper to helpers
rust: sync: Add __rust_helper to helpers
rust: refcount: Add __rust_helper to helpers
rust: rcu: Add __rust_helper to helpers
rust: processor: Add __rust_helper to helpers
...
affinity of unbound kthreads (node or custom cpumask) against
housekeeping (CPU isolation) constraints and CPU hotplug events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset isolated
partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making nohz_full=
also mutable through cpuset in the future.
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Merge tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"The kthread code provides an infrastructure which manages the
preferred affinity of unbound kthreads (node or custom cpumask)
against housekeeping (CPU isolation) constraints and CPU hotplug
events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset
isolated partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making
nohz_full= also mutable through cpuset in the future"
* tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (33 commits)
doc: Add housekeeping documentation
kthread: Document kthread_affine_preferred()
kthread: Comment on the purpose and placement of kthread_affine_node() call
kthread: Honour kthreads preferred affinity after cpuset changes
sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
kthread: Include kthreadd to the managed affinity list
kthread: Include unbound kthreads in the managed affinity list
kthread: Refine naming of affinity related fields
PCI: Remove superfluous HK_TYPE_WQ check
sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
cpuset: Remove cpuset_cpu_is_isolated()
timers/migration: Remove superfluous cpuset isolation test
cpuset: Propagate cpuset isolation update to timers through housekeeping
cpuset: Propagate cpuset isolation update to workqueue through housekeeping
PCI: Flush PCI probe workqueue on cpuset isolated partition change
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
sched/isolation: Flush memcg workqueues on cpuset isolated partition change
cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
...
Cpuset isolated partitions are now included in HK_TYPE_DOMAIN. Testing
if a CPU is part of an isolated partition alone is now useless.
Remove the superflous test.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Testing housekeeping_cpu() will soon require that either the RCU "lock"
is held or the cpuset mutex.
When CPUs get isolated through cpuset, the change is propagated to
timer migration such that isolation is also performed from the migration
tree. However that propagation is done using workqueue which tests if
the target is actually isolated before proceeding.
Lockdep doesn't know that the workqueue caller holds cpuset mutex and
that it waits for the work, making the housekeeping cpumask read safe.
Shut down the future warning by removing this test. It is unecessary
beyond hotplug, the workqueue is already targeted towards isolated CPUs.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Gabriele Monaco <gmonaco@redhat.com>
The code local is_leap() helper was tried to be replaced by the RTC
is_leap_year() function. Unfortunately the two aren't exactly equivalent,
as the kunit variant uses a signed value for the year and the RTC an
unsigned one.
Since the KUnit tests cover a 16000 year range around the epoch they use
year values that are very comfortably negative and hence get mishandled
when passed into is_leap_year().
The change was reverted, so add a comment which prevents further attempts
to do so.
[ tglx: Adapted to the revert ]
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260130-kunit-fix-leap-year-v1-1-92ddf55dffd7@kernel.org
There is no point in iterating through individual tick dependency bits when
the tick_stop tracepoint is disabled, which is the common case.
When the trace point is disabled, return immediately based on the atomic
value being zero or non-zero, skipping the per-bit evaluation.
This optimization improves the hot path performance of tick dependency
checks across all contexts (idle and non-idle), not just nohz_full CPUs.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ionut Nechita (Sunlight Linux) <sunlightlinux@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260128074558.15433-3-sunlightlinux@gmail.com
cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
accounting has a nanoseconds granularity.
Use the appropriate indicator instead to make that deduction.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/aXozx0PXutnm8ECX@localhost.localdomain
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It turns out that __run_hrtimer() will trace like:
<idle>-0 [032] d.h2. 20705.474563: hrtimer_cancel: hrtimer=0xff2db8f77f8226e8
<idle>-0 [032] d.h1. 20705.474563: hrtimer_expire_entry: hrtimer=0xff2db8f77f8226e8 now=20699452001850 function=tick_nohz_handler/0x0
Which is a bit nonsensical, the timer doesn't get canceled on
expiration. The cause is the use of the incorrect debug helper.
Fixes: c6a2a17702 ("hrtimer: Add tracepoint for hrtimers")
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143208.219595606@infradead.org
The "valid" readout delay between the two reads of the watchdog is larger
than the valid delta between the resulting watchdog and clocksource
intervals, which results in false positive watchdog results.
Assume TSC is the clocksource and HPET is the watchdog and both have a
uncertainty margin of 250us (default). The watchdog readout does:
1) wdnow = read(HPET);
2) csnow = read(TSC);
3) wdend = read(HPET);
The valid window for the delta between #1 and #3 is calculated by the
uncertainty margins of the watchdog and the clocksource:
m = 2 * watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 750us for the TSC/HPET case.
The actual interval comparison uses a smaller margin:
m = watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 500us for the TSC/HPET case.
That means the following scenario will trigger the watchdog:
Watchdog cycle N:
1) wdnow[N] = read(HPET);
2) csnow[N] = read(TSC);
3) wdend[N] = read(HPET);
Assume the delay between #1 and #2 is 100us and the delay between #1 and
Watchdog cycle N + 1:
4) wdnow[N + 1] = read(HPET);
5) csnow[N + 1] = read(TSC);
6) wdend[N + 1] = read(HPET);
If the delay between #4 and #6 is within the 750us margin then any delay
between #4 and #5 which is larger than 600us will fail the interval check
and mark the TSC unstable because the intervals are calculated against the
previous value:
wd_int = wdnow[N + 1] - wdnow[N];
cs_int = csnow[N + 1] - csnow[N];
Putting the above delays in place this results in:
cs_int = (wdnow[N + 1] + 610us) - (wdnow[N] + 100us);
-> cs_int = wd_int + 510us;
which is obviously larger than the allowed 500us margin and results in
marking TSC unstable.
Fix this by using the same margin as the interval comparison. If the delay
between two watchdog reads is larger than that, then the readout was either
disturbed by interconnect congestion, NMIs or SMIs.
Fixes: 4ac1dd3245 ("clocksource: Set cs_watchdog_read() checks based on .uncertainty_margin")
Reported-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/20250602223251.496591-1-daniel@quora.org/
Link: https://patch.msgid.link/87bjjxc9dq.ffs@tglx
When __do_ajdtimex() was introduced to handle adjtimex for any
timekeeper, this reference to tk_core was not updated. When called on an
auxiliary timekeeper, the core timekeeper would be updated incorrectly.
This gets caught by the lock debugging diagnostics because the
timekeepers sequence lock gets written to without holding its
associated spinlock:
WARNING: include/linux/seqlock.h:226 at __do_adjtimex+0x394/0x3b0, CPU#2: test/125
aux_clock_adj (kernel/time/timekeeping.c:2979)
__do_sys_clock_adjtime (kernel/time/posix-timers.c:1161 kernel/time/posix-timers.c:1173)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)
Update the correct auxiliary timekeeper.
Fixes: 775f71ebed ("timekeeping: Make do_adjtimex() reusable")
Fixes: ecf3e70304 ("timekeeping: Provide adjtimex() for auxiliary clocks")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260120-timekeeper-auxclock-leapstate-v1-1-5b358c6b3cfd@linutronix.de
Since ktime_t has become an alias to s64, these helpers are unnecessary.
Migrate the few remaining users to the regular helpers and remove the
now dead code.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-3-1a698ef0ddae@linutronix.de
This constant is only used in a single place and is has a very generic
name polluting the global namespace.
Move the constant closer to its only user.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-2-1a698ef0ddae@linutronix.de
In a vain attempt to consolidate the email zoo switch everything to the
kernel.org account.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove SYSCTL_INT_CONV_CUSTOM and replace it with proc_int_conv. This
converter function expects a negp argument as it can take on negative
values. Update all jiffies converters to use explicit function calls.
Remove SYSCTL_CONV_IDENTITY as it is no longer used.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Replace SYSCTL_USER_TO_KERN_INT_CONV and SYSCTL_KERN_TO_USER_INT_CONV
macros with function implementing the same logic.This makes debugging
easier and aligns with the functions preference described in
coding-style.rst. Update all jiffies converters to use explicit function
implementations instead of macro-generated versions.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
As discussed in [1], removing __cond_lock() will improve the readability
of trylock code. Now that Sparse context tracking support has been
removed, we can also remove __cond_lock().
Change existing APIs to either drop __cond_lock() completely, or make
use of the __cond_acquires() function attribute instead.
In particular, spinlock and rwlock implementations required switching
over to inline helpers rather than statement-expressions for their
trylock_* variants.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207082832.GU7145@noisy.programming.kicks-ass.net/ [1]
Link: https://patch.msgid.link/20251219154418.3592607-25-elver@google.com
New network transport protocols want NIC drivers to get hardware timestamps
of all incoming packets, and possibly all outgoing packets.
One example is the upcoming 'Swift congestion control' which is used by TCP
transport and is the primary need for timecounter_cyc2time(). This means
timecounter_cyc2time() can be called more than 100 million times per second
on a busy server.
Inlining timecounter_cyc2time() brings a 12% improvement on a UDP receive
stress test on a 100Gbit NIC.
Note that FDO, LTO, PGO are unable to magically help for this case,
presumably because NIC drivers are almost exclusively shipped as modules.
Add an unlikely() around the cc_cyc2ns_backwards() case, even if FDO (when
used) is able to take care of this optimization.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://research.google/pubs/swift-delay-is-simple-and-effective-for-congestion-control-in-the-datacenter/
Link: https://patch.msgid.link/20251129095740.3338476-1-edumazet@google.com
This is the first half of the driver changes:
- A treewide interface change to the "syscore" operations for
power management, as a preparation for future Tegra specific
changes.
- Reset controller updates with added drivers for LAN969x, eic770
and RZ/G3S SoCs.
- Protection of system controller registers on Renesas and Google SoCs,
to prevent trivially triggering a system crash from e.g. debugfs
access.
- soc_device identification updates on Nvidia, Exynos and Mediatek
- debugfs support in the ST STM32 firewall driver
- Minor updates for SoC drivers on AMD/Xilinx, Renesas, Allwinner, TI
- Cleanups for memory controller support on Nvidia and Renesas
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Merge tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull SoC driver updates from Arnd Bergmann:
"This is the first half of the driver changes:
- A treewide interface change to the "syscore" operations for power
management, as a preparation for future Tegra specific changes
- Reset controller updates with added drivers for LAN969x, eic770 and
RZ/G3S SoCs
- Protection of system controller registers on Renesas and Google
SoCs, to prevent trivially triggering a system crash from e.g.
debugfs access
- soc_device identification updates on Nvidia, Exynos and Mediatek
- debugfs support in the ST STM32 firewall driver
- Minor updates for SoC drivers on AMD/Xilinx, Renesas, Allwinner, TI
- Cleanups for memory controller support on Nvidia and Renesas"
* tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (114 commits)
memory: tegra186-emc: Fix missing put_bpmp
Documentation: reset: Remove reset_controller_add_lookup()
reset: fix BIT macro reference
reset: rzg2l-usbphy-ctrl: Fix a NULL vs IS_ERR() bug in probe
reset: th1520: Support reset controllers in more subsystems
reset: th1520: Prepare for supporting multiple controllers
dt-bindings: reset: thead,th1520-reset: Add controllers for more subsys
dt-bindings: reset: thead,th1520-reset: Remove non-VO-subsystem resets
reset: remove legacy reset lookup code
clk: davinci: psc: drop unused reset lookup
reset: rzg2l-usbphy-ctrl: Add support for RZ/G3S SoC
reset: rzg2l-usbphy-ctrl: Add support for USB PWRRDY
dt-bindings: reset: renesas,rzg2l-usbphy-ctrl: Document RZ/G3S support
reset: eswin: Add eic7700 reset driver
dt-bindings: reset: eswin: Documentation for eic7700 SoC
reset: sparx5: add LAN969x support
dt-bindings: reset: microchip: Add LAN969x support
soc: rockchip: grf: Add select correct PWM implementation on RK3368
soc/tegra: pmc: Add USB wake events for Tegra234
amba: tegra-ahb: Fix device leak on SMMU enable
...
* Move jiffies converters out of kernel/sysctl.c
Moved the jiffies converters into kernel/time/jiffies.c and replaced
the pipe-max-size proc_handler converter with a macro based version.
This is all part of the effort to relocate non-sysctl logic out of
kernel/sysctl.c into more relevant subsystems. No functional changes.
* Generalize proc handler converter creation
Removed duplicated sysctl converter logic by consolidating it in
macros. These are used inside sysctl core as well as in pipe.c and
jiffies.c. Converter kernel and user space pointer args are now
automatically const qualified for the convenience of the caller. No
functional changes.
* Miscellaneous
Fixed kernel-doc format warnings, removed unnecessary __user
qualifiers, and moved the nmi_watchdog sysctl into .rodata.
* Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. It went into linux-next after rc2, giving it a good 4/5 weeks
of testing.
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Merge tag 'sysctl-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl updates from Joel Granados:
- Move jiffies converters out of kernel/sysctl.c
Move the jiffies converters into kernel/time/jiffies.c and replace
the pipe-max-size proc_handler converter with a macro based version.
This is all part of the effort to relocate non-sysctl logic out of
kernel/sysctl.c into more relevant subsystems. No functional changes.
- Generalize proc handler converter creation
Remove duplicated sysctl converter logic by consolidating it in
macros. These are used inside sysctl core as well as in pipe.c and
jiffies.c. Converter kernel and user space pointer args are now
automatically const qualified for the convenience of the caller. No
functional changes.
- Miscellaneous
Fix kernel-doc format warnings, remove unnecessary __user
qualifiers, and move the nmi_watchdog sysctl into .rodata.
- Testing
This series was run through sysctl selftests/kunit test suite in
x86_64. It went into linux-next after rc2, giving it a good 4/5 weeks
of testing.
* tag 'sysctl-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (21 commits)
sysctl: Wrap do_proc_douintvec with the public function proc_douintvec_conv
sysctl: Create pipe-max-size converter using sysctl UINT macros
sysctl: Move proc_doulongvec_ms_jiffies_minmax to kernel/time/jiffies.c
sysctl: Move jiffies converters to kernel/time/jiffies.c
sysctl: Move UINT converter macros to sysctl header
sysctl: Move INT converter macros to sysctl header
sysctl: Allow custom converters from outside sysctl
sysctl: remove __user qualifier from stack_erasing_sysctl buffer argument
sysctl: Create macro for user-to-kernel uint converter
sysctl: Add optional range checking to SYSCTL_UINT_CONV_CUSTOM
sysctl: Create unsigned int converter using new macro
sysctl: Add optional range checking to SYSCTL_INT_CONV_CUSTOM
sysctl: Create integer converters with one macro
sysctl: Create converter functions with two new macros
sysctl: Discriminate between kernel and user converter params
sysctl: Indicate the direction of operation with macro names
sysctl: Remove superfluous __do_proc_* indirection
sysctl: Remove superfluous tbl_data param from "dovec" functions
sysctl: Replace void pointer with const pointer to ctl_table
sysctl: fix kernel-doc format warning
...
by in_hardirq() and marked deprecated in 2020.
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Merge tag 'core-core-2025-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core irq cleanup from Thomas Gleixner:
"Tree wide cleanup of the remaining users of in_irq() which got
replaced by in_hardirq() and marked deprecated in 2020"
* tag 'core-core-2025-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide: Remove in_irq()
- Prevent a thundering herd problem when the timekeeper CPU is delayed
and a large number of CPUs compete to acquire jiffies_lock to do the
update. Limit it to one CPU with a separate "uncontended" atomic
variable.
- A set of improvements for the timer migration mechanism:
- Support imbalanced NUMA trees correctly
- Support dynamic exclusion of CPUs from the migrator duty to allow the
cpuset/isolation mechanism to exclude them from handling timers of
remote idle CPUs.
- The usual small updates, cleanups and enhancements
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Merge tag 'timers-core-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner:
- Prevent a thundering herd problem when the timekeeper CPU is delayed
and a large number of CPUs compete to acquire jiffies_lock to do the
update. Limit it to one CPU with a separate "uncontended" atomic
variable.
- A set of improvements for the timer migration mechanism:
- Support imbalanced NUMA trees correctly
- Support dynamic exclusion of CPUs from the migrator duty to allow
the cpuset/isolation mechanism to exclude them from handling
timers of remote idle CPUs
- The usual small updates, cleanups and enhancements
* tag 'timers-core-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers/migration: Exclude isolated cpus from hierarchy
cpumask: Add initialiser to use cleanup helpers
sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any
cgroup/cpuset: Rename update_unbound_workqueue_cpumask() to update_isolation_cpumasks()
timers/migration: Use scoped_guard on available flag set/clear
timers/migration: Add mask for CPUs available in the hierarchy
timers/migration: Rename 'online' bit to 'available'
selftests/timers/nanosleep: Add tests for return of remaining time
selftests/timers: Clean up kernel version check in posix_timers
time: Fix a few typos in time[r] related code comments
time: tick-oneshot: Add missing Return and parameter descriptions to kernel-doc
hrtimer: Store time as ktime_t in restart block
timers/migration: Remove dead code handling idle CPU checking for remote timers
timers/migration: Remove unused "cpu" parameter from tmigr_get_group()
timers/migration: Assert that hotplug preparing CPU is part of stable active hierarchy
timers/migration: Fix imbalanced NUMA trees
timers/migration: Remove locking on group connection
timers/migration: Convert "while" loops to use "for"
tick/sched: Limit non-timekeeper CPUs calling jiffies update
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Merge tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
"This contains substantial namespace infrastructure changes including a new
system call, active reference counting, and extensive header cleanups.
The branch depends on the shared kbuild branch for -fms-extensions support.
Features:
- listns() system call
Add a new listns() system call that allows userspace to iterate
through namespaces in the system. This provides a programmatic
interface to discover and inspect namespaces, addressing
longstanding limitations:
Currently, there is no direct way for userspace to enumerate
namespaces. Applications must resort to scanning /proc/*/ns/ across
all processes, which is:
- Inefficient - requires iterating over all processes
- Incomplete - misses namespaces not attached to any running
process but kept alive by file descriptors, bind mounts, or
parent references
- Permission-heavy - requires access to /proc for many processes
- No ordering or ownership information
- No filtering per namespace type
The listns() system call solves these problems:
ssize_t listns(const struct ns_id_req *req, u64 *ns_ids,
size_t nr_ns_ids, unsigned int flags);
struct ns_id_req {
__u32 size;
__u32 spare;
__u64 ns_id;
struct /* listns */ {
__u32 ns_type;
__u32 spare2;
__u64 user_ns_id;
};
};
Features include:
- Pagination support for large namespace sets
- Filtering by namespace type (MNT_NS, NET_NS, USER_NS, etc.)
- Filtering by owning user namespace
- Permission checks respecting namespace isolation
- Active Reference Counting
Introduce an active reference count that tracks namespace
visibility to userspace. A namespace is visible in the following
cases:
- The namespace is in use by a task
- The namespace is persisted through a VFS object (namespace file
descriptor or bind-mount)
- The namespace is a hierarchical type and is the parent of child
namespaces
The active reference count does not regulate lifetime (that's still
done by the normal reference count) - it only regulates visibility
to namespace file handles and listns().
This prevents resurrection of namespaces that are pinned only for
internal kernel reasons (e.g., user namespaces held by
file->f_cred, lazy TLB references on idle CPUs, etc.) which should
not be accessible via (1)-(3).
- Unified Namespace Tree
Introduce a unified tree structure for all namespaces with:
- Fixed IDs assigned to initial namespaces
- Lookup based solely on inode number
- Maintained list of owned namespaces per user namespace
- Simplified rbtree comparison helpers
Cleanups
- Header Reorganization:
- Move namespace types into separate header (ns_common_types.h)
- Decouple nstree from ns_common header
- Move nstree types into separate header
- Switch to new ns_tree_{node,root} structures with helper functions
- Use guards for ns_tree_lock
- Initial Namespace Reference Count Optimization
- Make all reference counts on initial namespaces a nop to avoid
pointless cacheline ping-pong for namespaces that can never go
away
- Drop custom reference count initialization for initial namespaces
- Add NS_COMMON_INIT() macro and use it for all namespaces
- pid: rely on common reference count behavior
- Miscellaneous Cleanups
- Rename exit_task_namespaces() to exit_nsproxy_namespaces()
- Rename is_initial_namespace() and make argument const
- Use boolean to indicate anonymous mount namespace
- Simplify owner list iteration in nstree
- nsfs: raise SB_I_NODEV, SB_I_NOEXEC, and DCACHE_DONTCACHE explicitly
- nsfs: use inode_just_drop()
- pidfs: raise DCACHE_DONTCACHE explicitly
- pidfs: simplify PIDFD_GET__NAMESPACE ioctls
- libfs: allow to specify s_d_flags
- cgroup: add cgroup namespace to tree after owner is set
- nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
Fixes:
- setns(pidfd, ...) race condition
Fix a subtle race when using pidfds with setns(). When the target
task exits after prepare_nsset() but before commit_nsset(), the
namespace's active reference count might have been dropped. If
setns() then installs the namespaces, it would bump the active
reference count from zero without taking the required reference on
the owner namespace, leading to underflow when later decremented.
The fix resurrects the ownership chain if necessary - if the caller
succeeded in grabbing passive references, the setns() should
succeed even if the target task exits or gets reaped.
- Return EFAULT on put_user() error instead of success
- Make sure references are dropped outside of RCU lock (some
namespaces like mount namespace sleep when putting the last
reference)
- Don't skip active reference count initialization for network
namespace
- Add asserts for active refcount underflow
- Add asserts for initial namespace reference counts (both passive
and active)
- ipc: enable is_ns_init_id() assertions
- Fix kernel-doc comments for internal nstree functions
- Selftests
- 15 active reference count tests
- 9 listns() functionality tests
- 7 listns() permission tests
- 12 inactive namespace resurrection tests
- 3 threaded active reference count tests
- commit_creds() active reference tests
- Pagination and stress tests
- EFAULT handling test
- nsid tests fixes"
* tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (103 commits)
pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls
nstree: fix kernel-doc comments for internal functions
nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
selftests/namespaces: fix nsid tests
ns: drop custom reference count initialization for initial namespaces
pid: rely on common reference count behavior
ns: add asserts for initial namespace active reference counts
ns: add asserts for initial namespace reference counts
ns: make all reference counts on initial namespace a nop
ipc: enable is_ns_init_id() assertions
fs: use boolean to indicate anonymous mount namespace
ns: rename is_initial_namespace()
ns: make is_initial_namespace() argument const
nstree: use guards for ns_tree_lock
nstree: simplify owner list iteration
nstree: switch to new structures
nstree: add helper to operate on struct ns_tree_{node,root}
nstree: move nstree types into separate header
nstree: decouple from ns_common header
ns: move namespace types into separate header
...
Move proc_doulongvec_ms_jiffies_minmax to kernel/time/jiffies.c. Create
a non static wrapper function proc_doulongvec_minmax_conv that
forwards the custom convmul and convdiv argument values to the internal
do_proc_doulongvec_minmax. Remove unused linux/times.h include from
kernel/sysctl.c.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Move integer jiffies converters (proc_dointvec{_,_ms_,_userhz_}jiffies
and proc_dointvec_ms_jiffies_minmax) to kernel/time/jiffies.c. Error
stubs for when CONFIG_PRCO_SYSCTL is not defined are not reproduced
because all the jiffies converters go through proc_dointvec_conv which
is already stubbed. This is part of the greater effort to move sysctl
logic out of kernel/sysctl.c thereby reducing merge conflicts in
kernel/sysctl.c.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
If kobject_create_and_add() fails on the first iteration, then the error
code is set to -ENOMEM which is correct. But if it fails in subsequent
iterations then "ret" is zero, which means success, but it should be
-ENOMEM.
Set the error code to -ENOMEM correctly.
Fixes: 7b5ab04f03 ("timekeeping: Fix resource leak in tk_aux_sysfs_init() error paths")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Malaya Kumar Rout <mrout@redhat.com>
Link: https://patch.msgid.link/aSW1R8q5zoY_DgQE@stanley.mountain
There is a race condition between timer_shutdown_sync() and timer
expiration that can lead to hitting a WARN_ON in expire_timers().
The issue occurs when timer_shutdown_sync() clears the timer function
to NULL while the timer is still running on another CPU. The race
scenario looks like this:
CPU0 CPU1
<SOFTIRQ>
lock_timer_base()
expire_timers()
base->running_timer = timer;
unlock_timer_base()
[call_timer_fn enter]
mod_timer()
...
timer_shutdown_sync()
lock_timer_base()
// For now, will not detach the timer but only clear its function to NULL
if (base->running_timer != timer)
ret = detach_if_pending(timer, base, true);
if (shutdown)
timer->function = NULL;
unlock_timer_base()
[call_timer_fn exit]
lock_timer_base()
base->running_timer = NULL;
unlock_timer_base()
...
// Now timer is pending while its function set to NULL.
// next timer trigger
<SOFTIRQ>
expire_timers()
WARN_ON_ONCE(!fn) // hit
...
lock_timer_base()
// Now timer will detach
if (base->running_timer != timer)
ret = detach_if_pending(timer, base, true);
if (shutdown)
timer->function = NULL;
unlock_timer_base()
The problem is that timer_shutdown_sync() clears the timer function
regardless of whether the timer is currently running. This can leave a
pending timer with a NULL function pointer, which triggers the
WARN_ON_ONCE(!fn) check in expire_timers().
Fix this by only clearing the timer function when actually detaching the
timer. If the timer is running, leave the function pointer intact, which is
safe because the timer will be properly detached when it finishes running.
Fixes: 0cc04e8045 ("timers: Add shutdown mechanism to the internal functions")
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251122093942.301559-1-zouyipeng@huawei.com
The timer migration mechanism allows active CPUs to pull timers from
idle ones to improve the overall idle time. This is however undesired
when CPU intensive workloads run on isolated cores, as the algorithm
would move the timers from housekeeping to isolated cores, negatively
affecting the isolation.
Exclude isolated cores from the timer migration algorithm, extend the
concept of unavailable cores, currently used for offline ones, to
isolated ones:
* A core is unavailable if isolated or offline;
* A core is available if non isolated and online;
A core is considered unavailable as isolated if it belongs to:
* the isolcpus (domain) list
* an isolated cpuset
Except if it is:
* in the nohz_full list (already idle for the hierarchy)
* the nohz timekeeper core (must be available to handle global timers)
CPUs are added to the hierarchy during late boot, excluding isolated
ones, the hierarchy is also adapted when the cpuset isolation changes.
Due to how the timer migration algorithm works, any CPU part of the
hierarchy can have their global timers pulled by remote CPUs and have to
pull remote timers, only skipping pulling remote timers would break the
logic.
For this reason, prevent isolated CPUs from pulling remote global
timers, but also the other way around: any global timer started on an
isolated CPU will run there. This does not break the concept of
isolation (global timers don't come from outside the CPU) and, if
considered inappropriate, can usually be mitigated with other isolation
techniques (e.g. IRQ pinning).
This effect was noticed on a 128 cores machine running oslat on the
isolated cores (1-31,33-63,65-95,97-127). The tool monopolises CPUs,
and the CPU with lowest count in a timer migration hierarchy (here 1
and 65) appears as always active and continuously pulls global timers,
from the housekeeping CPUs. This ends up moving driver work (e.g.
delayed work) to isolated CPUs and causes latency spikes:
before the change:
# oslat -c 1-31,33-63,65-95,97-127 -D 62s
...
Maximum: 1203 10 3 4 ... 5 (us)
after the change:
# oslat -c 1-31,33-63,65-95,97-127 -D 62s
...
Maximum: 10 4 3 4 3 ... 5 (us)
The same behaviour was observed on a machine with as few as 20 cores /
40 threads with isocpus set to: 1-9,11-39 with rtla-osnoise-top.
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: John B. Wyatt IV <jwyatt@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/20251120145653.296659-8-gmonaco@redhat.com
Cleanup tmigr_clear_cpu_available() and tmigr_set_cpu_available() to
prepare for easier checks on the available flag.
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251120145653.296659-4-gmonaco@redhat.com
Keep track of the CPUs available for timer migration in a cpumask. This
prepares the ground to generalise the concept of unavailable CPUs.
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251120145653.296659-3-gmonaco@redhat.com
The timer migration hierarchy excludes offline CPUs via the
tmigr_is_not_available function, which is essentially checking the
online bit for the CPU.
Rename the online bit to available and all references in function names
and tracepoint to generalise the concept of available CPUs.
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251120145653.296659-2-gmonaco@redhat.com
tk_aux_sysfs_init() returns immediately on error during the auxiliary clock
initialization loop without cleaning up previously allocated kobjects and
sysfs groups.
If kobject_create_and_add() or sysfs_create_group() fails during loop
iteration, the parent kobjects (tko and auxo) and any previously created
child kobjects are leaked.
Fix this by adding proper error handling with goto labels to ensure all
allocated resources are cleaned up on failure. kobject_put() on the
parent kobjects will handle cleanup of their children.
Fixes: 7b95663a3d ("timekeeping: Provide interface to control auxiliary clocks")
Signed-off-by: Malaya Kumar Rout <mrout@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251120150213.246777-1-mrout@redhat.com
In commit 0345691b24 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle") the
new function report_idle_softirq() was created by breaking code out of the
existing can_stop_idle_tick() for kernels v5.18 and newer.
In doing so, the code essentially went from this form:
if (A) {
static int ratelimit;
if (ratelimit < 10 && !C && A&D) {
pr_warn("NOHZ tick-stop error: ...");
ratelimit++;
}
return false;
}
to a new function:
static bool report_idle_softirq(void)
{
static int ratelimit;
if (likely(!A))
return false;
if (ratelimit < 10)
return false;
...
pr_warn("NOHZ tick-stop error: local softirq work is pending, handler #%02x!!!\n",
pending);
ratelimit++;
return true;
}
commit a7e282c777 ("tick/rcu: Fix bogus ratelimit condition") realized
ratelimit was essentially set to zero instead of ten, and hence *no*
softirq pending messages would ever be issued, but "fixed" it as:
- if (ratelimit < 10)
+ if (ratelimit >= 10)
return false;
However, this fix introduced another issue:
When ratelimit is greater than or equal 10, even if A is true, it will
directly return false. While ratelimit in the original code was only used
to control printing and will not affect the return value.
Restore the original logic and restrict ratelimit to control the printk and
not the return value.
Fixes: 0345691b24 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle")
Fixes: a7e282c777 ("tick/rcu: Fix bogus ratelimit condition")
Signed-off-by: Wen Yang <wen.yang@linux.dev>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251119174525.29470-1-wen.yang@linux.dev
Several functions in kernel/time/tick-oneshot.c are missing parameter and
return value descriptions in their kernel-doc comments. This causes
warnings during doc generation.
Update the kernel-doc blocks to include detailed @param and Return:
descriptions for better clarity and to fix kernel-doc warnings. No
functional code changes are made.
Signed-off-by: Sunday Adelodun <adelodunolaoluwa@yahoo.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251106113938.34693-3-adelodunolaoluwa@yahoo.com
The hrtimer core uses ktime_t to represent times, use that also for the
restart block. CPU timers internally use nanoseconds instead of ktime_t
but use the same restart block, so use the correct accessors for those.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251110-restart-block-expiration-v1-3-5d39cc93df4f@linutronix.de
Several drivers can benefit from registering per-instance data along
with the syscore operations. To achieve this, move the modifiable fields
out of the syscore_ops structure and into a separate struct syscore that
can be registered with the framework. Add a void * driver data field for
drivers to store contextual data that will be passed to the syscore ops.
Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Bring in the shared branch with the kbuild tree to enable
'-fms-extensions' for 6.19. Further namespace cleanup work
requires this extension.
Signed-off-by: Christian Brauner <brauner@kernel.org>
Idle migrators don't walk the whole tree in order to find out if there
are timers to migrate because they recorded the next deadline to be
verified within a single check in tmigr_requires_handle_remote().
Remove the related dead code and data.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024132536.39841-7-frederic@kernel.org
The CPU doing the prepare work for a remote target must be online from
the tree point of view and its hierarchy must be active, otherwise
propagating its active state up to the new root branch would be either
incorrect or racy.
Assert those conditions with more sanity checks.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024132536.39841-5-frederic@kernel.org
When a CPU from a new node boots, the old root may happen to be
connected to the new root even if their node mismatch, as depicted in
the following scenario:
1) CPU 0 boots and creates the first group for node 0.
[GRP0:0]
node 0
|
CPU 0
2) CPU 1 from node 1 boots and creates a new top that corresponds to
node 1, but it also connects the old root from node 0 to the new root
from node 1 by mistake.
[GRP1:0]
node 1
/ \
/ \
[GRP0:0] [GRP0:1]
node 0 node 1
| |
CPU 0 CPU 1
3) This eventually leads to an imbalanced tree where some node 0 CPUs
migrate node 1 timers (and vice versa) way before reaching the
crossnode groups, resulting in more frequent remote memory accesses
than expected.
[GRP2:0]
NUMA_NO_NODE
/ \
[GRP1:0] [GRP1:1]
node 1 node 0
/ \ |
/ \ [...]
[GRP0:0] [GRP0:1]
node 0 node 1
| |
CPU 0... CPU 1...
A balanced tree should only contain groups having children that belong
to the same node:
[GRP2:0]
NUMA_NO_NODE
/ \
[GRP1:0] [GRP1:0]
node 0 node 1
/ \ / \
/ \ / \
[GRP0:0] [...] [...] [GRP0:1]
node 0 node 1
| |
CPU 0... CPU 1...
In order to fix this, the hierarchy must be unfolded up to the crossnode
level as soon as a node mismatch is detected. For example the stage 2
above should lead to this layout:
[GRP2:0]
NUMA_NO_NODE
/ \
[GRP1:0] [GRP1:1]
node 0 node 1
/ \
/ \
[GRP0:0] [GRP0:1]
node 0 node 1
| |
CPU 0 CPU 1
This means that not only GRP1:0 must be created but also GRP1:1 and
GRP2:0 in order to prepare a balanced tree for next CPUs to boot.
Fixes: 7ee9887703 ("timers: Implement the hierarchical pull model")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024132536.39841-4-frederic@kernel.org
Initializing the tmc's group, the group's number of children and the
group's parent can all be done without locking because:
1) Reading the group's parent and its group mask is done locklessly.
2) The connections prepared for a given CPU hierarchy are visible to the
target CPU once online, thanks to the CPU hotplug enforced memory
ordering.
3) In case of a newly created upper level, the new root and its
connections and initialization are made visible by the CPU which made
the connections. When that CPUs goes idle in the future, the new link
is published by tmigr_inactive_up() through the atomic RmW on
->migr_state.
4) If CPUs were still walking up the active hierarchy, they could observe
the new root earlier. In this case the ordering is enforced by an
early initialization of the group mask and by barriers that maintain
address dependency as explained in:
b729cc1ec2 ("timers/migration: Fix another race between hotplug and idle entry/exit")
de3ced72a7 ("timers/migration: Enforce group initialization visibility to tree walkers")
5) Timers are propagated by a chain of group locking from the bottom to
the top. And while doing so, the tree also propagates groups links
and initialization. Therefore remote expiration, which also relies
on group locking, will observe those links and initialization while
holding the root lock before walking the tree remotely and update
remote timers. This is especially important for migrators in the
active hierarchy that may observe the new root early.
Therefore the locking is unnecessary at initialization. If anything, it
just brings confusion. Remove it.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024132536.39841-3-frederic@kernel.org
Both the "do while" and "while" loops in tmigr_setup_groups() eventually
mimic the behaviour of "for" loops.
Simplify accordingly.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024132536.39841-2-frederic@kernel.org
On large NUMA systems, while running a test program that saturates the
inter-processor and inter-NUMA links, acquiring the jiffies_lock can be
very expensive.
If the cpu designated to do jiffies updates (tick_do_timer_cpu) gets
delayed and other cpus decide to do the jiffies update themselves, a large
number of them decide to do so at the same time.
The inexpensive check against tick_next_period is far quicker than actually
acquiring the lock, so most of these get in line to obtain the lock. If
obtaining the lock is slow enough, this spirals into the vast majority of
CPUs continuously being stuck waiting for this lock, just to obtain it and
find out that time has already been updated by another cpu. For example, on
one random entry to kdb by manually-injected NMI, 2912 of 3840 CPUs were
observed to be stuck there.
To avoid this, allow only one non-timekeeper CPU to call
tick_do_update_jiffies64() at any given time, resetting ts->stalled jiffies
only if the jiffies update function is actually called.
With this change, manually interrupting the test at most two CPUs are
observed to invoke tick_do_update_jiffies64() - the timekeeper and one
other.
Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/20251027183456.343407-1-steve.wahl@hpe.com
This old alias for in_hardirq() has been marked as deprecated since
2020; remove the stragglers.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251024180654.1691095-1-willy@infradead.org
The loop in tk_aux_sysfs_init() uses `i <= MAX_AUX_CLOCKS` as the
termination condition, which results in 9 iterations (i=0 to 8) when
MAX_AUX_CLOCKS is defined as 8. However, the kernel is designed to support
only up to 8 auxiliary clocks.
This off-by-one error causes the creation of a 9th sysfs entry that exceeds
the intended auxiliary clock range.
Fix the loop bound to use `i < MAX_AUX_CLOCKS` to ensure exactly 8
auxiliary clock entries are created, matching the design specification.
Fixes: 7b95663a3d ("timekeeping: Provide interface to control auxiliary clocks")
Signed-off-by: Haofeng Li <lihaofeng@kylinos.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/tencent_2376993D9FC06A3616A4F981B3DE1C599607@qq.com
Core & protocols
----------------
- Improve drop account scalability on NUMA hosts for RAW and UDP sockets
and the backlog, almost doubling the Pps capacity under DoS.
- Optimize the UDP RX performance under stress, reducing contention,
revisiting the binary layout of the involved data structs and
implementing NUMA-aware locking. This improves UDP RX performance by
an additional 50%, even more under extreme conditions.
- Add support for PSP encryption of TCP connections; this mechanism has
some similarities with IPsec and TLS, but offers superior HW offloads
capabilities.
- Ongoing work to support Accurate ECN for TCP. AccECN allows more than
one congestion notification signal per RTT and is a building block for
Low Latency, Low Loss, and Scalable Throughput (L4S).
- Reorganize the TCP socket binary layout for data locality, reducing
the number of touched cachelines in the fastpath.
- Refactor skb deferral free to better scale on large multi-NUMA hosts,
this improves TCP and UDP RX performances significantly on such HW.
- Increase the default socket memory buffer limits from 256K to 4M to
better fit modern link speeds.
- Improve handling of setups with a large number of nexthop, making dump
operating scaling linearly and avoiding unneeded synchronize_rcu() on
delete.
- Improve bridge handling of VLAN FDB, storing a single entry per bridge
instead of one entry per port; this makes the dump order of magnitude
faster on large switches.
- Restore IP ID correctly for encapsulated packets at GSO segmentation
time, allowing GRO to merge packets in more scenarios.
- Improve netfilter matching performance on large sets.
- Improve MPTCP receive path performance by leveraging recently
introduced core infrastructure (skb deferral free) and adopting recent
TCP autotuning changes.
- Allow bridges to redirect to a backup port when the bridge port is
administratively down.
- Introduce MPTCP 'laminar' endpoint that con be used only once per
connection and simplify common MPTCP setups.
- Add RCU safety to dst->dev, closing a lot of possible races.
- A significant crypto library API for SCTP, MPTCP and IPv6 SR, reducing
code duplication.
- Supports pulling data from an skb frag into the linear area of an XDP
buffer.
Things we sprinkled into general kernel code
--------------------------------------------
- Generate netlink documentation from YAML using an integrated
YAML parser.
Driver API
----------
- Support using IPv6 Flow Label in Rx hash computation and RSS queue
selection.
- Introduce API for fetching the DMA device for a given queue, allowing
TCP zerocopy RX on more H/W setups.
- Make XDP helpers compatible with unreadable memory, allowing more
easily building DevMem-enabled drivers with a unified XDP/skbs
datapath.
- Add a new dedicated ethtool callback enabling drivers to provide the
number of RX rings directly, improving efficiency and clarity in RX
ring queries and RSS configuration.
- Introduce a burst period for the health reporter, allowing better
handling of multiple errors due to the same root cause.
- Support for DPLL phase offset exponential moving average, controlling
the average smoothing factor.
Device drivers
--------------
- Add a new Huawei driver for 3rd gen NIC (hinic3).
- Add a new SpacemiT driver for K1 ethernet MAC.
- Add a generic abstraction for shared memory communication devices
(dibps)
- Ethernet high-speed NICs:
- nVidia/Mellanox:
- Use multiple per-queue doorbell, to avoid MMIO contention issues
- support adjacent functions, allowing them to delegate their
SR-IOV VFs to sibling PFs
- support RSS for IPSec offload
- support exposing raw cycle counters in PTP and mlx5
- support for disabling host PFs.
- Intel (100G, ice, idpf):
- ice: support for SRIOV VFs over an Active-Active link aggregate
- ice: support for firmware logging via debugfs
- ice: support for Earliest TxTime First (ETF) hardware offload
- idpf: support basic XDP functionalities and XSk
- Broadcom (bnxt):
- support Hyper-V VF ID
- dynamic SRIOV resource allocations for RoCE
- Meta (fbnic):
- support queue API, zero-copy Rx and Tx
- support basic XDP functionalities
- devlink health support for FW crashes and OTP mem corruptions
- expand hardware stats coverage to FEC, PHY, and Pause
- Wangxun:
- support ethtool coalesce options
- support for multiple RSS contexts
- Ethernet virtual:
- Macsec:
- replace custom netlink attribute checks with policy-level checks
- Bonding:
- support aggregator selection based on port priority
- Microsoft vNIC:
- use page pool fragments for RX buffers instead of full pages to
improve memory efficiency
- Ethernet NICs consumer, and embedded:
- Qualcomm: support Ethernet function for IPQ9574 SoC
- Airoha: implement wlan offloading via NPU
- Freescale
- enetc: add NETC timer PTP driver and add PTP support
- fec: enable the Jumbo frame support for i.MX8QM
- Renesas (R-Car S4): support HW offloading for layer 2 switching
- support for RZ/{T2H, N2H} SoCs
- Cadence (macb): support TAPRIO traffic scheduling
- TI:
- support for Gigabit ICSS ethernet SoC (icssm-prueth)
- Synopsys (stmmac): a lot of cleanups
- Ethernet PHYs:
- Support 10g-qxgmi phy-mode for AQR412C, Felix DSA and Lynx PCS
driver
- Support bcm63268 GPHY power control
- Support for Micrel lan8842 PHY and PTP
- Support for Aquantia AQR412 and AQR115
- CAN:
- a large CAN-XL preparation work
- reorganize raw_sock and uniqframe struct to minimize memory usage
- rcar_canfd: update the CAN-FD handling
- WiFi:
- extended Neighbor Awareness Networking (NAN) support
- S1G channel representation cleanup
- improve S1G support
- WiFi drivers:
- Intel (iwlwifi):
- major refactor and cleanup
- Broadcom (brcm80211):
- support for AP isolation
- RealTek (rtw88/89) rtw88/89:
- preparation work for RTL8922DE support
- MediaTek (mt76):
- HW restart improvements
- MLO support
- Qualcomm/Atheros (ath10k_
- GTK rekey fixes
- Bluetooth drivers:
- btusb: support for several new IDs for MT7925
- btintel: support for BlazarIW core
- btintel_pcie: support for _suspend() / _resume()
- btintel_pcie: support for Scorpious, Panther Lake-H484 IDs
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"Core & protocols:
- Improve drop account scalability on NUMA hosts for RAW and UDP
sockets and the backlog, almost doubling the Pps capacity under DoS
- Optimize the UDP RX performance under stress, reducing contention,
revisiting the binary layout of the involved data structs and
implementing NUMA-aware locking. This improves UDP RX performance
by an additional 50%, even more under extreme conditions
- Add support for PSP encryption of TCP connections; this mechanism
has some similarities with IPsec and TLS, but offers superior HW
offloads capabilities
- Ongoing work to support Accurate ECN for TCP. AccECN allows more
than one congestion notification signal per RTT and is a building
block for Low Latency, Low Loss, and Scalable Throughput (L4S)
- Reorganize the TCP socket binary layout for data locality, reducing
the number of touched cachelines in the fastpath
- Refactor skb deferral free to better scale on large multi-NUMA
hosts, this improves TCP and UDP RX performances significantly on
such HW
- Increase the default socket memory buffer limits from 256K to 4M to
better fit modern link speeds
- Improve handling of setups with a large number of nexthop, making
dump operating scaling linearly and avoiding unneeded
synchronize_rcu() on delete
- Improve bridge handling of VLAN FDB, storing a single entry per
bridge instead of one entry per port; this makes the dump order of
magnitude faster on large switches
- Restore IP ID correctly for encapsulated packets at GSO
segmentation time, allowing GRO to merge packets in more scenarios
- Improve netfilter matching performance on large sets
- Improve MPTCP receive path performance by leveraging recently
introduced core infrastructure (skb deferral free) and adopting
recent TCP autotuning changes
- Allow bridges to redirect to a backup port when the bridge port is
administratively down
- Introduce MPTCP 'laminar' endpoint that con be used only once per
connection and simplify common MPTCP setups
- Add RCU safety to dst->dev, closing a lot of possible races
- A significant crypto library API for SCTP, MPTCP and IPv6 SR,
reducing code duplication
- Supports pulling data from an skb frag into the linear area of an
XDP buffer
Things we sprinkled into general kernel code:
- Generate netlink documentation from YAML using an integrated YAML
parser
Driver API:
- Support using IPv6 Flow Label in Rx hash computation and RSS queue
selection
- Introduce API for fetching the DMA device for a given queue,
allowing TCP zerocopy RX on more H/W setups
- Make XDP helpers compatible with unreadable memory, allowing more
easily building DevMem-enabled drivers with a unified XDP/skbs
datapath
- Add a new dedicated ethtool callback enabling drivers to provide
the number of RX rings directly, improving efficiency and clarity
in RX ring queries and RSS configuration
- Introduce a burst period for the health reporter, allowing better
handling of multiple errors due to the same root cause
- Support for DPLL phase offset exponential moving average,
controlling the average smoothing factor
Device drivers:
- Add a new Huawei driver for 3rd gen NIC (hinic3)
- Add a new SpacemiT driver for K1 ethernet MAC
- Add a generic abstraction for shared memory communication
devices (dibps)
- Ethernet high-speed NICs:
- nVidia/Mellanox:
- Use multiple per-queue doorbell, to avoid MMIO contention
issues
- support adjacent functions, allowing them to delegate their
SR-IOV VFs to sibling PFs
- support RSS for IPSec offload
- support exposing raw cycle counters in PTP and mlx5
- support for disabling host PFs.
- Intel (100G, ice, idpf):
- ice: support for SRIOV VFs over an Active-Active link
aggregate
- ice: support for firmware logging via debugfs
- ice: support for Earliest TxTime First (ETF) hardware offload
- idpf: support basic XDP functionalities and XSk
- Broadcom (bnxt):
- support Hyper-V VF ID
- dynamic SRIOV resource allocations for RoCE
- Meta (fbnic):
- support queue API, zero-copy Rx and Tx
- support basic XDP functionalities
- devlink health support for FW crashes and OTP mem corruptions
- expand hardware stats coverage to FEC, PHY, and Pause
- Wangxun:
- support ethtool coalesce options
- support for multiple RSS contexts
- Ethernet virtual:
- Macsec:
- replace custom netlink attribute checks with policy-level
checks
- Bonding:
- support aggregator selection based on port priority
- Microsoft vNIC:
- use page pool fragments for RX buffers instead of full pages
to improve memory efficiency
- Ethernet NICs consumer, and embedded:
- Qualcomm: support Ethernet function for IPQ9574 SoC
- Airoha: implement wlan offloading via NPU
- Freescale
- enetc: add NETC timer PTP driver and add PTP support
- fec: enable the Jumbo frame support for i.MX8QM
- Renesas (R-Car S4):
- support HW offloading for layer 2 switching
- support for RZ/{T2H, N2H} SoCs
- Cadence (macb): support TAPRIO traffic scheduling
- TI:
- support for Gigabit ICSS ethernet SoC (icssm-prueth)
- Synopsys (stmmac): a lot of cleanups
- Ethernet PHYs:
- Support 10g-qxgmi phy-mode for AQR412C, Felix DSA and Lynx PCS
driver
- Support bcm63268 GPHY power control
- Support for Micrel lan8842 PHY and PTP
- Support for Aquantia AQR412 and AQR115
- CAN:
- a large CAN-XL preparation work
- reorganize raw_sock and uniqframe struct to minimize memory
usage
- rcar_canfd: update the CAN-FD handling
- WiFi:
- extended Neighbor Awareness Networking (NAN) support
- S1G channel representation cleanup
- improve S1G support
- WiFi drivers:
- Intel (iwlwifi):
- major refactor and cleanup
- Broadcom (brcm80211):
- support for AP isolation
- RealTek (rtw88/89) rtw88/89:
- preparation work for RTL8922DE support
- MediaTek (mt76):
- HW restart improvements
- MLO support
- Qualcomm/Atheros (ath10k):
- GTK rekey fixes
- Bluetooth drivers:
- btusb: support for several new IDs for MT7925
- btintel: support for BlazarIW core
- btintel_pcie: support for _suspend() / _resume()
- btintel_pcie: support for Scorpious, Panther Lake-H484 IDs"
* tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1536 commits)
net: stmmac: Add support for Allwinner A523 GMAC200
dt-bindings: net: sun8i-emac: Add A523 GMAC200 compatible
Revert "Documentation: net: add flow control guide and document ethtool API"
octeontx2-pf: fix bitmap leak
octeontx2-vf: fix bitmap leak
net/mlx5e: Use extack in set rxfh callback
net/mlx5e: Introduce mlx5e_rss_params for RSS configuration
net/mlx5e: Introduce mlx5e_rss_init_params
net/mlx5e: Remove unused mdev param from RSS indir init
net/mlx5: Improve QoS error messages with actual depth values
net/mlx5e: Prevent entering switchdev mode with inconsistent netns
net/mlx5: HWS, Generalize complex matchers
net/mlx5: Improve write-combining test reliability for ARM64 Grace CPUs
selftests/net: add tcp_port_share to .gitignore
Revert "net/mlx5e: Update and set Xon/Xoff upon MTU set"
net: add NUMA awareness to skb_attempt_defer_free()
net: use llist for sd->defer_list
net: make softnet_data.defer_count an atomic
selftests: drv-net: psp: add tests for destroying devices
selftests: drv-net: psp: add test for auto-adjusting TCP MSS
...
- Further consolidation of the VDSO infrastructure and the common data
store.
- Simplification of the related Kconfig logic
- Improve the VDSO selftest suite
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Merge tag 'timers-vdso-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull VDSO updates from Thomas Gleixner:
- Further consolidation of the VDSO infrastructure and the common data
store
- Simplification of the related Kconfig logic
- Improve the VDSO selftest suite
* tag 'timers-vdso-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests: vDSO: Drop vdso_test_clock_getres
selftests: vDSO: vdso_test_abi: Add tests for clock_gettime64()
selftests: vDSO: vdso_test_abi: Test CPUTIME clocks
selftests: vDSO: vdso_test_abi: Use explicit indices for name array
selftests: vDSO: vdso_test_abi: Drop clock availability tests
selftests: vDSO: vdso_test_abi: Use ksft_finished()
selftests: vDSO: vdso_test_abi: Correctly skip whole test with missing vDSO
selftests: vDSO: Fix -Wunitialized in powerpc VDSO_CALL() wrapper
vdso: Add struct __kernel_old_timeval forward declaration to gettime.h
vdso: Gate VDSO_GETRANDOM behind HAVE_GENERIC_VDSO
vdso: Drop Kconfig GENERIC_VDSO_TIME_NS
vdso: Drop Kconfig GENERIC_VDSO_DATA_STORE
vdso: Drop kconfig GENERIC_COMPAT_VDSO
vdso: Drop kconfig GENERIC_VDSO_32
riscv: vdso: Untangle Kconfig logic
time: Build generic update_vsyscall() only with generic time vDSO
vdso/gettimeofday: Remove !CONFIG_TIME_NS stubs
vdso: Move ENABLE_COMPAT_VDSO from core to arm64
ARM: VDSO: Remove cntvct_ok global variable
vdso/datastore: Gate time data behind CONFIG_GENERIC_GETTIMEOFDAY
- Further preparations for modular clocksource/event drivers
- The usual device tree updates to support new chip variants and the
related changes to thise drivers
- Avoid a 64-bit division in the TEGRA186 driver, which caused a build
fail on 32-bit machines.
- Small fixes, improvements and cleanups all over the place
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Merge tag 'timers-clocksource-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull clocksource updates from Thomas Gleixner:
- Further preparations for modular clocksource/event drivers
- The usual device tree updates to support new chip variants and the
related changes to thise drivers
- Avoid a 64-bit division in the TEGRA186 driver, which caused a build
fail on 32-bit machines.
- Small fixes, improvements and cleanups all over the place
* tag 'timers-clocksource-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
dt-bindings: timer: exynos4210-mct: Add compatible for ARTPEC-9 SoC
clocksource/drivers/sh_cmt: Split start/stop of clock source and events
clocksource/drivers/clps711x: Fix resource leaks in error paths
clocksource/drivers/arm_global_timer: Add auto-detection for initial prescaler values
clocksource/drivers/ingenic-sysost: Convert from round_rate() to determine_rate()
clocksource/drivers/timer-tegra186: Don't print superfluous errors
clocksource/drivers/timer-rtl-otto: Simplify documentation
clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts
clocksource/drivers/timer-rtl-otto: Drop set_counter function
clocksource/drivers/timer-rtl-otto: Work around dying timers
clocksource/drivers/timer-ti-dm : Capture functionality for OMAP DM timer
clocksource/drivers/arm_arch_timer_mmio: Add MMIO clocksource
clocksource/drivers/arm_arch_timer_mmio: Switch over to standalone driver
clocksource/drivers/arm_arch_timer: Add standalone MMIO driver
ACPI: GTDT: Generate platform devices for MMIO timers
clocksource/drivers/nxp-pit: Add NXP Automotive s32g2 / s32g3 support
dt: bindings: fsl,vf610-pit: Add compatible for s32g2 and s32g3
clocksource/drivers/vf-pit: Rename the VF PIT to NXP PIT
clocksource/drivers/vf-pit: Unify the function name for irq ack
clocksource/drivers/vf-pit: Consolidate calls to pit_*_disable/enable
...
- Address the inconsistent shutdown sequence of per CPU clockevents on
CPU hotplug, which onoly removed it from the core but failed to invoke
the actual device driver shutdown callback. This keeps the timer
active, which prevents power savings and causes pointless noise in
virtualization.
- Encapsulate the open coded access to the hrtimer clock base, which is a
private implementation detail, so that the implementation can be
changed without breaking a lot of usage sites.
- Enhance the debug output of the clocksource watchdog to provide better
information for analysis.
- The usual set of cleanups and enhancements all over the place
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Merge tag 'timers-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner:
- Address the inconsistent shutdown sequence of per CPU clockevents on
CPU hotplug, which only removed it from the core but failed to invoke
the actual device driver shutdown callback. This kept the timer
active, which prevented power savings and caused pointless noise in
virtualization.
- Encapsulate the open coded access to the hrtimer clock base, which is
a private implementation detail, so that the implementation can be
changed without breaking a lot of usage sites.
- Enhance the debug output of the clocksource watchdog to provide
better information for analysis.
- The usual set of cleanups and enhancements all over the place
* tag 'timers-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Fix spelling mistakes in comments
clocksource: Print durations for sync check unconditionally
LoongArch: Remove clockevents shutdown call on offlining
tick: Do not set device to detached state in tick_shutdown()
hrtimer: Reorder branches in hrtimer_clockid_to_base()
hrtimer: Remove hrtimer_clock_base:: Get_time
hrtimer: Use hrtimer_cb_get_time() helper
media: pwm-ir-tx: Avoid direct access to hrtimer clockbase
ALSA: hrtimer: Avoid direct access to hrtimer clockbase
lib: test_objpool: Avoid direct access to hrtimer clockbase
sched/core: Avoid direct access to hrtimer clockbase
timers/itimer: Avoid direct access to hrtimer clockbase
posix-timers: Avoid direct access to hrtimer clockbase
jiffies: Remove obsolete SHIFTED_HZ comment
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Merge tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
"This contains a larger set of changes around the generic namespace
infrastructure of the kernel.
Each specific namespace type (net, cgroup, mnt, ...) embedds a struct
ns_common which carries the reference count of the namespace and so
on.
We open-coded and cargo-culted so many quirks for each namespace type
that it just wasn't scalable anymore. So given there's a bunch of new
changes coming in that area I've started cleaning all of this up.
The core change is to make it possible to correctly initialize every
namespace uniformly and derive the correct initialization settings
from the type of the namespace such as namespace operations, namespace
type and so on. This leaves the new ns_common_init() function with a
single parameter which is the specific namespace type which derives
the correct parameters statically. This also means the compiler will
yell as soon as someone does something remotely fishy.
The ns_common_init() addition also allows us to remove ns_alloc_inum()
and drops any special-casing of the initial network namespace in the
network namespace initialization code that Linus complained about.
Another part is reworking the reference counting. The reference
counting was open-coded and copy-pasted for each namespace type even
though they all followed the same rules. This also removes all open
accesses to the reference count and makes it private and only uses a
very small set of dedicated helpers to manipulate them just like we do
for e.g., files.
In addition this generalizes the mount namespace iteration
infrastructure introduced a few cycles ago. As reminder, the vfs makes
it possible to iterate sequentially and bidirectionally through all
mount namespaces on the system or all mount namespaces that the caller
holds privilege over. This allow userspace to iterate over all mounts
in all mount namespaces using the listmount() and statmount() system
call.
Each mount namespace has a unique identifier for the lifetime of the
systems that is exposed to userspace. The network namespace also has a
unique identifier working exactly the same way. This extends the
concept to all other namespace types.
The new nstree type makes it possible to lookup namespaces purely by
their identifier and to walk the namespace list sequentially and
bidirectionally for all namespace types, allowing userspace to iterate
through all namespaces. Looking up namespaces in the namespace tree
works completely locklessly.
This also means we can move the mount namespace onto the generic
infrastructure and remove a bunch of code and members from struct
mnt_namespace itself.
There's a bunch of stuff coming on top of this in the future but for
now this uses the generic namespace tree to extend a concept
introduced first for pidfs a few cycles ago. For a while now we have
supported pidfs file handles for pidfds. This has proven to be very
useful.
This extends the concept to cover namespaces as well. It is possible
to encode and decode namespace file handles using the common
name_to_handle_at() and open_by_handle_at() apis.
As with pidfs file handles, namespace file handles are exhaustive,
meaning it is not required to actually hold a reference to nsfs in
able to decode aka open_by_handle_at() a namespace file handle.
Instead the FD_NSFS_ROOT constant can be passed which will let the
kernel grab a reference to the root of nsfs internally and thus decode
the file handle.
Namespaces file descriptors can already be derived from pidfds which
means they aren't subject to overmount protection bugs. IOW, it's
irrelevant if the caller would not have access to an appropriate
/proc/<pid>/ns/ directory as they could always just derive the
namespace based on a pidfd already.
It has the same advantage as pidfds. It's possible to reliably and for
the lifetime of the system refer to a namespace without pinning any
resources and to compare them trivially.
Permission checking is kept simple. If the caller is located in the
namespace the file handle refers to they are able to open it otherwise
they must hold privilege over the owning namespace of the relevant
namespace.
The namespace file handle layout is exposed as uapi and has a stable
and extensible format. For now it simply contains the namespace
identifier, the namespace type, and the inode number. The stable
format means that userspace may construct its own namespace file
handles without going through name_to_handle_at() as they are already
allowed for pidfs and cgroup file handles"
* tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (65 commits)
ns: drop assert
ns: move ns type into struct ns_common
nstree: make struct ns_tree private
ns: add ns_debug()
ns: simplify ns_common_init() further
cgroup: add missing ns_common include
ns: use inode initializer for initial namespaces
selftests/namespaces: verify initial namespace inode numbers
ns: rename to __ns_ref
nsfs: port to ns_ref_*() helpers
net: port to ns_ref_*() helpers
uts: port to ns_ref_*() helpers
ipv4: use check_net()
net: use check_net()
net-sysfs: use check_net()
user: port to ns_ref_*() helpers
time: port to ns_ref_*() helpers
pid: port to ns_ref_*() helpers
ipc: port to ns_ref_*() helpers
cgroup: port to ns_ref_*() helpers
...
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Merge tag 'kernel-6.18-rc1.clone3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull copy_process updates from Christian Brauner:
"This contains the changes to enable support for clone3() on nios2
which apparently is still a thing.
The more exciting part of this is that it cleans up the inconsistency
in how the 64-bit flag argument is passed from copy_process() into the
various other copy_*() helpers"
[ Fixed up rv ltl_monitor 32-bit support as per Sasha Levin in the merge ]
* tag 'kernel-6.18-rc1.clone3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
nios2: implement architecture-specific portion of sys_clone3
arch: copy_thread: pass clone_flags as u64
copy_process: pass clone_flags as u64 across calltree
copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64)
It's misplaced in struct proc_ns_operations and ns->ops might be NULL if
the namespace is compiled out but we still want to know the type of the
namespace for the initial namespace struct.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The timer drivers could be converted into modules. The different
functions to register the clocksource or the clockevent are already
exporting their symbols for modules but the sched_clock_register()
function is missing.
Export the symbols so the drivers using this function can be converted
into modules.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Will McVicker <willmcvicker@google.com>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/20250602151853.1942521-8-daniel.lezcano@linaro.org
Simply derive the ns operations from the namespace type.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Correct several typos found in comments across various files in the
kernel/time directory.
No functional changes are introduced by these corrections.
Signed-off-by: Haofeng Li <lihaofeng@kylinos.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
And drop ns_free_inum(). Anything common that can be wasted centrally
should be wasted in the new common helper.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
There's a lot of information that namespace implementers don't need to
know about at all. Encapsulate this all in the initialization helper.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Every namespace type has a container_of(ns, <ns_type>, ns) static inline
function that is currently not exposed in the header. So we have a bunch
of places that open-code it via container_of(). Move it to the headers
so we can use it directly.
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Support the generic ns lookup infrastructure to support file handles for
namespaces.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Don't cargo-cult the same thing over and over.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.17-rc7).
No conflicts.
Adjacent changes:
drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
9536fbe10c ("net/mlx5e: Add PSP steering in local NIC RX")
7601a0a462 ("net/mlx5e: Add a miss level for ipsec crypto offload")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.17-rc6).
Conflicts:
net/netfilter/nft_set_pipapo.c
net/netfilter/nft_set_pipapo_avx2.c
c4eaca2e10 ("netfilter: nft_set_pipapo: don't check genbit from packetpath lookups")
84c1da7b38 ("netfilter: nft_set_pipapo: use avx2 algorithm for insertions too")
Only trivial adjacent changes (in a doc and a Makefile).
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
A typical set of messages that gets printed as a result of the clocksource
watchdog finding the TSC unstable usually does not contain messages
indicating CPUs being ahead of or behind the CPU from which the check is
carried out. That fact suggests that the TSC does not experience time skew
between CPUs (if the clocksource.verify_n_cpus parameter is set to a
negative value) but quantitative information is missing.
The cs_nsec_max value printed by the "CPU %d check durations" message
actually provides a worst case estimate of the time skew. If all CPUs have
been checked, the cs_nsec_max value multiplied by 2 is the maximum
possible time skew between the TSCs of any two CPUs on the system. The
worst case estimate is derived from two boundary cases:
1. No time is consumed to execute instructions between csnow_begin and
csnow_mid while all the cs_nsec_max time is consumed by the code between
csnow_mid and csnow_end. In this case, the maximum undetectable time skew
of a CPU being ahead would be cs_nsec_max.
2. All the cs_nsec_max time is consumed to execute instructions between
csnow_begin and csnow_mid while no time is consumed by the code between
csnow_mid and csnow_end. In this case, the maximum undetectable time skew
of a CPU being behind would be cs_nsec_max.
The worst case estimate assumes a system experiencing a corner case
consisting of the two boundary cases.
Always print the "CPU %d check durations" message so that the maximum
possible time skew measured by the TSC sync check can be compared to the
time skew measured by the clocksource watchdog.
Signed-off-by: Jiri Wiesner <jwiesner@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/all/aIuXXfdITXdI0lLp@incl
When testing softirq based hrtimers on an ARM32 board, with high resolution
mode and NOHZ inactive, softirq based hrtimers fail to expire after being
moved away from an offline CPU:
CPU0 CPU1
hrtimer_start(..., HRTIMER_MODE_SOFT);
cpu_down(CPU1) ...
hrtimers_cpu_dying()
// Migrate timers to CPU0
smp_call_function_single(CPU0, returgger_next_event);
retrigger_next_event()
if (!highres && !nohz)
return;
As retrigger_next_event() is a NOOP when both high resolution timers and
NOHZ are inactive CPU0's hrtimer_cpu_base::softirq_expires_next is not
updated and the migrated softirq timers never expire unless there is a
softirq based hrtimer queued on CPU0 later.
Fix this by removing the hrtimer_hres_active() and tick_nohz_active() check
in retrigger_next_event(), which enforces a full update of the CPU base.
As this is not a fast path the extra cost does not matter.
[ tglx: Massaged change log ]
Fixes: 5c0930ccaa ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Co-developed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250805081025.54235-1-wangxiongfeng2@huawei.com
tick_shutdown() sets the state of the clockevent device to detached
first and the invokes clockevents_exchange_device(), which in turn
invokes clockevents_switch_state().
But clockevents_switch_state() returns without invoking the device shutdown
callback as the device is already in detached state. As a consequence the
timer device is not shutdown when a CPU goes offline.
tick_shutdown() does this because it was originally invoked on a online CPU
and not on the outgoing CPU. It therefore could not access the clockevent
device of the already offlined CPU and just set the state.
Since commit 3b1596a21f tick_shutdown() is called on the outgoing CPU, so
the hardware device can be accessed.
Remove the state set before calling clockevents_exchange_device(), so that
the subsequent clockevents_switch_state() handles the state transition and
invokes the shutdown callback of the clockevent device.
[ tglx: Massaged change log ]
Fixes: 3b1596a21f ("clockevents: Shutdown and unregister current clockevents at CPUHP_AP_TICK_DYING")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20250906064952.3749122-2-maobibo@loongson.cn
