Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core and kernfs changes for 6.9-rc1.

  Nothing all that crazy here, just some good updates that include:

   - automatic attribute group hiding from Dan Williams (he fixed up my
     horrible attempt at doing this.)

   - kobject lock contention fixes from Eric Dumazet

   - driver core cleanups from Andy

   - kernfs rcu work from Tejun

   - fw_devlink changes to resolve some reported issues

   - other minor changes, all details in the shortlog

  All of these have been in linux-next for a long time with no reported
  issues"

* tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits)
  device: core: Log warning for devices pending deferred probe on timeout
  driver: core: Use dev_* instead of pr_* so device metadata is added
  driver: core: Log probe failure as error and with device metadata
  of: property: fw_devlink: Add support for "post-init-providers" property
  driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link
  driver core: Adds flags param to fwnode_link_add()
  debugfs: fix wait/cancellation handling during remove
  device property: Don't use "proxy" headers
  device property: Move enum dev_dma_attr to fwnode.h
  driver core: Move fw_devlink stuff to where it belongs
  driver core: Drop unneeded 'extern' keyword in fwnode.h
  firmware_loader: Suppress warning on FW_OPT_NO_WARN flag
  sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group.
  firmware_loader: introduce __free() cleanup hanler
  platform-msi: Remove usage of the deprecated ida_simple_xx() API
  sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()
  sysfs: Document new "group visible" helpers
  sysfs: Fix crash on empty group attributes array
  sysfs: Introduce a mechanism to hide static attribute_groups
  sysfs: Introduce a mechanism to hide static attribute_groups
  ...

Pull timer updates from Thomas Gleixner:
 "A large set of updates and features for timers and timekeeping:

   - The hierarchical timer pull model

     When timer wheel timers are armed they are placed into the timer
     wheel of a CPU which is likely to be busy at the time of expiry.
     This is done to avoid wakeups on potentially idle CPUs.

     This is wrong in several aspects:

       1) The heuristics to select the target CPU are wrong by
          definition as the chance to get the prediction right is
          close to zero.

       2) Due to #1 it is possible that timers are accumulated on
          a single target CPU

       3) The required computation in the enqueue path is just overhead
          for dubious value especially under the consideration that the
          vast majority of timer wheel timers are either canceled or
          rearmed before they expire.

     The timer pull model avoids the above by removing the target
     computation on enqueue and queueing timers always on the CPU on
     which they get armed.

     This is achieved by having separate wheels for CPU pinned timers
     and global timers which do not care about where they expire.

     As long as a CPU is busy it handles both the pinned and the global
     timers which are queued on the CPU local timer wheels.

     When a CPU goes idle it evaluates its own timer wheels:

       - If the first expiring timer is a pinned timer, then the global
         timers can be ignored as the CPU will wake up before they
         expire.

       - If the first expiring timer is a global timer, then the expiry
         time is propagated into the timer pull hierarchy and the CPU
         makes sure to wake up for the first pinned timer.

     The timer pull hierarchy organizes CPUs in groups of eight at the
     lowest level and at the next levels groups of eight groups up to
     the point where no further aggregation of groups is required, i.e.
     the number of levels is log8(NR_CPUS). The magic number of eight
     has been established by experimention, but can be adjusted if
     needed.

     In each group one busy CPU acts as the migrator. It's only one CPU
     to avoid lock contention on remote timer wheels.

     The migrator CPU checks in its own timer wheel handling whether
     there are other CPUs in the group which have gone idle and have
     global timers to expire. If there are global timers to expire, the
     migrator locks the remote CPU timer wheel and handles the expiry.

     Depending on the group level in the hierarchy this handling can
     require to walk the hierarchy downwards to the CPU level.

     Special care is taken when the last CPU goes idle. At this point
     the CPU is the systemwide migrator at the top of the hierarchy and
     it therefore cannot delegate to the hierarchy. It needs to arm its
     own timer device to expire either at the first expiring timer in
     the hierarchy or at the first CPU local timer, which ever expires
     first.

     This completely removes the overhead from the enqueue path, which
     is e.g. for networking a true hotpath and trades it for a slightly
     more complex idle path.

     This has been in development for a couple of years and the final
     series has been extensively tested by various teams from silicon
     vendors and ran through extensive CI.

     There have been slight performance improvements observed on network
     centric workloads and an Intel team confirmed that this allows them
     to power down a die completely on a mult-die socket for the first
     time in a mostly idle scenario.

     There is only one outstanding ~1.5% regression on a specific
     overloaded netperf test which is currently investigated, but the
     rest is either positive or neutral performance wise and positive on
     the power management side.

   - Fixes for the timekeeping interpolation code for cross-timestamps:

     cross-timestamps are used for PTP to get snapshots from hardware
     timers and interpolated them back to clock MONOTONIC. The changes
     address a few corner cases in the interpolation code which got the
     math and logic wrong.

   - Simplifcation of the clocksource watchdog retry logic to
     automatically adjust to handle larger systems correctly instead of
     having more incomprehensible command line parameters.

   - Treewide consolidation of the VDSO data structures.

   - The usual small improvements and cleanups all over the place"

* tag 'timers-core-2024-03-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (62 commits)
  timer/migration: Fix quick check reporting late expiry
  tick/sched: Fix build failure for CONFIG_NO_HZ_COMMON=n
  vdso/datapage: Quick fix - use asm/page-def.h for ARM64
  timers: Assert no next dyntick timer look-up while CPU is offline
  tick: Assume timekeeping is correctly handed over upon last offline idle call
  tick: Shut down low-res tick from dying CPU
  tick: Split nohz and highres features from nohz_mode
  tick: Move individual bit features to debuggable mask accesses
  tick: Move got_idle_tick away from common flags
  tick: Assume the tick can't be stopped in NOHZ_MODE_INACTIVE mode
  tick: Move broadcast cancellation up to CPUHP_AP_TICK_DYING
  tick: Move tick cancellation up to CPUHP_AP_TICK_DYING
  tick: Start centralizing tick related CPU hotplug operations
  tick/sched: Don't clear ts::next_tick again in can_stop_idle_tick()
  tick/sched: Rename tick_nohz_stop_sched_tick() to tick_nohz_full_stop_tick()
  tick: Use IS_ENABLED() whenever possible
  tick/sched: Remove useless oneshot ifdeffery
  tick/nohz: Remove duplicate between lowres and highres handlers
  tick/nohz: Remove duplicate between tick_nohz_switch_to_nohz() and tick_setup_sched_timer()
  hrtimer: Select housekeeping CPU during migration
  ...

Boqun pointed out that workqueues aren't handling BH work items on offlined
CPUs. Unlike tasklet which transfers out the pending tasks from
CPUHP_SOFTIRQ_DEAD, BH workqueue would just leave them pending which is
problematic. Note that this behavior is specific to BH workqueues as the
non-BH per-CPU workers just become unbound when the CPU goes offline.

This patch fixes the issue by draining the pending BH work items from an
offlined CPU from CPUHP_SOFTIRQ_DEAD. Because work items carry more context,
it's not as easy to transfer the pending work items from one pool to
another. Instead, run BH work items which execute the offlined pools on an
online CPU.

Note that this assumes that no further BH work items will be queued on the
offlined CPUs. This assumption is shared with tasklet and should be fine for
conversions. However, this issue also exists for per-CPU workqueues which
will just keep executing work items queued after CPU offline on unbound
workers and workqueue should reject per-CPU and BH work items queued on
offline CPUs. This will be addressed separately later.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: http://lkml.kernel.org/r/Zdvw0HdSXcU3JZ4g@boqun-archlinux

When CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel will report
the work functions which violate the intensive_threshold_us repeatedly.
And now, only when the violate times exceed 4 and is a power of 2,
the kernel warning could be triggered.

However, sometimes, even if a long work execution time occurs only once,
it may cause other work to be delayed for a long time. This may also
cause some problems sometimes.

In order to freely control the threshold of warninging, a boot argument
is added so that the user can control the warning threshold to be printed.
At the same time, keep the exponential backoff to prevent reporting too much.

By default, the warning threshold is 4.

tj: Updated kernel-parameters.txt description.

Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

The implementation of the NOHZ pull at expiry model will change the timer
bases per CPU. Timers, that have to expire on a specific CPU, require the
TIMER_PINNED flag. If the CPU doesn't matter, the TIMER_PINNED flag must be
dropped. This is required for call sites which use the timer alternately as
pinned and not pinned timer like workqueues do.

Therefore use add_timer_global() in __queue_delayed_work() for non-bound
delayed work to make sure the TIMER_PINNED flag is dropped.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-7-anna-maria@linutronix.de

- set_work_data() takes a separate @flags argument but just ORs it to @data.
  This is more confusing than helpful. Just take @data.

- Use the name @flags consistently and add the parameter to
  set_work_pool_and_{keep|clear}_pending(). This will be used by the planned
  disable/enable support.

No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

clear_work_data() is only used in one place and immediately followed by
smp_mb(), making it equivalent to set_work_pool_and_clear_pending() w/
WORK_OFFQ_POOL_NONE for @pool_id. Drop it. No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

The planned disable/enable support will need the same logic. Let's factor it
out. No functional changes.

v2: Update function comment to include @irq_flags.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

The bits of work->data are used for a few different purposes. How the bits
are used is determined by enum work_bits. The planned disable/enable support
will add another use, so let's clean it up a bit in preparation.

- Let WORK_STRUCT_*_BIT's values be determined by enum definition order.

- Deliminate different bit sections the same way using SHIFT and BITS
  values.

- Rename __WORK_OFFQ_CANCELING to WORK_OFFQ_CANCELING_BIT for consistency.

- Introduce WORK_STRUCT_PWQ_SHIFT and replace WORK_STRUCT_FLAG_MASK and
  WORK_STRUCT_WQ_DATA_MASK with WQ_STRUCT_PWQ_MASK for clarity.

- Improve documentation.

No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

The cancel path used bool @is_dwork to distinguish canceling a regular work
and a delayed one. The planned disable/enable support will need passing
around another flag in the code path. As passing them around with bools will
be confusing, let's introduce named flags to pass around in the cancel path.

WORK_CANCEL_DELAYED replaces @is_dwork. No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>