Merge tag 'timers-core-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git...

Merge tag 'timers-core-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer subsystem updates from Ingo Molnar:

 - Various preparatory cleanups & enhancements of the timer-wheel code,
   in preparation for the WIP 'pull timers at expiry' timer migration
   model series (which will replace the current 'push timers at enqueue'
   migration model), by Anna-Maria Behnsen:

      - Update comments and clean up confusing variable names

      - Add debug check to warn about time travel

      - Improve/expand timer-wheel tracepoints

      - Optimize away unnecessary IPIs for deferrable timers

      - Restructure & clean up next_expiry_recalc()

      - Clean up forward_timer_base()

      - Introduce __forward_timer_base() and use it to simplify and
        micro-optimize get_next_timer_interrupt()

 - Restructure the get_next_timer_interrupt()'s idle logic for better
   readability and to enable a minor optimization.

 - Fix the nextevt calculation when no timers are pending

 - Fix the sysfs_get_uname() prototype declaration

* tag 'timers-core-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Fix nextevt calculation when no timers are pending
  timers: Rework idle logic
  timers: Use already existing function for forwarding timer base
  timers: Split out forward timer base functionality
  timers: Clarify check in forward_timer_base()
  timers: Move store of next event into __next_timer_interrupt()
  timers: Do not IPI for deferrable timers
  tracing/timers: Add tracepoint for tracking timer base is_idle flag
  tracing/timers: Enhance timer_start tracepoint
  tick-sched: Warn when next tick seems to be in the past
  tick/sched: Cleanup confusing variables
  tick-sched: Fix function names in comments
  time: Make sysfs_get_uname() function visible in header