linux/kernel/time
Linus Torvalds 70293240c5 Two regression fixes for the timer and timer migration code:
1) Prevent endless timer requeuing which is caused by two CPUs racing out
      of idle. This happens when the last CPU goes idle and therefore has to
      ensure to expire the pending global timers and some other CPU come out
      of idle at the same time and the other CPU wins the race and expires
      the global queue. This causes the last CPU to chase ghost timers
      forever and reprogramming it's clockevent device endlessly.
 
      Cure this by re-evaluating the wakeup time unconditionally.
 
   2) The split into local (pinned) and global timers in the timer wheel
      caused a regression for NOHZ full as it broke the idle tracking of
      global timers. On NOHZ full this prevents an self IPI being sent which
      in turn causes the timer to be not programmed and not being expired on
      time.
 
      Restore the idle tracking for the global timer base so that the self
      IPI condition for NOHZ full is working correctly again.
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Merge tag 'timers-urgent-2024-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "Two regression fixes for the timer and timer migration code:

   - Prevent endless timer requeuing which is caused by two CPUs racing
     out of idle. This happens when the last CPU goes idle and therefore
     has to ensure to expire the pending global timers and some other
     CPU come out of idle at the same time and the other CPU wins the
     race and expires the global queue. This causes the last CPU to
     chase ghost timers forever and reprogramming it's clockevent device
     endlessly.

     Cure this by re-evaluating the wakeup time unconditionally.

   - The split into local (pinned) and global timers in the timer wheel
     caused a regression for NOHZ full as it broke the idle tracking of
     global timers. On NOHZ full this prevents an self IPI being sent
     which in turn causes the timer to be not programmed and not being
     expired on time.

     Restore the idle tracking for the global timer base so that the
     self IPI condition for NOHZ full is working correctly again"

* tag 'timers-urgent-2024-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Fix removed self-IPI on global timer's enqueue in nohz_full
  timers/migration: Fix endless timer requeue after idle interrupts
2024-03-23 14:49:25 -07:00
..
alarmtimer.c rtc: class: make rtc_class constant 2024-03-08 12:05:10 +01:00
clockevents.c clockevents: Make clockevents_subsys const 2024-02-07 15:11:24 +01:00
clocksource-wdtest.c clocksource: Scale the watchdog read retries automatically 2024-02-21 12:00:42 +01:00
clocksource.c clocksource: Scale the watchdog read retries automatically 2024-02-21 12:00:42 +01:00
hrtimer.c tick: Split nohz and highres features from nohz_mode 2024-02-26 11:37:32 +01:00
itimer.c time: Prevent undefined behaviour in timespec64_to_ns() 2020-10-26 11:48:11 +01:00
jiffies.c clocksource: Make clocksource watchdog test safe for slow-HZ systems 2021-08-28 17:01:32 +02:00
Kconfig sched/idle: Conditionally handle tick broadcast in default_idle_call() 2024-03-01 21:04:27 +01:00
Makefile timers: Implement the hierarchical pull model 2024-02-22 17:52:32 +01:00
namespace.c vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy 2022-12-01 11:35:40 +01:00
ntp_internal.h ntp: Make the RTC synchronization more reliable 2020-12-11 10:40:52 +01:00
ntp.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00
posix-clock.c posix-clock: introduce posix_clock_context concept 2023-10-15 20:07:52 +01:00
posix-cpu-timers.c posix-cpu-timers: Implement the missing timer_wait_running callback 2023-04-21 15:34:33 +02:00
posix-stubs.c posix-timers: Get rid of [COMPAT_]SYS_NI() uses 2023-12-20 21:30:27 -08:00
posix-timers.c posix-timers: Refer properly to CONFIG_HIGH_RES_TIMERS 2023-06-18 22:41:53 +02:00
posix-timers.h posix-clocks: Introduce clock_get_ktime() callback 2020-01-14 12:20:51 +01:00
sched_clock.c time/sched_clock: Provide sched_clock_noinstr() 2023-06-05 21:11:04 +02:00
test_udelay.c time/debug: Fix memory leak with using debugfs_lookup() 2023-02-09 20:12:27 +01:00
tick-broadcast-hrtimer.c time/tick-broadcast: Remove RCU_NONIDLE() usage 2023-01-13 11:48:16 +01:00
tick-broadcast.c tick/broadcast: Make broadcast device replacement work correctly 2023-05-08 23:18:16 +02:00
tick-common.c tick: Assume timekeeping is correctly handed over upon last offline idle call 2024-02-26 11:37:32 +01:00
tick-internal.h tick: Move broadcast cancellation up to CPUHP_AP_TICK_DYING 2024-02-26 11:37:32 +01:00
tick-legacy.c timekeeping: remove xtime_update 2020-10-30 21:57:07 +01:00
tick-oneshot.c time: Fix various kernel-doc problems 2023-01-03 11:07:58 +01:00
tick-sched.c tick: Assume timekeeping is correctly handed over upon last offline idle call 2024-02-26 11:37:32 +01:00
tick-sched.h tick/sched: Fix build failure for CONFIG_NO_HZ_COMMON=n 2024-02-29 17:41:29 +01:00
time_test.c time: test: Fix incorrect format specifier 2024-02-27 15:26:08 -07:00
time.c time: add kernel-doc in time.c 2023-07-14 13:47:07 -06:00
timeconst.bc time: Add SPDX license identifiers 2018-11-23 11:51:20 +01:00
timeconv.c time: Improve performance of time64_to_tm() 2021-06-24 11:51:59 +02:00
timecounter.c time/timecounter: Mark 1st argument of timecounter_cyc2time() as const 2021-04-16 21:03:50 +02:00
timekeeping_debug.c timekeeping/debug: No need to check return value of debugfs_create functions 2019-01-29 20:08:41 +01:00
timekeeping_internal.h timekeeping/vsyscall: Provide vdso_update_begin/end() 2020-08-06 10:57:30 +02:00
timekeeping.c A large set of updates and features for timers and timekeeping: 2024-03-11 14:38:26 -07:00
timekeeping.h asm-generic: cross-architecture timer cleanup 2020-12-16 00:07:17 -08:00
timer_list.c tick: Split nohz and highres features from nohz_mode 2024-02-26 11:37:32 +01:00
timer_migration.c timers/migration: Fix endless timer requeue after idle interrupts 2024-03-19 10:14:55 +01:00
timer_migration.h timers: Implement the hierarchical pull model 2024-02-22 17:52:32 +01:00
timer.c timers: Fix removed self-IPI on global timer's enqueue in nohz_full 2024-03-19 10:14:55 +01:00
vsyscall.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00