linux/kernel/time
Frederic Weisbecker 175cc3ab28 posix-cpu-timers: Force next_expiration recalc after timer deletion
A timer deletion only dequeues the timer but it doesn't shutdown
the related costly process wide cputimer counter and the tick dependency.

The following code snippet keeps this overhead around for one week after
the timer deletion:

	void trigger_process_counter(void)
	{
		timer_t id;
		struct itimerspec val = { };

		val.it_value.tv_sec = 604800;
		timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id);
		timer_settime(id, 0, &val, NULL);
		timer_delete(id);
	}

Make sure the next target's tick recalculates the nearest expiration and
clears the process wide counter and tick dependency if necessary.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210726125513.271824-3-frederic@kernel.org
2021-08-10 17:09:59 +02:00
..
alarmtimer.c alarmtimer: Check RTC features instead of ops 2021-05-11 21:28:04 +02:00
clockevents.c clockevents: Use list_move() instead of list_del()/list_add() 2021-06-22 17:16:46 +02:00
clocksource-wdtest.c clocksource: Provide kernel module to test clocksource watchdog 2021-06-22 16:53:17 +02:00
clocksource.c clocksource: Replace deprecated CPU-hotplug functions. 2021-08-10 14:53:58 +02:00
hrtimer.c The time and timers updates contain: 2021-04-26 09:54:03 -07:00
itimer.c time: Prevent undefined behaviour in timespec64_to_ns() 2020-10-26 11:48:11 +01:00
jiffies.c clocksource: Reduce clocksource-skew threshold 2021-06-22 16:53:16 +02:00
Kconfig -----BEGIN PGP SIGNATURE----- 2021-06-29 12:31:16 -07:00
Makefile time: Improve performance of time64_to_tm() 2021-06-24 11:51:59 +02:00
namespace.c timens: Delete no-op time_ns_init() 2021-02-05 19:32:09 +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-clocks: Rename the clock_get() callback to clock_get_timespec() 2020-01-14 12:20:49 +01:00
posix-cpu-timers.c posix-cpu-timers: Force next_expiration recalc after timer deletion 2021-08-10 17:09:59 +02:00
posix-stubs.c posix-timers: Make clock_nanosleep() time namespace aware 2020-01-14 12:20:55 +01:00
posix-timers.c posix-timers: Remove redundant initialization of variable ret 2021-08-10 17:02:11 +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: Mark sched_clock_read_begin/retry() as notrace 2020-10-26 11:34:31 +01:00
test_udelay.c time/debug: Remove dentry pointer for debugfs 2021-03-18 11:20:26 +01:00
tick-broadcast-hrtimer.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00
tick-broadcast.c timer_list: Print name of per-cpu wakeup device 2021-05-31 17:04:49 +02:00
tick-common.c tick/broadcast: Prefer per-cpu oneshot wakeup timers to broadcast 2021-05-31 17:04:45 +02:00
tick-internal.h timer_list: Print name of per-cpu wakeup device 2021-05-31 17:04:49 +02:00
tick-legacy.c timekeeping: remove xtime_update 2020-10-30 21:57:07 +01:00
tick-oneshot.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00
tick-sched.c Updates to the tick/nohz code in this cycle: 2021-06-28 12:22:06 -07:00
tick-sched.h timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00
time_test.c time/kunit: Add missing MODULE_LICENSE() 2021-06-28 07:40:23 +02:00
time.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00
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 ARM: 2021-05-01 10:14:08 -07:00
timekeeping.h asm-generic: cross-architecture timer cleanup 2020-12-16 00:07:17 -08:00
timer_list.c timer_list: Print name of per-cpu wakeup device 2021-05-31 17:04:49 +02:00
timer.c timers: Move clearing of base::timer_running under base:: Lock 2021-07-27 20:57:44 +02:00
vsyscall.c timekeeping, clocksource: Fix various typos in comments 2021-03-22 23:06:48 +01:00