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b061c7a513
linux/kernel/time
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Miroslav Lichvar b061c7a513 timekeeping: Update multiplier when NTP frequency is set directly 
When the NTP frequency is set directly from userspace using the
ADJ_FREQUENCY or ADJ_TICK timex mode, immediately update the
timekeeper's multiplier instead of waiting for the next tick.

This removes a hidden non-deterministic delay in setting of the
frequency and allows an extremely tight control of the system clock
with update rates close to or even exceeding the kernel HZ.

The update is limited to archs using modern timekeeping
(!ARCH_USES_GETTIMEOFFSET).

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2018-07-10 12:44:25 -07:00
..
alarmtimer.c alarmtimer: Init nanosleep alarm timer on stack 2018-03-29 16:10:07 +02:00
clockevents.c clockevents: Retry programming min delta up to 10 times 2017-10-19 16:29:15 +02:00
clocksource.c clocksource: Move inline keyword to the beginning of function declarations 2018-05-16 22:21:32 +02:00
hrtimer.c posix-timers: Fix nanosleep_copyout() for CONFIG_COMPAT_32BIT_TIME 2018-06-19 09:23:19 +02:00
itimer.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
jiffies.c jiffies: Revert bogus conversion of NSEC_PER_SEC to TICK_NSEC 2017-03-07 11:03:28 +01:00
Kconfig sched/isolation: Eliminate NO_HZ_FULL_ALL 2018-02-15 15:40:37 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ntp_internal.h Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 17:56:58 -08:00
ntp.c jiffies: Introduce USER_TICK_USEC and redefine TICK_USEC 2018-04-06 09:28:50 +02:00
posix-clock.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
posix-cpu-timers.c posix-cpu-timers: Remove lockdep_assert_irqs_disabled() 2018-06-12 17:18:37 +02:00
posix-stubs.c Merge branch 'linus' into timers/2038 2018-05-19 13:55:40 +02:00
posix-timers.c Merge branch 'linus' into timers/2038 2018-05-19 13:55:40 +02:00
posix-timers.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sched_clock.c timers, sched_clock: Update timeout for clock wrap 2017-03-23 12:30:27 -07:00
test_udelay.c time: Avoid timespec in udelay_test 2016-06-20 12:47:26 -07:00
tick-broadcast-hrtimer.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tick-broadcast.c tick/broadcast: Use for_each_cpu() specially on UP kernels 2018-05-15 22:45:54 +02:00
tick-common.c Power management updates for 4.18-rc1 2018-06-05 09:38:39 -07:00
tick-internal.h Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME 2018-04-26 14:53:32 +02:00
tick-oneshot.c clockevents: Fix kernel messages split across multiple lines 2018-04-17 17:18:04 +02:00
tick-sched.c Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME 2018-04-26 14:53:32 +02:00
tick-sched.h nohz: Gather tick_sched booleans under a common flag field 2018-04-09 11:54:57 +02:00
time.c time: Make sure jiffies_to_msecs() preserves non-zero time periods 2018-06-22 17:48:36 +02:00
timeconst.bc time: Introduce jiffies64_to_nsecs() 2017-02-01 09:13:45 +01:00
timeconv.c time: Add time64_to_tm() 2016-06-20 12:47:15 -07:00
timecounter.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
timekeeping_debug.c PM / timekeeping: Print debug messages when requested 2017-07-23 00:03:43 +02:00
timekeeping_internal.h kdb: use __ktime_get_real_seconds instead of __current_kernel_time 2018-01-25 08:40:18 -06:00
timekeeping.c timekeeping: Update multiplier when NTP frequency is set directly 2018-07-10 12:44:25 -07:00
timekeeping.h Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME 2018-04-26 14:53:32 +02:00
timer_list.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 20:27:54 -07:00
timer.c timers: Adjust a kernel-doc comment 2018-05-13 15:55:43 +02:00