linux/kernel/time
John Stultz 3d88d56c58 time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting
Due to how the MONOTONIC_RAW accumulation logic was handled,
there is the potential for a 1ns discontinuity when we do
accumulations. This small discontinuity has for the most part
gone un-noticed, but since ARM64 enabled CLOCK_MONOTONIC_RAW
in their vDSO clock_gettime implementation, we've seen failures
with the inconsistency-check test in kselftest.

This patch addresses the issue by using the same sub-ns
accumulation handling that CLOCK_MONOTONIC uses, which avoids
the issue for in-kernel users.

Since the ARM64 vDSO implementation has its own clock_gettime
calculation logic, this patch reduces the frequency of errors,
but failures are still seen. The ARM64 vDSO will need to be
updated to include the sub-nanosecond xtime_nsec values in its
calculation for this issue to be completely fixed.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Daniel Mentz <danielmentz@google.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "stable #4 . 8+" <stable@vger.kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Link: http://lkml.kernel.org/r/1496965462-20003-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-06-20 10:41:50 +02:00
..
Kconfig rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL 2015-07-06 13:52:18 -07:00
Makefile time: Remove CONFIG_TIMER_STATS 2017-02-10 11:15:08 +01:00
alarmtimer.c alarmtimer: Rate limit periodic intervals 2017-06-04 15:21:18 +02:00
clockevents.c clockevents: Make clockevents_config() static 2017-03-23 12:14:05 -07:00
clocksource.c sched/clock, clocksource: Add optional cs::mark_unstable() method 2017-01-14 11:29:43 +01:00
hrtimer.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
itimer.c sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h> 2017-03-02 08:42:39 +01:00
jiffies.c jiffies: Revert bogus conversion of NSEC_PER_SEC to TICK_NSEC 2017-03-07 11:03:28 +01:00
ntp.c ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
ntp_internal.h ntp: Fix second_overflow's input parameter type to be 64bits 2015-12-16 16:50:56 -08:00
posix-clock.c time: Change k_clock timer_set() and timer_get() to use timespec64 2017-04-14 21:49:56 +02:00
posix-cpu-timers.c posix-timers: Make signal printks conditional 2017-05-23 23:39:57 +02:00
posix-stubs.c time: Change k_clock nsleep() to use timespec64 2017-04-14 21:49:56 +02:00
posix-timers.c time: Change k_clock nsleep() to use timespec64 2017-04-14 21:49:56 +02:00
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 ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
tick-broadcast.c tick/broadcast: Make tick_broadcast_setup_oneshot() static 2017-06-12 18:56:01 +02:00
tick-common.c ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
tick-internal.h tick/broadcast: Make tick_broadcast_setup_oneshot() static 2017-06-12 18:56:01 +02:00
tick-oneshot.c ktime: Get rid of the union 2016-12-25 17:21:22 +01:00
tick-sched.c cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely 2017-03-23 02:12:14 +01:00
tick-sched.h Revert "nohz: Fix collision between tick and other hrtimers" 2017-02-16 12:19:18 -08:00
time.c time: delete current_fs_time() 2017-05-12 15:57:15 -07:00
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.c time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting 2017-06-20 10:41:50 +02:00
timekeeping.h timekeeping: Remove unused timekeeping_{get,set}_tai_offset() 2017-01-06 16:47:28 -08:00
timekeeping_debug.c timekeeping: Use deferred printk() in debug code 2017-02-15 11:46:08 +01:00
timekeeping_internal.h clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
timer.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
timer_list.c sysrq: Reset the watchdog timers while displaying high-resolution timers 2017-03-23 12:46:53 -07:00