summaryrefslogtreecommitdiff
path: root/include/linux/time64.h
AgeCommit message (Collapse)AuthorFilesLines
2015-08-17time: Introduce struct itimerspec64Baolin Wang1-0/+35
The struct itimerspec is not year 2038 safe on 32bit systems due to the limitation of the struct timespec members. Introduce itimerspec64 which uses struct timespec64 instead and provide conversion functions. Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2015-06-12time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edgeJohn Stultz1-0/+1
Currently, leapsecond adjustments are done at tick time. As a result, the leapsecond was applied at the first timer tick *after* the leapsecond (~1-10ms late depending on HZ), rather then exactly on the second edge. This was in part historical from back when we were always tick based, but correcting this since has been avoided since it adds extra conditional checks in the gettime fastpath, which has performance overhead. However, it was recently pointed out that ABS_TIME CLOCK_REALTIME timers set for right after the leapsecond could fire a second early, since some timers may be expired before we trigger the timekeeping timer, which then applies the leapsecond. This isn't quite as bad as it sounds, since behaviorally it is similar to what is possible w/ ntpd made leapsecond adjustments done w/o using the kernel discipline. Where due to latencies, timers may fire just prior to the settimeofday call. (Also, one should note that all applications using CLOCK_REALTIME timers should always be careful, since they are prone to quirks from settimeofday() disturbances.) However, the purpose of having the kernel do the leap adjustment is to avoid such latencies, so I think this is worth fixing. So in order to properly keep those timers from firing a second early, this patch modifies the ntp and timekeeping logic so that we keep enough state so that the update_base_offsets_now accessor, which provides the hrtimer core the current time, can check and apply the leapsecond adjustment on the second edge. This prevents the hrtimer core from expiring timers too early. This patch does not modify any other time read path, so no additional overhead is incurred. However, this also means that the leap-second continues to be applied at tick time for all other read-paths. Apologies to Richard Cochran, who pushed for similar changes years ago, which I resisted due to the concerns about the performance overhead. While I suspect this isn't extremely critical, folks who care about strict leap-second correctness will likely want to watch this. Potentially a -stable candidate eventually. Originally-suggested-by: Richard Cochran <richardcochran@gmail.com> Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com> Reported-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/1434063297-28657-4-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-22time: Include math64.h in time64.hXunlei Pang1-0/+1
On 32-bit systems, timespec64_add_ns() calls __iter_div_u64_rem() which needs math64.h, and we want to include time64.h in some cases. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23time: More core infrastructure for timespec64John Stultz1-0/+28
Helper and conversion functions for timespec64. Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23time64: Add time64.h header and define struct timespec64John Stultz1-0/+162
Define the timespec64 structure and standard helper functions. [ tglx: Make it 32bit only. 64bit really can map timespec to timespec64 ] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>