linux/kernel/time
Thomas Gleixner c1ad348b45 tick: Nohz: Rework next timer evaluation
The evaluation of the next timer in the nohz code is based on jiffies
while all the tick internals are nano seconds based. We have also to
convert hrtimer nanoseconds to jiffies in the !highres case. That's
just wrong and introduces interesting corner cases.

Turn it around and convert the next timer wheel timer expiry and the
rcu event to clock monotonic and base all calculations on
nanoseconds. That identifies the case where no timer is pending
clearly with an absolute expiry value of KTIME_MAX.

Makes the code more readable and gets rid of the jiffies magic in the
nohz code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Link: http://lkml.kernel.org/r/20150414203502.184198593@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-04-22 17:06:50 +02:00
..
alarmtimer.c hrtimer: Get rid of hrtimer_get_res() 2015-04-22 17:06:49 +02:00
clockevents.c clockevents: Cleanup dead cpu explicitely 2015-04-03 08:44:37 +02:00
clocksource.c clocksource: Improve comment explaining clocks_calc_max_nsecs()'s 50% safety margin 2015-04-03 08:18:35 +02:00
hrtimer.c tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
itimer.c time/timers: Move all time(r) related files into kernel/time 2014-06-23 11:22:35 +02:00
jiffies.c tick: Move clocksource related stuff to timekeeping.h 2015-04-01 14:22:58 +02:00
Kconfig clockevents: Remove CONFIG_GENERIC_CLOCKEVENTS_BUILD 2015-04-01 14:22:57 +02:00
Makefile clockevents: Remove CONFIG_GENERIC_CLOCKEVENTS_BUILD 2015-04-01 14:22:57 +02:00
ntp_internal.h timekeeping: Convert timekeeping core to use timespec64s 2014-07-23 10:17:54 -07:00
ntp.c time: Add y2038 safe update_persistent_clock64() 2015-04-03 08:18:20 +02:00
posix-clock.c
posix-cpu-timers.c all arches, signal: move restart_block to struct task_struct 2015-02-12 18:54:12 -08:00
posix-timers.c hrtimer: Get rid of hrtimer_get_res() 2015-04-22 17:06:49 +02:00
sched_clock.c timers, sched/clock: Clean up the code a bit 2015-03-27 08:34:01 +01:00
test_udelay.c time: Rename udelay_test.c to test_udelay.c 2014-11-21 11:59:55 -08:00
tick-broadcast-hrtimer.c timers/tick/broadcast-hrtimer: Fix suspicious RCU usage in idle loop 2015-03-23 10:50:05 +01:00
tick-broadcast.c clockevents: Cleanup dead cpu explicitely 2015-04-03 08:44:37 +02:00
tick-common.c hrtimer: Get rid of hrtimer softirq 2015-04-22 17:06:50 +02:00
tick-internal.h tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
tick-oneshot.c clockevents: Manage device's state separately for the core 2015-03-27 10:26:19 +01:00
tick-sched.c tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
tick-sched.h tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
time.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-01-25 17:47:34 -08:00
timeconst.bc time/timers: Move all time(r) related files into kernel/time 2014-06-23 11:22:35 +02:00
timeconv.c
timecounter.c timecounter: keep track of accumulated fractional nanoseconds 2014-12-30 18:29:27 -05:00
timekeeping_debug.c timekeeping: Convert timekeeping core to use timespec64s 2014-07-23 10:17:54 -07:00
timekeeping_internal.h clocksource: Move cycle_last validation to core code 2014-07-23 15:01:51 -07:00
timekeeping.c hrtimer: Make offset update smarter 2015-04-22 17:06:49 +02:00
timekeeping.h hrtimer: Make offset update smarter 2015-04-22 17:06:49 +02:00
timer_list.c tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00
timer_stats.c timer stats: Add a 'Collection: active/inactive' line to timer usage statistics 2013-10-10 09:59:25 +02:00
timer.c tick: Nohz: Rework next timer evaluation 2015-04-22 17:06:50 +02:00