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authorThomas Gleixner <tglx@linutronix.de>2015-04-14 23:08:58 +0200
committerThomas Gleixner <tglx@linutronix.de>2015-04-22 17:06:50 +0200
commitc1ad348b452aacd784fb97403d03d71723c72ee1 (patch)
tree8f57456095d7125463a9647701acfe24b9d96ffc /kernel/time/tick-internal.h
parenttick: Sched: Restructure code (diff)
downloadlinux-c1ad348b452aacd784fb97403d03d71723c72ee1.tar.xz
linux-c1ad348b452aacd784fb97403d03d71723c72ee1.zip
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>
Diffstat (limited to 'kernel/time/tick-internal.h')
-rw-r--r--kernel/time/tick-internal.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index b64fdd8054c5..65273f0a11ed 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -137,3 +137,5 @@ extern void tick_nohz_init(void);
# else
static inline void tick_nohz_init(void) { }
#endif
+
+extern u64 get_next_timer_interrupt(unsigned long basej, u64 basem);