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| author |   Thomas Gleixner <tglx@linutronix.de> | 2015-04-14 21:08:58 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-04-22 17:06:50 +0200 |
| commit | c1ad348b452aacd784fb97403d03d71723c72ee1 (patch) | |
| tree | 8f57456095d7125463a9647701acfe24b9d96ffc /kernel/time/timer_list.c | |
| parent | tick: Sched: Restructure code (diff) | |
| download | linux-dev-c1ad348b452aacd784fb97403d03d71723c72ee1.tar.xz linux-dev-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/timer_list.c')
| -rw-r--r-- | kernel/time/timer_list.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c index 6232fc536185..66f39bba5353 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -191,7 +191,7 @@ static void print_cpu(struct seq_file *m, int cpu, u64 now) P_ns(idle_sleeptime); P_ns(iowait_sleeptime); P(last_jiffies); - P(next_jiffies); + P(next_timer); P_ns(idle_expires); SEQ_printf(m, "jiffies: %Lu\n", (unsigned long long)jiffies); @@ -289,7 +289,7 @@ static void timer_list_show_tickdevices_header(struct seq_file *m) static inline void timer_list_header(struct seq_file *m, u64 now) { - SEQ_printf(m, "Timer List Version: v0.7\n"); + SEQ_printf(m, "Timer List Version: v0.8\n"); SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES); SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now); SEQ_printf(m, "\n"); |