nohz: Avoid tick's double reprogramming in highres mode
authorViresh Kumar <viresh.kumar@linaro.org>
Thu, 12 Jun 2014 10:54:41 +0000 (16:24 +0530)
committerFrederic Weisbecker <frederic@kernel.org>
Fri, 22 Aug 2014 16:47:35 +0000 (18:47 +0200)
commit2a16fc93d2c9568e16d45db77c7b5f15e1921cf1
tree5488a9508a8767e248aab6029f623e7e9dfbb224
parentb5e995e671d8e4d7a75b339ce78ecc586014b0eb
nohz: Avoid tick's double reprogramming in highres mode

In highres mode, the tick reschedules itself unconditionally to the
next jiffies.

However while this clock reprogramming is relevant when the tick is
in periodic mode, it's not that interesting when we run in dynticks mode
because irq exit is likely going to overwrite the next tick to some
randomly deferred future.

So lets just get rid of this tick self rescheduling in dynticks mode.
This way we can avoid some clockevents double write in favourable
scenarios like when we stop the tick completely in idle while no other
hrtimer is pending.

Suggested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
kernel/time/tick-sched.c