• Thomas Gleixner's avatar
    tick: Nohz: Rework next timer evaluation · c1ad348b
    Thomas Gleixner authored
    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: default avatarThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    Acked-by: default avatarPeter 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.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
rcutree.h 3.53 KB