NOHZ: Check for nohz active instead of nohz enabled

2013-11-19T13:59:50Z

RCU and the fine grained idle time accounting functions check tick_nohz_enabled. But that variable is merily telling that NOHZ has been enabled in the config and not been disabled on the command line. But it does not tell anything about nohz being active. That's what all this should check for. Matthew reported, that the idle accounting on his old P1 machine showed bogus values, when he enabled NOHZ in the config and did not disable it on the kernel command line. The reason is that his machine uses (refined) jiffies as a clocksource which explains why the "fine" grained accounting went into lala land, because it depends on when the system goes and leaves idle relative to the jiffies increment. Provide a tick_nohz_active indicator and let RCU and the accounting code use this instead of tick_nohz_enable. Reported-and-tested-by: Matthew Whitehead Signed-off-by: Thomas Gleixner Reviewed-by: Steven Rostedt Reviewed-by: Paul E. McKenney Cc: john.stultz@linaro.org Cc: mwhitehe@redhat.com Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1311132052240.30673@ionos.tec.linutronix.de

locking: Move the rtmutex code to kernel/locking/

2013-11-06T08:23:59Z

Suggested-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-p9ijt8div0hwldexwfm4nlhj@git.kernel.org [ Fixed build failure in kernel/rcu/tree_plugin.h. ] Signed-off-by: Ingo Molnar

rcu: Move RCU-related source code to kernel/rcu directory

2013-10-15T19:53:31Z

Signed-off-by: Paul E. McKenney Reviewed-by: Ingo Molnar

linux/kernel/rcu/tree_plugin.h, branch v3.13

NOHZ: Check for nohz active instead of nohz enabled

locking: Move the rtmutex code to kernel/locking/

rcu: Move RCU-related source code to kernel/rcu directory