Re: linux-next 20111025: warnings in rcu_idle_exit_common()/rcu_idle_enter_common()

Paul E. McKenney
2011-11-02T15:19:46Z

On Wed, Nov 02, 2011 at 11:01:46PM +0800, Wu Fengguang wrote:
> On Wed, Nov 02, 2011 at 10:56:26PM +0800, Steven Rostedt wrote:
> > On Wed, 2011-11-02 at 07:44 -0700, Paul E. McKenney wrote:
> >
> > > rcu: Fix idle-task checks
> > >
> > > RCU has traditionally relied on idle_cpu() to determine whether a given
> > > CPU is running in the context of an idle task, but recent changes have
> > > invalidated this approach.
> >
> > Correct. idle_cpu() returns if the CPU is idle or not, not if the CPU is
> > running the idle thread. If the CPU wakes up on the idle thread and
> > there's tasks on the run queue, then idle_cpu() will return false, even
> > though the task running is the idle thread. But the CPU itself is not
> > technically idle.
> >
> > Acked-by: Steven Rostedt <rostedt@goodmis.org>
>
> With the patch I no longer see the RCU warnings. Below is the full dmesg.
>
> Tested-by: Wu Fengguang <fengguang.wu@intel.com>

... and your Tested-by.

Thank you all!!!

Thanx, Paul