On Thu, Sep 18, 2014 at 10:39:25AM -0700, Paul E. McKenney wrote:

On Thu, Sep 18, 2014 at 10:37:33AM -0700, Paul E. McKenney wrote:

quoted

A stop_cpus() will force a context switch on all CPUs, though it is
a rather big hammer.

And I was reminded by the very next email that kick_all_cpus_sync() is
another possibility -- it forces an interrupt on all online CPUs, idle
or not.

I actually have a patch
http://lkml.kernel.org/r/1409815075-4180-2-git-send-email-chuansheng.liu@intel.com
that changes that, because apparently there are idle loops that don't
actually exit on interrupt :-)

But yes, something like the wake_up_all_idle_cpus() should do.