Re: [PATCH 05/32] nohz: Move rcu dynticks idle mode handling to idle enter/exit APIs

Peter Zijlstra
2011-08-30T11:19:40Z

On Tue, 2011-08-30 at 01:35 +0200, Frederic Weisbecker wrote:
>
> OTOH it is needed to find non-critical sections when asked to cooperate
> in a grace period completion. But if no callback have been enqueued on
> the whole system we are fine.

Its that 'whole system' clause that I have a problem with. It would be
perfectly fine to have a number of cpus very busy generating rcu
callbacks, however this should not mean our adaptive nohz cpu should be
bothered to complete grace periods.

Requiring it to participate in the grace period state machine is a fail,
plain and simple.