On Thu, 13 Apr 2017 16:38:07 +0200 Peter Zijlstra <pet...@infradead.org> wrote:
> On Thu, Apr 13, 2017 at 09:48:40AM -0400, Steven Rostedt wrote: > > On Thu, 13 Apr 2017 10:44:53 +0200 > > Peter Zijlstra <pet...@infradead.org> wrote: > > > > > On Wed, Apr 12, 2017 at 02:27:44PM -0400, Steven Rostedt wrote: > > > > + * schedule_idle() is similar to schedule_preempt_disable() except > > > > + * that it never enables preemption. > > > > > > That's not right. The primary distinction is that it doesn't call > > > sched_submit_work(). > > > > That has nothing to do with fixing synchronize_rcu_tasks(), which is > > the entire point of my patch, thus it is *not* the primary distinction. > > It is. The only reason you _can_ avoid that preemption window is by not > doing sched_submit_work(). We are talking apples and oranges here. It's a distinction of the generic call to schedule_preempt_disable() and only one instance of the callers can actually run that. But it is not the idle case, in which case it is a nop. But we are now bike shedding the issue. > > The moment you need to call that, the preemption window comes back. I'll update my change log and comment and repost. Thanks, -- Steve
