Re: [PATCH][RFC] x86, hotplug: Use zero page for monitor when resuming from hibernation

[Peter Zijlstra]

On Mon, Jun 06, 2016 at 03:59:06PM +0000, Chen, Yu C wrote:

> > > + if (hibernation_in_resume())
> > > +         mwait_ptr = empty_zero_page;
> > > + else
> > > +         mwait_ptr = &current_thread_info()->flags;
> > 
> > Why is this conditional? Is there any case in which the zero page is not 
> > also
> > correct?
> I'm thinking of avoid unnecessary wakeup for normal CPU offline,  for 
> example, 
> if one  driver uses  the zero page and access it.

Writing to the zero page would be a major fail.