From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH][RFC] x86, hotplug: Use zero page for monitor when
 resuming from hibernation
Date: Mon, 6 Jun 2016 18:40:33 +0200
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To: "Chen, Yu C" <yu.c.chen@intel.com>
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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.