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From: Peter Zijlstra <peterz@infradead.org>
To: "Chen, Yu C" <yu.c.chen@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Pavel Machek <pavel@ucw.cz>, "Brown, Len" <len.brown@intel.com>,
	Borislav Petkov <bp@suse.de>,
	Zhu Guihua <zhugh.fnst@cn.fujitsu.com>,
	Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH][RFC] x86, hotplug: Use zero page for monitor when resuming from hibernation
Date: Mon, 6 Jun 2016 18:40:33 +0200	[thread overview]
Message-ID: <20160606164033.GD30154@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <36DF59CE26D8EE47B0655C516E9CE6402876CB97@shsmsx102.ccr.corp.intel.com>

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.

  reply	other threads:[~2016-06-06 16:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-06 14:19 [PATCH][RFC] x86, hotplug: Use zero page for monitor when resuming from hibernation Chen Yu
2016-06-06 14:25 ` Peter Zijlstra
2016-06-06 15:59   ` Chen, Yu C
2016-06-06 16:40     ` Peter Zijlstra [this message]
2016-06-06 17:34       ` Brian Gerst
2016-06-06 21:05       ` H. Peter Anvin
2016-06-07  8:03 ` Pavel Machek
2016-06-07  8:44   ` Chen Yu
2016-06-07  9:13     ` Borislav Petkov
2016-06-07  9:43       ` Chen Yu

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