Re: [PATCH v4] x86/power: Fix 'nosmt' vs. hibernation triple fault during resume

From: Rafael J. Wysocki
Date: Mon Jun 03 2019 - 06:07:38 EST


On Friday, May 31, 2019 6:19:52 PM CEST Josh Poimboeuf wrote:
> On Fri, May 31, 2019 at 05:41:18PM +0200, Jiri Kosina wrote:
> > On Fri, 31 May 2019, Josh Poimboeuf wrote:
> >
> > > The only question I'd have is if we have data on the power savings
> > > difference between hlt and mwait. mwait seems to wake up on a lot of
> > > different conditions which might negate its deeper sleep state.
> >
> > hlt wakes up on basically the same set of events, but has the
> > auto-restarting semantics on some of them (especially SMM). So the wakeup
> > frequency itself shouldn't really contribute to power consumption
> > difference; it's the C-state that mwait allows CPU to enter.
>
> Ok. I reluctantly surrender :-) For your v4:
>
> Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
>
> It works as a short term fix, but it's fragile, and it does feel like
> we're just adding more duct tape, as Andy said.

OK, the v4 queued up then, thanks!