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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Andy Lutomirski <luto@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	the arch/x86 maintainers <x86@kernel.org>,
	Pavel Machek <pavel@ucw.cz>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4] x86/power: Fix 'nosmt' vs. hibernation triple fault during resume
Date: Fri, 31 May 2019 10:26:26 -0500	[thread overview]
Message-ID: <20190531152626.4nmyc7lj6mjwuo2v@treble> (raw)
In-Reply-To: <nycvar.YFH.7.76.1905311651450.1962@cbobk.fhfr.pm>

On Fri, May 31, 2019 at 04:54:20PM +0200, Jiri Kosina wrote:
> On Fri, 31 May 2019, Andy Lutomirski wrote:
> 
> > For that matter, what actually happens if we get an SMI while halted?  
> > Does RSM go directly to sleep or does it re-fetch the HLT?
> 
> Our mails just crossed, I replied to Josh's mwait() proposal patch a 
> minute ago.

Good catch.  I agree that mwait seems unsafe across resume and my patch
is bogus.

Andy, in the short term it sounds like you're proposing to make
native_play_dead() use hlt_play_dead() unconditionally.  Right?

That would simplify things and also would fix Jiri's bug I think.  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.

Andy, for your long term idea to use INIT IPI, I wonder if that would
work with SMT siblings?  Specifically I wonder about the Intel issue
that requires siblings to have CR4.MCE set.

-- 
Josh

  reply	other threads:[~2019-05-31 15:26 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28 21:31 [PATCH] x86/power: Fix 'nosmt' vs. hibernation triple fault during resume Jiri Kosina
2019-05-29  8:06 ` Rafael J. Wysocki
2019-05-29  9:03 ` Peter Zijlstra
2019-05-29 10:32 ` [PATCH v2] " Jiri Kosina
2019-05-29 12:02   ` Peter Zijlstra
2019-05-29 16:10   ` Josh Poimboeuf
2019-05-29 16:26     ` Jiri Kosina
2019-05-29 17:00       ` Peter Zijlstra
2019-05-29 17:15         ` Thomas Gleixner
2019-05-29 17:17       ` Josh Poimboeuf
2019-05-29 17:29         ` Jiri Kosina
2019-05-29 18:02           ` Jiri Kosina
2019-05-29 20:26 ` [PATCH v3] " Jiri Kosina
2019-05-29 21:25   ` Pavel Machek
2019-05-29 21:27     ` Jiri Kosina
2019-05-29 21:53       ` Pavel Machek
2019-05-29 22:09 ` [PATCH v4] " Jiri Kosina
2019-05-30  8:46   ` Rafael J. Wysocki
2019-05-30 21:27     ` Thomas Gleixner
2019-05-30 21:38       ` Rafael J. Wysocki
2019-05-30 23:38         ` Josh Poimboeuf
2019-05-30 23:42           ` Jiri Kosina
2019-05-31  5:14             ` Josh Poimboeuf
2019-05-31  8:26               ` Rafael J. Wysocki
2019-05-31  8:47               ` Jiri Kosina
2019-05-31  8:57                 ` Rafael J. Wysocki
2019-05-31 14:24                   ` Andy Lutomirski
2019-05-31 14:31                     ` Jiri Kosina
2019-05-31 14:33                       ` Jiri Kosina
2019-05-31 14:46                       ` Andy Lutomirski
2019-05-31 14:54                         ` Jiri Kosina
2019-05-31 15:26                           ` Josh Poimboeuf [this message]
2019-05-31 15:41                             ` Jiri Kosina
2019-05-31 16:19                               ` Josh Poimboeuf
2019-05-31 16:51                                 ` Andy Lutomirski
2019-05-31 18:11                                   ` Josh Poimboeuf
2019-06-03 10:03                                 ` Rafael J. Wysocki
2019-05-31 16:23                           ` Andy Lutomirski
2019-05-31 21:05                             ` Jiri Kosina
2019-05-31 21:22                               ` Andy Lutomirski
2019-06-03 14:23                                 ` Sean Christopherson
2019-06-03 15:24                                   ` Jiri Kosina
2019-06-03 16:18                                     ` Sean Christopherson
2019-05-31 12:09               ` Jiri Kosina
2019-05-31 14:51               ` Jiri Kosina
2019-05-31 12:18             ` Pavel Machek
2019-05-30 10:47   ` Pavel Machek

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