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From: Borislav Petkov <bp@alien8.de>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>,
	tigran@aivazian.fsnet.co.uk, tglx@linutronix.de, mingo@elte.hu,
	hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org,
	Linux PM mailing list <linux-pm@lists.linux-foundation.org>
Subject: Re: [BUGFIX][PATCH] Freezer, CPU hotplug, x86 Microcode: Fix task freezing failures
Date: Tue, 4 Oct 2011 15:46:53 +0200	[thread overview]
Message-ID: <20111004134653.GC3148@gere.osrc.amd.com> (raw)
In-Reply-To: <4E8B06E0.2090501@linux.vnet.ibm.com>

On Tue, Oct 04, 2011 at 06:45:12PM +0530, Srivatsa S. Bhat wrote:
> I would like to propose a modified solution to the problem:
> 
> Taking a CPU offline:
> * Upon a CPU_DEAD notification, just like the code originally did, we free
>   the kernel's copy of the microcode and invalidate it. So no changes here.
>  
> Bringing a CPU online:
> * When a CPU_ONLINE or CPU_ONLINE_FROZEN notification is received, 
>   a. If the userspace is not frozen, we request microcode from userspace and
>      apply it to the cpu.
> 
>   b. However if we find that the userspace is frozen at that moment, we defer
>      applying microcode now and register a callback function to be executed
>      immediately when the userspace gets thawed. This callback function would
>      request microcode from userspace and apply it to the cpu.

No need for that if we can drop the whole re-requesting of ucode on
CPU_ONLINE* (see my other mail). Let me run some tests before though.

Thanks.

-- 
Regards/Gruss,
Boris.

  reply	other threads:[~2011-10-04 13:46 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-02 19:05 Srivatsa S. Bhat
2011-10-02 19:36 ` Rafael J. Wysocki
2011-10-02 19:50 ` Tejun Heo
2011-10-02 20:04   ` Srivatsa S. Bhat
2011-10-03  0:40     ` Tejun Heo
2011-10-03  5:51       ` Srivatsa S. Bhat
2011-10-03  8:47         ` Borislav Petkov
2011-10-04  7:15           ` Tejun Heo
2011-10-04 13:15             ` Srivatsa S. Bhat
2011-10-04 13:46               ` Borislav Petkov [this message]
2011-10-04 17:14                 ` Borislav Petkov
2011-10-04 19:49                   ` Rafael J. Wysocki
2011-10-04 20:57                   ` Srivatsa S. Bhat
2011-10-05  7:21                     ` Borislav Petkov
2011-10-05  8:51                       ` Srivatsa S. Bhat
2011-10-05 20:26                         ` Rafael J. Wysocki
2011-10-05 21:15                           ` Srivatsa S. Bhat
2011-10-05 22:43                             ` Rafael J. Wysocki
2011-10-06  6:50                               ` Srivatsa S. Bhat
2011-10-06  8:34                                 ` Borislav Petkov
2011-10-06 15:47                                   ` Srivatsa S. Bhat
2011-10-06 18:11                                     ` Srivatsa S. Bhat
2011-10-06 20:35                                     ` [BUGFIX][PATCH RESEND] " Srivatsa S. Bhat
2011-10-06 22:13                                       ` Tejun Heo
2011-10-06 22:34                                         ` Borislav Petkov
2011-10-07 16:48                                           ` Srivatsa S. Bhat
2011-10-07 18:05                                             ` Borislav Petkov
2011-10-04 13:25             ` [BUGFIX][PATCH] " Borislav Petkov
2011-10-05  8:33         ` Srivatsa S. Bhat

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