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Date: Wed, 02 Mar 2011 19:13:42 +0300
From: Cyrill Gorcunov <gorcunov@openvz.org>
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To: Ingo Molnar <mingo@elte.hu>
CC: Don Zickus <dzickus@redhat.com>, "Huang, Ying" <ying.huang@intel.com>,
        "Maciej W. Rozycki" <macro@linux-mips.org>,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -tip 2/2 resend] x86, traps: Drop nmi_reason_lock until
 it is really needed
References: <4D6E631B.6040701@openvz.org> <20110302154645.GA11827@elte.hu> <4D6E6886.2060707@openvz.org> <20110302160315.GA12620@elte.hu>
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On 03/02/2011 07:03 PM, Ingo Molnar wrote:
...
> 
> Well, the lock serializes the read-out of the 'NMI reason' port, the handling of 
> whatever known reason and then the reassertion of the NMI (on 32-bit). 
> 
> EDAC has a callback in pci_serr_error() - and this lock serializes that. So we 
> cannot just remove a lock like that, if there's any chance of parallel execution on 
> multiple CPUs.
> 
> Thanks,
> 
> 	Ingo

OK, probably we need some UV person CC'ed (not sure whom) just to explain the
reason for such nmi-listening model. Meanwhile -- lets drop my patch.

-- 
    Cyrill