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From: Andi Kleen <andi@firstfloor.org>
To: Don Zickus <dzickus@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>, Ingo Molnar <mingo@elte.hu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC 4/6] x86, NMI, Rewrite NMI handler
Date: Fri, 10 Sep 2010 18:03:56 +0200	[thread overview]
Message-ID: <20100910180356.44ac7097@basil.nowhere.org> (raw)
In-Reply-To: <20100910155605.GG4879@redhat.com>

On Fri, 10 Sep 2010 11:56:05 -0400
Don Zickus <dzickus@redhat.com> wrote:

> On Fri, Sep 10, 2010 at 10:51:03AM +0800, Huang Ying wrote:
> > The original NMI handler is quite outdated in many aspects. This
> > patch try to fix it.
> > 
> > In original code, NMI reason io port (0x61) is only processed on
> > BSP. This makes it impossible to hot-remove BSP. To solve the issue,
> > a raw spinlock is used to make the port can be processed on any CPU.
> 
> Do we really want to use a spinlock inside the nmi handler?

As long as it's only between CPUs
(that is only ever used between different NMI handlers) 
that's fine.  It's certainly safer than having races between CPUs.

> I thought the NMIs sent to the io port are only routed to one cpu as
> determined by the io-apic?  Is it spread out to other cpus now?

There can be cases where it can happen I believe.

-Andi
 
-- 
ak@linux.intel.com -- Speaking for myself only.

  reply	other threads:[~2010-09-10 16:04 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-10  2:51 [RFC 1/6] x86, NMI, Add symbol definition for NMI magic constants Huang Ying
2010-09-10  2:51 ` [RFC 2/6] x86, NMI, Add touch_nmi_watchdog to io_check_error delay Huang Ying
2010-09-10  2:51 ` [RFC 3/6] x86, NMI, Rename memory parity error to PCI SERR error Huang Ying
2010-09-13  1:02   ` Robert Richter
2010-09-13  2:02     ` Huang Ying
2010-09-16  8:18       ` Robert Richter
2010-09-17  0:08         ` Huang Ying
2010-09-17  9:14           ` Robert Richter
2010-09-19  0:20             ` Huang Ying
2010-09-20  8:00               ` Robert Richter
2010-09-20 12:59                 ` Borislav Petkov
2010-09-21  0:22                   ` Huang Ying
2010-09-21  6:37                     ` Borislav Petkov
2010-09-21 14:08                       ` Doug Thompson
2010-09-21 23:04   ` Maciej W. Rozycki
2010-09-23  5:37     ` huang ying
2010-09-29  0:26       ` Maciej W. Rozycki
2010-09-10  2:51 ` [RFC 4/6] x86, NMI, Rewrite NMI handler Huang Ying
2010-09-10 15:56   ` Don Zickus
2010-09-10 16:03     ` Andi Kleen [this message]
2010-09-10 18:29       ` Don Zickus
2010-09-13  2:09         ` Huang Ying
2010-09-13 14:04           ` Don Zickus
2010-09-14  5:12             ` Huang Ying
2010-09-14 13:37               ` Don Zickus
2010-09-13  1:16   ` Robert Richter
2010-09-10  2:51 ` [RFC 5/6] x86, NMI, Add support to notify hardware error with unknown NMI Huang Ying
2010-09-10 16:02   ` Don Zickus
2010-09-10 16:19     ` Andi Kleen
2010-09-10 18:40       ` Don Zickus
2010-09-13  2:19         ` Huang Ying
2010-09-13 14:11           ` Don Zickus
2010-09-13 15:24             ` Andi Kleen
2010-09-13 15:47               ` Don Zickus
2010-09-13 16:57                 ` Andi Kleen
2010-09-13 17:53                   ` Don Zickus
2010-09-13 18:07                     ` Andi Kleen
2010-09-13 18:23                       ` Don Zickus
2010-09-13 18:36                         ` Andi Kleen
2010-09-13 19:36                           ` Don Zickus
2010-09-13 20:49                             ` Andi Kleen
2010-09-13 21:25                               ` Valdis.Kletnieks
2010-09-14  7:48                                 ` Andi Kleen
2010-09-14 17:54                                   ` Valdis.Kletnieks
2010-09-14 12:21                             ` Ingo Molnar
2010-09-14 13:45                               ` Don Zickus
2010-09-14 19:34                               ` Cyrill Gorcunov
2010-09-15  9:29                                 ` Ingo Molnar
2010-09-10  2:51 ` [RFC 6/6] x86, NMI, Remove do_nmi_callback logic Huang Ying
2010-09-10 16:13   ` Don Zickus
2010-09-13  2:27     ` Huang Ying
2010-09-13  6:24       ` Ingo Molnar
2010-09-10 20:37 ` [RFC 1/6] x86, NMI, Add symbol definition for NMI magic constants Peter Zijlstra
2010-09-10 22:58   ` H. Peter Anvin
2010-09-11  8:50   ` Andi Kleen
2010-09-13  1:30     ` Robert Richter
2010-09-21 21:48 ` Don Zickus
2010-09-21 22:19   ` Andi Kleen
2010-09-22 16:07     ` Don Zickus
2010-09-23  9:29       ` huang ying
2010-09-23 14:16         ` Don Zickus
2010-09-24 11:50           ` huang ying
2010-09-24 14:29             ` Don Zickus
2010-09-23  9:51   ` huang ying

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