From: Andi Kleen <ak@suse.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: willy@debian.org, ishii.hironobu@jp.fujitsu.com,
linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org
Subject: Re: [RFC/PATCH, 2/4] readX_check() performance evaluation
Date: Wed, 28 Jan 2004 20:15:54 +0000 [thread overview]
Message-ID: <20040128211554.0cc890fb.ak@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0401281205250.28145@home.osdl.org>
On Wed, 28 Jan 2004 12:06:12 -0800 (PST)
Linus Torvalds <torvalds@osdl.org> wrote:
>
>
> On Wed, 28 Jan 2004, Andi Kleen wrote:
> >
> > On Wed, 28 Jan 2004 11:33:33 -0800 (PST)
> > Linus Torvalds <torvalds@osdl.org> wrote:
> >
> > > For example, if checking for an error involves actually reading a value
> > > from a bridge register, then that implies some _serious_ amount of
> > > serialization and external CPU stuff.
> >
> > Which is _extremly_ hard to do from an MCE handler ...
>
> So don't do it in the MCE handler.
>
> Just set a flag aka "may need checking", and let the check be done by the
> actual "read_pcix_error()" code.
Where would you put the flag?
Doing it global may give false errors for the wrong device with async MCEs
and on SMP.
For putting it into the pci_dev you need to take logs to walk the list.
If you delay it to a softirq for safely getting the lock it would be set too late.
Putting it into a different table indexed by pci index would be also racy
with hotplug.
-Andi
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <ak@suse.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: willy@debian.org, ishii.hironobu@jp.fujitsu.com,
linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org
Subject: Re: [RFC/PATCH, 2/4] readX_check() performance evaluation
Date: Wed, 28 Jan 2004 21:15:54 +0100 [thread overview]
Message-ID: <20040128211554.0cc890fb.ak@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0401281205250.28145@home.osdl.org>
On Wed, 28 Jan 2004 12:06:12 -0800 (PST)
Linus Torvalds <torvalds@osdl.org> wrote:
>
>
> On Wed, 28 Jan 2004, Andi Kleen wrote:
> >
> > On Wed, 28 Jan 2004 11:33:33 -0800 (PST)
> > Linus Torvalds <torvalds@osdl.org> wrote:
> >
> > > For example, if checking for an error involves actually reading a value
> > > from a bridge register, then that implies some _serious_ amount of
> > > serialization and external CPU stuff.
> >
> > Which is _extremly_ hard to do from an MCE handler ...
>
> So don't do it in the MCE handler.
>
> Just set a flag aka "may need checking", and let the check be done by the
> actual "read_pcix_error()" code.
Where would you put the flag?
Doing it global may give false errors for the wrong device with async MCEs
and on SMP.
For putting it into the pci_dev you need to take logs to walk the list.
If you delay it to a softirq for safely getting the lock it would be set too late.
Putting it into a different table indexed by pci index would be also racy
with hotplug.
-Andi
next prev parent reply other threads:[~2004-01-28 20:15 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-28 1:54 [RFC/PATCH, 2/4] readX_check() performance evaluation Hironobu Ishii
2004-01-28 1:54 ` Hironobu Ishii
2004-01-28 2:55 ` Linus Torvalds
2004-01-28 2:55 ` Linus Torvalds
2004-01-28 4:44 ` Paul Mackerras
2004-01-28 4:44 ` Paul Mackerras
2004-01-28 8:58 ` Russell King
2004-01-28 16:15 ` Linus Torvalds
2004-01-28 16:15 ` Linus Torvalds
2004-01-28 17:01 ` Grant Grundler
2004-01-28 17:01 ` Grant Grundler
2004-01-28 18:20 ` Matthew Wilcox
2004-01-28 19:19 ` Andi Kleen
2004-01-28 19:19 ` Andi Kleen
2004-01-28 19:33 ` Linus Torvalds
2004-01-28 19:33 ` Linus Torvalds
2004-01-28 19:40 ` Andi Kleen
2004-01-28 19:40 ` Andi Kleen
2004-01-28 20:06 ` Linus Torvalds
2004-01-28 20:06 ` Linus Torvalds
2004-01-28 20:15 ` Andi Kleen [this message]
2004-01-28 20:15 ` Andi Kleen
2004-01-28 20:19 ` [RFC/PATCH, 2/4] readX_check() performance evaluation II Andi Kleen
2004-01-28 20:19 ` Andi Kleen
2004-01-28 20:28 ` [RFC/PATCH, 2/4] readX_check() performance evaluation Linus Torvalds
2004-01-28 20:28 ` Linus Torvalds
2004-01-28 20:30 ` Linus Torvalds
2004-01-28 20:30 ` Linus Torvalds
2004-01-28 21:09 ` Andi Kleen
2004-01-28 21:09 ` Andi Kleen
2004-01-28 21:43 ` Linus Torvalds
2004-01-28 21:43 ` Linus Torvalds
2004-01-28 21:52 ` Andi Kleen
2004-01-28 21:52 ` Andi Kleen
2004-01-28 22:21 ` Linus Torvalds
2004-01-28 22:21 ` Linus Torvalds
2004-01-28 22:39 ` Andi Kleen
2004-01-28 22:39 ` Andi Kleen
2004-01-28 22:59 ` Linus Torvalds
2004-01-28 22:59 ` Linus Torvalds
2004-01-29 12:24 ` Hironobu Ishii
2004-01-29 12:24 ` Hironobu Ishii
2004-01-28 22:15 ` David S. Miller
2004-01-28 22:15 ` David S. Miller
2004-01-28 3:09 ` Matthew Wilcox
2004-01-28 3:09 ` Matthew Wilcox
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