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From: Borislav Petkov <bp@alien8.de>
To: Don Zickus <dzickus@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>,
	linux-edac <linux-edac@vger.kernel.org>,
	Borislav Petkov <bp@suse.de>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Tony Luck <tony.luck@intel.com>,
	Tomasz Nowicki <tomasz.nowicki@linaro.org>,
	"Chen, Gong" <gong.chen@linux.intel.com>,
	Wolfram Sang <wsa@the-dreams.de>, Lv Zheng <lv.zheng@intel.com>,
	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	Huang Ying <ying.huang@intel.com>
Subject: Re: [RFC PATCH 5/5] GHES: Make NMI handler have a single reader
Date: Tue, 28 Apr 2015 18:22:29 +0200	[thread overview]
Message-ID: <20150428162229.GH19025@pd.tnic> (raw)
In-Reply-To: <20150428153521.GE98296@redhat.com>

On Tue, Apr 28, 2015 at 11:35:21AM -0400, Don Zickus wrote:
> Your solution seems much simpler. :-)

... and I love simpler :-)

> I followed up in another email stating I mis-spoke.  I forgot this still
> uses the NMI_LOCAL shared NMI.  So every perf NMI, will also call the GHES
> handler to make sure NMIs did not piggy back each other.  So I don't believe

And this is something we should really fix - perf and RAS should
not have anything to do with each other. But I don't know the NMI
code to even have an idea how. I don't even know whether we can
differentiate NMIs, hell, I can't imagine the hardware giving us a
different NMI reason through get_nmi_reason(). Maybe that byte returned
from NMI_REASON_PORT is too small and hangs on too much legacy crap to
even be usable. Questions over questions...

> the NMI reason lock is called a majority of the time (except when the NMI is
> swallowed, but that is under heavy perf load...).

..

> We both agree the mechanics of the spinlock are overkill here and cause much
> cache contention.  Simplifying it to just 'reads' and return removes most of
> the problem.

Right.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

  reply	other threads:[~2015-04-28 16:22 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-27  9:22 [RFC PATCH 0/5] GHES NMI handler cleanup Borislav Petkov
2015-03-27  9:22 ` [RFC PATCH 1/5] GHES: Carve out error queueing in a separate function Borislav Petkov
2015-03-27  9:22 ` [RFC PATCH 2/5] GHES: Carve out the panic functionality Borislav Petkov
2015-03-27  9:22 ` [RFC PATCH 3/5] GHES: Panic right after detection Borislav Petkov
2015-03-27  9:22 ` [RFC PATCH 4/5] GHES: Elliminate double-loop in the NMI handler Borislav Petkov
2015-03-27  9:22 ` [RFC PATCH 5/5] GHES: Make NMI handler have a single reader Borislav Petkov
2015-04-01  7:45   ` Jiri Kosina
2015-04-01 13:49     ` Borislav Petkov
2015-04-23  8:39       ` Jiri Kosina
2015-04-23  8:59         ` Borislav Petkov
2015-04-23 18:00           ` Luck, Tony
2015-04-27 20:23             ` Borislav Petkov
2015-04-28 14:30     ` Don Zickus
2015-04-28 14:42       ` Don Zickus
2015-04-28 14:55       ` Borislav Petkov
2015-04-28 15:35         ` Don Zickus
2015-04-28 16:22           ` Borislav Petkov [this message]
2015-04-28 18:44             ` Don Zickus
2015-05-04 15:40               ` Borislav Petkov
2015-04-27  3:16   ` Zheng, Lv
2015-04-27  8:46     ` Borislav Petkov
2015-04-28  0:44       ` Zheng, Lv
2015-04-28  2:24       ` Zheng, Lv
2015-04-28  7:38         ` Borislav Petkov
2015-04-28 13:38   ` Zheng, Lv
2015-04-28 13:59     ` Borislav Petkov
2015-04-29  0:24       ` Zheng, Lv
2015-04-29  0:49       ` Zheng, Lv
2015-04-29  8:13         ` Borislav Petkov
2015-04-30  8:05           ` Zheng, Lv
2015-04-30  8:48             ` Borislav Petkov
2015-05-02  0:34               ` Zheng, Lv

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