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From: Michael Ellerman <mpe@ellerman.id.au>
To: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Michal Suchanek <msuchanek@suse.com>,
	Ananth Narayan <ananth@in.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Laurent Dufour <ldufour@linux.vnet.ibm.com>
Subject: Re: [PATCH v7 8/9] powerpc/mce: Add sysctl control for recovery action on MCE.
Date: Thu, 09 Aug 2018 00:56:00 +1000	[thread overview]
Message-ID: <87o9ecaovz.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <153365146712.14256.11869543914717297278.stgit@jupiter.in.ibm.com>

Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> writes:
> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>
> Introduce recovery action for recovered memory errors (MCEs). There are
> soft memory errors like SLB Multihit, which can be a result of a bad
> hardware OR software BUG. Kernel can easily recover from these soft errors
> by flushing SLB contents. After the recovery kernel can still continue to
> function without any issue. But in some scenario's we may keep getting
> these soft errors until the root cause is fixed. To be able to analyze and
> find the root cause, best way is to gather enough data and system state at
> the time of MCE. Hence this patch introduces a sysctl knob where user can
> decide either to continue after recovery or panic the kernel to capture the
> dump.

I'm not convinced we want this.

As we've discovered it's often not possible to reconstruct what happened
based on a dump anyway.

The key thing you need is the content of the SLB and that's not included
in a dump.

So I think we should dump the SLB content when we get the MCE (which
this series does) and any other useful info, and then if we can recover
we should.

cheers

  reply	other threads:[~2018-08-08 14:56 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-07 14:15 [PATCH v7 0/9] powerpc/pseries: Machine check handler improvements Mahesh J Salgaonkar
2018-08-07 14:16 ` [PATCH v7 1/9] powerpc/pseries: Avoid using the size greater than RTAS_ERROR_LOG_MAX Mahesh J Salgaonkar
2018-08-07 14:16 ` [PATCH v7 2/9] powerpc/pseries: Defer the logging of rtas error to irq work queue Mahesh J Salgaonkar
2018-08-07 14:16 ` [PATCH v7 3/9] powerpc/pseries: Fix endainness while restoring of r3 in MCE handler Mahesh J Salgaonkar
2018-08-13 11:23   ` [v7, " Michael Ellerman
2018-08-07 14:16 ` [PATCH v7 4/9] powerpc/pseries: Define MCE error event section Mahesh J Salgaonkar
2018-08-08 14:42   ` Michael Ellerman
2018-08-10 10:29     ` Mahesh Jagannath Salgaonkar
2018-08-16  4:14       ` Michael Ellerman
2018-08-16 14:44         ` Segher Boessenkool
2018-08-17 11:22         ` Mahesh Jagannath Salgaonkar
2018-08-07 14:17 ` [PATCH v7 5/9] powerpc/pseries: flush SLB contents on SLB MCE errors Mahesh J Salgaonkar
2018-08-07 16:54   ` Michal Suchánek
2018-08-10 10:30     ` Mahesh Jagannath Salgaonkar
2018-08-08  9:04   ` Nicholas Piggin
2018-08-10 10:30     ` Mahesh Jagannath Salgaonkar
2018-08-07 14:17 ` [PATCH v7 6/9] powerpc/pseries: Display machine check error details Mahesh J Salgaonkar
2018-08-07 14:17 ` [PATCH v7 7/9] powerpc/pseries: Dump the SLB contents on SLB MCE errors Mahesh J Salgaonkar
2018-08-09  1:05   ` Michael Ellerman
2018-08-10 10:32     ` Mahesh Jagannath Salgaonkar
2018-08-10 10:49       ` Mahesh Jagannath Salgaonkar
2018-08-11  4:33   ` Nicholas Piggin
2018-08-13  4:17     ` Mahesh Jagannath Salgaonkar
2018-08-13 14:27       ` Nicholas Piggin
2018-08-14 10:57         ` Mahesh Jagannath Salgaonkar
2018-08-14 12:47           ` Aneesh Kumar K.V
2018-08-07 14:17 ` [PATCH v7 8/9] powerpc/mce: Add sysctl control for recovery action on MCE Mahesh J Salgaonkar
2018-08-08 14:56   ` Michael Ellerman [this message]
2018-08-08 15:37     ` Aneesh Kumar K.V
2018-08-08 16:09       ` Michal Suchánek
2018-08-10 11:04         ` Michael Ellerman
2018-08-09  6:34       ` Michael Ellerman
2018-08-09  8:02         ` Nicholas Piggin
2018-08-09  8:09           ` Ananth N Mavinakayanahalli
2018-08-09  8:33             ` Nicholas Piggin
2018-08-09 10:26               ` Michal Suchánek
2018-08-10  7:31                 ` Nicholas Piggin
2018-08-09  1:43     ` Nicholas Piggin
2018-08-07 14:18 ` [PATCH v7 9/9] powernv/pseries: consolidate code for mce early handling Mahesh J Salgaonkar

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