From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mauro Carvalho Chehab Subject: Re: [PATCH 3/3] mce: acpi/apei: trace: Enable ghes memory error trace event Date: Mon, 12 Aug 2013 11:44:04 -0300 Message-ID: <20130812114404.3bd64fa0@samsung.com> References: <1375986471-27113-1-git-send-email-naveen.n.rao@linux.vnet.ibm.com> <1375986471-27113-4-git-send-email-naveen.n.rao@linux.vnet.ibm.com> <20130808163822.67e0828a@samsung.com> <20130810180322.GC4155@pd.tnic> <20130812083355.47c1bae8@samsung.com> <5208D80D.5030206@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mailout4.w2.samsung.com ([211.189.100.14]:43308 "EHLO usmailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755582Ab3HLOoN (ORCPT ); Mon, 12 Aug 2013 10:44:13 -0400 In-reply-to: <5208D80D.5030206@linux.vnet.ibm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Naveen N. Rao" Cc: Borislav Petkov , tony.luck@intel.com, bhelgaas@google.com, rostedt@goodmis.org, rjw@sisk.pl, lance.ortiz@hp.com, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Aristeu Rozanski Filho Em Mon, 12 Aug 2013 18:11:49 +0530 "Naveen N. Rao" escreveu: > On 08/12/2013 05:03 PM, Mauro Carvalho Chehab wrote: > > Em Sat, 10 Aug 2013 20:03:22 +0200 > > Borislav Petkov escreveu: > > > >> On Thu, Aug 08, 2013 at 04:38:22PM -0300, Mauro Carvalho Chehab wrote: > >>> Em Thu, 08 Aug 2013 23:57:51 +0530 > >>> "Naveen N. Rao" escreveu: > >>> > >>>> Enable memory error trace event in cper.c > >>> > >>> Why do we need to do that? Memory error events are already handled > >>> via edac_ghes module, > >> > >> If APEI gives me all the required information in order to deal with the > >> hardware error - and it looks like it does - then the additional layer > >> of ghes_edac is not needed. > > > > APEI is just the mechanism that collects the data, not the mechanism > > that reports to userspace. > > I think what Boris is saying is that ghes_edac isn't adding anything > more here given what we get from APEI structures. So, there doesn't seem > to be a need to add dependency on edac for this purpose. > > Further, ghes_edac seems to require EDAC_MM_EDAC to be compiled into the > kernel (not a module). So, more dependencies. > > > > > The current implementation is that APEI already reports those errors > > via ghes_edac driver. It also reports the very same error via MCE > > (although the APEI interface to MCE is currently broken for everything > > that it is not Nehalem-EX - as it basically emulates the MCE log for > > that specific architecture). > > So, I looked at ghes_edac and it basically seems to boil down to > trace_mc_event. Yes. It also provides the sysfs nodes that describe the memory. > But, this only seems to expose the APEI data as a string > and doesn't look to really make all the fields available to user-space > in a raw manner. Not sure how well this can be utilised by a user-space > tool. Do you have suggestions on how we can do this? There's already an userspace tool that handes it: https://git.fedorahosted.org/cgit/rasdaemon.git/ What is missing there on the current version is the bits that would allow to translate from APEI way to report an error (memory node, card, module, bank, device) into a DIMM label[1]. At the end, what really matters is to be able to point to the DIMM(s) in a way that the user can replace them (e. g. using the silk screen labels on the system motherboard). [1] It does such translation for the other EDAC drivers, via a configuration file that does such per-system mapping. Extending it to also handle APEI errors shouldn't be hard. > > Thanks, > Naveen > -- Cheers, Mauro