linux-kernel - Re: [RFC PATCH 0/8] EDAC, mce_amd: Add a tracepoint for the decoded error

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Message-ID: <20170727130909.GB28548@nazgul.tnic>
Date:   Thu, 27 Jul 2017 15:09:09 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Ingo Molnar <mingo@...nel.org>
Cc:     linux-edac <linux-edac@...r.kernel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Tony Luck <tony.luck@...el.com>,
        Yazen Ghannam <Yazen.Ghannam@....com>, X86 ML <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 0/8] EDAC, mce_amd: Add a tracepoint for the decoded
 error

On Thu, Jul 27, 2017 at 10:39:27AM +0200, Ingo Molnar wrote:
> I don't think so: we routinely log several KB per event worth of call chains via 
> perf tracing just fine.
> 
> So I'd suggest logging more than less, and making it more verbose is definitely 
> the way to go.

No no, you're missing the point: we do dump *all* that information - it
is just spread between two tracepoints - trace_mce_record() and this new
one.

BUT(!), I just realized, I *think* I can address this much more
elegantly: extend trace_mce_record() by adding the decoded string as
its last argument. And that's fine, I'm being told, because adding
arguments to the tracepoints is not a big deal, removing them is hard.
And actually, we have added args before, come to think of it:

5828c46f2c07 x86/mce/AMD: Save MCA_IPID in MCE struct on SMCA systems
db819d60f672 x86/mce: Add support for new MCA_SYND register

So lemme look into that - it would be much nicer this way because I
don't need to add a second TP at all.

I agree with the rest but you're obviously preaching to the choir.

:-)

-- 
Regards/Gruss,
    Boris.

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