linux-kernel - Re: [PATCH RFC] x86/mce: Move MCE sysfs attributes out of the per-cpu location

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Message-ID: <503E14DC.3060507@linux.vnet.ibm.com>
Date:	Wed, 29 Aug 2012 18:40:52 +0530
From:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
To:	Borislav Petkov <bp@...64.org>
CC:	tony.luck@...el.com, andi@...stfloor.org, ananth@...ibm.com,
	x86@...nel.org, linux-kernel@...r.kernel.org, mingo@...hat.com,
	hpa@...or.com, tglx@...utronix.de, linux-edac@...r.kernel.org
Subject: Re: [PATCH RFC] x86/mce: Move MCE sysfs attributes out of the per-cpu
 location

On 08/29/2012 04:10 PM, Borislav Petkov wrote:
> On Wed, Aug 29, 2012 at 03:56:04PM +0530, Naveen N. Rao wrote:
>> Hmmm.. Can't we just deprecate these? ;) Perhaps we can consider
>> adding newer tunables in the right place.
>
> In case you haven't noticed yet: I'm all on your side.

Yup, I know :)

I had my doubts when I sent this patch (hence the RFC tag) and I was 
only wondering above if it'll be a good idea to limit such tunables 
going forward. We could force all _new_ MCE tunables to be global, 
except where they actually apply on a per-processor basis.

>
> But let me ask you this: these attributes grow to a large number with
> a large number of cores but why is this a problem? We have a bunch of
> redundant attributes in sysfs, so what?
>
> See what I mean?
>

Well, it's ugly and does not make much sense, as I'm sure you noticed. 
On a 10-core, 8-socket machine with HT, we'll end up with nearly a 
thousand such entries!

I don't know how much resource this takes up (if any) and like you said, 
this may just be a "so what?", but I wanted to bring this up and see if 
we could/want to do anything about this. I'm certainly fine if we want 
to ignore this.

Thanks,
Naveen

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