Re: [PATCH] x86/mce: Increase the size of the MCE pool from 2 to 8 pages

From: Borislav Petkov
Date: Mon Oct 16 2023 - 10:41:25 EST


On Mon, Oct 16, 2023 at 07:24:34AM -0700, Dave Hansen wrote:
> On 10/16/23 07:14, Yazen Ghannam wrote:
> > 1) Keep the current config size for boot time.
> > 2) Add a kernel parameter
> > and/or sysfs file to allow users to request additional genpool capacity.
> > 3) Use gen_pool_add(), or whichever, to add the capacity based on user
> > input. Maybe this can be expanded later to be automatic. But I think it
> > simpler to start with explicit user input.
>
> I guarantee virtually nobody will ever use an explicit kernel interface
> to bump the size up. It'll be the same exact folks that recompile their
> kernels.
>
> An automatic resizing one doesn't have to be fancy and only has to
> expand once:

Can we slow down here pls?

You expand once and then that stuck bit error increases its rate of MCEs
reported and all of a sudden that raised size is overflowed again.

Or, you add logic which thresholds duplicate errors similar to the cmci
storm logic we have.

*If* that is the case at all.

So can we analyze first what type of errors are reported and why they're
overflowing the pool before we do ad-hoc hackery?

Thx.

--
Regards/Gruss,
Boris.

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