Re: [PATCH v6 00/16] Rate limit AER logs

Hello,

This work is mostly due to Jon Pan-Doh and Karolina Stolarek.  I rebased
this to v6.15-rc1, factored out some of the trace and statistics updates,
and added some minor cleanups.

Proposal
========

When using native AER, spammy devices can flood kernel logs with AER errors
and slow/stall execution. Add per-device per-error-severity ratelimits for
more robust error logging. Allow userspace to configure ratelimits via
sysfs knobs.

Motivation
==========

Inconsistent PCIe error handling, exacerbated at datacenter scale (myriad
of devices), affects repairabilitiy flows for fleet operators.

Exposing PCIe errors/debug info in-band for a userspace daemon (e.g.
rasdaemon) to collect/pass on to repairability services will allow for more
predictable repair flows and decrease machine downtime.

Background
==========

AER error spam has been observed many times, both publicly (e.g. [1], [2],
[3]) and privately. While it usually occurs with correctable errors, it can
happen with uncorrectable errors (e.g. during new HW bringup).

There have been previous attempts to add ratelimits to AER logs ([4], [5]).
The most recent attempt[5] has many similarities with the proposed
approach.

I have been testing this series locally with and without faults triggered
using the AER error injection facility.  No issues thus far.

And, as such...

Tested-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

Thank you!

	Krzysztof