RE: [EXTERNAL] Re: [PATCH] EDAC: update edac printk wrappers to use printk_ratelimited.

From: Lei Wang (DPLAT)
Date: Wed May 05 2021 - 15:02:22 EST


Hi Boris,

We found a corner case in production environment that there are ~500 CE errors per second. The SoC otherwise functions just fine. Making printk ratelimited reduced CE error logging to < 20 per second. Though this is just one case so far, we think moving to printk_ratelimited could benefit broader use as well, by helping control the amount of kernel logging. In most running condition, the error rate is way below the limit. And in an error case like this one, vast error logging would not provide much valuable details, rather it's storming the kernel logging.

Thanks,
-Lei

-----Original Message-----
From: Borislav Petkov <bp@xxxxxxxxx>
Sent: Wednesday, May 5, 2021 11:01 AM
To: wangglei <wangglei@xxxxxxxxx>
Cc: mchehab@xxxxxxxxxx; tony.luck@xxxxxxxxx; james.morse@xxxxxxx; rric@xxxxxxxxxx; linux-edac@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Lei Wang (DPLAT) <Wang.Lei@xxxxxxxxxxxxx>; Hang Li <hangl@xxxxxxxxxxxxx>; tyhicks@xxxxxxxxxxxxxxxxxxx; Brandon Waller <bwaller@xxxxxxxxxxxxx>
Subject: [EXTERNAL] Re: [PATCH] EDAC: update edac printk wrappers to use printk_ratelimited.

On Wed, May 05, 2021 at 10:30:27AM -0700, Lei Wang wrote:
> Update printk to the ratelimited version, so that in some corner cases
> when vast of CE errors show up, the kernel logging can be suppressed.

Err, why?

--
Regards/Gruss,
Boris.

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