Comment 4 for bug 1791246

So it appears that the mpt2sas driver is heavily spamming kernel messages and this causes a massive backlog. The low-latency kernel trying to log these to the backing store and this is causing more load.

I've changed the messages to be pr_err_ratelimited and the issue goes away. I'll send a fix for the driver upstream. Meanwhile, since this is triggered only by hard hammering of the sysfs entries I think I'll add a autodetection of kernel log spamming in the stressor and flag this automatically.