On Thu, 5 Nov 2020 at 19:24, Pavel Machek <pavel@xxxxxx> wrote: > > Hi! > > > From: Joel Stanley <joel@xxxxxxxxx> > > > > commit a02f6d42357acf6e5de6ffc728e6e77faf3ad217 upstream. > > > > It's not done anything for a long time. Save the percpu variable, and > > emit a warning to remind users to not expect it to do anything. > > > > This uses pr_warn_once instead of pr_warn_ratelimit as testing > > 'ppc64_cpu --smt=off' on a 24 core / 4 SMT system showed the warning > > to be noisy, as the online/offline loop is slow. > > I don't believe this is good idea for stable. It is in 5.9-rc2, and > likely mainline users will get userspace fixed, but that warning is > less useful for -stable users. The warning is about the existing behaviour of the kernel. It does let the user know that they won't see any difference in behaviour when tweaking the smt_snooze_delay variable, which was a real issue that Anton hit. I agree that the future commit that removes smt_snooze_delay from the kernel should not be backported. Cheers, Joel > > (And besides, it does not fix any serious bug). > > Best regards, > Pavel > > -- > http://www.livejournal.com/~pavelmachek
