On 2016-11-09 16:38:07 [+0100], Borislav Petkov wrote: > On Wed, Nov 09, 2016 at 03:22:21PM +0100, Sebastian Andrzej Siewior wrote: > > I want to get rid of non-symmetrical part and the arch hook which should > > be part of the hp notifier itself. I wouldn't be too much afraid about > > the when point in time when the notifier runs: It is the *first* > > notifier that will be invoked on the target CPU. This is only a few > > lines after the old hook. Nothing else long delaying should be invoked. > > So I'm not sure *everything* mcheck_cpu_init() does should be in hotplug > and toggle on and off. For example, we should set CR4.MCE once during > init and that's it. Not turn it on and off. It would be pretty pointless > IMO. > > That's why the hotplug callback mce_disable_cpu() doesn't fiddle with > CR4 - it only clears the bits in MCi_CTL. And I think we should remain > that way.
The behaviour was not changed - it was only reorganized to keep in one spot. > The initial, one-time enabling of MCE features per core should be done > only once per boot and that's it. It is. You still want this in your hotplug code in case someone replaces (physically) your CPU (say a larger NUMA box). Sebastian
