On Fri, Nov 9, 2018 at 4:22 PM Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > > > > > On Nov 9, 2018, at 4:05 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > > > Commit f77084d96355 "x86/mm/pat: Disable preemption around > > __flush_tlb_all()" addressed a case where __flush_tlb_all() is called > > without preemption being disabled. It also left a warning to catch other > > cases where preemption is not disabled. That warning triggers for the > > memory hotplug path which is also used for persistent memory enabling: > > I don’t think I agree with the patch. If you call __flush_tlb_all() in a context where you might be *migrated*, then there’s a bug. We could change the code to allow this particular use by checking that we haven’t done SMP init yet, perhaps. Hmm, are saying the entire kernel_physical_mapping_init() sequence needs to run with pre-emption disabled?
