On Fri, Apr 17, 2015 at 12:38:07PM +0200, Paolo Bonzini wrote: > > > On 17/04/2015 12:36, Peter Zijlstra wrote: > > Now you make everybody pay for your crap, x86-64 paravirt or not. Keep > > the cost by those who need it. > > > > Please take it out, ASAP. > > I'll just implement the static key. Can you first show that: preempt_out: int cpu = smp_processor_id(); if (vcpu->cpu != cpu) vcpu->cpu = cpu; preempt_in: int cpu = smp_processor_id(); if (unlikely(vcpu->cpu != cpu)) do_vcpu_migration_callback(cpu); Is actually a measurable performance hit and we actually _need_ the migration callback? Also, it looks like you already do exactly this for other things, look at: kvm_sched_in() kvm_arch_vcpu_load() if (unlikely(vcpu->cpu != cpu) ... ) So no, I don't believe for one second you need this. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
