> This change is a trade-off. > PRO: This patch would improve the case of preemption on s390. This is probably a corner case as most distros have preemption off anyway. > CON: The downside is that kvm_vcpu_yield_to is called also from kvm_vcpu_on_spin. Here we want to avoid the scheduler overhead for a wrong decision. Won't most of that part be covered by: if (!ACCESS_ONCE(vcpu->preempted)) vcpu->preempted is only set when scheduled out involuntarily. It is cleared when scheduled in. s390 sets it manually, to speed up waking up a vcpu. So when our task is scheduled in (an PF_VCPU is set), this check will already avoid scheduler overhead in kvm_vcpu_on_spin() or am I missing something? -- 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
