On Mon, Jan 27, 2025 at 08:48:03AM -0800, Sean Christopherson wrote: > If vhost_task_create() fails, then the call_once() will "succeed" and mark the > structure as ONCE_COMPLETED. The first KVM_RUN will fail with -ENOMEM, but any > subsequent calls will succeed, including in-flight KVM_RUNs on other threads. The criteria for returning -ENOMEM for any KVM_RUN is if we have a NULL nx_huge_page_recovery_thread vhost_task. So I think that part, at least, is fine. The call_once is just needed to ensure that only the very first KVM_RUN even tries to create it. If the vhost_task_create fails, then all the KVM_RUN threads will see the NULL nx_huge_page_recovery_thread and return -ENOMEM. What you're suggesting here will allow a subsequent thread to attempt creating the vhost task if the first one failed. Maybe you do want to try again, but the current upstream code doesn't retry this, so I thought it best to keep that behavior.
