On Mon, 22 Jun 2009, Gregory Haskins wrote: > Davide Libenzi wrote: > > On Mon, 22 Jun 2009, Michael S. Tsirkin wrote: > > > > > >> On Mon, Jun 22, 2009 at 11:03:22AM -0700, Davide Libenzi wrote: > >> > >>> In your case of kernel-to-kernel scenario, why would you need eventfd at > >>> all, if userspace role in that model is simply to create it? > >>> > >> That's not 100% true. We have a mode where userspace is the producer > >> and/or consumer (migration mode) and we switch between that and > >> direct kernel-to-kernel communication. > >> > > > > Then you'd need to ask yourself how to handle your complex case inside the > > KVM code, so that other eventfd users are not affected by the extra fat > > needed to handle your scenarios. Thing that seem to be continuosly tried. > > A file* based kernel-to-kernel interface is rather wrong IMO. > > > > Well, I will point out that the interface in question is > eventfd_signal(struct file *), and you were the one that invented it > afaict. Can't help it if we like it :) Yes, I did. The case for eventfd was dual. First, it was a communication link between userspace and kernel, for things like KAIO. Second, it was a faster and smaller userspace replacement for things people used pipes before. In all those cases, at least one reference of the file* is alive in userspace. Even with the above case in mind, today I'd still use the eventfd_ctx as internal kernel API accessory. - Davide -- 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
