Hi On Tue, Jul 5, 2016 at 1:12 PM, Michael S. Tsirkin <m...@redhat.com> wrote: > On Tue, Jul 05, 2016 at 11:18:38AM +0200, Marc-André Lureau wrote: >> Hi >> >> On Tue, Jul 5, 2016 at 12:35 AM, Michael S. Tsirkin <m...@redhat.com> wrote: >> > On Mon, Jul 04, 2016 at 11:56:56PM +0200, Marc-André Lureau wrote: >> >> Hi >> >> >> >> On Mon, Jul 4, 2016 at 5:47 PM, Michael S. Tsirkin <m...@redhat.com> >> >> wrote: >> >> > Why does vhost_user_set_log_base need to return error? >> >> > If backend is not there to handle this message, >> >> > then it is not changing memory so it's ok to ignore the error. >> >> >> >> How do you know it's not changing the memory? >> > >> > either it closed socket intentionally or it exited >> > and kernel cleaned up. >> >> And if it closed intentionally during migration, we want to catch this >> as a bug since it may still modify the memory > > You can't prevent backend bugs I think.
Right, but it's best to provide an error when you can detect backend bugs. >> >> Furthermore, if the migration happened, it's because backend claim >> >> VHOST_F_LOG_ALL, thus it should really not fail >> > >> > I don't see why - could you explain pls? >> >> If the backend claims migration support, it shouldn't have bad >> migration behaviour such as closing the vhost-user socket. > > But I don't see why it's bad. If it's not modifying memory then > it does not need to log any changes. "if it's not modifying memory"... I fail to understand why some code path check error code, and some don't. Ignoring error and running further may lead to wrong assumptions and later issues. I also fail to understand why providing more useful error messages is bad. I feel quite strongly about having more consistent error checking in vhost-user, I don't get why you don't. -- Marc-André Lureau
