On Wed, Oct 9, 2024 at 4:10 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote: > > On Wed, Oct 09, 2024 at 03:28:19PM GMT, Jason Wang wrote: > >On Mon, Oct 7, 2024 at 9:31 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote: > >> > >> On Fri, Oct 04, 2024 at 09:58:15AM GMT, Cindy Lu wrote: > >> >The vhost is now using vhost_task and working as a child of the owner thread. > >> >While this makes sense from containerization POV, some old userspace is > >> >confused, as previously vhost not > >> > >> not what? > >> > >> > and so was allowed to steal cpu resources > >> >from outside the container. So we add the kthread API support back > >> > >> Sorry, but it's not clear the reason. > >> > >> I understand that we want to provide a way to bring back the previous > >> behavior when we had kthreads, but why do we want that? > >> Do you have examples where the new mechanism is causing problems? > >> > > > >The main difference is whose (kthreadd or the owner) attributes > >(namespace, affinities) would vhost thread inherit. > > > >The owner's attributes tend to be different from kthreadd, so > >management might be surprised for example, vhost might be created in > >different namespaces or having different scheduling affinities. > > Okay, so this requires some API to allow the managment to understand how > the device vhost will be created. > > But why do we need to restore the old behavior with a kthread where the > resource accounting is completely disconnected from userspace? > For the old managments that don't expect this? Yes, as such change can be easily noticed by the user space that breaks existing management layers or tools. > > BTW I would suggest adding all this information in this commit, in the > parameter/IOCTL documentation, and in the cover letter because IMHO it > is very important. I've asked this in the past. Cindy, please make sure such information were included in the next version in the cover letter. Thanks > > Thanks, > Stefano >
