On Tue, Sep 22, 2015 at 01:50:47PM +0200, Marc-André Lureau wrote: > hi > > On Tue, Sep 22, 2015 at 1:41 PM, Michael S. Tsirkin <m...@redhat.com> wrote: > > There's a single log at the moment: > > static struct vhost_log *vhost_log; > > > > But all devices are updated by the memory core, we don't > > have a list in the vhost code. > > Do you mean that all devices will have their memory listener restart > the log, so they all point to the same global vhost_log?
Exactly. > >> >> Is there a clear benefit > >> >> of this? since the memory isn't shared without the memfd passed to > >> >> another process and the overhead of memfd is probably quite small, and > >> >> pre-shm or future resize will not use the shared memory already. > >> > > >> > For example, THP doesn't work for memfd at the moment, > >> > so all accesses are a bit slower. > >> > >> What's THP? How is it slower once the fd is mmap? > > > > Transparent huge page. This process doesn't work for > > memfd AFAIK. > > > >> > Really, I don't want to merge hacks. Switching from non memfd > >> > to memfd but not back has all the signs of one. > >> > Let's do it cleanly please. > >> > >> The current code isn't switching existing logs either. What would be > >> simpler to do is to allocate a different log region for the "share" > >> case. So there would be no need to switch other non-shareable logs (to > >> the cost of using twice the memory needed). > > > > OK, that's not too bad. Let's go for it. > > > ok, working on new patch I've tentatively applied the multiqueue patches, please make sure yours work on top. > -- > Marc-André Lureau
